Shure M810E User's Manual
Contents
1. but without NOMA In this mode if the Local Global switch is in Local a manual mix of channel in puts is present at the Line output The Off Attenuation level of the Gated Direct Out signal is infinite 14 3 Forindividual channel modifications the first number of the reference designation refers to its channel number i e R1027 refers to a Chan nel 1 resistor X7216 refers to a Channel 7 jumper etc All references to Channels 1 through 8 in the following paragraphs use Channel 1 jumpers and resistors as reference Modifications affecting the Master section are preceded by the number 9 X901 etc To gain access to the main printed circuit board remove the 8 Phillips head screws securing the top cover and remove the top cover Most modifica tions can be made from the top of the main board Procedure Short jumper X901 Remove resistors R900 and R909 Procedure Remove resistor R9230 Install new resistor at jumper X914 Procedure Remove resistors R9177 and R9180 Install new resistor R at jumper X907 Procedure Remove resistor R9024 Procedure Short jumper X106 Remove resistor R1011 Procedure Short jumpers X101 X102 X105 and X106 Remove resistors R1011 and R1020 Procedure Short jumpers X104 and X906 in Master section Remove re sistor R1011 SCM810 Speech Gate for Mixing Console The SCM810 can be used in conjunction with large mixing consoles to pro vide automatic mixing for talk shows panel2. meets European Union EMC Immunity Requirements EN 50 082 1 1992 Replacement Parts BIOCK CONNSCION Ret T 95A8580 Knob Master amp Phones white ccccceeeeeeeeeeeeeeeeeeeeeeeeeeees 95A8238 Knob Channel Gain blue cccceeccesssseecesseseeesseneeeesseeees 95B8238 Line Power Cord SCM810 sseseeseeeeeeereneee 95A8389 Line Power Cord SCMSG810E sees 95A8247 10 46 o Meter 95A8889 For systems requiring other mains connectors obtain a power cord with an IEC 320 type mating connector for connection to the SCM810 and an appropriate plug on the other end for connection to the mains The supplied cord uses Harmonized IEC Cordage with color coding as follows Brown Line Blue Neutral Green Yellow Ground ADVANCED FUNCTIONS The SCM810 s Advanced Functions are recommended only for those who are technically knowledgeable and familiar with audio electronics LOGIC CONNECTION SPECIFICATIONS The logic functions of the SCM810 expand the mixer s range of installation and control options Logic can be used for everything from simple cough switches to elaborate computer controlled room systems Shure s AMS Update publication contains additional applications of advanced logic This publication is available by contacting Shure s Applications Group The fol lowing logic functions are available for each channel GATE OUT Follows channel gating and goes
3. FUNCTIONS ssesele erre 10 LOGIC CONNECTION SPECIFICATIONS ssseeer ee 10 SUGGESTED LOGIC APPLICATIONS 1 0 4 du we ented oae uta D PSS Rw Sees 11 VOLTAGE SELECTION 5 35 date waded Gas Mes am dat ne de ee eee da bees 13 INTERNAL MODIFICATIONS 000000 cee eee 14 ee Ol a Ce NS oo 10 IMPORTANT SAFETY INSTRUCTIONS READ these instructions KEEP these instructions HEED all warnings FOLLOW all instructions DO NOT use this apparatus near water CLEAN ONLY with dry cloth DO NOT block any ventilation openings Install in accordance with the manu facturer s instructions DO NOT install near any heat sources such as radiators heat registers stoves or other apparatus including amplifiers that produce heat 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 wider blade or the third prong are provided for your safety If the provided plug does not fit into your out let consult an electrician for replacement of the obsolete outlet PROTECT the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus This symbol indicates that there are important operating and maintenance instructions in the literature accompanying this unit _ ON
4. MUTE 6 GATE 6 O RIDE 5 MUTE 8 GATE 8 O RIDE 7 LOGIC CONNECTIONS Logic Function Input Connector Pin No Channel GATE OUT1 GATE OUT 2 GATE OUT 3 GATE OUT 4 GATE OUT 5 GATE OUT 6 GATE OUT 7 GATE OUT 8 OVERRIDE IN OVERRIDE IN OVERRIDE IN OVERRIDE IN OVERRIDE IN OVERRIDE IN OVERRIDE IN OVERRIDE IN 1 2 3 4 5 6 T 8 oOoNgQGAAUON gt ONDOABRWNH ONDOABRWN MUTE IN 8 SUGGESTED LOGIC APPLICATIONS This section contains suggestions on the uses of the SCM810 s logic capa bilities Note that uses of these functions are not limited to the listed appli cations The user is limited only by individual imagination and creativity For additional suggestions and solutions to installation problems contact Shure s Applications Group In the following paragraphs the wiring diagrams refer to the DB 25 connec tor pins shown in Figure 4 Cough Button The talker can turn off his or her microphone during coughing or private conversations by installing an SPST pushbutton switch between the MUTE IN and Logic Ground pins for each channel to be modified see Figure 12 Channels 1 2 and 3 modified When a channel is muted no audio is passed See Dead Zone on MUTE IN Defeat in nternal Modifications section for more information on MUTE IN logic LOGIC GROUND COUGH BUTTONS FIGURE 12 Chairperson Controlled Muting The chairperson can by activating a switch silence all other micropho
