Alesis M1 Active MkII Manual
Contents
1. OBTAINING REPAIR SERVICE Before contacting Alesis check all your connections and make sure you ve read the manual Customers in the USA and Canada If the problem persists call Alesis USA at 1 800 5 ALESIS and request the Technical Support department Talk the problem over with one of our technicians if necessary you will be given a return order RO number and instructions on how to return the unit All units must be shipped prepaid and COD shipments will not be accepted For prompt service indicate the RO number on the shipping label Units without an RO will not be accepted If you do not have the original packing ship the M1 Active Mk2 in a sturdy carton with shock absorbing materials such as styrofoam blocks or bubble pack surrounding the unit Make sure 40 M1 Active Reference Manual Troubleshooting the drivers will not be pressed on by the packing in shipment Shipping damage caused by inadequate packing is not covered by the Alesis warranty Tape a note to the top of the unit describing the problem include your name and a phone number where Alesis can contact you if necessary as well as instructions on where you want the product returned Alesis will pay for standard one way shipping back to you on any repair covered under the terms of this warranty Next day service is available for a surcharge Field repairs are not normally authorized during the warranty period and repair attempts by unqualified personnel2. Better amplifier speaker coupling for woofers Better crossover performance working into a constant impedance load Better subjective sound quality than high level passive networks Easier control over driver sensitivity differences Easier manipulation of phase time delay resonance and various kinds of shaping contouring and equalization Specifically in the case of the M1 Active MIO the wide mid frequency polar response of the tweeter can be utilized down to a low 2000 Hz thereby mating more cohesively with the 6 5 non woven carbon fiber NWCF woofer This low crossover point is only possible through the use of a steep electronic fourth order 24 dB per octave rolloff high pass filter 12 M1 Active Reference Manual About the M1 Active Mk2 THE 1 ACTIVE MK2 POWER SUPPLY The M1 Active Mk2 employs a regulated switching power supply This type of supply has previously only been available in amplifiers sold at the very high end of the Pro Audio market Most power amp customers are familiar with the large transformer and output capacitors in high quality amplifiers These large components are used to keep the amplifier s supply rails as close to DC as possible For traditional supplies bigger is better But by using Pulse Width Modulation PWM and output voltage feedback in the M1 Active Mk2 we have the equivalent of near infinite transformer and output capacitors but at a fraction of the cost PWM provides protect
3. Since the M1 Active Mk2s are self powered DO NOT connect them to the speaker output of another amplifier such as a powered mixer or hi fi receiver Connect them only to the line level outputs of such devices 4 dBu nominal 24 dBu maximum 10 M1 Active Reference Manual About the M1 Active Mk2 TONE Tonally every effort has been made to create a powered monitor that is as linear as possible representing a flat frequency response from 50Hz to 20KHz 2dB see p 21 Additionally the use of electronic crossovers within the critical upper midrange frequencies has reduced phase and time delay anomalies often associated with passive crossovers By including discrete woofer and tweeter amplifiers and application specific electronic high and low pass crossover filters in the same enclosure the tonal accuracy of the M1 Active Mk2 will always remain constant ABOUT THE DRIVERS The M1 Active Mk2 s 6 5 woofer cone is made of proprietary non woven carbon fiber This material is 25 lighter than polypropylene with twice the stiffness for quicker transient response in the low to midbass region and vastly improved midrange intelligibility over polypropylene at 2000 Hz The non woven carbon fiber cone along with the closed cell synthetic rubber surround are both nearly impervious to ozone direct sunlight heat and humidity Therefore after an initial break in period the sound should remain virtually unchanged for the life of the
4. of the listening triangle The classic studio monitor layout used to be that the tweeters be placed to the outside of a horizontally oriented speaker In the past this configuration was actually beneficial in time aligning the tweeter with the woofer if the cabinets were not toed in toward the listener However this configuration is highly prone to comb filtering effects if the listener s head is moved from side to side while mixing This comb filtering causes the mid to high frequency tones to get louder then softer then louder again as you move your head from side to side making it very confusing when trying to mix with precision Some people still believe that stereo separation is improved with tweeters to the outside but this is advice left over from the early days the sixties of stereo recordings when correct stereo often meant a complete hard right or hard left placement of an instrument or singer As stereo mixing techniques changed toward placing the vocalist for example in the center the old tweeters out orientation would indeed widen the image if one s head were kept in the exact center position But this set up proves to be very tiring very quickly for the recording engineer And to others who are listening to the mix from either side of the engineer the sound will seem to be coming primarily from the speaker closest to them Fortunately recording techniques have changed radically sin
5. 2 conductor output jack that is either a 1 4 phone or RCA phono type These may be plugged directly into the M1 Active Mk2 s LINE IN jacks M1 Active Mk2 Reference Manual 27 Speaker Installation But do NOT plug the speaker output of an amplifier receiver or similar device into the LINE INPUT jack Use only line level sources Plugging too loud of a signal into the LINE INPUT jack may damage the electronics Balanced 4 dBu line level sources Professional recording and processing equipment typically provides a balanced 3 conductor signal output that is a higher voltage 1 24 volts nominal level than most synthesizers and stereo equipment The LINE INPUT jacks are designed to handle these balanced inputs Balanced sources often feature XLR outputs Connect them with an XLR to XLR cable Many consoles such as the Alesis Studio series feature balanced outputs on 1 4 jacks you may use a TRS to TRS balanced phone cable or an XLR to 1 4 inch phone TRS tip ring sleeve cable as shown below The advantage of using an XLR on the speaker side is that it is a locking connector and cannot be accidentally disconnected D B NOTE Use high quality input connectors which conform to industry standard sleeve dimensions Some off brand connectors particularly cheap 1 4 TRS plugs do not provide reliable connections because of slight dimensional differences SETTING THE INPUT LEVEL CONTROL 28 In most cases the INPUT LEVE
6. Active Mk2 is set vertically in its column configuration the horizontal dispersion left and right of the speaker is widest and the vertical dispersion up and down is narrowest Unfortunately a vertical setup will also increase room effects so there are minimum recommended setup distances from side and back walls the speakers should be a minimum of 2 5 feet from the side walls and 3 feet from the rear walls See the illustration on page 26 After you ve got the requisite distances from the side and back walls it s often helpful to adjust the 7 to 12 foot equilateral listening triangle distances What you want to find is the maximum distance that you can separate the two speakers while still holding a solid center image If you get this placement correct and you ve done a good job in the mix you should be rewarded with a soundstage that accurately places the musicians in the width and depth perspective in which they were recorded The sound should be very similar to what you heard at your mixing board with possibly a little more ambience contributed by the listening room The other playback check mode sometimes considered of greater importance than the home environment is to listen to your mix over a car audio system Bear in mind that an expertly designed car audio system can approach the imaging and soundstaging capabilities of an optimally setup studio or living room but most times this is NOT the case The inherent limitatio
