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Old 12-11-07, 02:31 PM   #10 (Link)
 
DrWho
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Re: Time aligning with REQ?


Quote:
brucek wrote: View Post
So you could align the mains to the sub and then the center to the sub and so on.
That doesn't work. The sub is bandwidth limited so the peak in the Energy Time Curve is going to be naturally delayed....aligning the peak of the other speakers to that of the sub will delay all of the other speakers for too long, which is going to introduce phase cancellation in the crossover passband.

The guys over at Syn-Aud-Con had a great article describing this limitation of the ETC. I'll see if I can't find it and post it. The nice thing about it is that it provided a way around it.

Since it seems you're more worried about the delay through the crossover, a very easy way to measure delay would be to measure your crossover directly. Download Audacity, which is a free multi-channel recording tool (or pick any stereo recording device of your choice). Then what you do is create a sound sample of a square wave, or click track or whatever....something that has a vertical rise at the beginning. Burn this sound to a CD and play it through your system. On the left channel of your recording device, record the direct output from the CD. On the right channel of your recording device, record the direct output from the crossover. You will first see your sound show up on the left channel and then later on the right channel. The time readout of your software will be able to give you the time offset. It'll probably take you 15 minutes to get everything set up and ready to test, and then just a few seconds for every channel of your crossover.


-Mike Bentz
~It's all about compromise~

"It's territorial with the soundboard. So you're mixing and some dude comes by spewing opinions and trying to turn knobs. It's akin to going up to an artist and painting over his unfinished masterpiece. You just want to shove your paint brush up his nose and throw the soundboard out the window!"

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