# Useful Method Of Comparing Acoustic Devices



## TooAural (Sep 4, 2012)

I'm wondering if there is a method of comparing two broadband absorbers, for example, against one another using REW? Will the measurements actually give me relevant data?

As an example, I recently measured two broadband absorbers against each other, and took more measurements with no absorbers at all. The mic was approximately four feet from the absorber, as were the monitors (but they were far from the mic). I placed the absorber in the corner. The monitors were about four feet away from the absorber somewhat along the wall, and the mic was closer to the other perpendicular wall.

When I measured one absorber, the other absorber was out of the room. When measuring without absorbers, they were both out of the room.

The measurements I'm seeing in REW only vary about 2 dB or so along the frequency range, but they vary widely within those 2 dBs. I really can't make heads or tales out of them because one appears to do well in one area where the other appears not to do as well, and vice versa.

Do I need more absorbers to make informed measurements? Should I be placing the mic further out in the room? Also note that there really isn't a "listening position" per se. This is a tracking, mixing and monitoring room so there will be mics in various locations.

Thanks.


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## goyop (May 4, 2010)

What are you using them for?


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## TooAural (Sep 4, 2012)

goyop said:


> What are you using them for?


Tracking, mixing (monitoring), and listening. I realize I need a variety of treatment in strategic locations
but in this case I wanted to compare one trap against another.


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## robbo266317 (Sep 22, 2008)

I think the effects of panels shows up most in the waterfall plot.
You can overlay two waterfalls, one with the panel and one without, to see the differences.
Maybe you should ask this question in the REW forum.


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## TooAural (Sep 4, 2012)

robbo266317 said:


> I think the effects of panels shows up most in the waterfall plot.
> You can overlay two waterfalls, one with the panel and one without, to see the differences.
> Maybe you should ask this question in the REW forum.


Thanks. I did not know you could overlay them. I had been switching back and forth.


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## goyop (May 4, 2010)

I have set up countless rooms and systems. I would recommend some of what you are doing already - map the room and see what you have. Place the trap wherever seems best from the data.

Now the critical part is the listening tests. IF YOU DO NOT EQ YOUR ROOM WITH PINK NOISE AND SUBSTANTIAL EQ IT WILL NEVER SOUND RIGHT. As you know you cannot EQ the entire room to be flat. Get the bass trap in the best place per plots and listening tests. Then EQ the room with pink noise, etc. for your primary listening spot. Meaning put the mic where your head will normally be during recording, mixing, etc.

Unless you can have a pro do it, this is the best. Also, if you do it right you will get very close at least for where your head will be. To get a flat room requires much more.

Good luck.


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