Receiver issue with calibration, or is this normal?

Discussion in 'AV Receivers' started by Eric_AP, Sep 2, 2003.

  1. Eric_AP

    Eric_AP Stunt Coordinator

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    This weekend I replaced my Onkyo TX-SR700 with a new TX-SR701 (surprisingly, CC agreed to do an even swap of my 6 month old 700 for a brand new 701 -- when I pointed out a minor defect that existed in the 700).

    Anyway, when doing speaker calibration with the new 701, I noticed what I believe may be an odd result, and wanted to get some thoughts from the people here.

    I calibrated using a digital Radio Shack SPL meter and the internal test tones (pink noise) from the 701. The results were that both my left AND right surrounds were set at the same level (+3 db). However, my surround right is only 8 feet from my listening position, and my left surround is 11 feet (actually slightly more than 11 feet), from my listening position.

    Logically, it would seem that my right surround should be set less than my left surround (at least 2 db difference or so -- based on the distance differential). However, after checking, and triple-checking my results, it kept coming up with an even match for both surround speakers.

    Note that I calibrated at the Onkyo reference level -- when you hit the test tone button on the 701, it automatically sets the volume on the receiver at 82 absolute value (or 0 relative value) -- and then tells you to adjust each speaker up or down so the SPL meter reads 75 db while at that volume.

    I also checked calibration at a much lower volume level (closer to what I listen to), and still came up with the same results -- matched settings for the left and right surrounds.

    To me, this makes it appear that the amplifier for the right surround in the new receiver may not be as powerful as it should be. Am I correct?

    Note that with my Onkyo 700, the right surround was set a few decibels less than the left surround, based on the calibration results using the internal test tones of the 700. To me, that seemed logical.

    The results with the 701 -- matched left/right surround settings -- don't seem quite as logical.

    Does this indicate a problem with the receiver (specifically the right amplifier). Or is what I am seeing considered normal?

    Note that I don't think this indicates an over productive (or excessively strong) left surround amplifier, as the results are in line with my front speakers, which are also about 11 feet away from the main listening position.

    My concern is, why do I have to bump up my right surround to the same level of my left surround, when my left surround is further away. And I did not need to do this with the Onkyo 700.

    Are these results considered within the normal range of differences between amplifiers (2 or 3 db)? Is 3 feet really not that much of a difference in distance for speakers, so I could expect these results?

    Since everything sounds fine at my calibrated settings, should I not be concerned about this apparent illogical calibration setting?

    I don't know if it makes a difference, but the 701 is a THX Select receiver -- the 700 was not. The 700 did not automatically go to a set volume level when you used the test tones -- the 701 automatically goes to a set volume level when using the test tones.

    Any thoughts?
     
  2. Eric_AP

    Eric_AP Stunt Coordinator

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    Anyone alive out there?
     
  3. Eric_AP

    Eric_AP Stunt Coordinator

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    No one has any thoughts on this? C'mon people -- throw me a bone.
     
  4. Richard Cook

    Richard Cook Stunt Coordinator

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    Maybe a daft question

    but have you checked that your surrounds are in phase with each other? This can heavily affect the apparant volume.

    If they are, I'm afraid it sounds like an output fault!
     
  5. Eric_AP

    Eric_AP Stunt Coordinator

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    The speakers are phased correctly.

    Do you think a 2 or 3 db issue, that is apparently corrected via the levels, is worth taking this receiver back?

    Wouldn't 2 or 3 db be a natural deviation, and not necessarily an output defect?
     
  6. Jim_Lan

    Jim_Lan Agent

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    could be connection or cable thing.. how about switching the speakers and see what numbers you get.
     
  7. JamieS

    JamieS Stunt Coordinator

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    Maybe I'm off base here but distance should not be the only thing that effects the level (especially with only a 3 foot difference) should it. I mean what about reflections, echos, doors curtains etc. My right rear is about 3 feet closer than my left but their levels are almost identical. This is confirmed with Avia. The internal test tones could be off I guess so you should try a disk BUT there are any number of factors that could make the level of the speakers change. If I calibrate mine with the door open on the side wall I get a difference[​IMG]
     
  8. Bob_Hammond

    Bob_Hammond Agent

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    I would try a couple of things before returning it.

    -Leave the speaker wires conencted and put the right speaker where the left is and vice versa. Rerun the tests and see what happens (Now the right amp is running the same speaker, but it is on the left)
    -Disconnect the speaker cables and swap the speakers as was suggested (Now the right amp is running the other speaker, but it is on the right)
    -Try one of the calibration disks instead of the internal test tones and see what happens

    Bob
     
  9. Eric_AP

    Eric_AP Stunt Coordinator

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    Unfortunately I can't switch the speakers (very easily). They are wall-mounted (not on stands).

    Moreover, if it was the speakers, wouldn't the difference have shown up in the calibration I did on the 700? The 700 showed results that I expected based on the distance differential.

    My real questions are:

    1. since the level controls apparently correct any deficiency -- is it something that I should be concerned about anyway?

    2. Is what I'm seeing considered within specs anyway, since we are talking a distance differential of 3 feet (not 15 feet). So perhaps 2 or 3 db difference in amps (in relation to each other) is "normal". Or is it not normal?

    The difference in calibration with my 700 was about 2 db.

    Also, I failed to mention that the speakers are about 7 feet high on the walls. So the closer speaker may fire more above me than the farther speaker. Could this explain the difference? Although I didn't see these results with the 700 (just the new 701 -- perhaps the 701 is more accurate then)?
     
  10. Steve_AS

    Steve_AS Second Unit

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    The difference is probably due to room acoustics.
     

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