SV Sound SVS PB2-Ultra Speaker User Manual
Contents
1. SVS PB2 Ultra Powered Box Dual Driver Subwoofer OWNERS GUIDE SVS The Bass Authority Contents Page 1 Welcome Page 2 About your new SV Subwoofer Pages 4 7 Setup integration and calibration Page 7 8 Powered box amp features Pages 9 11 Parametric equalizer PEQ Pages 12 13 Variable tuning Pages 14 15 Bass demos Last update 27 January 2004 Page 2 SV Subwoofers Welcome From the entire SVS team congratulations on your pur chase of the standard in home theater and music bass Your new subwoofer isn t some generic mass produced box built someplace you can t even find on a map It s made in Ohio USA by home audio enthusiasts like you Designed tested and assem bled by hand while using state of the art automation and materials your SVS is without a doubt one of the best investments you ll ever make in bringing music and theater home What s more we ll help you to set up your sub right and in no time you ll be giving demos of your favorite music DVDs or digital music to all your friends and neighbors we pity them if you live in an apartment please be kind This isn t just a subwoofer after all it s a carefully designed audio component carefully tuned in our labs by bass authority and Sub human Tom Vodhanel You re unlikely to have heard or felt bass like this before unless i2. Lift off Scene 13 35 15 2 Coming home Scene 53 2 05 43 SV Subwoofers Page 15 More Bassy demo scenes e Titanic You love it or you hate it Regardless of which side of the ship you sit on this flick does some serious rumbling for you 1 We can t leave him Scene 22 2 21 50 2 Ship Splitting 2 41 30 3 Last Gasp 2 42 05 e Blade Not one for the kiddies but loaded with deep bass 1 Footstep Scene 4 7 15 2 Door blown Scene 20 50 05 e Aliens Not just another modern sci fi horror classic this one rocks from intro to final scene 1 Ship drop Scene 9 41 20 2 Awakenings Scene 15 1 12 52 e Apocalypse Now Making This Vietnam war movie Francis Ford Copolla nearly went crazy imagine what it ll do to your subwoofer 1 Chopper ride Scene 2 0 19 47 2 ARC LIGHT Scene 4 0 26 02 3 Grenade launch Scene 12 1 27 58 e Contact SETI with a bass twist or two along the way 1 Bombing Scene 28 1 36 30 2 Space truckin Scene 33 1 55 56 e Dark City One of Roger Ebert s favorites think he likes bass too 1 Let the tuning commence Scene 8 34 30 2 City makeover Scene 15 1 27 45 Warranty 45 day money back warranty If you are not completely satisfied with the performance of your subwoofer return it to us for a full refund of the purchase price Just a few minor st
3. Q adjustment the following formula is needed More on Q in a moment Formula 1 Highest Frequency X Center Point Y Center Point Y Page 11 SV Subwoofers The LEVEL control is the amount of attenuation on the signal located at the center frequency MIN is equal to 0dB and MAX is equal to 12dB cut Each hash mark reduces the Center Point in question by 1 5dB The FREQ control short for frequency is the adjustment for the center point of the cut and should target the highest peak frequency in the room s response Each hash mark for this control moves the center frequency for the desired cut 5Hz within a range of 20 80Hz Adjustments of the parametric equalizer The first step to adjusting a PEQ is determining the Center Point of the cut Determining the Center Point allows us to establish a target or baseline for further adjustments In this example again look ing to the graph in Figure 3 the peak frequency is roughly 40Hz At this stage we ll estimate the beginning lowest frequency and the end highest frequency of the peak In Figure 3 the beginning would be located somewhere near 25Hz and the end or Highest Frequency would be near 50Hz This would be a 25Hz bandwidth with a Center Point located at 37 5Hz the midpoint between 25 and 50hz Notice that the center point of 37 5Hz is not located precisely at the peak frequency in the response curve which was estimated at 40Hz Why If we
4. different subwoofer level settings depending on the listening mode you are in With Dolby Digital as your mode use the above calibration routine You may well find that CD Stereo music calls for a lower bass settings The above is a guide experi ment some The louder your master volume though the more you should back off the sub level to compensate Avoid your driver bottoming resulting in a loud clack Location and measurement You should take the above measurements from your typical preferred seat for watching movies center cushion right Be advised strong bass levels can vary significantly simply by moving a few feet Such is the nature of long wave length low bass sound Try different locations and different levels for your subwoofer Calibrating with the subwoofer s volume too high and often too low is the most common subwoofer setup error Powered Box Features we looked the world over for the best sub amp that s still affordable In the end we designed our own The result A custom North American made amp with amazing build quality durability and unbeatable features Volume Gain Use gain in conjunction with your receiver s subwoofer output level control to dial in a bass calibration to your liking Start calibration with the sub s volume gain no more than 1 4 to 1 3 of the way up turned clockwise from the left Crossover Frequency If you use your DD DTS receiver processor s i
