# Room Acoustics...need help for analysis



## nergenek (Dec 21, 2014)

Good day to ALL :wave:

I am new in the forum ( http://www.hometheatershack.com/forums/welcome-member-introduction/111530-hello-central-europe.html ), not new in the high-end audio but new in room acoustics...

My grand children are growing and starting quickly to be very interested by any equipment around...so I was obliged to take a radical decision by moving my high-end stereo gear from our living (65m2) to an upstairs' room (3,5m x 4,5m) with a sloped ceiling under the roof...The room is plenty of cupboards as I also combined my office with the music listening function and I believe that the cupboards filled in by books and files are also playing "bass trap" roles when placed in the corners but also "diffusor" roles when placed at the first reflection points...

After finding the right places for the speakers and the listening point I am rather satisfied by the sound and the soundstage but as any audiophile I am driven by the feeling of trying to find the Nirvana...being an engineer is also pushing me to have some scientific explanations...that's why I am here and that's why I purchased a minidsp umik-1, I downloaded REW and made my first measurements...

Pictures of the room are attached.

I am also trying if some "acoustic harmonisers = bass trap + diffusor in the same column", namely DAAD4 and DAAD3 from Acustica Applicata borrowed from my Belgian dealer and placed at the different available places in the room to discover if they have a real effect or not ?

Info about DAADs can be found here : http://www.acusticaapplicata.com/daad.php?lang=eng

The SPL and RT60 results placing the mike to the listener's ear position are attached.

The .mdat files are also attached in message #3 below.

The green drawings are with 2 x DAAD4 and 2 x DAAD3 in the room, the brownish drawings are without any acoustic treatment...

So my first questions to the gurus of the forum are :

*Do you think that the DAADs are doing any positive or negative contribution to my room ?*

*Do you think that I need any particular treatment by looking to these measurements ?*

Many thanks in advance for your valuable help :help:

Greetings from Belgium,
Nuri


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## JohnM (Apr 11, 2006)

Not the best sub-forum for this post, I'll move it to the Home Audio Acoustics forum. It would be good to attach the .mdat file for your measurement so people can see other views of the data, such as the waterfall and the unsmoothed low frequency behaviour.


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## nergenek (Dec 21, 2014)

OK thank you for your help...
The related .mdat files are attached...


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## JohnM (Apr 11, 2006)

The peak around 52 Hz is reduced a little and certainly decays faster with the devices, and the response overall is slightly smoother, but there isn't a substantial impact anywhere else. The locations of the devices in the room will affect how well they work, though probably somewhat unpredictably, so worth experimenting. Might get more substantial changes from some acoustic panels, but other folk here are much better qualified to comment on possible treatment options so I hope some will chime in. Does it sound much different with the devices in place?


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## nergenek (Dec 21, 2014)

As the furnitures permit I tried all the different places in the room for the placement of the acoustical elements and frankly speaking I did not hear any substantial sonic differences...that's why I went down to the measurement way to see if science will show me some important differences to convince me spending all this budget for these elements :scratch:


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## Blacklightning (Nov 22, 2011)

Looking at your data and room pics the DAAD's are helping the room but Bass traps are the last thing you need.
Your speakers are doing very well in that room and I wish my results are on par with yours after I'm done with treatment.

From what I have read diffuse are great for large rooms and are the last step for getting the final 5% out of your medium size room.

If I was you I would play around with some simple panels and try and reduce your 5ms reflection.


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## nergenek (Dec 21, 2014)

Thank you JohnM and Blacklightning for your replies which are supporting my feelings about the sonic response of my room...

Do you think that this kind of panels ( http://hofa-akustik.de/en/modules/diffusor/ ) placed at the available places on the walls will help to reduce some reflection ?


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## Blacklightning (Nov 22, 2011)

Forget about diffusor's at this point go for absorption. 

http://hofa-akustik.de/en/modules/absorber-eco/

Get a couple of those and test for your reflection points.

Run a full sweep with just the left speaker and then just the right and post the REW file. When I did this the guys here really helped me out and I was able to pin point problems.

Diffusion are tricky and need to be tuned to problem frequencies (I believe) they should be the last thing you do in a medium sized room. "I" would not use Diffusion in your room at all as it is on the small side.

I think your reelection at 1-3ms (Milliseconds) is from the sloped wall above your speakers and the reflection right after 5ms is from the left wall.


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## nergenek (Dec 21, 2014)

L and R measurements .mdat file is now attached...They are pretty different as on the right side there is a window and on the left side there is an open door...

Anyway I hope that some analysis and recommendations from the experts will follow :wave:


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## Blacklightning (Nov 22, 2011)

Now I'm no expert but this is what I see.
Blue = Right
Red = Left

Impulse chart, this will let you know how your speakers will image. You want the Impulse to be the same. Your Right speaker is reflecting more "echos" than your left speaker. You can see this at 2 ms, 8ms, 11ms, 13-14ms.

Frequency response, You do not have large peaks and nulls. I'm guessing the door was open when you ran this. Your bass seems a little high from 80-50hz. Not a big deal.

Waterfall, your room rings at the low end. Bass traps are in order.

Overall I like what I see. Start with a few panels and go from there. Work on getting the right and left sounding the same.


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## nergenek (Dec 21, 2014)

Many thanks...you are giving me very valuable hints...so you are an expert :T and the only one who is helping me...:crying:

During the WE I will make more measurements with the curtains closed and the door closed and see the results...if anything remarkable I will post the results...

Have a nice WE...


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