7. may invalidate the warranty Correspondence address for customers in the USA Alesis Product Support 1633 26th Street Santa Monica CA 90404 THIS IS NOT A SERVICE LOCATION DO NOT SHIP UNITS TO THIS ADDRESS Customers outside the USA and Canada Contact your local Alesis distributor for any warranty assistance The Alesis Limited Warranty applies only to products sold to users in the USA and Canada Customers outside of the USA and Canada are not covered by this Limited Warranty and may or may not be covered by an independent distributor warranty in the country of sale Do not return products to the factory unless you have been given specific instructions to do so M1 Active Mk2 Reference Manual 41 Specifications SPECIFICATIONS ENCLOSURE MATERIALS AND CONSTRUCTION Front baffle painted in metallic charcoal gray one inch 1 thick MDF with radiused edges to minimize diffraction Sides and rear baffle covered in metallic charcoal gray vinyl laminate over five eighths inch 0 625 thick MDF Dual ports with 45 inlet and flared front baffle outlet allow precise phase accurate woofer to port frequency transition Ports also aid in cooling internally mounted primary amplifier heat sink Flush mount rubber woofer trim ring allows consistent power response characteristic at wide off axis angles Flush mount tweeter plate assures smooth off axis response UL approved fiberglass acoustical damping material damps int
8. pairs a 5 channel system requires the purchase of a single speaker breaking up a pair Some dealers may request that you purchase in pairs only others may be able to arrange purchase of a single unit For the rear channels we recommend a mirror image pair although this is less critical than in the front As discussed above for music only recording the signal level to the center channel will be attenuated over the levels of the left and right speakers As a starting point we would recommend that you set the center channel level 6dB below the left and right channels To get these levels fairly accurate a white or pink noise source such as from a test CD is very helpful along with an inexpensive sound level meter such as the Radio Shack cat no 33 2050 If you are recording audio for video the center channel signal level should be the same as left and right channels The left center right speaker layout configuration can remain the same as for an audio only mix With all front speakers operating at equal levels the sweet spot listening area will become very large but the wall of mono effect mentioned above in regards to music will be of little consequence since most of the dialogue will be mixed specifically into the center channel M1 Active Mk2 Reference Manual 33 Surround Sound PLACEMENT OF REAR SURROUNDS 34 The following suggestions for optimal M1 Active Mk2 placement are derived from several sources 1 Sta
9. product Alesis proprietary design tweeter features a special wave guide baffle to improve polar response a silk dome and low viscosity ferrofluid formulated specifically to retain the best balance of transient response to power handling The shielded tweeter utilizes a vented pole piece with a separate rear chamber to lower the free air resonance The low 2000Hz crossover point of this tweeter produces a very widely dispersed low distortion signal within the critical midrange frequencies It is these frequencies which are often the most problematic to get right during a mix The tweeter is designed for an optimal response for non fatiguing long term high level nearfield mixdowns This design results in a flat linear mix when played back on home or car systems from appropriate distances MAGNETIC SHIELDING Your M1 Active Mk2s are at home in recording environments wherein video is major component They are magnetically shielded for use in fairly close proximity 3 minimum to a computer monitor or video screen Non shielded components can make the colors of a screen smear or appear out of focus if the speaker is too close Magnetic shielding was designed into both the woofer and the tweeter from the beginning so that the system exhibits about low magnetic leakage Shielding of both the woofer and the tweeter is accomplished by the use of a second opposing field oriented bucking magnet M1 Active Mk2 Reference
10. 31 About surround sound 31 Center speakers in music mixes 32 Placement of the center M1 Active Mk2 speaker in the studio 33 Placement of rear surrounds 34 Mixing for discrete six channel reproduction matched vs specialized speakers 37 TROUBLESHOOTING 242000000000 nn nn nn nn nn nn nn nn nn nn nn nn nn nun 39 Troubleshooting Index 39 Maintenance 40 SPECIFICATIONS nn ann nn na nn nnn 42 Enclosure 42 Transducers 42 Crossover section 43 Amplifier Section 43 Acoustic Section 43 General 43 INDEX a a a aaa a aa mann Hama 9 44 ALESIS LIMITED WARRANTY uuu0000nn nn nun nn nun nn nun nn nun nun nun nun nun aag aaa ag aasa 45 M1 Active Mk2 Reference Manual 1 Contents Safety Warnings INTRODUCTION Thank you for purchasing the Alesis M1 Active Mk2 Biamplified Reference Monitors To take full advantage of the M1 Active Mk2 s operation and to enjoy long and trouble free use please read this user s manual carefully We value any comments you may have about this monitor system this manual your Alesis dealer or our factory service Please take a minute now to fill out your warranty card and tell us what you think How TO USE THIS MANUAL This manual is divided into the following sections describing the various features of the M1 Active Mk2 Though we recommend you take time to read through the entire manual once carefully those having general knowledge abou
11. 8 M1 Active Reference Manual AAcesis Limirrep WARRANTY ALESIS CORPORATION ALESIS warrants this product to be free of defects in material and workmanship for a period of one 1 year for parts and for a period of one 1 year for labor from the date of original retail purchase This warranty is enforceable only by the original retail purchaser and cannot be transferred or assigned The purchaser should complete and return the enclosed warranty card within 14 days of purchase During the warranty period ALESIS shall at its sole and absolute option either repair or replace free of charge any product that proves to be defective on inspection by ALESIS or its authorized service representative In all cases disputes concerning this warranty shall be resolved as prescribed by law To obtain warranty service the purchaser must first call or write ALESIS at the address and telephone number printed below to obtain a Return Authorization Number and instructions concerning where to return the unit for service All inquiries must be accompanied by a description of the problem All authorized returns must be sent to ALESIS or an authorized ALESIS repair facility postage prepaid insured and properly packaged Proof of purchase must be presented in the form of a bill of sale canceled check or some other positive proof that the product is within the warranty period ALESIS reserves the right to update any unit returned for repair ALESIS reserves the right t
12. EVIOUS SECTION OF THIS MANUAL TO ENSURE SAFE OPERATION OF THESE UNITS Connect the M1 Active Mk2s to the specified power using the AC cables supplied The AC cables are removable If the distance to your AC outlet is longer or shorter than the supplied cable you may substitute an approved standard NEMA to CEE power cable of the correct length available from most electronics stores GROUNDING CONNECT THE M1 ACTIVES TO A PROPERLY GROUNDED OUTLET ONLY DO NOT USE ADAPTERS WHICH REMOVE THE SAFETY GROUND PROTECTION OR CUT OFF THE GROUNDING PRONG ON THE POWER CORD Proper grounding is essential for user safety and low noise If you experience 60 cycle hum in your sound system as a result of different ground potentials between different units in your system plug all units into the same AC circuit if the total power load allows and make sure other devices in the system are properly grounded themselves The M1 Active features balanced inputs so if it is properly connected to other balanced units AC ground potentials will not affect the audio If you cannot get rid of ground loops consult a professional electrician familiar with sound system power designs USE CLEAN POWER The M1 Active Mk2 s internal power supply is designed to filter out most AC line noise However it is still good practice to plug your sound equipment into an AC circuit that is not shared with lighting dimmers refrigerators air conditioning units or other appliances th
13. IC SECTION 25 watts 4Q load 0 025 THD rated power 9V usec gt 112dB rated output Free Field Frequency Response 2dB 50Hz to 20KHz Lower Cutoff Frequency Upper Cutoff Frequency Maximum Peak SPL per pair Maximum short term SPL GENERAL Power Consumption AC Dropout Voltage Weight Dimensions H x W x D M1 Active Mk2 Reference Manual 40Hz 10dB 23 5KHz 10dB gt 118dB SPL 1m 80Hz to 3 0KHz gt 105dB SPL Im 120 watts with musical program loud mix 12 watts quiescent idle 120V AC version 80V AC 240V AC versions 160V AC 19 5 Ibs 8 9 kg each 15 38 1 cm x 8 5 21 6 cm x 10 25 3 cm 43 INDEX 1 4 input plugs 27 AC cables 26 AC power 13 26 43 amplifiers 10 12 43 balanced 27 biamplified 10 center channel 32 crossover 11 43 frequency response 43 with ports plugged 24 front baffle 42 fuse 13 Ground loop 39 grounding 26 INPUT LEVEL 28 detent 29 interference 7 LINE IN 27 Magnetic shielding 11 42 mounting 19 nearfield 15 noise 26 phase 39 placement 17 horizontal 21 surround 34 vertical 22 Playback check mode 23 Polarity 27 ports 14 plugging 24 power supply 13 reflections 17 20 21 Safety 3 service 4 40 spacing 19 SPL 29 subwoofer 24 Surround sound 31 time alignment circuit 12 tweeter 11 42 mirror to inside 20 offset 14 warranty 9 45 woofer 11 42 XLR 2
