Room treatment advice

[tarkus]

Hi all,

Recently got a batch of some acoustic panels (CSR Martini Absorb XHD 100mm) and put it all around my room. It definitely sounds better in terms of clarity which I'm happy with. I actually have 6 whole (2.4 x 1.2m) panels unopened, and am considering using them or selling them.

Here is my room, all the black stuff is the XHD:

The corners I just have single small panels, I know it probably isn't doing much:

The RT60 measurements have gone down are now around the 300-400ms range. Here is my frequency response:

This is before DIRAC, which I will be applying using my SHD Studio. I'll probably bump the subs a bit before DIRAC for a house curve but the above is set flat-ish.

What would be the best way to try get rid of the troughs at around 200 hz using my remaining XHD panels or is it not possible? Does it even matter when I will be correcting with DIRAC (although I've found it doesn't correct as much as I'd like - I'm still playing with it)? Also, would there be any benefit just double stacking my remaining panels so it is mostly 200mm thickness of XHD around the walls?

If it matters, equipment is:

- Minidsp SHD Studio
- Topping D90SE for the mains and E30 for the subs
- 2x Benchmark AHB2
- Revel F206 and 2x Rhythmik F12 subs

Many thanks

 

[Holmz]

…
What would be the best way to try get rid of the troughs at around 200 hz using my remaining XHD panels or is it not possible?
…

I think that you probably want “boxy bass traps” in the corners, but the 200Hz is not too bad in terms of a suck out.

…
Also, would there be any benefit just double stacking my remaining panels so it is mostly 200mm thickness of XHD around the walls?
..

If are not over damped already, you could be soon.

I would think that covering the door behind the chair and put some diffusers back there, on the sides, might be better.

Assuming that the reflections bounce around like a pong game, then the front wall or back does that axis.
The sides are another axis.
And the ceiling floor the Z-axis

Some shoved into the in the upper spaces might be good.
The lower half of the wall a seems totally covered but the top half at least looks a bit non symmetric.

 

[Dj7675]

My favorite thread on the topic. Lots of discussion.

Perceptual Effects of Room Reflections

Perceptual Effects of Room Reflections By Amir Majidimehr [Note: This article was originally published in the Widescreen Review Magazine, titled "it is not simple!"] When Gary Reber asked me to write an article for the 20th anniversary of Widescreen Review magazine I was stumped at first...

www.audiosciencereview.com

My only comment would be there isn’t a need to treat the entire room. In a stereo room not absorbing all side reflections might be preferred by many. Rear wall reflection absorption seems to often be recommended as well as ceiling. But it can be overdone.. and then starts to sound unnatural to me. I don’t think you see an acoustic people recommending 100% treatment from the floor up.

 

[hemiutut]

Hi all,

Recently got a batch of some acoustic panels (CSR Martini Absorb XHD 100mm) and put it all around my room. It definitely sounds better in terms of clarity which I'm happy with. I actually have 6 whole (2.4 x 1.2m) panels unopened, and am considering using them or selling them.

Here is my room, all the black stuff is the XHD:

The corners I just have single small panels, I know it probably isn't doing much:

The RT60 measurements have gone down are now around the 300-400ms range. Here is my frequency response:

This is before DIRAC, which I will be applying using my SHD Studio. I'll probably bump the subs a bit before DIRAC for a house curve but the above is set flat-ish.

What would be the best way to try get rid of the troughs at around 200 hz using my remaining XHD panels or is it not possible? Does it even matter when I will be correcting with DIRAC (although I've found it doesn't correct as much as I'd like - I'm still playing with it)? Also, would there be any benefit just double stacking my remaining panels so it is mostly 200mm thickness of XHD around the walls?

If it matters, equipment is:

- Minidsp SHD Studio
- Topping D90SE for the mains and E30 for the subs
- 2x Benchmark AHB2
- Revel F206 and 2x Rhythmik F12 subs

Many thanks

Can you put the REW .mdat file without vs acoustic treatment?

10 cm thick panels is inappropriate
to control the lower and higher frequencies in the locations they are placed.
Besides, the resistivity to the flow of the air passage in its panels is very high.
It is not the most recommended.

Written with translator.

Greetings

 

[tarkus]

I think that you probably want “boxy bass traps” in the corners, but the 200Hz is not too bad in terms of a suck out.

If are not over damped already, you could be soon.

I would think that covering the door behind the chair and put some diffusers back there, on the sides, might be better.

Assuming that the reflections bounce around like a pong game, then the front wall or back does that axis.
The sides are another axis.
And the ceiling floor the Z-axis

Some shoved into the in the upper spaces might be good.
The lower half of the wall a seems totally covered but the top half at least looks a bit non symmetric.

Thanks for the replies.

Yes it looks asymmetric and a bit weird but actually hanging these off the sloping walls and ceiling is a bit beyond my scope at the moment, as they are quite heavy and will need a secure way of fastening.

I'm aware of the possibility of over-damping but was hoping the sloping ceiling will have prevent this? How do the sloped ceilings come into play regarding reflection vs straight walls?

From my reading (including the excellent thread linked above), there is no 100% consensus on absorption at the first reflection, there are those who take Floyd Toole's work as bible and those who don't. I understand I might be sacrificing soundstage, but for my personal tastes I think I prefer to have clarity and precision imaging anyway.

Unfortunately I seem to have lost my pre-treatment measurements somehow. Will try to recover them but it will be a bit different anyway as I swapped out a couch for the chair pictured in the OP when I was putting in the panels, so it will not be the same conditions (no more absorption by the couch, different MLP z-axis).

I think I will play with changing the MLP slightly to see if the 200hz suck out changes, as well as keep some panels to play around with (? more at the corners)

 

[Hipper]

It would be more informative if your measurements were shown with 'no smoothing'. This will show more details of the peaks and troughs of your measurements compare to the 1/6 smoothing you are using.

The ideal would be to get treatment to sort out the lower frequencies and Dirac to cover a bit higher up but, for the range above say 1kHz it might be best to either leave it alone or make alterations like a tone control would.

I have no experience of sloping ceilings. I imagine there will be bass issues like any corners but how you place bass traps in those corners seems difficult.

Other ways of controlling bass are careful positioning of your speakers and chair (I use 'The Thirds' as described here: The Thirds ) and using subwoofers.

You certainly could add more material in the corners. If you can cut those panels, one way would be to keep the 'triangle' shape and fill the gap behind - some air gaps are OK. Alternatively just bunch four panels together to give you a 40cm x 40cm block (my GIK bass traps are 40cm x 40cm).

Like you I like a dryer sound. I've put 7cm thick panels beside my speakers to stop side wall reflections:

There are no other panels on the side walls. There are four panels on both the front and back walls (mostly 16cm) and those Soffit Bass Traps which are 40cm square in the four wall-wall corners and all the wall-ceiling corners.

More details of how I went about this are here (post 60):

https://www.audiosciencereview.com/...in-room-measurements.13540/page-3#post-411614