How do you level match surround back speakers

[GlocksRock]

Since Avia only allows for 5.1 calibration, how does one go about properly level matching the surround back speakers?

I tried using my internal test tones, but I don't trust them. When I calibrated my speakers using Avia, I then switched over to the receivers internal tones and found that the levels didn't match all around, the fronts showed as being louder than the rears, but I tend to trust the avia disc more than my receivers tones. What I did was just set my surround back levels to match the surround levels of the receivers internal tones, figuring that since the surruond levels were set with avia, the surround backs should be close... but since the surrounds levels didn't match the front or center's levels, I'm not sure I fully trust it to be properly matched. Any suggestions?

 

[avaserfi]

After I used my internal tones I switched over to Avia to compare and it was the same, but to test the rears I turned on PL IIx to matrix the surrounds to my rears and tested them that way. I know its not ideal, but it was the best I could come up with.

 

[GlocksRock]

I had the PLIIx on when I set the surround levels initially with Avia, would that cause the surround backs to play anything? Maybe I should recalibrate on standard Dolby Digital and then switch it over to PLIIx to see if there is a difference.

 

[jcPanny]

Speaker calibration

Glocks,
Are you using an SPL meter? You wont get repeatable results by ear. Also, subtle changes in the orientation or the location of the meter can effect the results. The differences could also be due to a pink noise calibration signal vs. a single tone in the receiver and speaker/room frequency response.

 

[AcuDefTechGuy]

Since Avia only allows for 5.1 calibration, how does one go about properly level matching the surround back speakers?

I tried using my internal test tones, but I don't trust them. When I calibrated my speakers using Avia, I then switched over to the receivers internal tones and found that the levels didn't match all around, the fronts showed as being louder than the rears, but I tend to trust the avia disc more than my receivers tones. What I did was just set my surround back levels to match the surround levels of the receivers internal tones, figuring that since the surruond levels were set with avia, the surround backs should be close... but since the surrounds levels didn't match the front or center's levels, I'm not sure I fully trust it to be properly matched. Any suggestions?

Do you mean the Yamaha's YPAO sound optimization for AUTOMATIC speaker setup did not produce the same results as using the Avia's/MANUAL speaker setup?

I would just use the Yamaha's Internal Test Tone and do a Manual speaker setup with a sound meter.

 

[GlocksRock]

Yes, I'm using an SPL meter and avia, I set all the levels to 85 DB.

Then I used not the YPAO, but went into the speaker setup and turned on the test tones and measured each of the speakers levels with the SPL meter and you would think since I just calibrated the levels with avia, I would get the same reading for each speaker, but I didn't. Now I wouldn't expect the same db reading for avia and the internal test tones, but I was getting inconsistent sound levels from the front and rears using the internal test tones. Keep in mind that all levels were matched using avia just before turning on the receivers internal tones. So this leads me to believe the internal tones aren't correct.

So what I did was just match the surround backs to the level that the surrounds were set to using the internal tones, since that's the only way to actually hear discreet sounds from the surround back speakers. So the only levels I adjusted by the internal tones were the surround backs, I left everything else calibrated the way I had with the avia setup.

Does this make sense?

 

[GlocksRock]

Maybe I should just rephrase my question... how did everyone else here with surround back speakers level match them?

 

[MDS]

The level of the tones on AVIA are higher (-20 dBFS) than the internal test tones of a receiver (-30 dBFS). If you calibrated using AVIA and 85 dB, when you play the internal test tone and measure the SPL it will be ~10 dB lower.

When you use any pink noise to calibrate levels you are setting the average level. The SPL will only equal the level you calibrated to when the level of the source you are playing is the same. Given that the average level of dialog in a movie is usually -31 dB, I think it is better to use test tones that match that level; ie the internal test tones or DVE.

Whether you use a -20 dB tone and calibrate to 85 dB or use a -30 dB tone and calibrate to 75 dB, the peak level will be the same (105 dB). The peak level is achieved when the digital audio sample is at a level of 0 dB (max).

 

[j_garcia]

Get Home Theater Tune Up, which is also by Ovation (the makers of Avia) since it has 6.1 tones.

I just use the receiver's tones, since it doesn't really matter what you use as long as you get them matched.

 

[AcuDefTechGuy]

Yes, I'm using an SPL meter and avia, I set all the levels to 85 DB.


So what I did was just match the surround backs to the level that the surrounds were set to using the internal tones, since that's the only way to actually hear discreet sounds from the surround back speakers. So the only levels I adjusted by the internal tones were the surround backs, I left everything else calibrated the way I had with the avia setup.

Does this make sense?

So first you used the Avia setup. Let's say all the channels are now at 85dB.

Then using the Yamaha internal test tones, you measured all the channels again. So now what is the SPL reading for all the channels?

If they are all 84 dB or 86 dB, etc., then you are set. But that's not the case.
If the main fronts are 86 dB and the surrounds are 84 dB, then I would set the Surround Backs to 84 dB also.

 

[GlocksRock]

The problem isn't the overall level of sound from one source to another... my issue is this... once calibrated with avia, all speakers read 85 db on the meter.

Switch over to the receiver's internal test tones, I know they aren't going to be at 85 db, but whatever, that's not the issue. Once level matched using avia, all 5 speakers, should read the same number... say 78 db. just for arguments sake, using the internal tones.

I'm getting say 78 for the front l & r 76 for the center and like 72 for the surround speakers. These may not be the actual numbers I'm getting, but are an accurate representation of my results.... so when I want to set the level of my surround back speakers, what db. would I cablibrate them to? Do I set them to the 78 db reading I get for the fronts, the 76 db. reading of the center, or set them to the same db. reading as I'm getting for the surrounds?

