Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 678 - AVS Forum | Home Theater Discussions And Reviews
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post #20311 of 20312 Unread Today, 06:09 PM
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This is a trick Markus showed me. It works very well for time aligning. I just picked the left or right channel and set a crossover (I use 80Hz to minimize IMD), then gradually increased my sub's distance checking the attached excess group delay plot each time.

After that, I changed my crossover slope frequency on my XMC-1 and did it all over again! Then I picked the best REW plot (probably had 20 plots) that had the most coherent phase and flattest excess group delay and lastly flattest amplitude. You can't just use amplitude at the 3dB crossover point by itself (I mean what if there was a dip there due to the room, and you kept trying to correct this dip by changing distance, never would, but you would likely pass the point of proper time alignment).

My room is very well treated as the attached excess delay plot is with no room correction software engaged (the other plots are with dirac engaged though).

For me, I found the best possible results by doing the above, then letting my PC do the room correction using the Dirac Live software. This means Dirac sees the left speaker + sub for the left channel so Dirac corrects everything together. I know this is backwards from every processor I've had, but man does it measure better.

The blue plots are from when I just let the XMC-1 and Dirac do everything, and it wasn't too bad, but there's a definite improvement in phase coherence and the waterfall plot (and even amplitude).

I still have a room issue near 200Hz (even though the amplitude is fixed by Dirac, Dirac did it at the expense of phase), but it is the most accurate bass I have ever heard/felt!

Quote:
Originally Posted by EndersShadow View Post
Ok I think the graphs are funky and won't show stuff right.

For taking a measurement with ASIO is it best to do it L + Sub, R + Sub, C + Sub, L & R + sub? What's the standard?

I think I may be mixing and matching my measurements I.E. one set with Center and Sub, the other w Left and Sub....

I'm trying to work on integrating the sub with my L/R best so which speakers should I be using to measure and adjust with?
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Last edited by etc6849; Today at 06:22 PM.
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post #20312 of 20312 Unread Today, 06:44 PM
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Use the Java sound drivers in REW preferences. You should see Streaming show up in the Dirac audio processor (DAP) when REW is doing the sweep. Also I wouldn't output the DAP to your ASIO soundcard driver. This is far to buggy (for me too) and not what's recommended when I read the Dirac Live manual.

Also, just spend your $750 on some cheap fabric and bulk 4'x2' 4" OC 703 insulation, and then just wrap them with burlap making 4" and 8" (two 4" pieces back to back). Later, you can stack two 8" pieces together for even more bass correction. I personally like having Dirac, but my system never sounded perfect (e.g. jaw dropping and real) until I had a lot of bass traps and absorption on the walls (ceiling and walls at the first reflection points). No reason to buy ready made bass traps with frame as they are a joke in comparison to what you get with a bulk OC 703 order.

Quote:
Originally Posted by GuidingGod View Post
Thanks for taking the time Jerry, much appreciated. Speaker placement unfortunately is dictated by the lady of the house so sort of non negotiable. The sub though is small and can be moved around if needed. I think a second sub of the same type will be the next splurge when funds allow.

In the meantime, I downloaded Dirac Live free trial for PC (since it is the main source for playback in this setup, containing all bluray rips and flac music et al). I ran through the setup, did the measurements and saved the target curve filters. There is a definite improvement in sound when listening to music...specifically, some vocals sound like a veil was removed. Secondly, there is some lessening of echoing (resonance? possibly because of the hard floor surface?) that I felt I was hearing before. Not sure how much is user bias but I really do feel I'm hearing an improvement.

A couple of questions:
(1) How do I do a reading in REW now, with Dirac filters engaged? I want to see what difference it has made on the graphs. But when I use Dirac as the default sound output in windows, REW refuses to measure anything, it just shuts down. I set the Dirac to output to ASIO. (attaching a couple of screenshots)

(2) Will spending funds, when they are available, on room treatments pay more dividends, more so than spending them on other things like Dirac for this setup, in your opinion?

Thanks again for taking the time.

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Last edited by etc6849; Today at 06:54 PM.
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