Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 402 - AVS Forum
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post #12031 of 12050 Old 10-22-2014, 06:44 AM
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Originally Posted by Frank D View Post
Graphs look really good with both subs and Audyessy engaged, but the really question is how does it sound to you? Have you have a chance to do any extensive testing (ie watching movies etc)?
I'm the kind of guy who doesn't want to feel as though I'm missing something. I think it sounds great, I just want it to be dialed in.
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post #12032 of 12050 Old 10-22-2014, 06:51 AM
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Originally Posted by bloodta View Post
I'm the kind of guy who doesn't want to feel as though I'm missing something. I think it sounds great, I just want it to be dialed in.
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
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post #12033 of 12050 Old 10-22-2014, 12:34 PM
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Quote:
Originally Posted by AustinJerry View Post
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
Guys, excuse my ignorance but I'm really new to REW, I opened the program today and upon opening it said a newer version is available, version V5.01 Beta 23, it mentions inprovements in certain areas and certain bug fixes especially the 6dB down with calibration mic, since Jerry said that if an SPL meter is used with the calibration of the mic this 6dB down would not have an effect. So should I update to this current version, is this the version all are using? Also can you give me a link (I'm not there yet) with the adapter needed to take the pre-out measurements after connecting a RCA cable to the pre-out I want to measure, I know I'm way ahead of myself but want to have everything I need. TIA
Cheers Jeff

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post #12034 of 12050 Old 10-22-2014, 02:02 PM
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Yes, generally you should always upgrade to the latest version of REW. I don't know which cable/adapter you are talking about, but Pre-out measurements are an advanced topic, and only used in very special situations. You should focus on walking before you try to run.
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post #12035 of 12050 Old 10-22-2014, 04:16 PM
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Originally Posted by AustinJerry View Post
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
How should I set the graph limits for the ETC graph?
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post #12036 of 12050 Old 10-22-2014, 04:18 PM
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Originally Posted by bloodta View Post
How should I set the graph limits for the ETC graph?
The guidelines for each type of REW graph are in the guide.
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post #12037 of 12050 Old 10-22-2014, 04:54 PM
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Originally Posted by AustinJerry View Post
The guidelines for each type of REW graph are in the guide.
Not sure about this ETC graph, is it correct?
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post #12038 of 12050 Old 10-22-2014, 05:35 PM
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Originally Posted by bloodta View Post
Not sure about this ETC graph, is it correct?
Did you follow the guide, p. 76? What you are presenting isn't even close to the example shown in the guide, and cannot be interpreted as shown.
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post #12039 of 12050 Old 10-22-2014, 05:55 PM
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Originally Posted by AustinJerry View Post
Did you follow the guide, p. 76? What you are presenting isn't even close to the example shown in the guide, and cannot be interpreted as shown.
To be honest, I'm not seeing anything about an ETC graph on page 76. I was looking at post #2 on page 1.
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post #12040 of 12050 Old 10-22-2014, 06:18 PM
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Originally Posted by bloodta View Post
To be honest, I'm not seeing anything about an ETC graph on page 76. I was looking at post #2 on page 1.
I am not understanding. Have you actually looked at the guide? It is linked in my sig.
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post #12041 of 12050 Old 10-22-2014, 06:27 PM
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Originally Posted by AustinJerry View Post
I am not understanding. Have you actually looked at the guide? It is linked in my sig.
Im very sorry, its been a long day, I just downloaded it and see exactly what you're saying. Great guide by the way, that'll come in very handy. Thanks
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post #12042 of 12050 Old 10-22-2014, 06:54 PM
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Originally Posted by bloodta View Post
Im very sorry, its been a long day, I just downloaded it and see exactly what you're saying. Great guide by the way, that'll come in very handy. Thanks
OK, we are on track now. Please don't be reluctant to ask questions.
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post #12043 of 12050 Old 10-23-2014, 01:22 PM
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OK, we are on track now. Please don't be reluctant to ask questions.
I appreciate it. Here's my graph.
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post #12044 of 12050 Old 10-23-2014, 01:36 PM
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Originally Posted by bloodta View Post
I appreciate it. Here's my graph.
Now draw a horizontal line at the -20dB mark, and extend it out to 20ms. Any measurement that extends above this line is something that would benefit from reflection control treatments. In your example graph, there is quite a bit of work to be done.

Thanks for re-doing the graph. When we are all using similar presentation techniques, interpretation is much easier.
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post #12045 of 12050 Old 10-23-2014, 01:58 PM
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Now draw a horizontal line at the -20dB mark, and extend it out to 20ms. Any measurement that extends above this line is something that would benefit from reflection control treatments. In your example graph, there is quite a bit of work to be done.

Thanks for re-doing the graph. When we are all using similar presentation techniques, interpretation is much easier.
That was a left front speaker graph. The speaker is 2 ft from the left wall. The left wall is a knee-wall. It goes up 6 feet then it angles 2 feet to the ceiling, the angled part is untreated, the straight part is treated. I believe this untreated angled part is the culprit. I did the string trick and it didn't touch any hard surfaces.
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post #12046 of 12050 Old 10-23-2014, 02:50 PM
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There are a lot of different approaches to finding and resolving reflections. One method that I find particularly effective is I have a couple of spare 2'x4' wall treatments. I simply place a treatment temporarily in a spot I suspect might be causing a reflection, and re-measure with REW. If you are committed to finding reflections (and bass resonances using the waterfall graph), improving things can be a lengthy process. But with each improvement, the reward is a better sounding listening room.

Here is a typical measurement in my room (and mine is nowhere as good as someone's like Jim19611961!):

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post #12047 of 12050 Old 10-23-2014, 03:12 PM
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Originally Posted by AustinJerry View Post
Now draw a horizontal line at the -20dB mark, and extend it out to 20ms. Any measurement that extends above this line is something that would benefit from reflection control treatments. In your example graph, there is quite a bit of work to be done.

Thanks for re-doing the graph. When we are all using similar presentation techniques, interpretation is much easier.
After playing with my treatments, heres a graph
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post #12048 of 12050 Old 10-23-2014, 04:38 PM
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After playing with my treatments, heres a graph

To my untrained eye that second graph is much improved over the first, correct?

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post #12049 of 12050 Old 10-23-2014, 05:13 PM
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To my untrained eye that second graph is much improved over the first, correct?
I agree, it looks quite a bit better. What did you do so quickly?
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post #12050 of 12050 Old 10-23-2014, 05:21 PM
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Ha, I cheated. I made a tunnel out of my 2x4ft, 2" oc703 around the speaker, and took some measurements. Sort of a proof of concept, to see if my panels are doing their job. I noticed some had a thin black backing on them, would those be considered faced?
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