Using REW to calculate speaker distance but not having any luck

[Greg C]

I can't seem to get repeatable results using REW to determine time delays for my speaker distances. I measured all my speakers to get time delays in REW, then entered those results into my Preamp. I expected results of repeated measurements on any single channel to at least come close to one another but they are all over the place. I've had variations as much as 1/2 meter. Surely I'm doing something wrong. I use the left front for a reference. I followed a guide I found on the MiniDSP site. I can't post a link to that guide according to the forum rules.
I'd appreciate some guidance.

Thanks,
Greg

 

[sam_adams]

If you set the 'Adjust clock with acoustic ref' under the section 'Impulse Response Calculation' in the Analysis preference tab, this will compensate for possible timing differences in the input and output clock rates:

One-half meter is about 1.5 ms easily within the range of possible device clock differences.

 

[Greg C]

Thank you for your suggestion, sam_adams. I checked and unfortunately that box was already ticked. I did some more reading last night and discovered that perhaps my testing volume was too low??? I'll try it again sometime today and see if I can stumble onto something. I'll report back.

Thanks again,

 

[Greg C]

How close should repeated measurements of any speaker distance/delay be?? What might one expect in terms of precision and repeatability??
I tried again today after playing with the settings and volume level. Playing is an accurate term because I'm way out of my wheelhouse. Still no repeatability.

 

[jtalden]

At my cluttered desk [5$ Mic flat on desktop and a little off-center under the monitor. Directional desktop speakers on rear corners and raised up 6 in.).
10 Measurements of right speaker using the left as the reference resulted in:
6 fell on top of each other (red, reference group)
3 fell ~0.4 ms more delayed (blue)
1 fell ~0.2 ms offset (green)

This is trivial for 80 Hz XO timing and marginal for a 200 Hz XO timing and no good at all above that.
I assume repeatability would be better in my AV area with cleaner direct sound to the mic but have never tested acoustic timing there. I normally use loopback timing.

This is just one quick data point.
Let us know what you get.

 

[Greg C]

I guess the whole exercise was moot anyway. I Just ran Audyessy and it changed all my settings in Manual setup, so any setup I enter will be over ridden with Audyessy anyway. If I want to change anything I’d have to edit it with the Audyessy app, save it and load it.
Thanks for the response!