# waterfall graph before and after initial room treatment - opinion request



## squareknot (Jul 31, 2017)

Hello, I'm new to this forum in that I knew it since a long time (since I discovered REW through a GENELEC product specialist) but only now I began experimenting with acoustic treatment.
I use a room in my house as a home recording studio, it's a rectangular room and it had a very bad acoustic performance. I finally managed to buy some absorbing panels and I began treating high frequencies.
I managed to do a before / after test with a Dayton Audio EMM-6 measurement microphone connected to my RME fireface UFX and to my GENELEC 8040 nearfield monitors.
Here is the result in the waterfall diagram, considering my present aim was to reduce reverberation on high frequencies.
I'd be really glad if anybody could give me an opinion. I'm also very open to discussion regarding panels type and placement strategies.

Thank you!

SK


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## JohnM (Apr 11, 2006)

The scaling is a little unusual on those graphs, they cover a very narrow dB range. Worth having a quick read of the post on scaling graphs.

To see effects of the panels at high frequency you are probably better looking at the 1/3 octave RT60 graph than the waterfall, that will better show how decays have changed above the bass range. Probably worth attaching the mdat file for your measurement, easier to look into it that way.


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## squareknot (Jul 31, 2017)

Hello thank you very much for your answer, I had read the guideline but I thought it was just for SPL curves so I just respected the 800 pixels recommendation, anyway thank you for your suggestion I'll keep it for the next time. Here are my mdat files though, I must say I've done it with both speakers even if I've read it should be made just one speaker at a time, but I wanted to be able to compare the second measurement with the initial one I had recorded in february.
Finally I had to do again the measurement tonight because REW saved a corrupted measurement this afternoon, I attached all the three of them if anybody is able to open it anyway.

Thank you!


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## squareknot (Jul 31, 2017)

I think I also managed to prepare the graph in the correct scale and size.

Thank you!


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## JohnM (Apr 11, 2006)

That really is a tough room. The panels have helped at the upper end, above 1 kHz the decay times are OK now. Below that still quite lively, and at the low frequency end there are some huge resonances. To deal with them you will need large areas of very thick treatments (rockwool, for example). Careful placement might help reduce the effect of some of the peaks, if the room is rectangular you can use the REW room simulator to see what different listing and speaker positions do to the response.


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## squareknot (Jul 31, 2017)

I had tried replying yesterday but my message went lost I believe.. thank you for your really interesting graph, that would be nice if you could tell me how you obtained it. Besides if you took part to the development of REW I send you my compliments for a valuable and useful tool.
Concerning rockwool I'm quite concerned about health implications, since the room is part of the apartment where I live.. I started treating with 12 600 x 600 mm 50 mm thick piramidal melamine foam panels..


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## JohnM (Apr 11, 2006)

Bass traps of any sort would almost certainly help. To generate the RT60 graph just click on the RT60 button in the graph selector that runs above the graph (the controls are discussed here and here). I captured the image above from the RT60 graph in the Overlays window (click the Overlays button to show that). In the graph controls I selected Topt (REW's optimum estimate of the RT60 time) and one-third octave bands.

I'm the only REW developer


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## squareknot (Jul 31, 2017)

Well pretty impressive!

I think REW grew up as some sort of reference point in the area of room acoustics! Here in Italy every professional in acoustics I heard talked well about it..!

I think I'll consider a donation to your account on the main REW site because your work is really worth it, and you were very kind to promptly assist me with my tests.

I'm just a novice in room acoustics but it is a fascinating discipline and my first attempt with those few panels was awarded with the results and further comforted by REWs data.

Is there in the forum a specific place where to discuss room treatment stuff? I didn't seem to find an explicit sub section, room EQing seems very popular but it's not my thing


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## JohnM (Apr 11, 2006)

Yes, there is the Home Audio Acoustics forum. There is also a lot of discussion of treatments for studios on Gearslutz.


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