5. its place When defeated microphones turn off after their preset hold time Hold Time Adjusts the time an activated microphone which is not locked on remains on after the talker stops talking Settings are 0 4 seconds or 1 0 second on pq 5 p t p t Um pq t Limiter off Off Attenuation Changes the off attenuation level from 15 dB to infinity With the 15 dB setting an unused microphone is 15 dB lower in level than when it is activated With the o setting an unused microphone is com pletely off Limiter Threshold Changes the output limiter threshold Settings are OFF factory setting 16 dBm 8 dBm or 4 dBm see nternal Modifica tions for other threshold settings Link Global Local Determines whether each linked SCM810 output con tains only its own program output or that of all linked mixers see Mixer Linking for more information INSTALLATION AND SYSTEM SETUP RACK MOUNTING THE MIXER To mount the SCM810 in a standard 483 mm 19 inch audio equipment rack slide the mixer into the rack and secure it with the supplied Phillips head screws as shown in Figure 4 Use all four screws SCM810 E CONNECTIONS Make audio connections as follows see Figure 5 1 Connect microphone or line level signal sources to the Channel Input connectors use conventional 2 conductor shielded cables 2 Insert a screwdriver or other tool in the slot above each block connec tor and adjust the input slide switch a
6. numbers are Fuse Type Shure Part No Whitefishes Part No 100 mA 250 V 80C258 218 100 200 mA 250 V 80BC8196 239 200 13 Mixer logic may be used with 15 volt CMOS logic if a pull up resistor is used with each GATE output see Figure 20 Channel 1 modified 15V 9 1K POWER SUPPLY e I lt CMOS LOGIC nk GROUND G1 M1 O O O O OO O O O 00 oO C O Os O9 QOO Qoo O OLO 01 15 VOLT CMOS FIGURE 20 Digital Controls or Microcomputers The SCM810 logic pins can interface with custom designed digital control circuitry or microcomputers for unlimited possibilities of system control functions 5 Replace the power cord with a cord rated for 230 V operation i e an IEC appliance connector on the equipment end and a CEE 7 7 Schuko mains connector on the other Similarly the SCM810E can be internally modified to operate from 120 Vac 50 60 Hz power For systems requiring other mains connectors obtain a power cord with an IEC 320 type mating connector for connection to the SCM810 and an appropriate plug on the other end for connection to the mains The supplied cord uses Harmonized IEC Cordage with color coding as follows Brown Line Blue Neutral Green Yellow Ground INTERNAL MODIFICATIONS WARNING All modifications must be performed by qualified service tech nicians This section describes SCM810 modifications that can be made usi
7. outputs is inverting Input Channel Activation Attack Time 4 ms Hold Time0 4 s Switchable to 1 0 s Decay Time0 5 s Off Attenuation 15 dB switchable to Overload and Shorting Protection Shorting outputs even for prolonged periods causes no damage Mi crophone inputs are not damaged by signals up to 3 V Line and Monitor inputs by signals up to 20 V Equalization Low frequency 6 dB octave cut adjustable corner from 25 to 320 Hz High frequency 6 dB at 5 kHz 8 dB at 10 kHz shelving Limiter Type Peak Threshold Switchable off 4 8 16 dBm at output Attack Time2 ms Recovery Time300 ms Indicator Lights red when limiting occurs Input LEDs Green on channel activation red at 6 dB below clipping Phantom Power 46 Vdc open circuit through 6 8 KQ series resistance per DIN 45 596 Operating Voltage SCM810 120 Vac rated nominal see Voltage Selection for 230 Vac op eration 50 60 Hz 200 mA SCM810E 230 Vac rated nominal see Voltage Selection for 120 Vac operation 50 60 Hz 100 mA Temperature Range Operating0 to 60 C 32 to 140 F Storage 30 to 70 C 20 to 165 F Overall Dimensions 44 5 mm H x 483 mm W x 317 mm D 1 3 4 x 19 x 12 1 2 inches Net Weight 4 3 kg 9 Ib 9 oz Certifications SCM810 Listed by Underwriters Laboratories Inc listed as Certified by Canadian Standards Association SCM810E Conforms to European Union directives eligible to bear CE marking VDE GS Certified to EN 60 950
8. the Ground wire will set the function s to the corresponding switch down position SHURE SHURE Incorporated http www shure com United States Canada Latin America Caribbean 5800 W Touhy Avenue Niles IL 60714 4608 U S A Phone 847 600 2000 U S Fax 847 600 1212 Intl Fax 847 600 6446 Europe Middle East Africa Shure Europe GmbH Phone 49 7131 72140 Fax 49 7131 721414 Asia Pacific Shure Asia Limited Phone 852 2893 4290 Fax 852 2893 4055 16