5. earth for the best most cost effective parts the few we don t make ourselves and meld them into finely tuned designs that define high performance home theater and music bass Still cost is always the second consideration at SVS Want woofers amps or even binding posts We ve tested and discarded plenty that didn t meet our tough standards If we use it whatever it is you know it made the grade Get cube ular Many subwoofers we ve seen are simply poorly made We did a host of studies that optimized the materials the size and even the enclosure finish to ensure a rigid design that was still compact for its performance and able to take the abuse your family and friends can dish out Proudly Made in the USA like most other SVS parts the cabinet is no ordinary box Selling direct means your sub and not glossy ads get first priority SVS is quality you can hear Stable downward firing woofer Our contemporary enclosure design is one plus but we ve also taken great lengths to allow for downward firing woofers Coupled with our unique base plates which minimize driver reactive forces you ll find our subs can take a tremendous amount of power and remain rock solid Compliant rubber feet on allow for stable placement on a variety of surfaces No rattling or buzzing allowed Custom low turbulence port designs When you listen to your trend setting ported sub you ll hear and feel bass like never before with a
6. easy to remember reference level Finally ensure your SVS s volume control is set no more than 1 4 to 1 3rd up at first It s also critical to check the subwoofer level control of your surround receiver before you begin the test tones Set it to no higher than 5 dB initially that s one quarter way up given a typical receiver s subwoofer channel level limits of 10 dB to 10 dB Your LFE trim if you have one should be set to OdB to start that s full up but this can be dialed down later to tame peaks if needed IMPORTANT Turn off ANY sound field processing modes peak limiters mid night mode etc Set the SPL meter to Slow and C weighting turn the range dial to 70dB Now play your receiver s internal test tones so you have something to measure with your SPL meter Better yet buy a calibration disk such as the Video Essentials Sound and Vision HT Tune Up or Avia DVDs A test disk s tones ensure your entire signal path from the DVD player to your speakers is set correctly Whatever you use when the tones start alternating from speaker to speaker watch your sound me ter now set each full range speaker s level to about 75 dB or 85dB if using Avia or S amp V by using the receiver s dedicated channel controls leaving receiver s master vol ume the same We recommend you turn down the receiver s subwoofer output level before you significantly lower your sub s volume gain control T
7. of the demo loop Line In Out Use one of the sub s Line In jacks to connect the subwoofer to the output jack of your receiver processor Feeding just one input is enough If you are using a conventional amp and or a stereo setup you can use the Line Out jacks to send sound filtered of deep bass information back to your system amp A simple RCA to RCA cable is all you need for either type configuration Auto On Your sub allows an Auto On mode or can be on all the time With the switch in the Auto position your subwoofer will sense that a DVD or CD etc has begun and switch on immediately the hard power switch mentioned below must be on naturally A few minutes after a movie finishes the auto on light will turn red switching the sub back off When running and sensing a signal the auto on LED will be green Sometimes with very low listening levels your subwoofer might not get enough of a bass signal from your surround sound processor to trip the auto on circuit Should you ever find this to be the case you may leave this switch to On or turn the receiver s subwoofer output up and the sub down Crossover enable switch If you allow your DD DTS surround sound receiver or processor to manage bass frequencies recommended this switch should be set to Disabled This eliminates the effects of the Crossover Frequency knob and allows your sub to reproduce just what it s fed f
