Acoustic treatment in a small room - advice, pure absorption vs combination diffusion/absorption?

[OZ-ZERO]

This is my small office (2.5m W x 3.5m L x 2.5m H). I have a 5.1 setup. I don't think the sound quality is as good as it should be. Occasionally sounds quite harsh with a lot of slap echo.

I have proposed to put 2x 244 Bass Traps on the rear wall and 2x 242 Acoustic Panels on the left wall. Treatment on the right wall is not possible, unless I put one panel horizontally under the window (Is there even any merit in doing this?)

Should I put a scatter plate on one (or two) of the 242 panels on the left wall or go for pure absorption only?

 

[TLS Guy]

This is my small office (2.5m W x 3.5m L x 2.5m H). I have a 5.1 setup. I don't think the sound quality is as good as it should be. Occasionally sounds quite harsh with a lot of slap echo.

I have proposed to put 2x 244 Bass Traps on the rear wall and 2x 242 Acoustic Panels on the left wall. Treatment on the right wall is not possible, unless I put one panel horizontally under the window (Is there even any merit in doing this?)

Should I put a scatter plate on one (or two) of the 242 panels on the left wall or go for pure absorption only?

When sound is harsh it is usually because the sound of the recording is harsh or the speakers are harsh.

That room is a problem, but aggravated by the speakers being right in the corner. That looks like a problem that would be hard to correct. This will be particularly aggravated if the speakers off axis response does not match the axis response well.

Having said that some acoustic treatment of the back wall to absorb sound would likely help. This is the classic live wall dead wall approach. Even a bookshelf on the back wall would make a difference and looks good. That is what I do to keep my back wall relatively dead and is a good solution.

Given that you have limited options for speaker placement I would deaden the walls around the speakers.

I'm not really an advocate of bass traps. In any event your room has a dominant dimension and bass traps probably won't help much.

As usual though I usually look at speakers. Speakers abound but good ones are still far and few between.

What are those speakers and has anyone measured them?

 

[Eppie]

That room is nothing but hard surfaces so some sound treatment makes sense in this instance. I agree with TLS Guy in that bass traps may not be worth the cost for that size room. If it is harshness that you wish to address, concentrate on the mid and upper frequencies first. I would start with absorption panels for the back and left side walls. I would not worry about below the window but if the window blind is hard vinyl you might want to consider clothe blinds or roman blinds. If you can't get any carpeting on the floor, then consider a diffuser on the ceiling. A clap test is a simple way of listening for decay time but if you have access to a measurement microphone you can use REW software to measure what the room is doing.

 

[OZ-ZERO]

When sound is harsh it is usually because the sound of the recording is harsh or the speakers are harsh.

That room is a problem, but aggravated by the speakers being right in the corner. That looks like a problem that would be hard to correct. This will be particularly aggravated if the speakers off axis response does not match the axis response well.

Having said that some acoustic treatment of the back wall to absorb sound would likely help. This is the classic live wall dead wall approach. Even a bookshelf on the back wall would make a difference and looks good. That is what I do to keep my back wall relatively dead and is a good solution.

Given that you have limited options for speaker placement I would deaden the walls around the speakers.

I'm not really an advocate of bass traps. In any event your room has a dominant dimension and bass traps probably won't help much.

As usual though I usually look at speakers. Speakers abound but good ones are still far and few between.

What are those speakers and has anyone measured them?

Would you suggest placing panels on the walls adjacent to the speakers (to the left and right as seen in the photos), or behind the speakers?

For the rear wall I was going to get 2x 244 panels. They have different options including full range, range limiter and scatter plate. What is preferred?

The speakers are the Monitor Audio Apex A10 and A40.

 

[OZ-ZERO]

I spoke to GIK about some treatment advice and they said using only absorbers would make the room 'dry/direct' and using the impression series will make the room more 'lively/musical'

This is comparing the 242 side panels and 244 rear wall, and Impression series for side/rear wall.

He said the Impression series would be less fatiguing than a 'dry room'

Is there any truth that absorbers increase listening fatigue?

Should I go with the advice and just pick the impression series all around?

 

[Eppie]

I spoke to GIK about some treatment advice and they said using only absorbers would make the room 'dry/direct' and using the impression series will make the room more 'lively/musical'

This is comparing the 242 side panels and 244 rear wall, and Impression series for side/rear wall.

He said the Impression series would be less fatiguing than a 'dry room'

Is there any truth that absorbers increase listening fatigue?

Should I go with the advice and just pick the impression series all around?

Did you send them photos of the room or just speak on the phone? Was it clear to them that all of the surfaces were hard reflective surfaces and that there was no carpeting? Less absorption on the side walls makes sense because you generally want some reflected sound from the side walls, but I would have expected them to recommend absorption on the back wall since the room echoes a lot. I think you can upload photos through their web site and they can then make recommendations. GIK has been around for years and generally should give good advice.

 

[OZ-ZERO]

Did you send them photos of the room or just speak on the phone? Was it clear to them that all of the surfaces were hard reflective surfaces and that there was no carpeting? Less absorption on the side walls makes sense because you generally want some reflected sound from the side walls, but I would have expected them to recommend absorption on the back wall since the room echoes a lot. I think you can upload photos through their web site and they can then make recommendations. GIK has been around for years and generally should give good advice.

Yes I sent photos.

Looking at this video they look like a pure wood panel over the panels - this looks more reflective than my actual wall itself!

 

[Trell]

Yes I sent photos.

Looking at this video they look like a pure wood panel over the panels - this looks more reflective than my actual wall itself!

I've a couple of threads with pictures of GIK Acoustic panels with scatter plates: home office and living room (post #32).

