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That was some good old fashioned debating at its finest ! Agree to disagree !
 
All,
I’m sorry if I offended anyone. That was certainly not my intent. I was hoping to take some of the mystique out of acoustics. I tried to keep my arguments to the point and not let it become personal. That must have gotten lost in my fervor to defend my position.

Rich,
I’m particularly sorry we couldn’t reach a friendlier outcome.
I will go back to lurking in the background and try not to step on anyone’s toes.

Scott

Scott,

You did not offend me; you just irked me but that's O.K. I enjoy a good debate (perhaps a little too much) and I enjoyed parrying with you. I too got lost in the fervor of the argument and I can get a little vicious sometimes. Sorry about that. It's the lawyer coming out in me.

Please DO NOT go back to lurking in the background. You seem to me to be very intelligent and have a lot of good knowledge to share. Even as much as we disagreed on certain points, we agreed on lots of things and I think we both learned something from each other. It's all good. :rocker:
 
OK, So back to the topic at hand.

In my opinion diffusion is better than absorbtion because if done well you can acheive the same or better result and acoustic energy is not lost.

Here is an easy to follow plan to build what normally would cost upwards of $500 dollars each for $10. These QRD diffusors are made and sold by RPG under the name Skyline Diffusors.

http://www.pmerecords.com/Diffusor.cfm

I'm going to make a couple and will report on my experience...
 
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Thanks for posting that link Scott. I have been thinking of building diffusors to compare with the absorbers I am currently using but have not had the time.

I stared at a picture of the skyline diffusor and started to try and guess at the length of each piece and make a drawing and gave up and decided to wait until I was ready to build them. Glad I didn't spend much time figuring it out.

I will be interested to hear how you think the diffusor compares to absorption in your system.
 
To all interested, here is a link to an excellent article on acoustic treatment

http://www.ethanwiner.com/acoustics.html

This article discusses the different types of treatment, why you might choose one over the other and gives simple diy ideas and plans for building them.

Here are a couple of excerpts:

Like diffusion, midrange and high frequency absorption helps minimize echoes and ringing. But unlike diffusion, absorption also reduces a room's reverb time. This makes the sound clearer and lets you hear better what is in the recording by minimizing the room's contribution. For example, if you make mixing decisions in a room that is too reverberant, you will probably add too little reverb electronically because what you hear includes the room's inherent reverb. Likewise, if the room is overly bright sounding due to insufficient absorption, your mixes will tend to sound muffled when played on other systems because the treble adjustments you make will be incorrect.
Therefore, diffusion is used to avoid flutter echo, ringing, and comb filtering, but without reducing the room's natural ambience.

Without question, the most effective absorber for midrange and high frequencies is rigid fiberglass. Owens-Corning 703 and 705, or equivalents...


Have fun...
 
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I'm going to make a couple and will report on my experience...

I finally got around to building some QRD diffusors. Here are some pics.

A single QRD:
f962_1.JPG

Four square QRDs:
QuadQRDo.jpg

Four offset QRDs:
QuadQRDi.jpg
 
Help

Scott,
Could you take a look at my system page and tell me where the diffusers would go in my room. I have a huge picture window behind the system that needs to be there WAF. However, could the diffusers be made out of styro-foam (sp) where I could move them easily? Interested in what you think.

Doug - out
 
Scott those are cool looking, I have nod played with any diffusion. I have a lot of natural diffusion from the fireplace stones and the step outs !
 
Next up some QRD gobos.

Scott, pretty cool looking.

Where are you going to place them?

I use four Skylines on the middle of the rear wall to good effect. If anything, I feel I might have too much diffusion back there.

Cheers,
 
Sorry guys I got a little ahead of myself on the gobos. These are primarily used in studios and location recording. They could be used in the home instead of mounting but would probably never pass the WAF test.

Here is a picture of what I'm going for:
StudioC.jpg

Just kidding...
 
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Scott,
Could you take a look at my system page and tell me where the diffusers would go in my room. I have a huge picture window behind the system that needs to be there WAF. However, could the diffusers be made out of styro-foam (sp) where I could move them easily? Interested in what you think.

Doug - out

As Jonfo mentioned the rear wall is an ideal place for diffusion. Diffusion is used mainly to tame flutter echo while at the same time keeping the liveliness of the space intact.

After looking at your space I would say you probably have an over abundance of liveliness and absorption would be better suited. Try a couple of 2" thick panels directly behind your speakers. I think you will notice a drastic improvement. You may be able to match the color of your walls:

http://www.gikacoustics.com/gik_242.html
 
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