9. AE L Qr OQ XX 00 Os Or OC O OF Ox OQ o9 OO0O000 0000 0 0 0 D 1N4148 N A FROM POWER AMP LOUDSPEAKER MUTING FIGURE 17 Filibuster Mode In normal operation when several people talk each microphone gates on so that no speech is missed In filibuster action a microphone that is gat ed on prevents other microphones from gating on Once a microphone has gated on other microphones cannot gate on until the talker has paused long enough for that microphone to gate off Thus the person talking has the floor and cannot be interrupted To establish this function first perform the internal Mute to Inhibit modifi cation see nternal Modifications Then connect all the MUTE IN pins of the modified channels together all the GATE OUT pins of the modified channels together and the GATE OUT pin of one modified channel to the MUTE IN pin of another modified channel see Figure 18 Channels 1 2 and 3 modified Turn the Last Mic Lock On switch SW702 position 2 to off NOTE To prevent high frequency oscillation do not wire a channel s GATE OUT pin to its own MUTE IN pin unless the Mute to Inhibit change has been made LOGIC GROUND M3 OO0O0O00000000000 00000000000 0 M2 JUMPER FILIBUSTER MODE FIGURE 18 Inhibit Function See nternal Modifications Diode Isolation of Logic Controls Two or more control functions using the same logic pins can be isolated with diodes In this m
10. LY USE attachments accessories specified by the manufacturer USE only with a cart stand tripod bracket or table specified by the manufacturer or sold with the apparatus When a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over UNPLUG this apparatus during lightning storms or when unused for long periods of time REFER all servicing to qualified service personnel Servicing is required when the apparatus has been damaged in any way such as power supply cord or plug is dam aged 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 DO NOT expose the apparatus to dripping and splashing DO NOT put objects filled with liquids such as vases on the apparatus This symbol indicates that dangerous voltage constituting a risk of electric shock is present within this unit WARNING Voltages in this equipment are hazardous to life No user serviceable parts inside Refer all servicing to qualified service personnel The safety certifications do not apply when the operating voltage is changed from the factory setting DESCRIPTION The Shure Model SCM810 E is an eight channel automatic microphone mixer designed for use in sound reinforcement audio recording and broadcast applications The SCM810 dramatically improves audio quality in any application where multiple microphone
11. M810E operates on 220 240 Vac power Each mixer is supplied with a power cord rack mounting hardware and a link cable Peak responding output limiter with selectable thresholds and LED indicator Active balanced microphone level XLR inputs and an active bal anced Mic Line level XLR output e Aux level input with manual level control Front panel headphones output with level control e Linking capability for up to 400 microphones e MaxBus Controls the number of channels that may be activated for a single sound source One talker activates only one channel even if multiple microphones hear that talker Last Mic Lock On Keeps the most recently activated micro phone open until another microphone is activated Without Last Mic Lock On a long pause in conversation would cause all micro phones to turn off which would sound as if the audio signal had been lost Last Mic Lock On ensures that background ambience is always present FRONT PANEL FEATURES Q o e o e o O N ua zl POWER O G gt Y Y 4 IMITER e O 0N 420 MASTER O cH o MODEL SCM810 FRONT PANEL FIGURE 1 O 9 o o Microphone Channel Gain Controls 1 8 Allows adjustment of microphone gain Input LED 1 8 Lights green when channel is active lights red at 6 dB below clipping level Low Cut Filter 1 8 Recessed screwdriver adjustment provides adjustable low frequency roll
12. Model SCM810 M810E User Guide SHURE SCM810 POWER e C PA demon A y SO cy LIMITER D 5 2 PHONES o 42 AUX INPUT MASTER SCM810 SCM810E EIGHT CHANNEL MICROPHONE MIXER 2005 Shure Incorporated Printed in U S A 27C8504 Rev 8 C TABLE OF CONTENTS DESCRIFTION PaL MP 3 SYSTEM FEATURE SIS aet suited puit conten ot eine aa a trices ues ME a RPM ME 3 OPERATING PRINCIPLES 45 9 2 Ra n ne rati ee e CPC RC ORC ee e Sex Ra 3 FRONT PANELTEATURES 3 dx end yn eel ERU a dli ER Gnd ete ete 4 REAR PANEL FEATURES 21 xdg e Y du So dC CCS PCIE Rede o oU ea 4 Blind C rr 5 INSTALLATION AND SYSTEM SETUP sseselele ees 6 RACK MOUNTING THE MIXER 4 dca oe ex oe ee he ea E a ih ao RC na 6 SCNICIO E CONNECTIONS sa 21497 th Sn Beer prey EHE dea tee XP beu 6 OUTPUT EINITER SETTINGS 2314 btc poi eae Rede ROS CREAR Robot re e deed 6 EQUALIZER FUNCTIONS suicide aae ud e Vo S BE ea ee hE ERR SOS a do RUPES e e e T USING AN EQUALIZER FEEDBACK CONTROLLER WITH AN AUTOMATIC MIXER 7 BASIC MIXER OPERATION 42 555 72 4 8 3 85 RUE Grit dae euenire ACA ESSE P doa Rees ws T NETWORKING MULTIPLE MIXERS sssleeeeee ns 8 GEOBAWILOCAL FUNCTIONS 44 cuiu to hx oe a EO a a Ea e ae 8 HINK CABLES Y du rhea ta Ap a Wee ens B74 gd tuto achat Sede atau tfe A a d 8 SPECIFICATIONS erac ee rapaces duh EE tet tek eb se EA Py C DD Fe e ERU eas a 9 ADVANCED
