Seeking advice on room treatment with an aesthetic requirement

[blackt@lon]

Hi all, I'm a long time lurker but would like to thank everyone for all their input and information I've gleaned over the years.

I would like some advice for room treatment. Allow me to provide some background information:

Room
- front wall is 3m (contiguous with dining room, total length is 7m)
- back wall is 3m
- both sides open (left side wall is 7m away, right side is open to balcony)
- ceiling is 3m high

Speaker setup
- Genelec 8351B
- digital streaming from Eversolo A8 to speakers via balanced XLR outputs
- speakers are GLM "tuned", but intend to tweak using REW or custom convolution filter, if needed

Requirements
- this is a new apartment, so I can install acoustic treatment during renovation.
- the aim of room treatment is to reduce reflections, thereby improving sound clarity and reduce echo when several people are talking simultaneously
- room aesthetics is very important to my wife and I. Ideally, we would like the treatment to be invisible.
- I could "maybe" convince her to go with a wood slat absorber panel on the back wall, such as this: https://www.artnovion.com/product-categories/6-absorption/products/1478-siena-k-broad-range
- but ideally, the treatment would look and feel like a wall that we can install wallpaper over
- I'm thinking if something like this would work: https://www.artnovion.com/product-categories/6-absorption/products/1179-helen-absorber-range
but I would replace the fabric with wallpaper stretched over the frame. The wall paper is silk fabric with paper backing.

Questions:
- Does anyone know if silk fabric is acoustically transparent, and if not, how much of an effect it would have on the performance of the absorber?
- Any other suggestions?

Thanks again for your help!

 

[kemmler3D]

Hi all, I'm a long time lurker but would like to thank everyone for all their input and information I've gleaned over the years.

I would like some advice for room treatment. Allow me to provide some background information:

Room
- front wall is 3m (contiguous with dining room, total length is 7m)
- back wall is 3m
- both sides open (left side wall is 7m away, right side is open to balcony)
- ceiling is 3m high

Speaker setup
- Genelec 8351B
- digital streaming from Eversolo A8 to speakers via balanced XLR outputs
- speakers are GLM "tuned", but intend to tweak using REW or custom convolution filter, if needed

Requirements
- this is a new apartment, so I can install acoustic treatment during renovation.
- the aim of room treatment is to reduce reflections, thereby improving sound clarity and reduce echo when several people are talking simultaneously
- room aesthetics is very important to my wife and I. Ideally, we would like the treatment to be invisible.
- I could "maybe" convince her to go with a wood slat absorber panel on the back wall, such as this: https://www.artnovion.com/product-categories/6-absorption/products/1478-siena-k-broad-range
- but ideally, the treatment would look and feel like a wall that we can install wallpaper over
- I'm thinking if something like this would work: https://www.artnovion.com/product-categories/6-absorption/products/1179-helen-absorber-range
but I would replace the fabric with wallpaper stretched over the frame. The wall paper is silk fabric with paper backing.

Questions:
- Does anyone know if silk fabric is acoustically transparent, and if not, how much of an effect it would have on the performance of the absorber?
- Any other suggestions?

Thanks again for your help!

Unfortunately, silk with paper backing will more or less prevent the acoustic treatment from working at all. If that's the only acceptable aesthetic solution then IMO don't bother, try another route.

Broadly speaking most absorbers only work when air is able to flow freely into a porous material. These 'velocity' absorbers reduce the motion of air - when that motion is due to a sound wave, it attenuates the sound.

A long way of saying the paper backing is going to stop it from working.

Silk might be OK. The loose rule of thumb is that if you can hold up the fabric, blow on it, and feel the air on the other side, it's suitable for covering an acoustic panel. But obviously the backing is going to be a problem.

There are also "pressure" absorbers which tend to be more for low frequencies, and don't need porous surfaces. I guess In theory you could put wallpaper on the face of a 'membrane' type "trap" and it would still work OK.

Oh, and welcome to ASR!


If you can get some of those, and then use heavy curtains, lots of rugs, upholstery, and so forth to absorb the highs, you might actually be in good shape.

 

[HiMu]

- Genelec 8351B

Do you have a GRADE report from your room?

 

[JakeK]

If you can get some of those, and then use heavy curtains, lots of rugs, upholstery, and so forth to absorb the highs, you might actually be in good shape.

+1 for using normal thick soft upholstery. Wall to wall carpet and underlay will absorb a lot of sound.