8. remove the plug by inserting your fingertips into the port flare and squeezing and pulling on the foam plug at the same time Be sure to select the sub sonic filter point on the back of your PB2 Ultra amp which coincides correctly with your new tuning point NOTE We strongly recommend you do NOT run a lower subsonic filter point than your port plug configuration would dictate espe cially if you are running the subwoofer at high sound pressure levels Moderate levels are doubly important if you put the subsonic filter into Bypass mode essentially turning off this key limiter This simple table indicates the settings you should use in setting up your sub blockers and the subsonic filter knob PB2 Ultra Tuning Chart Subsonic Filter Knob Stock tune no ports blocked 25Hz With one port blocked 20Hz With two ports blocked 16Hz Look to the next page for a computer simulated response chart showing the reduc tion of upper bass when adding one and then two port blockers to your SVS along with addition woofer excursion needed to keep up with the lower frequencies The bottom line Many customers feel the slight loss in upper bass output to be insig nificant compared to the deeper response the port block gives We let you decide yeyo Butun e431 7ad SAS Page 14 SV Subwoofers Bassy demo scenes to die for So now what You ve got one of the best theater and music bass sub systems on the planet you re calibrated
9. subwoofer Page 12 SV Subwoofers Subsonic Filter and Port Tuning Y our new PB2 Ultra subwoofer not only comes with our Tri Power port flares but custom port plugs and variable subsonic filter which allow your sub to be tuned to even lower frequencies than its stock configuration For most people and most rooms your SVS is already configured for the best blend of extension how deep low your sub goes and output how loud it gets at a variety of bass frequencies However we know that bass is a very personal taste and no two rooms will react exactly the same with any subwoofer So we in clude a custom port plug that when inserted into a port allows you the user to experiment with a substantially lower tune As with all such devices there are compromises when tuning a sub lower Installing a port block takes some capacity from upper reaches of bass installing two port plugs naturally limits upper bass response even more So while you will indeed get more bass down low where DVD and music bass is more rare but quite exciting you ll sacrifice total output capacity above the stock tuning point of the sub where bass is more common You should decide if the effect is pleasing on the sorts of movies and music you enjoy How to do it To insert a port plug simply squeeze the foam on one end and press the plug into a port flare until it is about 1 lower than the edge of the surface of the sub You can
10. want to see what she II do But of course Since finding those scenes can be a bit trying we ve compiled a list of our old favorites below After all calibration with test tones is important but it s movies and music this sub is itching to show off Chapter stops for DVDs are shown with movie time in hours min utes seconds What are you waiting for Just hit PLAY e The Iron Giant Great family animation with SERIOUS bass including strong peaks below 25 Hz Jump to 1 Chase thru the forest Scene 8 20 00 into the movie 2 Robot Landing Train Impact Scene 10 25 40 3 Green Boom Scene 27 1 11 40 e Antz Another good family movie though not perhaps for small children Extremely loud bass above 30 Hz Terror from Above Scene 17 51 48 e The Matrix Modern violent science fiction classic with plenty of shoot em up bass blasts Here s some subtle and not so subtle 1 Where we are grown Scene 12 42 55 2 Landing in fight Scene 15 50 51 3 Chopper shootout Scene 31 1 47 15 e Das Boot Arguably one of the most compelling war pictures of all time with bass approaching 20 Hz Very loud very deep 1 Depth charges Scene 21 59 30 2 Storm surfing Scene 25 1 15 15 3 Hitting bottom Scene 17 53 15 Side B e Apollo 13 Moving story with some surprisingly subtle but re vealing bass where it counts 1