14. L control should NOT be set at full rotation For best system dynamic range follow the instructions below The goal is to set the input level of the M1 Active Mk2s for the desired listening level when all the rest of the system is at its nominal operating level Nominal means its normal average level expecting peaks from 8 to 15 dB above that on occasion For the best signal to noise ratio everything before the M1 Active Mk2 should be as loud as possible The M1 Active Mk2s INPUT LEVEL control being last in the signal chain is the worst place to make up gain lost earlier in the system M1 Active Reference Manual Speaker Installation TO SET THE LEVEL WITH A MIXER 1 Turn on all system components the M1 Active Mk2s last and turn the M1 Active Mk2 s INPUT LEVEL control all the way down Play program through the mixer and raise the mixer s fader levels until its meter averages around 0 VU Raise the Control Room Output to its nominal position usually 2 o clock or 3 4 of the way up On one speaker raise its INPUT LEVEL CONTROL for a comfortable level in the engineer s seat if you have a sound pressure meter 85 dB SPL is a common standard for listening Match the level for the other speaker Note that the numbers on the back panel are only a rough guide for precise left right imaging use pink noise or test tones and a sound pressure meter The Input Level control has a 28 dB range with a ce
15. M 1 ACTIVE REFERENCE MANUAL 2001 ALESIS CORPORATION M k2 Alesis M1 Active Mk2 Reference Manual Copyright 2001 Alesis Studio Electronics Inc All rights reserved Reproduction in whole or in part is prohibited M1 Active Mk2 and Superport are trademarks of Alesis Studio Electronics Inc ALESIS CONTACT INFORMATION Alesis Studio Electronics Inc 1633 26th Street Santa Monica CA 90404 USA Do not use this address for repair service Telephone 800 5 ALESIS 800 525 3747 E Mail support alesis com Website http www alesis com Contents Safety Warnings CONTENTS Introduction 2 IMPORTANT SAFETY INSTRUCTIONS mmmmmmnnmnnnnnnnnannnnnnnnnnnnnmnnnnnnnnnnnnn 3 Safety symbols used in this product 3 Instructions de S curit Importantes French 5 Information to the User for Class A Digital Device FCC Part 15 Class A 7 CE Declaration of Conformity 8 ABOUT THE M1 ACTIVE MK2 mmmmnmmnnnmnnnnnnmnnnnnnnnnnnmnnnnnnnnnnnnnnnnnnnnnnnnn 9 Unpacking and Inspection 9 Inside your new speakers 10 About Nearfield monitoring 15 SPEAKER INSTALLATION 224 aaa aaas aaas ag non nn nn nn nn aaa ag nn nn nun nn nun aaa nun nn aaas ass 17 Avoiding reflections in the studio 17 Stereo nearfield placement of the M1 Active Mk2 20 Connections 26 Setting the Input Level control 28 SURROUND SOUND uuunununnnnnnnnnnnnnnnnnnnn nun nn nun nun nun nun nun nun nun
16. Manual 11 About the M1 Active Mk2 THE 1 ACTIVE 2 BI AMPLIFIERS amp ELECTRONIC CROSSOVERS The M1 Active Mk2 uses a 75W woofer amp and a 25W tweeter amp along with 4 order high and low pass electronic crossover filters centered at 2000Hz Electronic crossovers which separate the frequencies before being sent to the amplifiers have fewer phase problems and less power loss than the traditional passive crossover used after the amplifier Fourth order filters are steep 24 dB per octave which minimizes the interaction between woofer and tweeter near the crossover point Additionally the high pass tweeter section of this system employs an electronic time alignment circuit Thus the launch of frequencies from both the woofer and the tweeter will originate at exactly the same time There are several advantages to using built in amplifiers and active electronic crossovers versus a passive network system most of which have been previously enumerated in Vance Dickason s Loudspeaker Design Cookbook Lower intermodulation distortion due to amplifier operation over a more narrow bandwidth Also clipping caused by low frequency overload is reduced being limited to only one driver within a two driver system Increased dynamic range The M1 Active Mk2 s 75W and 25W amplifiers in their bi amp setup will clip at about the same levels as one 200W amplifier operating into a passive crossover Improved transient response
17. Surround Sound Corner mount only if head to rear distance is less than 3 M1 Active Mk2 Reference Manual 35 Surround Sound WALL MOUNTING Once your have located the general area for the horizontal and vertical position you need to find a wall stud Attach shelving brackets or other commercial speaker mounting device into the wall stud then attach the M1 Active Mk2s to the mount allowing room for the rear panel input and AC connections The M1 Active Mk2s weigh 19 5 Ibs so it is vitally important that any stand they re resting on be securely mounted through the wall material usually 3 4 sheetrock which by itself does not have the strength to support the speakers and into a wooden stud using hardened screws or other fastener rated to hold at least two times that weight 36 M1 Active Reference Manual Surround Sound MIXING FOR DISCRETE SIX CHANNEL REPRODUCTION MATCHED VS SPECIALIZED SPEAKERS While most speaker systems for monitoring music in surround use the same speaker cabinet in all positions both front and rear keep in mind that most consumer video surround installations use a different speaker in the rear channels These rear speakers typically do not have the same directionality or wide frequency response of the M1 Active Mk2s When mixing for film speakers with a broad ambient non directional response are used to mimic the multi speaker situation in most movie theatres Keep this in mind when maki
18. ables with this equipment to ensure compliance with FCC Rules INDUSTRY CANADA DIGITAL APPARATUS INTERFERENCE CAUSING EQUIPMENT STANDARD ICES 003 ISSUE 2 This Class A digital apparatus meets all requirements of the Canadian Interference Causing Equipment Regulations M1 Active Mk2 Reference Manual 7 Contents Safety Warnings CE DECLARATION OF CONFORMITY This product conforms to current applicable CE standards for safety For a detailed description of the standards used please see the web site Alesis com 8 M1 Active Reference Manual About the M1 Active Mk2 CHAPTER 1 THE 1 Active 2 UNPACKING AND INSPECTION Your M1 Active Mk2 Biamplified Reference Monitors were packed carefully at the factory and the shipping carton was designed to protect the speakers during shipping Please retain this container in the highly unlikely event that you need to return the speakers for servicing The shipping carton should contain the following items This instruction manual M1 Actives with the same serial numbers as shown on the shipping cartons Two AC power cords NEMA to CEE type Alesis warranty card Two pieces of adhesive backed non skid foam DAC It is important to register your purchase if you have not already filled out your warranty card and mailed it back to Alesis please take the time to do so now The M1 Active Mk2s are designed as mirror imaged pairs If you have received a pair whe
19. ack on a monopolar surround system Ifthe control room is completely damped with sound absorption on all surfaces This renders the reverberant field generating properties of a bipole dipole speaker ineffective Dolby Surround Dolby Pro Logic and Dolby Digital are trademarks of Dolby Laboratories Inc M1 Active Reference Manual TROUBLESHOOTING Troubleshooting CHAPTER 4 TROUBLESHOOTING INDEX If you experience problems while using the M1 Active Surround systems please use the following table to locate possible causes and solutions before contacting Alesis Technical Support for assistance Symptom Cause Solution Hum or buzz Ground loop between source and speaker Use balanced cables Put M1 Actives on the same AC power circuit as the mixer No sound Speaker Check input cable disconnected connections INPUT LEVEL down Turn up input control on back panel AC power noton Blue LED on front should be on Check switch and power input cable Unfocused sound bass frequencies muddy or missing Inputs out of phase Check and connections from mixer to input Verify pin 2 is hot Subwoofer being used improperly Install port plugs when using a subwoofer Poor mix Compare to commercial CD of similar style time to remix your track Distorted output Power amp Tum down level overloading speakers Damaged speaker Swap c