The problem is that the levels aren't the same for each speaker using the internal tones, even though they had just been properly calibrated using avia so I don't know how to properly match them since avia doesn't have surround back tones.

 

[GlocksRock]

So first you used the Avia setup. Let's say all the channels are now at 85dB.

Then using the Yamaha internal test tones, you measured all the channels again. So now what is the SPL reading for all the channels?

If they are all 84 dB or 86 dB, etc., then you are set. But that's not the case.
If the main fronts are 86 dB and the surrounds are 84 dB, then I would set the Surround Backs to 84 dB also.

Yes, this is basically the case, but I'm getting different readings for most of the speakers when using the internal tones... for now I have them matching the reading of the surrounds using the internal tones since thats what they are closest to.

 

[MDS]

Use the internal test tones for all channels and get them as close to 75 dB as possible. Then you have calibrated the levels for all sources - not just the dvd input (although that is usually close enough).

 

[AcuDefTechGuy]

I have them matching the reading of the surrounds using the internal tones since thats what they are closest to.

I think that's what I would do.

So now if you set all the speakers to the same level using the Yamaha test tones to 85 dB, what happens when you then use the Avia Test Tone?

Too bad you don't another source with 7.1 Surround----like a blu-ray player with 7.1 output & it's own internal test tone, etc.

As for me, I have two surround left speakers and two surround right speakers in my 5.1 HT.
7.1 HT doesn't have much use yet. Ironically, none of the current 7.1 PCM movies have impressive sounds when compared to the 5.1 PCM or 5.1 TrueHD movies.

My previous setup was 7.1HT, but I didn't get any use of my surround Backs. They were just sitting there silent with their own dedicated amplifiers on

 

[GlocksRock]

I use the PLIIx decoder with all my tv and dvd's so I get plenty of use out of my rear surrounds. But to answer your question about what happens when I cablibrate all levels using the receiver, and switch to avia, the channels aren't matched... I get the same results as earlier, but basically in reverese. I think I remember hearing somthing about avia 2, but since it's not out yet, that doesn't help me.

www.avia2.com

 

[AcuDefTechGuy]

I use the PLIIx decoder with all my tv and dvd's so I get plenty of use out of my rear surrounds. But to answer your question about what happens when I cablibrate all levels using the receiver, and switch to avia, the channels aren't matched... I get the same results as earlier, but basically in reverese. I think I remember hearing somthing about avia 2, but since it's not out yet, that doesn't help me.

So you watch movies that are encoded with Dolby Digital or DTS with just plain Dolby ProLogic IIx?
But Dolby ProLogic IIx is not for Dolby Digital, right?
Wouldn't Dolby Digital or DTS have clearer sound?

 

[avaserfi]

So you watch movies that are encoded with Dolby Digital or DTS with just plain Dolby ProLogic IIx?
But Dolby ProLogic IIx is not for Dolby Digital, right?
Wouldn't Dolby Digital or DTS have clearer sound?

Say you are watching a DTS track and you turn on PLIIx your 5.1 signal stays in DTS or whatever the source is playing, but your two rear speakers get a matrixed signal based on the original and that is what PLIIx does for you. (I do the same thing as Glocks during movies and turn PLIIx on.

Basically you get DTS+PLIIx (or XXXXX-PLIIx) which is exactly what my receiver shows when I do so .

 

[GlocksRock]

PLIIx is overlayed on top of DD or DTS, it's not like the old pro logic. You can have PLIIx on top of THX on top of DTS-ES or DD if you want.

 

[mtrycrafts]

Yes, I'm using an SPL meter and avia, I set all the levels to 85 DB.

Then I used not the YPAO, but went into the speaker setup and turned on the test tones and measured each of the speakers levels with the SPL meter and you would think since I just calibrated the levels with avia, I would get the same reading for each speaker, but I didn't. Now I wouldn't expect the same db reading for avia and the internal test tones, but I was getting inconsistent sound levels from the front and rears using the internal test tones. Keep in mind that all levels were matched using avia just before turning on the receivers internal tones. So this leads me to believe the internal tones aren't correct.

So what I did was just match the surround backs to the level that the surrounds were set to using the internal tones, since that's the only way to actually hear discreet sounds from the surround back speakers. So the only levels I adjusted by the internal tones were the surround backs, I left everything else calibrated the way I had with the avia setup.

Does this make sense?

If you level matched all 5 ch with Avia, then you cross checked the internal test tones and the back were not level with the fronts, that would indicate the internal tones are not reliable. that is why a disc is usually recommended as it goes through the whole audio signal path compared to the internal test tone that may bypass some of the total chain.

How far off were the rears from the fronts with the internal tones after you used the Avia? Was the left surround and right surround also not level between the two ch? Is your receiver THX certified?
Just level match all ch with Avia and forget it.

 

[GlocksRock]

If you level matched all 5 ch with Avia, then you cross checked the internal test tones and the back were not level with the fronts, that would indicate the internal tones are not reliable. that is why a disc is usually recommended as it goes through the whole audio signal path compared to the internal test tone that may bypass some of the total chain.

How far off were the rears from the fronts with the internal tones after you used the Avia? Was the left surround and right surround also not level between the two ch? Is your receiver THX certified?
Just level match all ch with Avia and forget it.

Yes, my receiver is THX certified, and I do believe the internal tones aren't reliable, hence my originaly question of how to properly level match the rear surrounds since Avia doesn't have surround back tones.

I can't recall exactly how far off the front and back were when using just the internal tones, but it was significant. Ithink the left and right levels were pretty close it was just the front and back that weren't good.

You say match all channels with avia and forget it, but I can't since avia doesn't have tones for the surround back.