13. anner a channel can be muted by an overall group mute switch or by its own cough button see Figure 19 Channels 1 3 and 5 modified D 1N4148 OR GROUP EQUIVALENT MUTE LOGIC MA vs veo GROUND O OO O0 QOO OO OOo o0 Q O10 0 OIO O OOo 0 OO O keL Ne COUGH BUTTONS l i DIODE ISOLATION OF LOGIC CONTROLS FIGURE 19 External Logic Devices SCMS810 logic levels are directly compatible with TTL and 5 volt CMOS log ic families For information on logic gate use refer to the TTL Cookbook and CMOS Cookbook both by D Lancaster Howard Sams Publishing Co VOLTAGE SELECTION The SCM810 can be internally modified to operate from 230 Vac 50 60 Hz power WARNING Voltages in this equipment are hazardous to life No user serviceable parts inside Refer all servicing to qualified service personnel The safety certifications of the SCM810 do not apply when the operating voltage is changed from the factory setting To change the operating voltage follow these steps 1 Disconnect the SCM810 from the AC power source 2 Remove the eight Phillips head screws securing the top cover 3 Locate Voltage Selector switch SW903 adjacent to power transformer T901 and using a screwdriver turn the center rotor to the 230 V posi tion 4 Locate Fuse F901 and remove it Replace it with a 100 mA 250 V time delay fuse for 230 volt operation 200 mA 250 V slow blow fuse for 120 volt operation Fuse part
14. c 50 Hz SCM810E full gain 1 kHz one channel activated source impedances Mic 150 Q Line 150 Q termina tions Line 10 kQ Phones 300 Q tip sleeve and ring sleeve Direct Out 10 kQ Auto mode equalization controls adjusted for flat response Frequency Response Ref 1 kHz channel controls centered 50 Hz to 20 kHz 2 dB 3 dB corner at 25 Hz Voltage Gain typical controls full clockwise Low impedance 80 dB 88 dB 34 dB mic 150 Q Send Return 20 dB 28 dB IER Inputs O Ump me 0 Designed for Actual Input use with typical Clipping Level Outputs mp me J OOo Designed for Actual Output use with typical Clipping Level Headphones 8 200 Q 300 Q 12 dBV 60 Q recommended Total Harmonic Distortion lt 0 1 at 18 dBV output level 50 Hz to 20 kHz through 20 Hz 20 kHz filter Input 1 and Master at 5 all other controls full counterclockwise Hum and Noise Equivalent Input Noise 125 dBV 150 Q source through 400 Hz 20 kHz filter Equivalent Input Hum and Noise HQ PERDERE RT 123 dBV 150 Q source through 20 Hz 20 kHz filter Output Hum and Noise through 20 Hz to 20 kHz filter channel controls full counterclockwise Master full counterclockwise llus 90 dBV Master full clockwise llle 70 dBV Common Mode Rejection gt 70 dB at 1 kHz Polarity Mic Line Send inputs to all outputs are non inverting Aux input to all
15. discussions and news shows Large consoles have channel insert jacks so that external signal process ing devices can be patched into individual channel signal paths With this modification the SCM810 can be placed into unbalanced insert jacks and the SCM810 used as a high quality external 8 channel speech gate This arrangement allows the operator complete control of each channel via the console s input control strip while the SCM810 keeps the number of open microphones to a minimum In this operational mode 1 The Direct Out jack tip is the input from the mixing console and the ring is the output to the mixing console 2 The SCM810 channel inputs faders and EQ do not function 3 NOMA does not function channel Off Attenuation is infinite 4 The front panel channel overload indicators indicate gating and over load for each input 5 The Local operating mode provides a non automatic audio signal at the output for use in external mixes 6 If the insert point on the mixing console is pre fader the gain trims should be set such that all microphone levels are similar MUTE IN Precedence to OVERRIDE IN Precedence With this modification and when both MUTE IN and OVERRIDE IN logic are grounded for a channel the Override mode will take precedence as sup plied the MUTE IN takes precedence over OVERRIDE IN Dead Zone on MUTE IN Defeat As supplied MUTE IN is intended for use as a momentary cough button or privacy function m
16. e following resistor values Off Attenuation Level Resistor Value 10 dB 18 kQ 30 dB 150 kQ 15 Procedure Short jumper X113 Remove resistors R1046 and R1058 Procedure Remove resistors R9088 and R9145 Install new resistor at jumper points X904 and X908 Increase Hold Time In addition to the dip switch SW702 options of 0 4 and 1 0 second hold Procedure Install a 470 k resistor across jumper points X902 Move DIP time the hold time can be increased to 1 5 seconds More than 1 5 sec switch down to 1 0 second position onds is not recommended Decrease Hold Time The hold time can be decreased from the factory preset of 0 4 seconds to Procedure Install a 2 MQ resistor at jumpers X903 0 3 seconds Less than 0 3 seconds is not recommended Remote Control of Link Global Local Off Attenuation Last Mic Lock on and Automatic Manual DIP Switches If desired these functions can each be remotely controlled with an SPST Procedure switch 1 Solder a wire in the pc board jumper hole adjacent to the desired func tion printed on the printed circuit board These jumpers are located just behind DIP switch SW902 2 Solder a wire in the pc board jumper hole marked GND near switch SW902 3 Set the desired DIP switch es to the Up position 4 Run the jumper wires to the desired remote location and solder them to an SPST toggle switch The wires can exit the SCM810 chassis above the DIP switches Shorting any wire to