20. at may induce noise into the power system M1 Active Reference Manual Speaker Installation POWER SWITCH The POWER switch is located on the back panel A blue power indicator lamp is on the front panel INPUT CONNECTIONS Almost any conventional line level source may be plugged into the M1 Active Mk2 s LINE INPUT jack The Line Input jack accepts both XLR and 1 4 input plugs wired either balanced or single ended unbalanced The best connection is to use a high quality XLR to XLR mic cable between the output of the source usually the CONTROL ROOM OUTPUT of the console and the speakers A conventional 1 4 patch cord mono TS type plug will also work for unbalanced sources which automatically ground the minus input Polarity Input connector wiring is printed to the left of the connector on the back panel and is as follows Pin 2 tip hot Pin 3 ring cold Shield Pin 1 sleeve ground A positive voltage on the hot connector will cause the drivers to move outwards Unbalanced Line Inpu Balanced Line Input Signal Tip Hot Tio Cold Ring Ground Sleeve Ground Sleeve Tip Tip 0 Sleeve Ring Sleeve Direct connection of unbalanced 10 dBV line level sources Most synthesizers drum machines effect devices cassette decks and CD players operate at this level Their average signal level is about 1 3 of a volt They have a
21. been developed as a mirror imaged pair with dual front mounted ports and an offset tweeter In some applications an extremely wide dispersion tweeter such as used in the M1 Active Mk2 will exhibit response dips if mounted exactly on center Wave guide style tweeters used in other products purposely limit dispersion and thus can be center mounted But as hi end audiophile speaker companies have found a high quality dome tweeter offset in the cabinet toward the stereo image center between the left and right speakers will have a flatter characteristic frequency and power response This flat power response more closely characterizes the way humans hear On a horizontal polar response curve of the M1 Active MIO with the cabinet placed vertically the tweeter response at one meter stays essentially symmetrical on either side of the cabinet s centerline This is because the angle subtended between the cabinet centerline to tweeter centerline 5 and the nominal nearfield listening distance 1 meter or 39 375 is only 1 27 degrees Thus acoustically speaking the offset tweeter design has no negative effects only the positive of smoothing the frequency response in the 2KHz 4KHz range In the tradition of the Alesis Superport design which uses the energy from the back of the speaker to enhance bass performance the M1 Active Mk2s use dual front baffle mounted long folded ports The dual ports on the M1 Active Mk2 are also non
22. ce the sixties Engineers have learned to how to place an instrument or singer within the mix so that an accurate re creation of the actual instrument and vocal positioning left to right and front to back is achieved In the M1 Active Mk2 advances in crossover design technologies and improvements in the off axis response of tweeter domes and woofer cone materials and profile have made the requirement for tweeters to be placed to the outside of the cabinet obsolete In fact using a non toed in tweeters out orientation with a modern wide dispersion design like the M1 Active Mk2 will increase the likelihood of hearing unwanted first reflections and a variety of phase anomalies in your mix 20 M1 Active Reference Manual Speaker Installation HORIZONTAL PLACEMENT RECOMMENDATION Traditionally proper horizontal placement of speaker systems slightly behind not on a meter bridge accomplished two purposes it allowed both woofer and tweeter to be at ear level and many times it permitted the recording engineer to see over the speakers and into the studio Horizontal placement is a recommended arrangement with the M1 Active Mkz2 because the left and right mirror imaged pair permits a symmetrical alignment of drivers and ports This will be conducive to a balanced mix See Figure 2 below Proper tweeter orientation is toward the stereo image center the middle as shown Ports are always faced toward the bottom side of the cabinet This
23. das Ger t nich in der Nahe von Heizk rpern Heizungsklappen oder anderen W rmequellen einschlie lich Verst rkern auf Verlegen Sie das Netzkabel des Ger tes niemals so da man dar ber stolpern kann oder da es gequetscht wird Benutzen Sie nur das vom Hersteller empfohlene Zubeh r Verwenden Sie ausschlie lich Wagen St nder Racks oder Tische die speziell f r professionelle Audio und Musikinstrumente geeignetsind Achten Sie immer darauf da die jeweiligen Ger te sicher installiert sind um Sch den und Verletzungen zu vermeiden Wenn Sie einen Rollwagen benutzen achten Sie darauf das dieser nicht umkippt um Verletzungen auszuschlie en Ziehen Sie w hrend eines Gewitters oder wenn Sie das Ger t ber einen l ngeren Zeitraum nicht benutzen den Netzstecher aus der Steckdose Die Wartung sollte nur durch qualifiziertes Fachpersonal erfolgen Die Wartung wird notwendig wenn das Ger t besch digt wurde oder aber das Stromkabel oder der Stecker Gegenst nde oder Fl ssigkeit in das Ger t gelangt sind das Ger t dem Regen oder Feuchtigkeit ausgesetzt war und deshalb nicht mehr normal arbeitet oder heruntergefallen ist Bei normalem Betrieb des Ger tes kommt es zu W rmeentwicklungen Wenn Sie das Ger t in einem Rack eingebaut haben sollte w hrend des Betriebes die Zufuhr von K hlluft stets gew hrleitstet sein Arbeiten Sie nie beigeschlossenem Rack Bei mehreren Rackger ten sollten diese mit einem geringen abstand vo
24. derived from sum and difference information encoded in the left and right channels The very attributes that make this matrix type system viable for video application make it less desirable for music only reproduction In practice there is a hard center dialog channel but there is also a sort of phantom mono channel developed between the left and center channel and the right and center channel This between channel phantom mono image exists because so much of the information contained in each channel left and center or right and center is identical Hence mono In the few music only recordings encoded in Dolby Pro Logic the derived center channel could lead to some drastic changes in spatial perception In developing the M1 Active Mk2s for use as left center and right front channel sources we wanted them to be useable in both audio video and audio only matrix type applications We discovered two already available solutions to the large wall of mono effect produced by Dolby Pro Logic when playing audio only material The first is easy Most home audio Dolby Pro Logic receivers will let you take the center channel out completely by putting the receiver in the phantom no center channel mode It preserves the classic stereo effect of the front channels while adding rear surround This method works well with most stereo only recordings which have no surround encoding But it s much better if the rear channels have true matrix m
25. e fonctionne pas normalement ou est tomb Cet appareil produit de la chaleur en fonctionnement normal Si cet appareil est utilis dans un rack veillez sa bonne ventilation lors de son utilisation Ne pas faire fonctionner dans un rack ferm S il y a d autres appareils dans le rack g n rant beaucoup de chaleur loignez les Ne pas intercaler cetappareil entre deux appareils produisant beaucoup de chaleur Ce produit utilis avec un amplificateur et un casqueou des enceintes est capable de produite des niveaux sonores pouvant engendrer une perte permanente del ouie Ne l utilisez pas pendant longtemps un niveau sonore lev ou un niveau non confortable Si vous remarquez une perte de l ouie ou un bourdonnement dans les oreilles consultez un sp cialiste M1 Active Mk2 Reference Manual 5 Contents Safety Warnings BEIM BENUTZEN DIESES PRODUKTES BEACHTEN SIE BITTE DIE FOLGENDEN SICHERHEITSHINWEISE GERMAN AT PON N 10 11 12 13 14 15 Lesen Sie die Hinweise Halten Sie sich an die Anleitung Beachten Sie alle Warnungen Beachten Sie alle Hinweise Bringen Sie das Ger t nie mit Wasser in Bertihrung Verwenden Sie zur Reinigung nur ein weiches Tuch Spr hen Sie keine fl ssiger Reiniger auf die Oberfl che dies konnte zur Besch digung der Vorderseite f hren und auch weitere Schaden verursachen Halten Sie sich beim Aufbau des Ger tes an die Angaben des Herstellers Stellen Sie
26. ed by a sixth subwoofer channel and more speakers The original Dolby Surround of the mid eighties was a matrixed three channel only system It had left right and a mono surround rear track which was usually played through two surround speakers In 1987 Dolby Pro Logic a four channel matrix system was introduced Pro Logic added a dedicated center channel to which most dialog was assigned The rear surround channel was still in mono In 1996 Dolby Digital AC 3 and DTS fully discrete six channel audio delivery platforms with separate left rear and right rear channels first became available to consumers on laserdisc and more recently on DVD Digital Versatile Disc With so many listeners hearing music through their multimedia systems it is important for engineers to produce music on surround systems even if they re not working for film or video applications Powered monitors like the Alesis M1 Active Mk2 Biamplified Reference Monitor have proven to be a simple cost effective way to add five channel surround to control rooms M1 Active Mk2 Reference Manual 31 Surround Sound CENTER SPEAKERS IN MUSIC MIXES In video applications with left center and right channels all set to deliver equal output the ear tends to hear dialog as coming only from the center channel It s a psychoacoustic effect because all right and all left channel signals are fed to the center In Dolby Pro Logic the center channel information is
