# RT60 plot, and do I need more traps?



## SRR (May 4, 2008)

The room is 19'L x 12'W x 8'H, I have 2'x4' traps that are: four 6 inch thick ones, two 4 inch thick ones, and two 2 inch thick ones. I also have some foam on the walls at the first reflection points totaling 4 feet by 3 feet, on each side. So do I need more traps, or should I get a Feedback Destroyer first?


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## bpape (Sep 14, 2006)

Can you post your setup, the frequency response, and the waterfalls? RT60 really isn't terribly applicable in small room acoustics.

In general, the amount of treatment you have sounds OK (I'd skip the foam though. The last thing you need is a ton of HF only absorption). I'd want to see how it's laid out where your speakers are in relation to boundaries, etc.


Bryan


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## SRR (May 4, 2008)

Waterfall coming up in next post.


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## SRR (May 4, 2008)

Waterfall.

Equipment is Onkyo 805, speakers are now QSC ADS82's, In wall sides and rear.


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## SRR (May 4, 2008)

Clickable thumb nails:


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## SRR (May 4, 2008)

Oh and here is the full range with 4 mic positions averaged. 1/3 octave smoothing.


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## bpape (Sep 14, 2006)

I suspect moving a couple of the 4" panels to the rear wall would be of benefit down lower in the bass rather than along the front wall. 2" panels on the front wall would be fine most likely.

Bryan


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## glaufman (Nov 25, 2007)

That waterfall is showing a bug in REW... switch the freq axis to LOG mode.


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## SRR (May 4, 2008)

Updated to log...

Looks much different. :yikes:

Is it bad doc?

Wife doesn't really want more traps, but I am game!!! :innocent:


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## glaufman (Nov 25, 2007)

EEK! Change it back! Quick! 
Well, that waterfall is more believable, it follows the shape of the FR. How unfortunate.
To me, more, bigger traps are almost always a good thing, but how effective they'll be at these freqs I'll leave to Bryan. (if broadband, it'll depend on how big they are).
Have you played at all with positioning?


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## SRR (May 4, 2008)

Positioning the subs as they are now, gives me the lowest response, the model on the subs is BIC's H100. I thought that getting ok response to 18-20HZ I am doing good. Moving them up along the side wall they only go down to 25Hz, if I have a graph of that I will post it. But from what I remember it might have been more flat.

Doh, just remembered why I haven't posted that, I took it with a RS meter, VS. my calibrated ECM8000.

Hmmm, looks like tomorrow I will be running more plots. Or the next day. or the day after...lol.

And yeah at one time I had a Epik Knight, without ANY traps just the foam, and putting in the traps did little for much under 100Hz maybe even higher but I am not exactly sure on that, it was two years ago.

Why I went from a Epic Knight, to BIC H100 twins, well I needed the money from the Epik, to pay a double mortgage payment, and well I didn't want to live with out subs to long, so I sprang for these because I could afford them, cause I am in a duplex (Knight gave us a couple visits from the police :hsd and I am sort of hoping that I have less problems in that area. Oh and the size difference, yesh!!!


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## glaufman (Nov 25, 2007)

SRR said:


> Positioning the subs as they are now, gives me the lowest response, the model on the subs is BIC's H100. I thought that getting ok response to 18-20HZ I am doing good. Moving them up along the side wall they only go down to 25Hz, if I have a graph of that I will post it. But from what I remember it might have been more flat.


It's sometimes a tradeoff, in a corner can give you more boundary gain, but can also excite more modes. Personally I have a thing against putting subs in corners for the flatness reason, in my mind it negates the benefit of having multiple subs in different locations. If you place them out from the corners, one can fill in gaps left by the other due to modal influences, but if they're both in corners the chances are greater that they'll both excite the same modes.


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## bpape (Sep 14, 2006)

Try the 2 on the rear wall. Make sure you get them up to be more centered on ear level. Set them on a chair or whatever temporarily. You might try the 6" ones.

Bryan


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