Room treatment - Diffuser and absorbers

[Nikhili]

My quest for a better listening experience in my listening space made me consider getting the room acoustically treated. This setup being in my bedroom I wanted to keep the treatment minimal.
I listen to most any genre but these days it is mostly been limited Jazz, Blues, Lounge, Folk, Country, Soft rock and Hindustani classical music mostly skewed towards string instruments. I've been playing sitar for a long time now (on and off!) and would like to believe that I have a fairly decent ear to notice subtle changes or otherwise.

Now coming back to the room treatment - Being a bedroom setup I have lot of limitations when it comes to speaker placement and listening position. The back wall is but some inches away from my listening position. Bare walls don't really help me here!

I had, in the recent past, tried the power conditioner by Invention Audio ( forum member Sandeep) and was quite happy with it. Sandeep had come over to my place and took a listen and I had expressed my desire to minimally treat the room. He suggested that I go for one diffuser and seven absorption panels. The diffuser to be of 48" x 48"(eventually ended up at 51" x 51") and absorption panels 24" x 48" each.
The diffuser, we had planned to place in the center of the front wall and two absorption panels each to it's left and right apart from 3 panels on the back wall.
A single piece diffuser of this size and with about 484 wooden blocks of varying length and all this placed on 18mm birch ply is not really easily manageable weight. The fact that the blocks are glued and the board does not have handle to hold/carry/lift made it tough with the logistics as well as mounting it.
Took me a few days to think about and come out with a fail safe way of mounting it. I didn't want it crashing on my gear or otherwise.
Got a few 304 grade stainless steel brackets of 5mm thickness, picked some anchor rawl bolts for these brackets (for the wall) and screws for the wood part of it, anchor wedge bolts (four of 4" bolts) to directly drill and get the board connected to the wall apart from a thick wooden strip below it for support. The tough part was to get it up to that position - 6 adults struggled to get it up there. The desk helped quite a bit. I wanted this diffuser to be in two pieces but it makes most sense if instead it is made in 4 pieces if it's something of this size.

How does it sound? I am quite pleased with the change in sound. It immediately gave more space and dimension. The airiness had gone up a few notches. The decay of the strings also went up and it was more realistic sounding as well. In general, it had more weight and most everything sounds better, I love the balance of my system apart from how sweet it sounds to my ears. Placebo? Maybe not!

The following are the tracks that I base the above mentioned upon. Source is CD Player.

Allan Taylor - Some Dreams, Time is short
Norah Jones - Seven Years, Nightingale
Amber Rubarth - Strive, Tundra
Charly Antolini - Sound Check with Nippy
Kari Bremnes - A lover in Berlin
Kitaro - Gaia
Shahid Parvez - Mishra Maloo, Bihag

And a few more pictures to go!

 

[renjith lal]

Very nice. Great effort Nikhil.
I have few questions.

Did you build the diffuser ?
How did you arrive at the location for acoustic panels at front wall, based on measurement ?
Did you try placing some acoustics panels at corners of room?

 

[liverpool_for_life]

Really heart-warming to see this level of effort to help the room acoustics in a bedroom setup. Of course, it's all worth it when you hear the difference! Congratulations.

 

[arj]

Really impressive ! Regarding the height of the wood blocks, is it based in any calculation or is it random ?

 

[Sandip Das]

What kind of matirial you use inside ur absorber panel?? @Nikhili

I'm build up some diy qrd diffuser and the result is good for me and now I'm thinking some absorber pannel.

 

[Nikhili]

Very nice. Great effort Nikhil.
I have few questions.

Did you build the diffuser ?
How did you arrive at the location for acoustic panels at front wall, based on measurement ?
Did you try placing some acoustics panels at corners of room?

Thanks, Renjith!

I got the diffuser made by Invention Audio (Sandeep/Sandyj on forum).

We haven't done any measurements and thankfully all seems well!

I have limitations with the side walls. To the left - I have wall to wall wardrobe and a big mirror which is about 6 feet from the left mirror and a door about 5 feet from the right speaker. there is another door just a bit after the door on the right after which is a huge cupboard. On two corners - I have used bass traps. I have a couple more absorption panels which are not fixed to the wall but I try to position them around first reflection point once in a while. I cannot have something permanent there unless I do it on the wood!
This apart I suppose adding in the front has a few benefits like virtual depth which in turn creates a sense of better spatial sound

Really heart-warming to see this level of effort to help the room acoustics in a bedroom setup. Of course, it's all worth it when you hear the difference! Congratulations.

Thanks! It was almost head boiling for the wife I go this done when she was traveling and sent pictures of it getting installed
To me it's worth it and I am happy!

Really impressive ! Regarding the height of the wood blocks, is it based in any calculation or is it random ?

Thanks! Though we haven't done any measurements we wanted to address what we felt needed to be addressed and came up with this mid band diffuser. It is calculated per the frequencies and I suppose the range is 500 - 3000 hz. The longest block is about 12"

What kind of matirial you use inside ur absorber panel?? @Nikhili

Wood wool mostly. A bit of foam on the front as well as the rear.