27. er problem of conventional designs when a broadband amplifier clips on a bass note it sends unusually high energy to the tweeter which tries to reproduce the square wave it is not invulnerable If you need higher power levels you are not using the speaker in a near field application For extremely loud mid field and far field monitoring we recommend the Alesis Monitor Two speaker with a 300 watt per channel amplifier Many studios will check recordings on both systems alternating to avoid ear fatigue and to gain perspective on the mix M1 Active Reference Manual Surround Sound CHAPTER 3 SuRROUND SOUND ABOUT SURROUND SOUND Surround sound is the term used for several different systems which use multiple channels of playback in the listening room to recreate a truly three dimensional sound experience The practice of recording music only in surround sound is a fairly recent innovation Surround sound for video however has been around for over ten years With modern encoding methods multichannel audio may be delivered to consumers on standard video tape video discs and even through broadcast with the proper encoders devices which take multiple channels of audio and combine them into two channels and decoders used at the receiving end to split the signal back into multiple channels Systems are in use which use three left right and surround five left center right left surround right surround often supplement
28. ernal mid frequency reflections from rear of woofer cone before entering port lessening IM distortion TRANSDUCERS 42 LOW FREQUENCY DRIVER 6 5 165mm diameter dynamic driver with proprietary non woven carbon fiber NWCF cone and 1 5 diameter long wind voice coil Dampened linear rubber surround with moderate internal damping and constant linear displacement Nomex spider 5 mm X max excursion capability Dual magnet structure uses top magnet in opposed bucking configuration for magnetic shielding HIGH FREQUENCY DRIVER 1 silk soft dome tweeter with special wave guide baffle Low viscosity ferrofluid cooling extends power handling while retaining impulse response capability Dual magnet structure uses top magnet in opposed bucking configuration for magnetic shielding M1 Active Reference Manual CROSSOVER SECTION Crossover type Input Impedance Low Frequency Filter AMPLIFIER SECTION Specifications 4 order 24dB octave Linkwitz Riley 2000Hz 20kQ balanced 10kQ unbalanced 4 order optimal Q high pass filter at 48Hz with 3 dB equalization Low FREQUENCY AMPLIFIER Rated power output Distortion Slew rate Signal to Noise ratio 75 watts 6Q load lt 0 02 THD 30 watts 8Q 20Hz 20kHz 19V usec gt 110dB referenced to 60 watts 80 A weighted 1kHz HIGH FREQUENCY AMPLIFIER Rated Power Output Distortion Slew rate Signal to Noise ratio ACOUST
29. ge speakers and mixing primary instruments and vocals into the surround channels So our basic recommendation for mixing an audio only six channel recording is to intentionally limit the frequency response of the rear speakers using a graphic equalizer or high pass 100 Hz pass 12 kHz rolloff filter on your mixer This will help you get a rough idea of what a home system playback will sound like This arrangement will also allow your mix to sound best over a well set up car audio system This is because professional installers have learned that a mobile system performs best when they concentrate on producing a soundstage across the front of the vehicle They do this by placing high quality drivers in the front of the vehicle which produce frequencies from the M1 Active Mk2 Reference Manual 37 Surround Sound 38 mid bass about 80H72 on up In the rear go the subwoofers and sometimes small full range drivers which provide fill So in essence today s best car audio systems are designed to produce an enveloping environment very similar to that of a home theater The use of M1 Active Mk2s or any monopolar speaker as full range surrounds would be useful in the following cases Ifthe surround speakers are just as important as the fronts in achieving specialized effect such as completely mixing the sax in the left rear only and a flute in the right rear If you know that your mix will always be played b
30. hannels to see if components the problem follows the speaker if so contact Technical Support M1 Active Mk2 Reference Manual 39 Troubleshooting MAINTENANCE CLEANING The cabinet surfaces of the M1 Active Mk2 are covered with a vinyl laminate Clean these surfaces when necessary with a lint free cloth dampened in warm soapy water USE ONLY A DRY CLOTH ON THE BACK PANEL OF THE POWER AMPLIFIER Do not attempt to clean the cabinet with a brush which may damage the surface or a sponge which may leave small crumbs in the texture Do not attempt to clean either of the drivers The M1 Active Mk2 Surround speakers require no periodic maintenance REFER ALL SERVICING TO ALESIS AN We believe that the M1 Active is one of the most reliable powered monitors that can be made using current technology and should provide years of trouble free use However should problems occur DO NOT attempt to service the unit yourself Service on this product should be performed only by qualified technicians THERE ARE NO USER SERVICEABLE PARTS INSIDE SERVICE Before sending the M1 Active Mk2s in for repair make sure they are faulty and that the problem isn t being caused by something else in the system Distortion or noise may be caused by a defective preamp cable equalizer etc or a loose connection in the system Connect the speakers to a system that is known to be working properly to check whether the monitors have malfunctioned
31. he costs for the required control room acoustic treatments were going through the roof no pun intended particularly beyond the budget limits of smaller project and home studios which were growing in numbers A new way of accurate monitoring was needed nearfield monitoring Nearfield monitors by their definition are intended for mounting close to the listener The idea here is to improve the direct acoustic path between the speaker and the listener by making it shorter thereby giving less opportunity for the always present indirect reflected sounds to get back in and muddle things up With nearfield monitoring the surrounding acoustic environment becomes a much less significant factor in establishing the monitor system s sound character A good set of small monitors properly placed in a reasonably non reverberant room and properly powered will yield surprisingly accurate results at budget prices Carried to another studio the same monitor should also provide repeatable results In fact some recording engineers carry their own speakers around because they know how they will sound in almost any room Now even the big studios use smaller speakers to augment their big monitoring systems and nearfield monitors have become proven tools in the recording business M1 Active Mk2 Reference Manual 15 About the M1 Active Mk2 16 M1 Active Reference Manual Speaker Installation CHAPTER 2 SPEAKER INSTALLATION Like any speaker system y
32. ion from line voltage surges that would otherwise destroy the amplifier No user replaceable fuse is required because nuisance tripping is eliminated And finally PWM practically eliminates hum because the line frequency 60 Hz transformer is replaced with a very high frequency 130 000 Hz transformer The regulated supply rails increase the amplifier dynamic range and reduce clipping distortion under heavy loading The compact size of the supply does not significantly reduce the internal air volume of the speaker cabinet And lastly full power can be maintained even with low or flat topped line voltages Note however that this switching supply is NOT a universal voltage type that may be used with any input voltage in any country simply by changing the cord If you wish to use the M1 Active Mk2s in a country whose line voltage is other than 120 volts AC they must be internally modified or used with a step down transformer THE CABINET AND PORT DESIGN The M1 Active cabinet construction employs vinyl composite material laminated to a 625 MDF medium density fiberboard core for the four sides and the rear The front panel is 1 thick MDF to withstand the greater demands of the drivers mounted on it The entire cabinet is braced extensively in random fashion to dissipate intramodal vibration M1 Active Mk2 Reference Manual 13 About the M1 Active Mk2 WHY THE TWEETERS ARE OFFSET The M1 Active Mk2 speakers have
