REW V5 Tips - Page 11 - Home Theater Forum and Systems - HomeTheaterShack.com

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post #101 of 114 Old 05-31-16, 03:15 PM Thread Starter
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Re: REW V5 Tips

Pink PN is probably a better solution for real time EQ, with the RTA on an RTA setting rather than Spectrum. No averaging required.
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post #102 of 114 Old 06-01-16, 08:17 AM
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Re: REW V5 Tips

Thanks for noise suggestion.

Would the sweep or the noise RTA be less influenced by the contribution of room reflections? And suggestions for appropriate time windows?

Thanks.
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post #103 of 114 Old 06-01-16, 05:52 PM Thread Starter
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Re: REW V5 Tips

To window out reflections requires an impulse response, so a sweep measurement. The width depends on the time to the reflection(s) to be removed, which in turn depends on how far you can place the speaker from all surfaces (including floor and ceiling). Best measuring suspended outside for an approximation to anechoic when suitably windowed.
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post #104 of 114 Old 06-05-16, 12:32 PM
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Re: REW V5 Tips

Hi ... sorry if this has been asked elsewhere, I've been searching and can't find it. How can I use REW to set the speaker distances on my surround pre-amp and also to make sure the polarity of my center speaker is right? I did the loopback calibration, and measured group delay (see attached graphs of left speaker and center). Not sure if this is close enough?
Thanks
Tom
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post #105 of 114 Old 06-05-16, 03:43 PM
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Re: REW V5 Tips

OK, I didn't have loopback as a timing reference enabled in the analysis section, so did that and looped back the 2nd channel (btw - any way to verify that the loopback is actually working? When I run soundcard calibration it always uses the measurement channel).

Now looking at the IRs for center and left speakers (with loopback reference timing enabled), here's what I get. Not a clear peak ... and it seems to start around zero for the left speaker, but quite negative delay for the center ... not sure what to do with that?

Thanks
Tom
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post #106 of 114 Old 06-05-16, 05:58 PM Thread Starter
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Re: REW V5 Tips

There is a thread on checking polarity here.

If you use the % FS scale the peaks will be easier to see. The centre measurement looks like there are two speakers playing as there are two peaks of the same level. When using loopback as a timing reference it would be very strange to have negative timings assuming outputs and inputs are on the same soundcard - difficult to see how a signal through the speaker could arrive earlier than a direct wired connection at the soundcard. Perhaps you should explain exactly how you have things wired up, preferably by starting a thread just for this since it doesn't really have any to do with the REW V5 tips.
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post #107 of 114 Old 06-05-16, 06:07 PM
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John - thanks for the input and the link, very helpful. Let me start a separate thread ...
Thanks again
Tom
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post #108 of 114 Old 03-03-17, 06:39 PM
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Re: REW V5 Tips

From my Audyssey on vs off graphs below, do you expert think the results are good enough, or more information is needed? Thank you in advance.
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REW V5 Tips-3.3.2017_7ch_audyssey_off.jpg  

REW V5 Tips-3.3.2017_7ch_audyssey_on.jpg  

REW V5 Tips-3.3.2017_7ch_audyssey_on_waterfall.jpg  

REW V5 Tips-3.3.2017_7ch_audyssey_off_waterfall.jpg  


Last edited by SHNEE; 03-03-17 at 06:51 PM.
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post #109 of 114 Old 03-04-17, 09:14 AM
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Re: REW V5 Tips

Hi shnee(I know you by another name lol). By "good enough", do mean flat enough? I've never known the phase information to be terribly useful, but the freq graph looks really nice to me. Curious, why you're measuring in 7ch stereo. I would think that could add combing, or other phase issues that would be irrelevant during actual listening. I would also prefer a house curve over flat.
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post #110 of 114 Old 03-04-17, 09:59 AM
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Re: REW V5 Tips

Haha, I think I know you from the other forum too. Thanks to REW, I have collected numerous graphs for my several setups including the two channel ones. I thought the HT setup was good enough based on the freq response graphs, so I have been too lazy to do try any manual adjustments after Audyssey. So yes, to me good enough means flat enough, though I do understand the waterfall graphs should be looked at too to see that decay times are not a problem. That may change because I have just been told by TheWarrior that I should pay attention to the phase graphs as well. That's something I never thought would make much difference in a real room playing real music, 99% movies in that room too and that's why I focused on getting the flattest response for 7 channel. I used 7 CH stereo for taking measurements only.

I thought maybe someone like JohnM or other resident experts here wouldn't mind enlightening me on whether the phase graphs indicate something of significance. I always assumed Audyssey had to do the balancing act, such that something could be made worse but the overall results would be better. All I can see from my REW graphs is that it has improved the frequency response from 10-110 Hz, a touch worse between 115-200 hz and didn't do much above 200 Hz. I don't know if it made the phase and decay times audibly better or worse as I am not 100% sure that I interpret the graphs correctly.

Last edited by SHNEE; 03-04-17 at 10:08 AM.
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