The distance readout is wrong

[asylum]

Hi all, i,ve ust started using REW, and i think i,m gonna really enjoy it, once i get
to know how to use it, i think i have it set up right, but the distance readouts are way off
from speaker to mic, in the region of a few feet, its probably soemthing stupid, all help
appreciated,
regards jim

[atledreier]

Just remember that REW will read total acoustic delay and translate this to distance. if your system introduce electrical delay that will read as longer distance than your measured distance. What you need to worry about is getting the REW-measured distance equal, that's the 'real' distance.

[asylum]

sorry i dont understand what you mean, but its out by about feet, which i guess is about 3 ms, which is alot i think, i dont i have 3 ms delay in my system, the stimulus signal is going from REW on my laptop to an rmw fireface AD -apogee rosettaDA - adam powerd speaker all 44.1, i work with this setup all the time, and have never noticed a delay, thanks for the reply.

[brucek]

i dont i have 3 ms delay in my system

You of course, must use the Left Channel as reference feature to use the System delay feature.
To test the accuracy, it's best to put a simple loopback cable from right channel line-out to right channel line-in (in addition to the Left Channel loopback required to use the Left channel as reference feature).

Then do a sweep from 0-10Khz. The result should be a delay of ~ 0.0ms +/- 0.1ms. Also note that the lower the bandwidth, the less accuracy you'll enjoy. If you only swept to 100Hz, you may get a system delay result of 1.0ms +/-0.3ms. This is over a foot. So you will get most accuracy with full range.

Running that loop test will show you the no delay result for reference and so if the problem is with the laptop or your system or whatever...

brucek

[asylum]

great thanks i'll give that a go?