11. exceptionally low noise and distortion Huge patented flared port fittings make the difference One DVD or music CD and you ll realize something special went into this product Stylish and understated From the hand finished American wood craftsmanship of the box to the elegant base you ll be amazed at how easy it is to lose your sub in a comer SVS s aren t tiny but this is one of those times size does matter There are countless brands of wannabe subs out there Fortunately you didn t just unpack one World class power Our Canadian built amps are manufactured with a level of fit and finish plus a collection of features and power practically unheard of at this price Did we mention power It s there in spades though we rate them conservatively And SVS starts with efficient subwoofer designs which don t require significant levels of power robbing equalization to go low and flat So our amps can work harder at reproducing low frequencies instead of struggling against a lack of enclosure space the bane of clean deep bass As a result we don t require the megawatts some subs do instead running cool and reliable in our vented enclosures These digital hybrid amps run so cool we can even dispense with old fashioned cooling fins Page 4 SV Subwoofers Setup calibrating and integration What s to know Well first of all setting up an SV Subwoofer is pretty darn easy There are a few key things to get
12. his helps keep input distortion to a minimum You should not be set much lower than 5 dB however since some adjustment room is needed to lower bass as needed If your subwoofer reading is still too high then turn down the sub s amp volume a little with each run SV Subwoofers Page 7 But what s too high Tastes vary and so do movie soundtracks but your SVS is capable of tremendous levels of low distortion low frequency bass far more than most commercial subs Take advantage of this especially if you like action movies with lots of 1 channel LFE action and give the sub a bit more bump during calibration also known as running the sub hot Keep in mind too that the human ear is relatively insensitive to low frequencies This coupled with the fact most folks don t watch mov ies at Dolby Digital theater reference level loud means turning the bass up a few deci bels usually yields a better movie sound experience What sub levels do we recommend If you watch movies at relatively moderate sound levels a good start is a range of 2dB to 3dB above your other channels as measured with your sound meter This means the test tone will waiver about 78 dB for the subwoofer portion of the calibration run 88dB with Avia Note You may want to rotate the sound meter SPL meter dial to 80dB to get a good reading with these higher levels Note too that many modern surround sound receivers allow a variety of
13. ipula tions should you choose to do this e The subwoofer must be returned in original shipping box e E mail SVS first for a return of merchandise number RMA and display this on the outside of the box e The sub must be insured during shipping SVS may arrange UPS pickup to ease any shipping damage issues e Shipping costs are not refundable 3 year warranty against defects in materials and workmanship SVS will repair or replace any item at its discretion and return to the customer as soon as possible Naturally this warranty does not cover any product subjected to misuse abuse or acci dental damage discovered by SVS Except as provided above SV Subwoofers makes no other war ranties express or implied Some states do not permit limitation or exclusion of implied warranties so exclusions may not apply to the purchaser The bottom line We re proud of these subwoofers and want you to be as happy owning one as we are selling one or more to you E mail us if you have any warranty question SV Subwoofers SV Subwoofers LLC 365 Stone Harbor Road SVs Holland Michigan 49424 The Bass Authority Fax 216 803 0195 Phone 703 845 1472 Email custsupport svsubwoofers com
14. it stops on MIN thus ensuring you do not inadvertently cause poor frequency response until such time as you properly configure the PEQ First you might ask yourself why use a PEQ The reason is quite simple Your room See most times even a superlative subwoofer which measures very evenly we say flat in an open domain no reflective boundaries will not measure the same in your home theater or music room Instead colliding bass waves can build up and cause a peak This is where a parametric equalizer helps out A PEQ is an electronic circuit which allows the user to manipulate the input signal so the acousti cal output is more desirable for their environment in many cases allowing the worst peak to be flattened By manipulating the input signal with your PEQ you can cut a wide or narrow peak in response located somewhere in the frequency range of the equalizer Importantly the equalizer found your sub only allows reduction of peaks and is cut only not a boost device Measure the room s response As indicated above you must have a firm understanding of your room s acoustical properties before you proceed with use of a PEQ To determine your room s natural response properties along with your sub woofer s in that room you will need an SPL meter as described on Page 6 and at least a pad of graph paper and a pencil for charting as below If you have graphing program similar to Microsoft Excel
