You may find the following links helpful. They are detailed explanations of some of the idiosycracies of Avia by it's author, Guy Kuo:

Guy Kuo on Subwoofer Calibration
Guy Kuo on Bass Management (scroll down about half way).


Mr. Kuo explains how the bass mangement settings interact with the speaker calibrations. The second one also has some excellent video calibration information.


Craig

 

Quote:

Originally Posted by mbroadus At the beginning of the calibration using HK's test tones, I attempted to adjust speaker levels using my ears and found that my center speaker ran 2-3dB hotter than my mains. I believe this is normal? My FR & FL mains were matched evenly. For my next calibration experiment, I'm going to attempt to adjust speaker levels using ears and the HK test tones and Avia disk. I think I have the subwoofer under control. I calibrated it when using Avia the first time but still may need some fine tuning with the new measurements.

Good luck!

 

Quote:

Originally Posted by umr Most of the SPL meters used on this forum are also directional to some degree. This makes accurate measurements a problem at any fixed position. If your capsule is larger than about 1/4" your SPL meter is going to be at least somewhat directional. I find that it is possible to come within +-0.5 db on the surrounds and mains with a good set of ears alone. I would use the SPL meter to get it close and fine tune by ear with band limited pink noise like that found on Avia. Adjusting the subwoofer is much more difficult. I find that a combination of sweeps and PRBS/MLS test signals measured with a reference grade microphone and analyzed with a waterfall chart gives me the best results with a subwoofer. I would also follow this up with a final tweak by ear based on reference material. The problem here is that the frequency response is narrow and frequency response anomalies can play havoc with a simple SPL measurement. This is very difficult to analyze without good test equipment.

At the beginning of the calibration using HK's test tones, I attempted to adjust speaker levels using my ears and found that my center speaker ran 2-3dB hotter than my mains. I believe this is normal? My FR & FL mains were matched evenly. For my next calibration experiment, I'm going to attempt to adjust speaker levels using ears and the HK test tones and Avia disk. I think I have the subwoofer under control. I calibrated it when using Avia the first time but still may need some fine tuning with the new measurements.

 

Quote:

Originally Posted by mbroadus I also trust the avia test tone results more so than HK's but I like the sound of the new calibrations, FL= +8, C= +6, FR= +8 @ 75dB MV=-15, than the previously calibrated Avia results, FL= -2, C= -2, FR= -2 @ 85dB MV=0. Could my measuring technique be to blame? During both calibrations, I was sitting in my normal position holding the meter head level while taking the readings. Would a tripod be more beneficial and provide more accurate results?

Most of the SPL meters used on this forum are also directional to some degree. This makes accurate measurements a problem at any fixed position. If your capsule is larger than about 1/4" your SPL meter is going to be at least somewhat directional. I find that it is possible to come within +-0.5 db on the surrounds and mains with a good set of ears alone. I would use the SPL meter to get it close and fine tune by ear with band limited pink noise like that found on Avia.


Adjusting the subwoofer is much more difficult. I find that a combination of sweeps and PRBS/MLS test signals measured with a reference grade microphone and analyzed with a waterfall chart gives me the best results with a subwoofer. I would also follow this up with a final tweak by ear based on reference material. The problem here is that the frequency response is narrow and frequency response anomalies can play havoc with a simple SPL measurement. This is very difficult to analyze without good test equipment.

 

Definitely use a tripod or something to hold the meter.

 

Quote:

Originally Posted by umr They should be similar. The results may vary because Avia uses properly band limited pink noise while the receiver may not. There may also be differences caused by different techniques. Avia and The 5.1 Audio Toolkit are the only sources I trust for setting channel levels properly.

I also trust the avia test tone results more so than HK's but I like the sound of the new calibrations, FL= +8, C= +6, FR= +8 @ 75dB MV=-15, than the previously calibrated Avia results, FL= -2, C= -2, FR= -2 @ 85dB MV=0.


Could my measuring technique be to blame? During both calibrations, I was sitting in my normal position holding the meter head level while taking the readings. Would a tripod be more beneficial and provide more accurate results?

 

Quote:

Originally Posted by cherry ghost Someone please correct me if I'm wrong, but something seems off here. The speaker levels in these two should be very similar.

I would expect that the relative settings would be similar, but I would go with the results from Avia, just because I don't really have any experience with the HK test tones. I know that there was a pretty big difference between DVE and the test tones in my old Yamaha...

Quote:

Originally Posted by mbroadus Does this mean that calibration at 85dB with master volume (MV) at 0 is going to be louder that calibration at 75dB with MV at -15?

I may be wrong here....but I would think that the resulting loudness would be similar between the two calibrations (85db @ 0 vs. 75db @ -15). You would just have more headroom on the volume dial (which may or may not be a good thing) in the case where you calibrated to -75db @ -15. Yeah?


Scott

 

Quote:

Originally Posted by cherry ghost Someone please correct me if I'm wrong, but something seems off here. The speaker levels in these two should be very similar.

They should be similar. The results may vary because Avia uses properly band limited pink noise while the receiver may not. There may also be differences caused by different techniques. Avia and The 5.1 Audio Toolkit are the only sources I trust for setting channel levels properly.

 

Quote:

Originally Posted by mbroadus Last night, I calibrated using the HK receiver test tones With master volume at 0 measured to 75dB: FL= -5, C= -8, FR= -4 The night before, I calibrated using Avia with master volume at 0 measured to 85dB. Results were FL= -2, C= -2, FR= -2.

Someone please correct me if I'm wrong, but something seems off here. The speaker levels in these two should be very similar.

 

Quote:

Originally Posted by ssteel01 All three should be valid...it's all about calibrating the speakers relative to each other. Whether they're calibrated to 75db at -15db on the receiver, 75db at 0 on the receiver or 85db using Avia shouldn't really be an issue. It'll just change where you set the volume on the receiver when you're listening to stuff. Hope that helped. Scott

Thanks for the response. Does this mean that calibration at 85dB with master volume (MV) at 0 is going to be louder that calibration at 75dB with MV at -15?

 

All three should be valid...it's all about calibrating the speakers relative to each other. Whether they're calibrated to 75db at -15db on the receiver, 75db at 0 on the receiver or 85db using Avia shouldn't really be an issue. It'll just change where you set the volume on the receiver when you're listening to stuff.


Hope that helped.


Scott