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Strange result when measuring speaker delays

1K views 2 replies 2 participants last post by  rak313 
#1 ·
I am trying to measure/verify speaker delays and I'm getting strange results.

I have the recommended setup from the manual with a sound card. Right line out of the sound card goes to both the sound card left line in, and to the center channel analog AVR input. A RS SPL meter connects to the sound card right line in.

I have "loopback as timing reference" checked in Analysis. I set all of my speaker distances to 3ft (the min i can set it).

I made a measurement with the RS SPL meter as close to the center speaker as I could get, looked at the impulse response. I got 4.5 ms. I then I moved the RS SPL meter back about 3 ft, and measured again and got 7 ms, as I should. So this made me think I'm doing it correctly.

Now for the strange part, regardless of how I change the distance settings in the AVR, the measured delay does not change. I have tried 3 ft, and 30 ft. for the center speaker, and 3ft and 30 ft for other speakers (while still testing the center). I also tried testing the right speaker with the same result.

Now my AVR is ancient, c 2004., and has HDMI 1.0, but I was using analog inputs (for this test only). I use the optical digital SPDIF when using it for movies (I know, its time to upgrade). Is it possible that delays are only applied to digital inputs? Or am I doing something wrong.

Sorry if this has been addressed a million times already.
 
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#2 ·
If you are using multichannel inputs on the AVR there is no delay being applied. Those inputs pass to the speaker outputs without any processing.

To see the impact of speaker distance settings try using one of the other AVR inputs as; Aux, CD, TV, etc.
If you use the left (or right) channel on one of those inputs then it should work.

Be advised that delays in AVRs are normally set relative to the greatest speaker distance set. That is if the CC is the greatest distance set then any other channel will delayed by the time that it takes to travel the difference in distances of the 2 setting. When the speaker distances are equal (at any distance value) then there is no need for any delay between those speakers and none will be added.

Example:
Set all channels to 5ft.
Use AUX left input for REW input. Measure - you should find no AVR added delay.
Change the CC distance to 10ft. Now the FL is 5 ft closer than the CC distance so there should be a delay added to a new FL measurement of about 4.4ms.
 
#3 ·
1)I started with CD inputs, and saw the same thing.
2) I realize it will only delay re the longest distance.

I tried 3ft and 30 ft. in the center, and in the right (4 combinations), while measuring the center, (and later on measuring the right). Still made no difference. Its kind if mute now, as I just bought a new Marantz 7702.

Thanks for the reply!
 
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