15. nternal crossover to manage bass frequencies highly recommended the setting of this knob on the sub is irrelevant Note Use the SVS s crossover Enable Disable switch discussed below to take advantage of this configuration Otherwise this knob is used to best blend your SVS to your other speakers Typically used in stereo only systems today Phase Think of bass waves as conflicting or enhancing each other depending on the 8 8 p 8 timing of their arrival at your listening location either together or not Since some of your room s bass might come from main center and or surround speakers as well as Page 8 SV Subwoofers your sub getting these bass wave forms to arrive in a complementary enhancing fashion is the difficult job of the phase control Essentially phase varies the tim ing of the bass waves coming from the sub But don t despair if you don t hear much difference with changes to the phase knob the effect of bass cancellation will vary by volume and frequency in your room and no single setting is likely to ever be perfect One technique to optimize phase is to find a nice bassy loop such as the menu of Godzilla and measure the loop s SPL response at various points As the loop runs you can have an assistant adjust the phase control When you see the most response on a given bass passage typically that s the setting with the least room induced cancellation for the frequencies
16. ompensate for this deficiency It s called a compensation chart Simply look to the below frequencies and add the required decibels dBs at the fre quency in question So if your system seems to be measuring 70dBs with a 20Hz tone then really it s putting out 77 5dBs This is a VERY substantial difference roughly TWICE the acoustical energy requiring several times the amplifier power to achieve You can see then how critical the below chart is if you are using your PEQ to even out or flatten the room response of your bass Add the following to your measurements PARAMETRIC EQ 10Hz add 20dBs 12Hz add 16 5dB 16Hz add 11 5dB 20Hz add 7 5dB 25Hz add 5dB 31 5Hz add 3dB 40Hz add 2 5dB 50Hz add 1 5dB 63Hz add 1 5dB 80Hz add 1 5dB N 100Hz add 2dB 125Hz add 5dB in SVS PEQ Controls Explanation of the controls Now that we understand how to measure the room s response the next step is to correct the problem areas with the parametric equalizer Before we start turning the controls we need to understand what the ad justments are and how they work Q This control determines how wide the correction will be Each hash mark on the amp s front plate represents 0 1 octave adjustments The HI mark is equal to 0 1 octave narrow and LO mark is equal to 9 octave wide In Figure 3 the highest peak is located at 40Hz and becomes flat again at 50Hz the Highest Fre quency of the peak To determine the
17. p This can only happen if you say Yes or ON in the Subwoofer selection during the all important setup menu of any typical Dolby Digital DTS capable receiver If you have a choice of crossover points for your bass usually 80Hz works best unless you have unusually small main speakers e Is your receiver connected to the sub amp Use a well shielded RCA cable sometimes called a patch cord to connect the subwoofer output of your DD DTS receiver to either input jack of your subwoofer s dedicated amplifier As mentioned earlier you ll need to split the bass signal with a Y Cable if you bought a pair of subs You only need feed one of the two inputs either Right or Left of any sin gle Powered Box SVS however e Is your Radio Shack sound pressure level SPL me ter ready This tool is simply vital to proper home theater au dio setup It s akin to a tire pressure gauge for your car The manual which comes with the SPL meter is excellent we recom mend you read it entirely Haven t got the meter yet Head down to your neighborhood Radio Shack and snag one We prefer the analog instead of the digital display model but both work well Ask for part number 33 4050 At about 40 it s a bar gain Proper configuration without this meter is practically impossible Getting ready to start now Make sure your receiver processor master volume is set at 00 dB or some other