 

[sandyjhyderabad]

Hi guys, I was the one who designed and built them. There are many things which came in to picture while designing those panels and diffuser.

It was an unexpected decision made by Nikhil. The reality line was he ordered a power conditioner for his setup. He loved the way it made an improvement over the sound from his speakers. Well after listening even I felt that yes it indeed made a nice difference and when Nikhil asked me what else can be done to improvise the performance then the first thing which came to my mind was to get decent acoustics in place. Now his overall 30 years of experience of playing sitar has got lots of things to do with psycho acoustic considerations hence the design is made in such a way that the extremities of the frequencies to be intact without any modifications. The system though was lost in coherence and balance earlier is not seriously good and the most amazing thing even today I feel in his setup is the lower notes of guitar has rounded and yet very very controlled tone and very mellow as well I just fell in love with that part after the acoustics. Now thats without basstraps as well. I had to do the math and also his problems in the room were clearly audible and the design was made as is. Just slamming a piece of glass wool or wood wool will not give the tonality what its offering right now at his place. The overall balance and the airy and transparent sound, yet very lively and just plays right is simply breath taking and it feels that nothing is lacking and makes you feel that you dont need any improvement in the balance after that. If anyone is in Hyderabad do have a visit to his place.

I always recommend choose the right person to do your setup properly. If one tries to find the right match by themselves it will take ages to find one or you will never find it ever in your life spending insane amount of money in wrong places and most importantly wasting your precious time. Im talkikng about that striking balance what you get with the nikhil`s setup. Im sure he need not spend even a buck for atleast next 15 to 20 years for his room acoustics. Thats how its made and whatever he is going to add is going to make his system improve in a constructive way.

 

[Sandip Das]

Wood wool mostly. A bit of foam on the front as well as the rear.

diffrence between wood wool or rock wool. any idea?

 

[sandyjhyderabad]

there are many variants in it but the basic difference is composition its like various type of ingredients.

 

[Sandip Das]

there are many variants in it but the basic difference is composition its like various type of ingredients.

what is the better matrial to build a absorber pannel.. rockwool / woodwool or high density sponge

 

[ONEMANARMY]

Excellent placement choice.
If possible do look into getting some DIY Rockwool panels to address the low frequencies.

what is the better matrial to build a absorber pannel.. rockwool / woodwool or high density sponge

For low frequencies; rockwool/glasswool, for highs and mids; foam/sponge.
Woodwool is a more lifestyle product and not the best choice.

I had made a very similar diffusor a few years ago. The only difference being that I had drawn a grid on the walls and glued the wooden pieces directly.
It was a painstaking job but well worth it.

 

[Nikhili]

Excellent placement choice.
If possible do look into getting some DIY Rockwool panels to address the low frequencies.

Thanks.
I am specifically not too keen on using materials which might pose health issues and hence not comfortable using rockwool or glass wool even if they are to benefit my listening experience. As such the texture of the bass is quite good and so is the overall balance. The generic foam bass traps that I am using offer only a slightly better experience I have them so thought may as well use

 

[sandyjhyderabad]

Its like ingredients everything has a got a reason why we are using that material in that location. Like said its like cooking. NO glasswool its bad for health. Nikhil is happy what else is required?

 

[Nikhili]

I had made a very similar diffusor a few years ago. The only difference being that I had drawn a grid on the walls and glued the wooden pieces directly.
It was a painstaking job but well worth it.

How did you go about doing so? Was it on a plastered/cemented, unpainted wall? Which specific adhesive did you use to stick the blocks on the wall!?

 

[ONEMANARMY]

I had picked up the formula for a skyline diffusor online. It's free
Then I got a carpenter to cut the wooden pieces as per the formula and got them stuck with super glue on an unpainted concrete wall.
Link attached below:

https://fullenglish.co/blog/2017/2/21/how-to-build-an-acoustic-diffuser

 

[Nikhili]

I had picked up the formula for a skyline diffusor online. It's free
Then I got a carpenter to cut the wooden pieces as per the formula and got them stuck with super glue on an unpainted concrete wall.
Link attached below:

https://fullenglish.co/blog/2017/2/21/how-to-build-an-acoustic-diffuser

Thanks for the information as well as the link!
I presume super glue is holding well. Did you get to compare the skyline with quadratic ?

 

[arj]

I had picked up the formula for a skyline diffusor online. It's free
Then I got a carpenter to cut the wooden pieces as per the formula and got them stuck with super glue on an unpainted concrete wall.
Link attached below:

https://fullenglish.co/blog/2017/2/21/how-to-build-an-acoustic-diffuser

Thanks for the link ! would you know if it does need to be wood only ?

 

[ONEMANARMY]

Thanks for the information as well as the link!
I presume super glue is holding well. Did you get to compare the skyline with quadratic ?

You're welcome.
Did not try any other type because I was quite happy with this

 

[ONEMANARMY]

Thanks for the link ! would you know if it does need to be wood all the time ?

Polystyrene has also been tried and liked by some, but I personally did not like it when I heard it.
I would say stick with wood.
No need to get exotic Mahogany, etc. just any soft local wood should do the job quite well.