33. ndard industry practice for home installations as recommended by the manufacturers of surround encoder decoder units 2 recommendations developed by Tom Holman for setting up THX surround theater sound systems and 3 Alesis engineers experience fine tuning the performance of the SMS Monitoring System in order to find the mounting configuration which results in the most natural and accurate surround placement With the many different playback systems in use there is room for interpretation of what the best placement is in a control room but the following represents a good starting point which you are free to change to your taste Vertically the M1 Active Mk2s should be placed on the side wall of the control room above your head with the woofers on top tweeters on the bottom The ideal location is to have the center of the speaker between the woofer and tweeter at 80 of the floor to ceiling height For a standard 8 foot ceiling height the center line would be at 96 x 80 76 8 from the floor Recommended positioning of surround speakers Horizontally place the M1 Active Mk2s slightly behind the 90 position at 110 on each side Make sure that at the position used there is still at least 3 feet to the back wall of your studio If you do not have at least 3 feet to the back of your studio then the speakers will work better if placed diagonally in the rear corner as shown on the next page M1 Active Reference Manual
34. neinander eingebaut werden Stapeln Sie dieses Ger t nicht zwischen Ger ten mit hoher W rmeentwicklung Dieses Produkt kann in Verbindung mit einem Verst rker und Kopfh rern oder Lautsprechern Lautst rkepegel erzeugen die anhaltende Geh rsch den verursachen Betreiben Sie es nicht ber l ngere Zeit mit hoher Lautst rke oder einem Pegel der Ihnen unangenehm is Wenn Sie ein Nachlassen des Geh rs oder ein Klingeln in den Ohren feststellen sollten Sie einen Ohrenarzt aufsuchen M1 Active Reference Manual Contents Safety Warnings INFORMATION TO THE USER FOR CLASS A DIGITAL Device FCC PART 15 CLASS A This equipment has been tested and found to comply with the limits for a class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause interference to radio communications Operation of this equipment in a residential area is likely to cause interference in which case the user will be required to correct the interference at his own expense The user is cautioned that changes and modifications made to the equipment without the approval of manufacturer could void the user s authority to operate this equipment Use only shielded and grounded c
35. ng music mixes with full range high power speakers like the M1 Active Mkz2s as the surround speakers The difference between music surround and video surround playback has a long history Dolby Pro Logic which works best with dipole i e speakers splayed in different directions out of phase surround speakers has been the standard for surround sound in the home for 10 years The most accepted home playback medium VHS videotape can only play back mono surround in Dolby Pro Logic VHS will not support Dolby Digital or DTS e There are only two playback mediums laser disc and DVD that support Dolby Digital discrete and DTS discrete After 20 years in existence laser disc has only a 2 market share Some digital satellite broadcasters have started broadcasting in Dolby Digital but these discrete broadcasts will be reserved for blockbuster movies initially Discrete Dolby Digital DTS and Sony s SDDS are most commonly mixed for theatrical release using surround not monopolar direct monitors Among the recording engineers who have recorded audio only the consensus seems to be that the role of the surround speaker is to give the listener a sense of immersion in the musical event This is done by reserving the rear channels for audience sounds in the case of a live recording or perhaps by reproducing the reverberant acoustics of the recording environment itself Other engineer producers prefer using five identical full ran
36. nly applies to products sold to purchasers in the United States of America or Canada The terms of this warranty and an obligations of Alesis under this warranty shall apply only within the country of sale Without limiting the foregoing repairs under this warranty shall be made only by a duly authorized Alesis service representative in the country of sale For warranty information in all other countries please refer to your local distributor ALESIS 1633 26th Street Santa Monica California 90404 1 800 5 ALESIS www alesis com PLEASE SEND IN YOUR WARRANTY CARD for more effective service and product update notices Alesis Corporation 1633 26th Street Santa Monica CA 90404 2001 Alesis Corporation Specifications Subject To Change Without Notice 7 51 0092 2 01 M1 Active Mk2 Reference Manual 45 M1 Active Reference Manual
37. ns of an always off axis listening position and the variables of speaker placement bass coupling boost in the small interior and numerous other factors make the car environment highly suspect So understand the sonic capabilities and deficiencies of your or other car audio systems and evaluate your mix accordingly M1 Active Mk2 Reference Manual 23 Speaker Installation 24 PLUGGING THE PORTS TO ADJUST FOR ROOM ACOUSTICS The low frequency response of the M1 Active Mk2s can be custom tailored by plugging the ports If the speakers must be placed less than one foot from a front wall or if they are too close to a corner then the bass may become exaggerated and inaccurate The rules of thumb for these situations are as follows a less than 1 foot from a front wall but away from any corner plug one port b less than 1 foot from a front wall and a corner plug both ports The plug can be wad of cloth to completely block the port s or a more porous material like fiberfill which will give less bass attenuation The bass output of the M1 Active is thus easily variable depending on in room positioning and or personal preference If the M1 Active Mk2s are to be used in a system with a subwoofer the proper blend of the two systems is critical if low bass accuracy is to be maintained Here again your ear is your most important piece of test equipment If the subwoofer such as the Alesis Point One or preamplifier ha
38. nter detent The detent has no particular meaning but helps in adding a mental reference position when attempting to set levels from in front of the speaker With the control at a maximum clockwise rotation 2 0 volt input will produce full amplifier output 102 dB SPL A weighted from two speakers at 1 meter For the technically minded here is an approximate chart of SPL levels for various settings of the INPUT LEVEL control measured at 1 meter from two speakers simultaneously all settings especially near the extremes of the range are subject to a plus or minus 2 dB error Mark 10 dBV 4 dBu nominal nominal 0 MIN dB SPL dB SPL M pa iem 7 2 15700 69 0 62 802 5 70 830 6 790 _ 1850 7 780 900 85 B5 55 rer sc iso 975 denotes recommended setting for control room use M1 Active Mk2 Reference Manual 29 Speaker Installation 30 AVOIDING DAMAGE The best protection against speaker failure is to mix at a reasonable listening level With a 4 dBu input and the input level control set to 6 the M1 Active Mk2 speakers produce a sound pressure level SPL of 85 decibels at 1 meter which is a good working level for mixing At maximum output before clipping they can generate peak levels 2 118 dB SPL at one meter a level which may cause hearing loss after prolonged exposure While the biamplified design of the M1 Active Mk2 avoids the common blown tweet
39. o change or improve design of the product at any time without rior notice This warranty does not cover claims for damage due to abuse neglect alteration attempted repair by unauthorized personnel and is limited to failures arising during normal use that are due to defects in material or workmanship in the product THE ABOVE WARRANTIES ARE IN LIEU OF ANY OTHER WARRANTIES OR REPRESENTATIONS WHETHER EXPRESS OR IMPLIED OR OTHERWISE WITH RESPECT TO THE PRODUCT AND SPECIFICALLY EXCLUDE ANY IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY OR OTHER IMPLIED WARRANTIES Some states do not allow limitations on how long an implied warranty lasts so the above limitation may not apply to you IN NO EVENT WILL ALESIS BE LIABLE FOR INCIDENTAL CONSEQUENTIAL INDIRECT OR OTHER DAMAGES RESULTING FROM THE BREACH OF ANY EXPRESS OR IMPLIED WARRANTY INCLUDING AMONG OTHER THINGS DAMAGE TO PROPERTY DAMAGE BASED ON INCONVENIENCE OR ON LOSS OF USE OF THE PRODUCT AND TO THE EXTENT PERMITTED BY LAW DAMAGES FOR PERSONAL INJURY Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you THIS CONTRACT SHALL BE GOVERNED BY THE INTERNAL LAWS OF THE STATE OF CALIFORNIA WITHOUT REFERENCE TO CONFLICTS OF LAWS This warranty gives you specific legal rights and you mar also have other rights required by law which at from state to state his warranty o