18. r right or left NOTE Stop now if you aren t TOTALLY familiar with your re ceiver s manual Ensure all power to your equipment is off when making these connections Also be certain your power outlet can handle a mini mum of 900 watts Use of convenience outlets on receivers are not recommended for your SVS c b DD DTS Processor Receiver Fig 1 oe me Subwoofer Out SV Subwoofers Page 5 More Setup calibrating and integration If you are running a pair of SV Subwoofers Fig 2 you will need to use a standard Y cable adapter d The best adaptor to use for this task has one male RCA connection and two female RCA outputs Radio Shack stocks them From the Y cable you can run a standard 75 Ohm RCA to RCA signal cable e to each sub thus splitting the Low Frequency Effects LFE and other bass signals from your receiver and effectively feeding both subwoofers with the same signal NOTE Now is a good time to select if you want ON always on or AUTO ON which turns your sub on only when a bass signal is present Y cable splitter from receiver e d DD DTS Processor Receiver d L Fig 2 oe Subwoofer Out Calibration This isn t only for tech minded folks it s critical to a proper configuration of your home theate
19. r sound system Fortunately adjusting channel balance or calibration is as easy to do as it is impor tant The first order of business is making sure your DD DTS surround sound system is set up properly We recommend you consult your audio video receiver or processor manual to refresh on the procedures to do this Generally this requires ensuring the receiver s test tones or a spe cial test disk like Video Essentials or Avia play back at the same volume from each of your system s full range speakers That s left center right left surround and right surround and if equipped center rear speakers plus the subwoofer More on sub level in a second Skip to page 7 Powered Box Features if you aren t familiar with your sub s amp and come back to calibration Some things to check as you get ready to calibrate e Are your speakers set to the correct size Your receiver processor should allow you to indicate if your speakers are Small or Large Selecting the size accordingly will ensure bass goes to most appro priate speakers and use the subwoofer correctly too In most instances set Page 6 SV Subwoofers ting ALL speakers to Small works best Let your sub make the bass Also is your subwoofer turned ON We don t mean is your subwoofer amplifier on that ll be important later too but rather is your receiver sending a bass signal to your sub am
20. right if you want to get the most out of your new equipment however Unpacking You re probably eager to fire up your sub we re the same way but take time to carefully unpack your sub Set the box and other protective shipping materials aside saving them in case you ever need to return the subwoofer for any reason Fold your box flat for storage even Location They say it s all about location right It s the same with setting up your subwoofer So where to put it Go for a corner if you can and avoid putting your sub where it might adjoin large open areas Studies have shown the deepest and flattest bass response is typically attained when a subwoofer is placed within a few feet of one of your room s corners Whether you put the sub in front or to the rear of your seating area usually makes surprisingly little audible difference Deep movie and music bass like that from Dolby Digital DD 5 1 channel DVDs and digital audio is largely non directional You can t tell where it is coming from even though you can hear and feel it Hook up see fig 1 There are a variety of ways to configure your new sub Usually a simple mono shielded 75 Ohm A V RCA type cable a is used to take the subwoofer output of your DD DTS surround sound receiver b and feed the low level input of the sub s amp There is no need to split the signal going to the sub c You can feed either one of the two amp inputs it doesn t matte
21. rom the receiver If you use the sub in a two channel stereo only configuration then Enable the crossover and adjust the knob to best blend the sub into the low frequency output of your speakers High level inputs outputs Not commonly used today but binding posts are there in case you don t have low level inputs outputs on your receiver processor Typically utilized only if you are not using a DD DTS compatible system Power This heavy duty two position switch next to the power cord will com pletely cut the power to your sub amp Flip this switch to off before you ever move the sub or change inputs or outputs AIC Connection Plug your sub into a dedicated A C outlet Convenience outlets of typical receivers often don t provide the needed current Avoid them Fuse User replaceable contact SVS if you have trouble finding one The fuse can be accessed by a small round door immediately next to the power cord fitting Page 9 SV Subwoofers Parametric Equalizer Important enough and challenging enough this feature gets its own section PEQ allows you to tame a peak in your room s response Peaks are quite common especially in large rooms or ones where your sub is far from your listening position NOTE A Sound Pressure Level meter is a must for proper use of the PEQ so get one before you tackle this control TO DISABLE THIS CONTROL Set the LEVEL control in the Parametric EQ feature group ing until