I got some very heavy acoustic curtains and they absorb a lot of sound and they can look like lovely normal curtains at your windows.

I would also consider adding some extra false curtains over a wall area if you need extra absorption that looks like normal unobtrusive decor.

I bought a curtain from them not expecting that much and they really are very heavy and really work. The double lined type I bought is probably overkill for most homes and this one will do the job: https://www.vocalboothtogo.co.uk/p/...50g-m2-40mm-grommets-blackout-thermal-curtain

Then there are the acoustic panels that can look like normal artwork on the walls but I have my doubts about how effective they are unless you cover a very large area with them. Don't bother with the foam tile types as they do about 1db at best or no noticeable difference at all. I got some to try and they look nice but do basically nothing!

 

[TheZebraKilledDarwin]

- room aesthetics is very important to my wife and I. Ideally, we would like the treatment to be invisible.
- I could "maybe" convince her to go with a wood slat absorber panel on the back wall, such as this: https://www.artnovion.com/product-categories/6-absorption/products/1478-siena-k-broad-range
- but ideally, the treatment would look and feel like a wall that we can install wallpaper over

If it sounds great by using natural materials, if also feels great to be in that room.
Have you ever lived in rooms with wooden panels and bookshelves? You will no longer want to live in a sterile zeitgeist shoebox.
And covering 83' Gennies and making DIY filters instead of Genelec's system?
Are you sure?

 

[TheZebraKilledDarwin]

- I'm thinking if something like this would work: https://www.artnovion.com/product-categories/6-absorption/products/1179-helen-absorber-range

If you look at the absorption graph

They absorb not much in the bass region.
Bass needs lots of volume of absorber material or active cancellation.

I'd recommend to measure your room and ask them (or any other provider of acoustic treatments), what they would recommend to also get the bass under control.

Questions:
- Does anyone know if silk fabric is acoustically transparent, and if not, how much of an effect it would have on the performance of the absorber?

You have 83' Gennies and ask if silk in front of them was a good idea? That's like throwing food away.
And why? Because a woman wants that?!? Tomorrow she will want something else anyway, if the TV told her so...

- Any other suggestions?

Make a deal:
After the third child she can get her wish to cover the Genelecs.
Chances in the West these days are very high, you will have the Gennies when she is long gone...

Thanks again for your help!

No problem!

 

[JakeK]

Further to that you could hang a thick persian style rug or two on the wall for decoration and effective sound absorption.

 

[basscleaner]

Before answer your questions you should be give to acoustician some important input information. What is the aim of this room use? What kind of sound sources do you plan to use in this room? What noise sources are close to your room (laundry, HVAC or any other devices), which can influence at your ears inside room? One should understand, that there are not the best acoustical materials, technologies or constructions, but the optimal mixing of it for the best result.

 

[Holmz]

Further to that you could hang a thick persian style rug or two on the wall for decoration and effective sound absorption.

It will not be effective at the lower frequencies though.
If it is spaced off the wall a bit then it can help, but that lead one more towards a kimono on a large dowel.

 

[JakeK]

It will not be effective at the lower frequencies though.
If it is spaced off the wall a bit then it can help, but that lead one more towards a kimono on a large dowel.

A very heavy curtain would be better in that way. Not sure what use a kimono would be other than decoration?

 

[Holmz]

A very heavy curtain would be better in that way. Not sure what use a kimono would be other than decoration?

For a velocity absorber to absorb, it needs to be away from the wall.

An Iranian/Persian rug would generally be pressed flat against the wall, and the same with a Dutch tapestry.
At least a kimono is normally displayed on rod, and not nailed to the wall.
Draperies are also a few inches off the wall, so they offer more chance of the wind rushing through them.
A drapery also is pleated, so that likely does some diffusion type of work as well.

The other place to get some absorption is from above… if the ceiling is high enough.

 

[basscleaner]

The gap between hard surface of wall or masonry and absorbent is important parameter of absorption coefficient, only when absorbent density is much more, than air density. It is important especially for low frequencies. But. of course, such a technique is much more capable for ceiling.

 

[analogonly]

Japanese silk screen behind the speakers with serious absorption behind the silk screen?

 

[basscleaner]

I can say nothing about absorbing features of the such a material, because it depends of density, gap, blowability, thickness and surface of this "Japanese silk screen". Any case, it would be better to know the measurement result for this construction or to calculate it by means of, for instance, ZORBA (www.insul.co.nz) or any similar computer analyzer.