17. es When using an SCM810 in MANUAL mode the master output drops by 9 dB when all 8 inputs are activated Conversely it will rise by 9 dB when switched back to AUTOMATIC mode 5 If a headphone monitor is to be used adjust the PHONES control knob until the desired volume level is reached The SCM810 E is now ready to use NOTE The SCM810 E mixer is fully automatic For most applications no additional adjustments are required NOTE The extreme sensitivity of the ntelliMix circuitry may allow some channel gating due to static discharge or electrical disturbance to the power or signal lines The unit will not be damaged normal operation will resume after the disturbance ceases NETWORKING MULTIPLE MIXERS If additional inputs are needed more SCM810 mixers as many as 50 can be linked using supplied link cables Such a configuration can provide up to 400 microphone inputs To link multiple mixers connect the LINK OUT of the first mixer to the LINK IN of the next mixer and so on see Figure 8 Leave the LINK IN jack of the first mixer and the LINK OUT jack of the ast mixer unconnected LINKING MIXERS FIGURE 8 GLOBAL LOCAL FUNCTIONS The Global Local switch selects which input channels appear at that linked mixer s output Set to the Global position a input channels appear at that mixer s output Set to the Local position only its own eight input channels appear at that mixer s output The Master level control in any m
18. l or Master Gain controls will increase the average output and in turn the amount of limiting As supplied the out put limiter is defeated However you can change the limiter threshold so that the peak output level is 4 8 or 16 dBm Refer to the nternal Mod ifications section EQUALIZER FUNCTIONS Low Cut Filter High Pass The low cut or high pass filter allows all frequencies above its cutoff point to pass from filter input to filter output without attenuation while frequencies below the cutoff are attenuated see Figure 6 The cutoff point is defined as the frequency where the signal has dropped 3 dB relative to the flat or bandpass region Below the cutoff point the filter exhibits increasingly more attenuation as the frequency diminishes The rate at which this atten uation occurs is defined in decibels per octave dB oct The SCM810 has a one pole low cut high pass filter of 6 dB per octave Low cut filters are ideally used for attenuating or rolling off the audio signal where extraneous noise excessive proximity effect or other unwanted ma terial is present For example the low frequency vibration cause by foot steps and vehicle traffic can be transmitted through microphone stands to the microphone and then into the sound system These frequencies typi cally ranging from 5 to 80 Hz are generally not desirable High Frequency Shelving The fixed frequency equalizer produces a 6 dB boost or cut at 5 kHz a
19. nd above see Figure 7 High frequency shelving is extremely useful for boosting flat frequency response tempering very sibilant vocal microphones or enhancing the sound of off axis lavalier microphones LLL eT er minnie PITA KOMM LL s ANU AL CTETUR 40 Cota H 20 5 000 FREQUENCY ey ro ETT pet AW Hn AT 1 1 1 AMPLITUDE dBV LOW CUT FILTER EFFECTS FIGURE 6 LLLI LLLA ew all Co er get LL tis nE n 4L NAM AMPLITUDE dBV 10 200 1 000 10 000 20 000 FREQUENCY Hz HIGH FREQUENCY SHELVING EFFECTS FIGURE 7 USING AN EQUALIZER FEEDBACK CONTROLLER WITH AN AUTOMATIC MIXER When setting up a sound system which has an outboard equalizer or feed back controller in the signal chain set the SCM810 to MANUAL This acti vates all microphone inputs so every possible feedback path is open With the SCM810 in MANUAL mode equalize the sound system and or Ring Out the room to set the feedback controller BASIC MIXER OPERATION 1 Turn on the Power switch Adjust each channel level so that its Overload LED flickers only during very loud speech or noise 3 Turn unused channel controls full counterclockwise 4 Adjust the SCM810 Master level control for the required output level as indicated by the output peak meter After equalizing the sound system set the SCM810 to AUTOMATIC mode Remember that the input of an automatic mixer drops by 3 dB every time the number activated inputs doubl
20. nel s OVERRIDE IN pins together to the Logic Ground pin The selected channels now function as they would in a non automatic mixer see Figure 15 Channels 1 2 and 3 modified LOGIC GROUND OO0O0O00000000 0 0 O0O000000000 0 GATING BYPASS FIGURE 15 Inhibiting Gating for Unwanted Sounds As described in the Operating Principles section MaxBus attempts to acti vate only one microphone per sound source Muting a microphone channel prevents its audio from appearing at the mixer s output However the mut ed microphone still communicates with other mic channels via MaxBus A sound source picked up by a muted microphone will not activate other mi crophones Sound sources that may cause unwanted microphone channel activation include A noisy fax machine or printer e A squeaky door A paging system loudspeaker e An audio teleconferencing return signal loudspeaker The SCM810 can prevent these and similar sounds from activating micro phones by taking the following steps 1 Place one microphone near the unwanted sound source Connect that microphone s signal to a channel input Or vul ad the unwanted sound source directly into a Mic Line channel input 2 Mute that channel using the logic terminal see Figure 16 Channel 1 is muted 3 Adjust that channel s gain control just to the level where other micro phones in the system do not activate for the unwanted sound If the channel gain is set too high other sys
