# Room Acoustic's



## colinmac (Apr 3, 2012)

Friends Finally, I'm trying to understand measurements I've taken of an all purpose live! room.
Room size; L 5 meters x w 3.4 m x h 3.m. The room is heavily carpeted floor and 1m up the walls.
I can see modes problems around 60-100Hz & 400-800Hz with bad attenuation from 5kHz onwards.
My response is to deal with low range & mid with broadband trapping..! To gain back the sparkle frequencies
I'm planning to use curved plywood diffusers on the walls with some as clouds on the ceiling.
Reading are Centre, Right, Left of room microphone height 2 meters.

Tools used, Microphone earthworks QTC30, Sound card Metric Halo UNL-2. Sound cal should be loaded
but I couldn't find a calibration for the mike.
If there's a friendly expert who can throw some good advise will be much appreciated.
Thanks
Colin
file attached hopefully..!


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## bpape (Sep 14, 2006)

Just understand that diffusion cannot add any energy back into the room. Once it's gone, it's gone. You might try a membrane of some sort over some of the excess absorption outside of the reflection zones.


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## NBPk402 (Feb 21, 2012)

bpape said:


> Just understand that diffusion cannot add any energy back into the room. Once it's gone, it's gone. You might try a membrane of some sort over some of the excess absorption outside of the reflection zones.


Would it work to make some wood slats to go over the sound absorption areas he has to diffuse some of it?


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## bpape (Sep 14, 2006)

That's one option though obviously it will take say 2x as much as just covering some with a membrane. Plus with a membrane you can somewhat control what frequency the absorption starts to roll off.


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## colinmac (Apr 3, 2012)

I agreed but I have a plan. Reflecting high frequencies back into the room
using convex plywood lacquered sheets. This will give me an option to perforate
a percentage of surface area if weird things occur. Suck it and hear..!


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## eclipse911t (Jan 8, 2013)

You have about a 230 DB range on your waterfall plots. Can you please change that to 50 DB and repost?


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## colinmac (Apr 3, 2012)

*Re: resize waterfall*

I hope this is what your looking for, still on the learning curve.






















colin


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## eclipse911t (Jan 8, 2013)

That is a range of about 120 DD. You're getting closer to 50.


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## colinmac (Apr 3, 2012)

*Re:resize 70 dB*

keeping you in the picture.























50dB would eliminate peaks.
Still learning..!


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## colinmac (Apr 3, 2012)

the suspense is killing me 50dB as requested.






















colin


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## eclipse911t (Jan 8, 2013)

You're going to hate me. How about 20 db up to 70.


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## colinmac (Apr 3, 2012)

Why not, here to help. Good practise. I've given an extra 4.6dB just in case..!
























colin


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## eclipse911t (Jan 8, 2013)

And just for your info:

http://www.hometheatershack.com/forums/rew-forum/934-please-read-posting-graph.html


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## eclipse911t (Jan 8, 2013)

It looks like this may be something you can fix with bass trapping to alleviate the ringing in the LF.

With waterfalls, I normally am looking for around a 30db drop in the standard 300ms window and trying to trap things down to 200ms or less with the exception of ULF.

Great links if you want to learn more.
http://realtraps.com/art_measuring.htm
http://ethanwiner.com/acoustics.html


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