Avia vs Onkyo Internal Sub Calibration

Discussion in 'Archived Threads 2001-2004' started by Greg Lee, Jan 8, 2002.

  1. Greg Lee

    Greg Lee Agent

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    I'm getting some weird results calibrating my new sub (SVS25-31cs) driven by PartsExpress 250W amp. This is in 6500 ft^3 room. Using the Avia sub balancing tones, with both reciever and amp volume maxed out, I can't get the sub to match the speaker level (speaker at 80 db) - its down about 3 db. But then with the internal reciever (Onkyo 696) level calibration, this max achievable level(but too-low level according to Avia) is 17 db too hot. I was expecting around 7db based on statements that the Onkyo sub tone is 10 db too low. Subjectively, the sub at this level sounds way to high.
    Any ideas on what's going on here?
    By the way - my rave on this sub will come soon. I can tell it will be pretty spectacular. But I'll withhold further comment until I get everything just right - Behringer BFD due to be delivered tomorrow!
    [​IMG]
     
  2. Pete Mazz

    Pete Mazz Supporting Actor

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    Speakers must be set to small to balance with Avia. It doesn't use the LFE channel like your receiver, it uses the bass management function to re-direct the LF to the sub, hence needing the "small" setting.

    Pete
     
  3. Greg Lee

    Greg Lee Agent

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    Thanks Pete. I had this same thought during my testing and confirmed that all speakers were set to small. So I'm afraid the mystery still exists. [​IMG]
     
  4. Matt Wallace

    Matt Wallace Second Unit

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    Hey Greg,

    Love my 696, too!

    There were threads a while back about how the Onkyo 595 and 696's internal test tones were 10db's off on the internal sub tone generator. I can't remember if it was higher or lower? I'll see if I can find it.

    Matt
     
  5. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    Yes, the Onkyo 595 and 696 are 10db too low on their internal subwoofer test tone. Also, to find reference level on the Onkyo, you have to use 80dB (which will match to Avia's 85dB). In other words, after you calibrate everything to 85dB with Avia, if you run the internal tones you should see each channel at about 80dB and the subwoofer should show at about 90dB. The Onkyo internal tones are all screwy... but you should get great results with Avia.

    You're cranking the amp and all you're getting is 80dB? Jesus... what speakers are you running with the 696? I've got a 595 pushing Polk R10's, and I can't even approach maxing out the amp without my ears bleeding.

    My only thought is that there's a phase problem here causing the mains to cancel out the subwoofer in the crossover range, making it difficult to calibrate. If your sub amp doesn't have a phase control, you might try swapping the positive and negative leads to the SVS and see if that works better.
     
  6. Greg Lee

    Greg Lee Agent

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    Let me clarify this a bit Jeremy - I easily achieve 80db with the 'regular' (5 channels) speakers - these are Home Theater Direct Level III's, which I claim 90 sensitivity. FWIW this is about '55' on the volume setting of the reciever. I have been calibrating to 80db w/ Avia.
    The problem is getting the sub level to match - even with the amp turned all the way up, and +12db boost to the sub at the reciever, the sub level on the Avia Left Main Sub balancing tone is 77 db.
    I had no problem previously getting the HTD sub to calibrate; of course it sounded crappy (hence the SVS[​IMG]) but the volume was there. And subjectively the volume is present with the SVS - in spite of the low level based on the Avia tones, it sounds way too loud relative to the mains.
    Note that the above figures are not corrected for the RS readings; at this stage of gross tuning I didn't think it mattered so much to take this into account.
    I am wondering about the 'bass boost' feature of the PartsExpress amp. I requested in the order to disable this, and I noticed that there is some handwriting on the pre-amp card where the relevant resistors must be changed, but nothing in the documentation I recieved confirms whether the bass boost is disabled. If its not, perhaps this boost could be the reason behind the perceived but not measured relative SPL.
    I wanted to add that I have experimented with the phase control (infinite on this amp, 0-180 discrete on the HTD) and maybe I have a tin ear, but I can't hear or measure any difference when changing this.
     
  7. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    While I can't tell you for sure why you're getting such low output, a handy way to check phase with Avia is this:

    In the verification/evaluation section, there are frequency sweeps for each channel. During these frequency sweeps, note the reading on your SPL meter in the crossover range (probably around 80hz). Adjust phase until you get the highest reading at around 80hz, because this is the point where the speakers and the subwoofer are reinforcing each other (hence, are in phase). Another way to find this point is to find the point of the MOST cancellation (i.e. when the meter reads the greatest dip at 80hz) and then use the opposite setting (subtracting 180 degrees, essentially).

    As for the low output, perhaps that's a question best asked of Tom and Ron with SVS. Have you tried e-mailing them?
     
  8. Ted Lee

    Ted Lee Lead Actor

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