22. t was in a top notch commercial movie theater or high end high cost audio boutique Movies and music in your home will never be quite the same again That s a promise Already have a question about your sub You might answer it by reading this manual we think you ll find it more informative than most For even more detailed discussion about set up topics check out our FAQs page at www svsubwoofers com We touch on all the key points you need to know and then some Maybe you just want to share a bit of bass news Or perhaps you have a story about your SV Subwoofer to share with us Maybe something we missed in our website No matter feel free to send a note straight to me rons svsubwoofers com It s not often you can talk to the guys who made your audio compo nents In this case we look forward to it Ron Stimpson Co Founder SVS SV Subwoofers Page 3 About your SV Subwoofer Other subwoofers might look like them but virtually none work like them Not at this price SVS s are decidedly different in how they are designed produced sold and even in the exceptional customer service after the sale No surprise then you could have spent much more and still not come close to the value and performance our Powered Box lines provide But what makes a subwoofer an SVS Quality parts sane prices You might be surprised at how inexpensive the components in most not so inexpensive subwoofers might be At SVS we scour the
23. this will save some time graphing the re sponse curves The last item to correctly measure the room s response is a test disc that can play specific frequencies The disc should contain frequencies from 20Hz to 100Hz One of the most popular frequency tests discs is Autosound 2000 CD 101 It can be found at www carsound com cds shtml and is quite inexpensive Freq 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 SPL 85 84 86 91 5 95 90 84 84 86 86 85 83 5 83 83 5 84 5 85 86 Room A Response Figure 3 96 93 90 87 84 81 4 20 40 60 80 100 Frequency Page 10 SV Subwoofers This disc allows the user to play 10Hz through 98Hz in one hertz increments allow ing very good resolution over your measurements Other good examples for test discs are Avia s Guide to Home Theater and Digital Video Essentials When meas uring the room s response use a minimum resolution of 5Hz Figure 3 on the previ ous page shows a theoretical illustration of a room s response Before you plot your results however it s important to note the Radio Shack sound meter is not totally linear in its accuracy down low All similar meters are off by the similar amount depending on the frequency so while its sensitivity below 20Hz is not what it is at 50Hz there is a simple way to c
24. used 40Hz as our center frequency and 50Hz as our high point cutoff we would only at tenuate the curve down to 30Hz This will leave a small bump in response near 25Hz because the correction would only be located between 30Hz to 50Hz Now that we determined the Center Point we can adjust the FREQ control knob to 37 5Hz or between the fourth and fifth hash marks clockwise from the left The next step will properly adjust the Q setting We again need to use Formula 1 and calculate the Q setting from Figure 3 using Highest Frequency and Center Point figures just determined above 50Hz 37 5Hz 0 33 37 5Hz 33 Q or just past the third hash mark clockwise from the left of this control Now that we have successfully adjusted the Q and Frequency controls we need to make the final Level adjustment In Figure 3 the adjustment should be somewhere near 10dB to 11dB or on the 8th hash mark from the left 1 5dB cut per hash mark completing the adjustments for the parametric equalizer Measure room response for accuracy After all the adjustments are made we recommend you measure the room again to make sure the adjustments are correct Ifthe new response curve is not acceptable then fine tune things some For example if the response curve still shows a small peak you should adjust the Level control again to compensate Make sure your overall SPL calibration is set as de scribed earlier in this manual and enjoy your optimized
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