REW+PEQ and Audyssey problems

[ddemeterio5]

Can anyone help me.

This PEQ stuff is driving me crazy. I took multiple mic position measurements using REW, got the average response and was able to correct a bump in 20 - 40 Hz region. Now when I ran the Audyssey setup it does not get the subwoofer distance correctly. My sub is on the front right corner. How do u measure this distance? Straight Line or Diagonal Line? I noticed that when I set the sub phase/delay at 90 degrees (12 o'clock) Audyssey will return a reasonable subwoofer distance although it will say that the sub is out of phase. Does this mean that this is the right phase/delay setting? My left and right front speakers would always be out of phase to Audyssey since it is a multi-driver design (Raw Acoustics RA8). My sub is the Rythmik Audio servo controlled sub with dual drivers (front and back).

What am I doing wrong? Does Audyssey have problems with PEQ? Should I just switch off PEQ and let Audyssey do everything?

[Kal Rubinson]

ddemeterio5 wrote:

Can anyone help me.

This PEQ stuff is driving me crazy. I took multiple mic position measurements using REW, got the average response and was able to correct a bump in 20 - 40 Hz region. Now when I ran the Audyssey setup it does not get the subwoofer distance correctly. My sub is on the front right corner. How do u measure this distance? Straight Line or Diagonal Line? I noticed that when I set the sub phase/delay at 90 degrees (12 o'clock) Audyssey will return a reasonable subwoofer distance although it will say that the sub is out of phase. Does this mean that this is the right phase/delay setting? My left and right front speakers would always be out of phase to Audyssey since it is a multi-driver design (Raw Acoustics RA8). My sub is the Rythmik Audio servo controlled sub with dual drivers (front and back).

What am I doing wrong? Does Audyssey have problems with PEQ? Should I just switch off PEQ and let Audyssey do everything?

With the correction, your PEQ is introducing a time delay which Audyssey properly detects and combines with the physical distance to insert the proper compensatory distance. This is quite common.

Kal

[ddemeterio5]

Kal Rubinson wrote:

With the correction, your PEQ is introducing a time delay which Audyssey properly detects and combines with the physical distance to insert the proper compensatory distance. This is quite common.

Kal

Are you saying that I should just ignore the distance that Audyssey returns? In your opinion is it advisable to use PEQ with Audyssey? How do you know if the phase/delay is set correctly?

[Anthony]

The easiest way to tell if the delay is correct is to wire your sub out of phase (if you can -- either an invert phase switch, or if it's a DIY sub, flip the leads to the speaker). Remeasure. If you see a deep null at the crossover point, then the mains and sub are exactly out of phase (meaning all the delays were set correctly).

Switch the phase back to normal (which will make the null go away) and enjoy.

It's not a perfect solution/test, but it works. In the old days, the way I set phase on a sub was to play an 80 Hz test tone and look at a radio shack SPL meter. With the phase inverted on the sub, you dialed the knob until you got a minimum. Un-invert the phase and the sub was all aligned with the mains. Now with the digital delays, it gets more complicated.

[Kal Rubinson]

ddemeterio5 wrote:

Are you saying that I should just ignore the distance that Audyssey returns?

No. The exact opposite. The Audyssey measurement is the acoustically correct distance.

In your opinion is it advisable to use PEQ with Audyssey?

I do not see a need for it, in general.

How do you know if the phase/delay is set correctly?

Well, you can measure it with REW.

Kal

[random username]

Anthony wrote:

The easiest way to tell if the delay is correct is to wire your sub out of phase (if you can -- either an invert phase switch, or if it's a DIY sub, flip the leads to the speaker). Remeasure. If you see a deep null at the crossover point, then the mains and sub are exactly out of phase (meaning all the delays were set correctly).

Are you sure it would be ok to do this with a servo sub? I would think you would want to flip the main leads and the servo feedback coil along with it but not sure. I'd be careful, anyway....these are a different animal.

[JimP]

I think what you're missing is that there is a difference between true physical distance and acoustical distance. Acoustical distance is usually longer on a subwoofer due to additional processing time required by the electronics to process the signal.

I'm using a SVS PB ultra 13 and a Velodyne SMS-1 subwoofer equalizer. I use REW to calculate the filters involved in the SMS-1. After all adjustments are made, the sub distance is 21 feet when the actual physical distance is something like 11 ft. Initially this bothered me as it seemed totally out of bounds. Of course it sounds better than it has at any other subwoofer distance setting.