When covering larger areas with acoustic panels the scatter plates are very useful to not make the room too "dead" as higher frequencies are not attenuated as much. I did not put any panels on the ceiling.

The rooms are "echoey" without the panels and are actually more pleasant to be in after installing them.

 

[OZ-ZERO]

I've a couple of threads with pictures of GIK Acoustic panels with scatter plates: home office and living room.

When covering larger areas with acoustic panels the scatter plates are very useful to not make the room too "dead" as higher frequencies are not attenuated as much. I did not put any panels on the ceiling.

The rooms are "echoey" without the panels and are actually more pleasant to be in after installing them.

Thanks. Did you find the sound quality was better with these installed? You also have these panels behind the MLP in your living room. I have read if you're close to the MLP you should have absorption only. Do you get any obvious bounce back compared to a normal wall?

 

[Trell]

Thanks. Did you find the sound quality was better with these installed? You also have these panels behind the MLP in your living room. I have read if you're close to the MLP you should have absorption only. Do you get any obvious bounce back compared to a normal wall?

Yes, I found the sound quality better after installing the panels and measurements showed some improvements. A/B testing of panels on/off wall is not particularly feasible, though.

As for absorption on the back wall: These are panels with thin scatter plates and not bigger diffusers that needs more distance. I've not noticed any problems or issues with my panels, though. Some bounce back there will be, per design, as well depending on frequency.

As I intended to cover a large part of the room with panels I was quite concerned that it could be too "dead", thus the scatter plates. I think I achieved that in rooms where the layout of furniture/speakers/subwoofers etc is quite inflexible.

 

[OZ-ZERO]

Yes, I found the sound quality better after installing the panels and measurements showed some improvements. A/B testing of panels on/off wall is not particularly feasible, though.

As for absorption on the back wall: These are panels with thin scatter plates and not bigger diffusers that needs more distance. I've not noticed any problems or issues with my panels, though. Some bounce back there will be, per design, as well depending on frequency.

As I intended to cover a large part of the room with panels I was quite concerned that it could be too "dead", thus the scatter plates. I think I achieved that in rooms where the layout of furniture/speakers/subwoofers etc is quite inflexible.

I presume there is less bounce back via the scatter plates than bare wall, correct?

I liked this design:

Do I need to worry about this reflecting too much because the slat size is so small?

 

[Trell]

I presume there is less bounce back via the scatter plates than bare wall, correct?

I liked this design:
View attachment 68590

Do I need to worry about this reflecting too much because the slat size is so small?

Hopefully you don't take this the wrong way.

I advice you to get an inexpensive measurement microphone to use with something like the free REW - Room Acoustics Software. With this you can get some "hard" data as base for your decisions, and that includes various placements of your subwoofer, speakers as well as "Main Listening Position" (moving your desktop). Experimentation is key here.

You've not said how you use your 5.1 system in your small room and what type of content you listen to. That sad, from your pictures of placement of speakers and MLP (main listening position) there is likely no need for the centre speaker as the front left/right would probably work just fine, if not better. Do note if you like to play "loud" your present speakers likely will sound very bad i.e. harsh.

Perhaps getting a good pair of active monitors will turn out to have a much nicer sound that you are not happy with now?

In my small home office there are two 2.1 setups (stereo+subwoofer) and the monitors are really good, but also expensive. On the other hand, buying enough panels from GIK Acoustics is also expensive, and I rather put my money into an excellent pair of active monitors. Well, I did both, but I think my point stands on its own.

I had good discussions with GIK Acoustics three years ago before I bought my panels from them (in stages) but the better information you give them the better advice they can give, and that includes actual audio measurements.

 

[OZ-ZERO]

Hopefully you don't take this the wrong way.

I advice you to get an inexpensive measurement microphone to use with something like the free REW - Room Acoustics Software. With this you can get some "hard" data as base for your decisions, and that includes various placements of your subwoofer, speakers as well as "Main Listening Position" (moving your desktop). Experimentation is key here.

You've not said how you use your 5.1 system in your small room and what type of content you listen to. That sad, from your pictures of placement of speakers and MLP (main listening position) there is likely no need for the centre speaker as the front left/right would probably work just fine, if not better. Do note if you like to play "loud" your present speakers likely will sound very bad i.e. harsh.

Perhaps getting a good pair of active monitors will turn out to have a much nicer sound that you are not happy with now?

In my small home office there are two 2.1 setups (stereo+subwoofer) and the monitors are really good, but also expensive. On the other hand, buying enough panels from GIK Acoustics is also expensive, and I rather put my money into an excellent pair of active monitors. Well, I did both, but I think my point stands on its own.

I had good discussions with GIK Acoustics three years ago before I bought my panels from them (in stages) but the better information you give them the better advice they can give, and that includes actual audio measurements.

I will take your suggestion on board with the meausrement microphone.

The Monitor Audio Apex are considered to be a very good set of speakers despite their size (have 5.25" drivers).

I use the 5.1 setup primary for games (and music). I listen to -20 dB on the receiver which is plenty loud for me.

I think acoustic treatment is probably going to be a cheaper option than upgrading my entire sound setup!

 

[Trell]

I will take your suggestion on board with the meausrement microphone.

The Monitor Audio Apex are considered to be a very good set of speakers despite their size (have 5.25" drivers).

I use the 5.1 setup primary for games (and music). I listen to -20 dB on the receiver which is plenty loud for me.

I think acoustic treatment is probably going to be a cheaper option than upgrading my entire sound setup!

5.25" drivers? They looked smaller than that in your pictures.

 

[OZ-ZERO]

5.25" drivers? They looked smaller than that in your pictures.

I used the 'zoom out' function to capture as much as the room as possible - which likely distorted the perspective!