John Sayers' Recording Studio Design Forum Archive

My system is placed where it's narrow. Using very thick basstraps on sidewalls is therefore not an option. On the left side, there's a wall without any isolation. I'm wandering how effective it is to place large rockwool of low density on the other side of that wall?

I've taken some pictures of the setup and also from dampening on the other side of the wall. To mye ears it's seems like the bass is tighten up placing two packages of 30 kg/m3 rockwool in the other room. I've taken a few meausurements too, but I'm getting inconsisten measurements using REW.

The pictures are not fully up to date. The frontwall has other treatment now and speakers are pulled out further from the wall.

On the left side I'm using 10 cm panels with 65 kg/m3 rockwool. On the right side either 7,5 cm or 10 cm thick panels. The pillows on the floor have 15 cm of rockwool with 65 kg/m3 density.

Oops. Pictures came in wrong order.

One concern would be an imbalance in LF response in the room but if you windows and your low isolation wall oppose each other that may be ok. What you are attempting is to dampen the outside room response so using hangers in that space would be best. You could then even go so far as to put some air ducts into the bottom of that wall to let the bass pass into it more easily...

gullfo wrote:One concern would be an imbalance in LF response in the room but if you windows and your low isolation wall oppose each other that may be ok. What you are attempting is to dampen the outside room response so using hangers in that space would be best. You could then even go so far as to put some air ducts into the bottom of that wall to let the bass pass into it more easily...

Thanks for answering.
I don't see why the bass response would be imbalance since bass is omnidirectional.
Not sure what you mean by using hangers.
Making holes in the wall isn't an option.
I may have misunderstood you, but my goal is to improve the sound in the listening room. I would like a better bass response. I assume less resonances and a shorter decay is what I can hope for by dampening on the other side of the wall.

I've taken measurements with Holm Impulse. The program doesn't have waterfall. It would be great if someone could take a look at them in another program. I've exported them as wav files (impulse response). The measurements are taken from 26-5000 Hz with both speakers.

Hmmm. Doesn't seem like it's possbile to uplod wav files her. I have to do something else. I can measure with REW, but I'm uncertain if I get correct measurements. I've a Lynx soundcard and calibrated mic with preamp. I get sometimes glitches though when Asio isn't used.

Measurements with REW. One graph for both speakers and one measured speakers individually.

A second measurement to see if they are consistent.

Your graphs do not extend far enough in the time domain to be able to see how the sound decays. You need to adjust the scale so that the graph shows most of the spectrum already fully decayed.

- Stuart -

Soundman2020 wrote:Your graphs do not extend far enough in the time domain to be able to see how the sound decays. You need to adjust the scale so that the graph shows most of the spectrum already fully decayed.

- Stuart -

Can you be more specific about exactly what I need to adjust?

BWO wrote:

Soundman2020 wrote:Your graphs do not extend far enough in the time domain to be able to see how the sound decays. You need to adjust the scale so that the graph shows most of the spectrum already fully decayed.

- Stuart -

Can you be more specific about exactly what I need to adjust?

Hi, maybe it's not a time domain issue, it's already 1000ms, try changing the "db" scale on the left, perhaps 20db to 100db instead of -20db to 100db.

Keith

maybe you can host the REW file directly so we could download it and look at directly? this will avoid needlessly posting large amounts of graphics which may or may not help someone to assist you. on the low frequency control/balance - there is a few ways to do it - one is to trap all the LF energy into your room and then try to balance it with all kinds of absorption, or allow the excess LF energy to escape and only deal with what is left. if you don't require high isolation, then allowing the energy to leave the space will generally help you get it under control. an ideal listening space is not a dead one. reflections are important. LF is generally considered "omnidirectional" because the wavelengths are longer than most rooms but there is still a source and there are still boundaries so modal response, wave propagation, etc all take a finite amount of time to ebb and flow and you can be assured that LF can indeed become unbalanced in a room.