Question relating to Sub calibration with Avia

Discussion in 'Archived Threads 2001-2004' started by Scott-C, Dec 31, 2001.

  1. Scott-C

    Scott-C Supporting Actor

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    Happy New Year HTF! In the spirit on "new beginnings" I'm going to try to articulate a problem with my HT that's bothered me all year. I know with your help, I can start 2002 with this problem resolved. Bear with me as I explain...
    The Equipment
    Yamaha DSP-A3090 integrated amp
    Monster Cable M351 subwoofer cable
    DefTech PF15TL+ subwoofer
    Avia Guide to Home Theater DVD
    The Connection
    I've connected one end of the sub cable to the line-level output on the back of the 3090 labeled "MONO SUBWOOFER". The other end is connected to the sub's "LFE In" input.
    The Problem
    The Yamaha 3090 has a feature/setting called "LFE Level" that is used to adjust the output level at the LFE channel. I have been assuming this is the setting I should access to calibrate my sub using Avia. The feature allows for a 20 Db adjustment range (-20 DB to 0 Db). While playing subwoofer test tones in Avia, I've tried to adjust this setting to match my sub to the rest of my speakers, but no matter what setting I choose, there is no difference. I can choose -20 Db, -10 Db, 0 Db, or anything in between, and the sub's level does not change one bit. In order to change the sub level, I have to go to the powered sub's volume control on the back of the sub and change it there. As a result of this problem, I have resigned myself to leaving the "LFE Level" at 0 Db, and adjusting the LFE level using the sub's amp level control. I'd much prefer, of course, to calibrate using the 3090's sub level control if possible.
    The Question
    How do I go about adjusting subwoofer level on the 3090? Do I have everything connected correctly? I have no idea why this won't work for me. I don't know if it's the connection, if this setting on my 3090 is defective, etc. I know of no other setting on the 3090 that allows the user to adjust the subwoofer level. Help! And, thanks in advance for reading this and for assisting.
     
  2. Ron Alcasid

    Ron Alcasid Stunt Coordinator

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    LFE level is not the same as the sub level. Avia's subwoofer calibration sounds are not recorded on the LFE track but are actually in the main channels. That is why LFE control has no effect. I'm not familiar with the Yamaha but there should be another menu where you can set the subwoofer level. Where did you set the levels for the other channels, it's usuallay on the same menu. In the speaker setup did you indicate that you have a sub? If in fact you don't have a sub level adjustment you can leave the LFE at 0dB and adjust the level at the sub. You aren't losing anything doing it that way, it might be preferable since you have finer control.
     
  3. Scott-C

    Scott-C Supporting Actor

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    Thanks, I had a suspicion Avia's tones may not have been on the LFE track. I've told the Yamaha that I have a sub, but there is not other subwoofer level control on the 3090 to control the non-LFE bass. I even called Yamaha directly and talked to their support dept, and they indicated the 3090 came out before they realized the importance of that feature.

    So I guess I'll continue to adjust the sub's level at the sub rather than at the receiver. I've read that it's better (sonically) to set the sub's amp level as high as possible and make adjustments with the receiver's level control, which is why I've been battling this issue.

    Well, I'll look on the bright side...this gives me one more reason to upgrade to separates soon!
     
  4. BruceD

    BruceD Screenwriter

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    Scott,

    The DVD VE (Video Essentials) does provide a separate LFE sub channel output calibration tone.

    This DVD would allow you to initially set the Yamaha LFE control to match, although I might set the the Yamaha's at -20dB and use the sub's volume to match/

    Then if you get a DVD where you think more bass is needed, you could bump up the Yamaha LFE trim.

    BruceD
     
  5. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    You are correct that there is no subwoofer level adjustment on that particular receiver (because it's an earlier AC-3 receiver, but still damn nice!). However, you can still properly calibrate with Avia. If you look in the Evaluation/Verification section, there are 6-channel pans which DO use noise in the LFE channel and should do fine for your setup.

    Here's what you need to do:

    Go into menu 1A and set the center channel to NRML. In menu 1B set rear speakers to SMALL. In 1C set main speakers to SMALL. In 1D set LFE BASS OUT to SW (subwoofer only). Then set the LFE level to its default of 0.