21. nes and be heard without interruption For operation in this mode connect all the MUTE IN pins together except that of the chairperson s channel and wire an SPST pushbutton or toggle switch between those MUTE IN and Logic Ground pins see Figure 13 the chairperson is shown as Channel 1 An alternative to a switch is to connect the chairperson s GATE OUT to the MUTE IN of other channels When the chairperson s microphone activates all other microphones mute LOGIC GROUND dl OO0O0O000 00000 0 mf m CHAIRPERSON CONTROLLED MUTING FIGURE 13 11 Remote Channel On Indicators Remote indicators can be used to indicate when a talker s microphone is on Connect the LEDs and a 5 volt supply to the GATE OUT pins as shown in Figure 14 Channels 1 2 and 3 shown modified To avoid switching clicks in the audio output do not ground the power supply negative terminal in the audio system or rack ground IMPORTANT If a single cable is used for the microphone audio signal and the LED dc power separate shielded pairs must be used Failure to carry the dc power on a shielded pair may result in audible clicking due to capac itive coupling between the dc power lines and microphone lines t 5 V POWER SUPPLY LOGIC GROUND R 470 amp 1 4 W REMOTE CHANNEL ON INDICATORS FIGURE 14 Disabling the Gating Function Bypass To keep certain microphones on at all times wire the desired microphone chan
22. ng sol der jumpers on the printed circuit board the pads where jumpers may be used are placed close together so that a single solder drop functions as a jumper Note too that 1 he only printed circuit board legends used for these modifications are jumpers X s and resistors R s 2 Where resistors are to be added through holes are present on the board Line Level Output to Mic Level Output Disable Master Level Control The Master gain control can be disabled so it cannot be tampered with The table indicates the resistor value to be used for the desired gain 10 kQ 6 dB Change Limiter Threshold All three threshold settings 16 8 and 4 dBm can be changed To shift the threshold down by 6 dB resistor R will be 82 kQ To shift the limiter thresholds up by 6 dB R will be 330 kQ Local Aux Operation With linked mixers the Aux input from a modified mixer does not link Direct Out to Post Fader A channel s Direct Out phone jacks can be changed from pre to post fader Direct Out to Post Fader Send Return Insert Changes a channel s 1 4 inch Direct Out jack to a post fader insert point Send is tip of phone jack return is ring Insert jacks are useful for inserting line level signal processors into a channel For instance a parametric EQ or compressor limiter can be inserted into a channel for additional process ing Direct Out to Gated Direct Out This post fader post EQ channel output is gated
23. nked mixer outputs Each mixer s Master level control only controls its own output Each output can be used independently NOTE The actual off attenuation in the 15 dB switch position increases as more mixers are linked This reduces excessive noise and reverberation contributed by the increased number of attenuated microphones In a linked system the Aux input of any mixer appears at each linked mix er s output See nternal Modifications to defeat the linking of Aux signals IMPORTANT When using the logic terminals on linked mixers connect the LOGIC GROUND terminals of each unit together Switching clicks may re sult if this is not done lE LJALA OOOO SCM810 C GLOBAL RECORDER 04 O4 O101 00 0 0 00 O O68 LINK SCM810 A LOCAL LOJAAL OO O Ode SCM810 B LOCAL o9 p S OO O OO gt LOUDSPEAKER LOUDSPEAKER bo 999 ee ES o H ul Z Z O O I I A CL O O T tcc O O S E T3 p G EE XJE X05 d LINKED SCM810 MIXERS FIGURE 9 connections they are variously referred to by Apple as shielded serial cable with two mini DIN 8 connectors and Apple System Peripheral 8 Cable SPECIFICATIONS Measurement Conditions unless otherwise specified Line voltage 120 Vac 60 Hz SCM810 or 230 Va
24. nterfaces with each channel s GATE OUT MUTE IN and OVERRIDE IN logic terminals See the Suggested Logic Applications section NOTE THIS IS NOT AN RS 232 PORT DIP Switch The 7 position DIP switch provides setup options for the mixer see DIP Switches section LINK IN OUT Jacks Allow multiple mixers to be stacked for addi tional inputs Up to 50 SCM810 mixers can be linked LINE OUTPUT Removable Block Connector Active balanced line level signal for connection to amplifiers recorders or other mixers Output can be modified to microphone level see nternal Modifications C 120VAC 50 60 Hz 200mA AUXIBOID OA DIRECT OUT DIRECT DIRECT DIRECT DIRECT DIRECT DIRECT DIRECT C LI NK NE O AUX IN rIC PHM LI OUT Mic PHM LINEOS Mic PHN LINEOUT uic PHwLuiNESU MIC PHM LINE wic PH Mr INIUT wic PHM L INEO wiG PHM LINE MICROPHONE LOGIC o OUTPUT SWITCH SWITCH OL oO OU QOL OL SWITCH MESS o pnm TE pu som oe C i WLS Try Sts P te t e ote toe O SWITCH BEHIND CONNECTOR SCM810 REAR PANEL FIGURE 2 AC Power Connector and Rocker Switch Connector supplies AC DIRECT OUT 1 4 inch Phone Jacks Provides non gated aux level signal from each channel Direct outs are wired pre fader and pre EQ Can be modified for use as a gated channel output send receive insert point or external speech gate for mixing consoles see nternal Modifications section AUX D O D O Switch Located behind the Line Output connector this