40. ono surround like applause encoded in the mix The second method of using Dolby Pro Logic gets the center channel back into the mix Most of these same home audio receivers have an audio only surround mode which significantly attenuates the output of the center channel in relation to the left and right The audible benefit here is that the mix sounds like a stereo only recording but the center image like a vocalist becomes a hard center There is no image wander as the frequencies change for instance And the classic listening sweet spot expands dramatically allowing for accurate soundstage and instrument placement when listening far off axis This attenuating of the center channel for audio only is also employed by advanced professional matrixed decoders such as the Circle Surround Miles Technology and Lexicon units 32 M1 Active Reference Manual Surround Sound PLACEMENT OF THE CENTER M1 ACTIVE MK2 SPEAKER IN THE STUDIO The left center and right speakers should all be placed in an arc so that the distance of all drivers to the listener is identical see page 29 The equilateral listening triangle as described earlier for stereo two channel playback should be retained with the center speaker placed vertically in the center exactly between the left and right vertical M1 Active Mk2s It does not matter what type of M1 Active Mk2 is used for the center speaker tweeter in or tweeter out Since M1 Active Mk2s are sold as
41. our M1 Active Mk2 speakers will work best when properly positioned in a suitable acoustic environment Achieving proper speaker placement is usually straightforward but even with nearfield monitors speaker placement and the acoustics of the listening room itself are too often overlooked and can become significant contributors to an inaccurate and uninspiring monitoring environment AVOIDING REFLECTIONS IN THE STUDIO While nearfield monitors are more forgiving of the surrounding room acoustics it is always prudent to optimize the listening environment whenever possible First the user should be aware of the effect that the size of the listening room can have on low frequency response In general the smaller the room the stronger the bottom end will be although placement within a larger room can also make a difference This has to do with the way low frequency waves travel in closed spaces If you find your monitor system to be either light or heavy on the bottom try moving them around within your listening room You should avoid locating your M1 Active Mk2s near reflective surfaces such as glass tile large open walls or table tops Still many rooms used for recording have these surfaces so the best way to deal with them is to place the monitors out in the room away from reflective walls windows and sizable objects Even with these reflective surfaces separated from the monitoring position typical mixing situations usually still have
42. pacing between the speakers Alesis recommends that the distance between the speakers for stereo applications equal the distance between the listener and either speaker In other words the listener and the two speakers are at the three corners of a triangle having equal length sides The illustration below shows this concept Note that both speakers are turned in somewhat so that the prime listening position is directly in front of each speaker Applications that require monitoring by more than one engineer are accommodated by a smaller rotation of the cabinets This will widen the prime listening position somewhat The speakers and listener should be at the three corners of a triangle having equal length sides Prime Listening Position NOTE On some mounting surfaces the vinyl finish of the M1 Active Mk2 s cabinet may cause it to slip too easily Included with this reference manual packet are two pieces of adhesive backed non skid foam If necessary apply the pad to either the bottom for vertical placement or cabinet side nearest the ports for horizontal placement If you plan on using the M1 Active Mk2s in both modes simply cut the pad in half and apply to both the bottom and the side nearest the ports M1 Active Mk2 Reference Manual 19 Speaker Installation STEREO NEARFIELD PLACEMENT OF THE M1 ACTIVE Nik2 NOTE We recommend that the M1 Active Mk2 speakers be placed with the tweeters to the inside not the outside
43. re the tweeters are both on the same side contact your dealer immediately M1 Active Mk2 Reference Manual 9 About the M1 Active Mk2 INSIDE YOUR NEW SPEAKERS es If you re in a hurry to get started skip ahead to Chapter 2 Speaker Installation for connection and placement tips ABOUT POWERED MONITORS The M1 Active Mk2s combine a speaker and amplifiers in the same compact cabinet Powered monitors are growing in popularity over the traditional separate amplifier and speakers for a number of reasons convenience and ease of hookup being only one of them You can connect a powered speaker directly to any line level source normally the control room output of a mixer simply by connecting a patch cord Another benefit is improved sound quality With careful design the speaker amplifier and electronic crossover can be optimised for each other The M1 Active Mk2s are biamplified meaning that low frequencies and high frequencies are handled not only by separate speakers the tweeter and the woofer but by separate amplifiers A pair of M1 Active Mk2s contain a total of four power amplifiers Because of the increased efficiency of biamplification these are much louder than a single channel power amplifier of the same wattage feeding a passive crossover as in other designs New technology makes it possible to make these high wattage amplifiers small enough to fit inside the speaker cabinet with very little weight or size gain
44. s 80Hz high pass filters built in for connection to the other amplifiers then no port plugging is necessary The proper match will have already been taken care of electronically In the absence of an 80Hz high pass filter feeding the M1 Active Mk2s you ll need to experiment with various degrees of port plugging to minimize the cancellations and nodes that can occur from bass sources placed several feet apart in a room In practice we ve found that a single port plugged with cloth is usually the best compromise See Figure 5 below It shows the approximate bass attenuation that can be expected with one port plugged M1 Active Reference Manual 105 100 95 90 85 dB spl 80 75 70 Speaker Installation FIG 1 SOUND PRESSURE LEVEL 10 Hz 50Hz 100 Hz 500Hz 1kHz 2kHz 5kHz 10kHz 40 kHz Frequency Without port With port M1 Active Mk2 Reference Manual 25 Speaker Installation CONNECTIONS 26 The M1 Active Mk2 has been designed to be as simple as possible to set up and use However please follow the instructions to ensure that you get the best possible performance from your monitors Before connecting the speakers make sure the power switches of the M1 Active Mk2s and any equipment they will be connected to are turned OFF AC POWER CABLE READ ALL SAFETY WARNINGS IN THE PR
45. s or rear panel as this may damage the speakers controls or cause a dangerous condition 7 Install in accordance with the manufacturer s instructions 8 Do not install near any heat sources such as radiators heat registers stoves or other apparatus including amplifiers that produce heat AN 9 Do not defeat the safety purpose of the polarized or grounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide blade or the third prong are provided for your safety When the provided plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet M1 Active Mk2 Reference Manual 3 Contents Safety Warnings 10 Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus 11 Use only attachments or accessories specified by the manufacturer 12 Use only with a cart stand bracket rack or table designed for use with professional audio or music equipment In any installation make sure that injury or damage will not result from cables pulling on the apparatus and its mounting If a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over 13 Unplug this apparatus during lightning storms or when unused for long periods of time IN 14 Refer all servicing to qualified
46. service personnel Servicing is required when the apparatus has been damaged in any way such as when the power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not operate normally or has been dropped 15 This product may be capable of producing sound levels that could cause permanent hearing loss Do not operate for along period of time at a high volume level or at a level that is uncomfortable If you experience any hearing loss or ringing in the ears you should consult an audiologist 4 M1 Active Reference Manual Contents Safety Warnings INSTRUCTIONS DE S CURIT IMPORTANTES FRENCH SYMBOLES UTILIS S DANS CE PRODUIT N Ce symbole alerte l utilisateur qu il existe des instructions de fonctionnement et de maintenance dans la documentation jointe avec ce produit Ay Ce symbole avertit l utilisateur de la pr sence d une tension non isol e l int rieur de l appareil pouvant engendrer des chocs lectriques QVI MS N por N 10 11 12 13 14 15 16 VEUILLEZ SUIVRE CES PR CAUTIONS LORS DE L UTILISATION DE L APPAREIL Lisez ces instructions Gardez ces instructions Tenez compte de tous les avertissements Suivez toutes les instructions N utilisez pas cet allareil proximit de l eau Ne nettoyez qu avec un chiffon humide Ne pas vaporiser de liquide nettoyant sur l appareil cela pourrai