    Run Avia's subwoofer calibration tones and (using the gain/level control on your sub) adjust the sub so that the level of the two tones match on your SPL meter. Then, go to the verification/evaluation section and run the 6-channel pan, paying attention to the SPL meter as this pan transitions to the LFE channel. The LFE tone should match up roughly with the level of the other tones (as per Avia creator Guy Kuo in another thread here). If it is too high, you can trim it down using the LFE control on your receiver (but you'll probably want to leave it at 0). That ought to get everything in order. I would recommend leaving the speakers set to NRML/SMALL and letting the sub handle all the bass, but if you have large speakers you can change them back after doing this calibration.

    The whole thing about turning down the receiver's subwoofer output so you can raise it on the sub itself is for two reasons:

    1) Some receivers have noisy sub outs when set to 0 that can be fixed by dropping the level to about -5. The Yamahas have never had any noise problems with sub output that I know of, so no problem there.

    2) It increases the available headroom of the subwoofer's amplifier. Again, once you calibrate, no worries so long as you aren't going too far above reference level when listening.

    Hope that helps!
     
  6. Jeremy Anderson

    Jeremy Anderson Screenwriter

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  7. Wayne A. Pflughaupt

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    Scott,

    Page 38 of the 3090 manual, where it describes “Set Menu” #3 LFE Level,” says “This adjustment is effective only when Dolby Surround AC-3 is decoded.” So, the AVIA disc would have to be Dolby Digital-encoded to activate this feature, and as you noted, it would not affect non-LFE programming.

    However, whoever told you that “it’s better (sonically) to set the sub’s amp level as high as possible” is confused. The sub’s gain setting (high, low or anywhere in between) doesn’t sonically affect anything. Its only purpose is to properly match the incoming signal to the amp’s output stages to insure maximum performance (read power). That might not be the most technically accurate description, but I think you get the idea.

    For instance, the sub might be fed by a receiver’s LFE output or pre-amp outputs. Or there may be outboard processors in front of it, like an equalizer, electronic crossover, or both. (In my set-up there is not only a crossover and EQ, but also another processor providing remote-controlled level adjustment.) Any of these scenarios insure that the sub is receiving signals of unpredictable magnitude – which is why a sub has a gain control.

    The other point raised here – increasing headroom – is a non-issue. The sub’s amp only has so much output power – no one can change that. Adjusting the gain control will affect the headroom of the amp’s input stages (i.e., insure they aren’t overdriven to the point of distortion), but it won’t squeeze a single additional watt from the output stages.

    Of course, Scott, it’s fine to upgrade equipment for any number of reasons, but don’t do it based on non-existent needs created by faulty information.

    Happy Holidays,

    Wayne A. Pflughaupt
     
  8. Scott-C

    Scott-C Supporting Actor

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    Thanks guys - this is great information.
    Wayne, my description of the reasons for using the 3090's LFE level control was probably not the greatest (my quote: I've read that it's better (sonically) to set the sub's amp level as high as possible and make adjustments with the receiver's level control, which is why I've been battling this issue.").
    What I meant is that I wanted to be able to adjust the LFE level "on the fly" using the 3090 rather than get up and fiddle with the sub's volume control, and I did hear that this reduces the possibility of distortion (though as Jeremy has stated Yamaha apparently doesn't have this problem).
     
  9. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    Your master volume will still turn the sub level up and down. For instance, if you calibrate so that your speakers and sub are both at 85db (which is reference level using the Avia disc, meaning maximum peaks of 105dB and 115dB LFE)... and then you turn it down so your speakers are at 75dB, your sub will now be at 75dB too. Once you calibrate to reference, you shouldn't have to do much fiddling.

    As for adjusting bass levels from your seat, there's no way to do it with that receiver. The LFE trim only affects sound in the LFE channel, not overall subwoofer level.
     
  10. Scott-C

    Scott-C Supporting Actor

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    Sounds good. Tomorrow I'm going to calibrate the sub's level to match the other 5 speakers. Thanks for the help.
     

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