25. ode only controls the level of its own output The Master level control is independent of the Global Local switch The out put level of each mixer is affected only by its own Master control All auto matic functions such as Last Mic Lock on and MaxBus are connected on all linked mixers and are not affected by the Global Local switch An example of the possibilities of this setup is shown in Figure 9 Here two SCM810s are set to Local and the resulting sound distribution provides local sound reinforcement while avoiding feedback This is a simple mix minus setup The third SCM810 is set to Global and feeds a tape recorder At the same time the automatic functions Last Mic Lock On etc remain common to all mixers The following table summarizes the mixer settings MIXER Link Global Audio Output Local Switch Contains A B C 8 id LINK CABLES Additional link cables are available as Shure Part No 95A1143 305 mm 12 in Longer cables in a variety of lengths are available from Apple Com puter as computer printer As long as the link jacks of all mixers are connected out to in sequentially leaving one Link In and one Link Out jack unconnected the automatic mix ing functions will be shared by all units All input signals appear at all linked mixer outputs There is no master slave relationship The output controls and functions of each linked mixer are post link and do not affect the signals appearing at other li
26. off high pass to reduce undesirable low frequency signals High Frequency Shelving Filter 1 8 Provides level boost or cut in mid high frequency region to compensate for off axis tone coloration or for cutting high frequency sibilance AUX Level Control Sets the input level for aux level equipment con nected to the adjacent 1 4 inch INPUT phone jack or rear panel 1 4 inch AUX input REAR PANEL FEATURES 0 0 9 e Aux INPUT 1 4 inch Phone Jack Mixes external auxiliary or line level sources into output This out is not automatic Signal appears at output of all linked mixers MASTER Level Control Determines the overall mix level Output Level Meter Nine segment LED meter indicates peak output signal level Last LED indicates limiter action PHONES Control and 1 4 inch Phone Jack Permits monitoring of mixer output through headphones The PHONES knob controls head phones output level POWER LED Lights green when unit is powered power to unit when plugged into a power source the rocker switch turns the unit on Microphone Logic DB 25 male connector i
27. s are required Any low im pedance dynamic or condenser microphone including wireless can be used with the SCM810 E Multiple SCM810 mixers can be linked to other SCM810 E mixers as well as to Shure Models FP410 SCM410 SCM800 and AMS8100 mixers SYSTEM FEATURES Fast acting noise free microphone selection that automatically adjusts to changes in background room noise e SMS gain adjustment as additional microphones are activat e e Last Mic Lock On circuit that maintains ambient sound Adjustable low frequency rolloff and high frequency shelving for each channel Channel activation and clipping indicators OPERATING PRINCIPLES The operating concept behind the SCM810 E Automatic Mixer is Shure s patented IntelliMix circuitry IntelliMix delivers seamless automatic mixing by combining three separate functions Noise Adaptive Threshold Distinguishes between constant background noise such as air conditioning and changing sound such as speech for each input channel It continuously adjusts the activation threshold so that only speech levels louder than the background noise activate a channel Each input channel has a two band equalizer and three logic terminals The equalizer reduces unwanted low frequency audio pickup and makes differ ent microphone types lavaliers boundary and handheld sound similar The logic terminals can be used to control external devices The SCM810 E operates on 100 120 Vac power the SC
28. s required microphone left posi tion microphone with 48 V phantom power center position or line level right switch position 3 Connect the SCM810 Line Level Output to the input of mixers EQs amplifiers or recorders 4 For headphones monitoring connect headphones to the front panel 1 4 inch PHONES jack 5 Connect the power cord to 120 Vac SCM810 or 230 Vac SCM810E If the operating voltage is to be changed refer to the Internal Modifications section OUTPUT LIMITER SETTINGS The output limiter prevents distortion during loud program peaks without af fecting normal program levels This prevents overloading of the devices connected to the SCM810 E output BENE 1 eee Oo O O O oO oO O O A RACK MOUNTING THE SCM810 E FIGURE 4 TO STEREO OR MONO HEADPHONES FROM AUX OR LINE LEVEL SOURCE uero OOo O07 Oo S o Loo ee oO i TO AMP REC MIXER INPUT CH 1 7 41 FROM MIC LINE SOURCE CH 1 8 TO AMP RECORD MIXER INPUT OR FROM AUX SOURCE CH 8 MIXER OUTPUT TO AMP REC MIXER INPUT LLL o Y TO LINKED SCM810 MIXERS TO ADVANCED FUNCTION WIRING TO 120 VAC POWER SOURCE AUDIO CONNECTIONS FIGURE 5 Increasing the individual channe
