Question Room Treatment

joust

Well-known Member
Hi All,

Now that the rest of the house renovation is nearly complete (I will post that on another thread at some point), it's time to start on the cinema room. This will be a somewhat dedicated room, about 3.9x5.5m in size, a projector only based setup (I already have a nice JVC X7000...), only small concession is that in the rear corner, we do have a desk (it doubles as my occasional office, and a desk/making area of the 9yo).

So, I'd like to make it as good as possible - I already have sign off to do whatever I like - blackboard black paint is already on the cards, but now I'm considering the sound side. So question goes (with no limitations) - what would be better, acoustic foam panels (like these from Amazon: https://www.amazon.co.uk/Pro-Acoust...coding=UTF8&psc=1&refRID=QKNSF94WW94VHHVPEMZD ), or build my own panels from 50mm deep wood, fill with RWA45 Rockwool and cover with devore fabric?

Any opinions and other installations welcome (I'm really struggling to understand how much I need to cover - all the wall, or just 'sections').

Joust
 

VoodooDoctor

Active Member

Peter Parker

Distinguished Member
Rather than paint, which is still quite reflective, I would suggest black velvet panels instead. I'd suggest the mvel22 velvet over Devore - it performs very similarly and is a lot cheaper, especially if you're doing the whole room
 

joust

Well-known Member
Rather than paint, which is still quite reflective, I would suggest black velvet panels instead. I'd suggest the mvel22 velvet over Devore - it performs very similarly and is a lot cheaper, especially if you're doing the whole room
Hi,

I'm still going to need some paint, as I won't be able to velvet everywhere - this is what was getting me thinking I could combine the 2, sound absorption and image contrast improvement.
 

DLxP

Well-known Member
I'm really struggling to understand how much I need to cover - all the wall, or just 'sections'

@kbarnes70 provided just about the most succinct and thorough explanation I've read of what to do, here.
 

Amar

Active Member

joust

Well-known Member
All,

Thanks for the advice so far.....so is the consensus its better to make a panel, rather than the foam panels I linked to?
 

Hoku

Active Member
I really would recommend looking at the GIK website videos before you start anything. (No affiliations). There are lots of other good YouTube videos too about bass nodes, how long sound waves are at different frequencies etc.

You need to ask yourself what are you actually trying to achieve with your room. So before you begin, you need to understand the acoustic properties of your room thoroughly, otherwise you're just shooting blind.

Some questions you should ask yourself:
Are your main front L&R speakers firing down the long edge of the room or the shorter?
Where is your seating position? Will it be up against the back wall, or will you have some space between your seating and the rear speakers?

Because if your speakers are firing along the shorter distance and the seating is at the back of the room AND your room is perfectly rectangular with a lowish straight ceiling, then you could have problems with bass nodes. Bass can have a tendency to build up at the back of the room, which if that's where your seating is, can make the bass sound bloated and heavy.

If so, then you need to treat the bass in your room. Many home made room treatments do not tame the bass at all, but affect treble reflections instead which may not be what you want to achieve in your room. Actually some side reflections can be welcome as they allow a sense of air and space in the recording.

If you visited your doctor and he gave you a prescription before you explained what the problem is, would you just go ahead and pop the pills?

Personally I would get the room set up with your speakers, furniture and equipment in position and just listen to it. Analyse what's going on. Are there too many reflections? Are there bass nodes in certain places in the room? Once you understand what issues the room is presenting, THEN develop / purchase acoustic treatment that deals with that specific problem.

If you randomly put unknown treatment around your room, you could end up with still having bass nodes all over the place but taming the treble so much that the overall effect is a dull unexciting sound.
 

BlueWizard

Distinguished Member
Here is a link to the GIK Acoustics Videos on YouTube -

youtube.com/user/GlennKuras/videos


And on their website -

Educational Videos - Acoustic Panels | Bass Traps | Diffusors | GIK Acoustics

One thing you want to consider when putting fabric on the wall is the Flame Retardant Characteristic of the cloth you use.

At the Theater I most often go to, they have a thin indoor/outdoor carpet like material on the walls.

But if you watch the videos, they do not cover the entire room in Acoustic Treatment. Generally you deal with the corners, the points of first reflection (walls and ceiling), and the far back wall away from the screen. You want some reflection in the room, but you don't want those reflections to dominate.

Can you tell us the construction of your room? That is - stone, brick, lumber frame, etc...?

There are a lot of videos on YouTube regarding acoustics, some DIY, others from professional installers. All are helpful in providing a general education on Acoustics.

And there are two principles in Room Acoustics -

- Diffusion
- Absorption


Diffusion does not eliminate reflection, rather it scatters them. Absorption obviously absorbs sound, but absorption solutions like Acoustic Foam can do both. Also, Acoustic Foam comes in a variety of colors from the right source.

Here is a post I made quite a while back on Room Acoustics, so some of the links no longer work -

Primer: Acoustics - Absorption & Diffusion

Just to get you started here are a couple of videos illustrating Diffusion -




Additional info and videos, Auralex Acoustics is a USA company but has worldwide distribution -

youtube.com/user/AuralexAcoustics/videos

https://www.auralex.com/wp-content/uploads/2018/02/902-1112.Studiofoam-Spec-Sheet-v20.pdf

Steve/bluewizard
 

BlueWizard

Distinguished Member
Here is a video that shows very clearly how Acoustic Treatment can stop reflections in a room -


This is more of a Home Studio than a Music/Movie room. But it is a nice illustration of the principle.

Steve/bluewizard
 

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