47. set up will promote a strongly focused center image such as for the vocalist And because the vocal image width will be narrower than if the speakers are placed vertically it will be possible to place the vocalist with great precision at stage center In this orientation there will be much less chance of first reflections from either sidewalls or the console coloring your mix Correct horizontal placement tweeters toward inside M1 Active Mk2 Reference Manual 21 Speaker Installation 22 VERTICAL PLACEMENT RECOMMENDATION Vertical placement of the M1 Active Mk2 as shown in Figure 3 is highly recommended This position will simulate the soundfield that will be heard in most consumers homes and to a great extent their cars For this reason even if the M1 Active Mk2s are positioned horizontally for all of the mixing the vertical position should always be used in the final playback check mode See next section There are a couple of possible drawbacks to vertical placement of a nearfield monitor relating mostly to room interaction effects Vertical placement allows the M1 Active Mk2s to portray your mix with the widest and deepest soundstage possible so many people in the control room have an image of the sweet spot However this wide a dispersion pattern in a control room with walls in too close proximity to the speakers can add strong reflections to the sound you hear muddying your mix Page 29 shows
48. symmetrical with relation to their distances from the woofer In developing the M1 Active Mk2 Alesis engineers determined that dual ports offset to the outside of the stereo image center gave the most coherent and extended low bass augmentation The ports are flared on the front baffle to provide smooth and quiet exit airflow while inside they are cut with a 45 angle and faced toward the amplifier s internal heat sink This arrangement aids in keeping the internal amps working at a more constant temperature At the same time this 45 angle increases the port s air entry efficiency 14 M1 Active Reference Manual About the M1 Active Mk2 ABOUT NEARFIELD MONITORING In the early days of recording most recording studios used big monitor speakers almost exclusively Unfortunately they also required high powered amplifiers and expensive acoustic treatment often poorly done of the entire control room Still a well constructed big monitoring system really was impressive to listen to a fact not overlooked by the studio owners who wanted to impress the record company executives who paid for the big studio s time These big systems had big level control knobs and clients enjoyed cranking up the volume Fortunately recording engineers and producers eventually learned that this was not the best way to accurately mix music because it wasn t the way most people listened to their radios cassettes and CD players Also big monitor systems and t
49. t abimer les contr les de la face avant ou engendrer des conditions dangeureuses Installez selon les recommandations du constructeur Ne pas installer proximil de sources de chaleur comme radiateurs cuisini re ou autre appareils don t les amplificateurs produisant de la chaleur Ne pas enlever la prise de terre du cordon secteur Une prise murale avec terre deux broches et une troisi rme reli e la terre Cette derni re est pr sente pour votre s curit Si le cordon secteur ne rentre pas dans la prise de courant demandez un lectricien qualifi de remplacer la prise Evitez de marcher sur le cordon secteur ou de le pincer en particulier au niveau de la prise et aux endroits o il sor de l appareil N utilisez que des accessoires sp cifi s par le constructeur N utilisez qu avec un stand rack ou table con us pour l utilisation d audio professionnel ou instruments de musique Dans toute installation veillez de ne rien endommager cause de c bles qui tirent sur des appareils et leur support D branchez l appareil lors d un orage ou lorsqu il n est pas utilis pendant longtemps Faites r parer par un personnel qualifi Une r paration est n cessaire lorsque l appareil a t endommag de quelque sorte que ce soit par exemple losrque le cordon secteur ou la prise sont endommag s si du liquide a coul ou des objets se sont introduits dans l appareil si celui ci a t expos la pluie ou l humidit n
50. t monitors should use the table of contents to reference specific functions Chapter 1 About the M1 Active Mk2 Engineering specifications and reasons why nearfield monitors have become so popular Chapter 2 Speaker Installation This chapter explains how to connect the M1 Active Mk2s to a mixer or other line level source and discusses proper speaker placement for stereo operation Chapter 3 Surround Sound If you are using the M1 Active Mk2 speakers in a multichannel surround sound setup you ll find helpful setup and operation information here Chapter 4 Troubleshooting This chapter contains troubleshooting tips and service information should problems occur When something important appears in the manual an icon like the one on the left will appear in the left margin This symbol indicates that this information is vital when operating the M1 Active Mk2s 2 M1 Active Reference Manual Contents Safety Warnings IMPORTANT SAFETY INSTRUCTIONS SAFETY SYMBOLS USED IN THIS PRODUCT This symbol alerts the user that there important operating maintenance instructions in the literature accompanying this unit PLEASE FOLLOW THESE PRECAUTIONS WHEN USING THIS PRODUCT Read these instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Do not use this apparatus near water 6 Clean only with a damp cloth Do not spray any liquid cleaner onto the speaker
51. the control room placement distance recommendations which should help you determine if your available recording space would work well with the M1 Active Mk2s set up vertically Correct vertical placement tweeters toward inside M1 Active Reference Manual Speaker Installation PLAYBACK CHECK MODE VERTICAL MID FIELD After you ve got your mix just right it s always good practice to perform a playback check by standing the M1 Active Mk2s vertically and making the listening triangle larger The purpose of the playback check is to simulate what your masterpiece will sound like in a typical home listening environment It is in this configuration that the imaging specificity of your mix can best be evaluated Generally in the playback check mode you want to arrange the speakers in the same equilateral listening triangle that you do in a nearfield setup but instead of each side of the triangle being about 3 feet long the distances between stereo speakers and to your listening position should be between 7 and 12 feet When setting the left and right speakers vertically place the tweeters toward the center with the ports toward the outside In this vertical position the M1 Active Mk2 becomes a line source speaker which is the most common home set up A 12 three way with woofer on bottom midrange in the center and tweeter at the top is a line source as are most forms of tower speakers When the M1
52. the top surface of the mixing board to deal with Unfortunately the board itself can be a major source of reflections and the additional acoustic conduction into the board can affect your monitor s amplitude and phase response Speaker placement on the console s meter bridge allows two different acoustic paths between the speakers and the recording engineer which results in undesirable comb filtering effects and poor imaging The first path is the direct one and the second is via a reflection off the mixer main control panel M1 Active Mk2 Reference Manual 17 Speaker Installation Direct Path A leon 40 ny Monitors placed on the console s meter bridge can directly radiate back onto the console control panel causing a strong delayed reflection at the listening position This kind of speaker placement also couples acoustic energy from the speaker s cabinet more readily into the console s chassis Both conditions should be reduced by placing the speakers on their own stands acoustically detached from and slightly behind the console as shown below In this location the reflective path off the console s control panel is now blocked by the meter bridge Direct Path Random Reflections Moving the monitors to a position behind the meter bridge causes the bridge to block the offending reflective path 18 M1 Active Reference Manual Speaker Installation Careful consideration should also be given to the physical s
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