29. switch selects either aux input function or direct output function for channel 8 Direct Out jack Left switch position is AUX IN center and right positions are DIRECT OUT INPUT 1 8 Removable Block Connectors Active balanced micro phone or line level inputs Input 1 8 MIC PHM LINE Switch Located behind the removable block connector this switch selects operation at either micro phone level left microphone level with 48 V phantom power cen ter or line level right signals DIP SWITCHES The rear panel DIP switch provides the following setup options The posi tions shown in bold type are the factory settings NOTE Switch positions and effects are shown in Figure 3 and also on the mixer label ea c c um c c MIXER DIP SWITCH SW702 REAR PANEL 12 3456 7 MODIFIABLE FUNCTION SWITCHES FIGURE 3 DIP SWITCH SW702 FUNCTIONS Manual Aut Last Mic Hold Time Off Attenuation Limiter Link A aia Lock On Level Threshold Local Global C Position C 5 Up 6 Up 5 Down 6 Up Auto 0 4 second 5 Up 6 Down 5 Down 6 Down Manual All mics off after 1 0 second oo completely off Local hold time Manual Auto Automatic activation is defeated in the Manual position In Manual mode functions as a standard 8x1 mixer Last Mic Lock On Last Mic Lock On feature keeps the most recently ac tivated microphone turned on until a newly activated microphone takes
30. tem microphones will be difficult to activate for desired sounds If set too low unwanted sounds will continue to activate other microphones INHIBITING GATING UNWANTED SOUNDS FIGURE 16 LOGIC GROUND M1 OO0O000000000005 OQ Or O Q Q Q O Q Q Q OQ QO Loudspeaker Muting Some applications require a loudspeaker to be placed near each talker to provide audio reinforcement or to permit telephone conversation or conference monitoring Each loudspeaker can cause feedback unless it is automatically switched off when the talker near it speaks To provide this function connect the GATE OUT terminal of each channel to a separate loudspeaker muting relay as shown in Figure 17 Channels 1 3 and 5 shown modified Recommended relays are Omron G6B 1174P US DC 12 Potter amp Brumfield R10 E1Y2 V185 or equivalent available through Digi Key and Newark Electronics NOTE A diode across each relay coil is required to suppress inductive volt age spikes which may damage the SCM810 An existing sound system using 24 volt relays can be used with the SCM810 without modification if the relay coil current draw is under 500 mA 12 N N N J J m J J D amp 3l 3l 3l ww e e e POWER SUPPLY Y Y Y i ig i LOGIC x GROUND E ah G3G5 in ewe U
31. to logic low sinks current when microphone is gated on 500 mA of current sinking ability is provided see Figure 10A ga E 10K 55K GATE ORC s e o C scm810 QUT DE um CIRCUIT FROM SCM810 gt CIRCUIT O LOGIC GROUND LOGIC EQUIVALENT CIRCUIT DIAGRAMS FIGURE 10 MUTE IN Applying logic low from GATE OUT or a switch closure to logic ground gates channel off see Figure 10B Channel output drops to o OVERRIDE IN Applying logic low from GATE OUT or a switch closure to logic ground forces channel on see Figure 10B Factory setting pro vides that when both Mute and Override are activated Mute takes prece dence see nternal Modifications for Override precedence LOGIC GROUND Logic ground is distinct from the SCM810 audio ground Make all logic ground connections to this pin including power supply ground of external logic circuitry To avoid switching clicks do not connect logic ground to audio chassis or rack grounds 10 Logic controls are accessed at the DB 25 multi pin connector on the rear panel Figure 11 The pin connections are given in the following table GATE 1 GATE 3 GATE 5 GATE 7 LOGIC MUTE 1 MUTE 3 MUTE 5 MUTE 7 GROUND O RIDE2 l vRIDE4 loripes orRIDEa 5585888888838 an an a a On Oe Oe MUTE 2 GATE 2 O RIDE 1 MUTE 4 GATE 4 O RIDE 3 LOGIC CONNECTOR FIGURE 11
32. ute when necessary However if the MUTE IN is in tended to be used so that the talker must unmute microphones to enable speech pickup unmute when needed this modification is needed This re moves the muted channel from the MaxBus which eliminates dead zones A dead zone is an area in which a microphone picks up a talker through a muted microphone and other microphones do not activate for that talker Change MUTE IN to Inhibit As supplied a channel will mute when its MUTE IN terminal is grounded The mute function can be changed to Inhibit by an internal modification for each channel After the modification a logic Low at the MUTE IN ter minal prevents that channel from gating on if it is off but allows it to remain on if it is already on IMPORTANT To prevent high frequency oscillation never connect a channel s GATE OUT to its own MUTE IN unless the Inhibit modification has been made Procedure Short jumpers X103 X107 X108 and X906 in the Master sec tion Remove resistors R1011 R1019 and R1020 Procedure Short jumper X114 Remove resistor R1046 Procedure Short jumper X115 Procedure Short jumper X111 Change OVERRIDE IN to MUTE IN for Use with Filibuster Mode This modification should only be performed with the Change MUTE IN to Inhibit modification described above Change Off Attenuation Level This modification changes the off attenuation level from 15 dB to a select ed value Select from th
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