Acoustic Treatment for Newly Built Studio Room

[EssyJ]

Hi all,
First time poster here and looking for some advice on acoustic treatment for my newly built studio/rehearsal room.
Just to give some background on my situation, my studio room was completed a couple of months ago (along with my new house) by a local builder using a spec provided by myself after months of research on the internet and talking to other people with personal experience in this area. The purpose of the room is mainly for recording of my own acoustic/electric guitar and vocal tracks, and also rock band rehearsal using acoustic drum kit, electric bass, 2 electric guitars and vocals. The layout of the room was designed with the ‘live end, dead end’ theory in mind, but I am open to suggestions as I have not undertaken any acoustic treatment as yet, hence my post.

The room dimensions (in millimetres) are:
4600 (length)
2800 (width)
2600 (height)

The wall construction consists of Green Glue resilient channel clips fixed to timber stud, and 24mm resilient channel. The drywall consists of 2 x 13mm soundchek plasterboard sheets with Quietwave membrane sandwiched in between, boards staggered and fixed to resilient channel.
Green Glue acoustic sealent was used in between all plasterboard joins.

The ceiling is constructed using Embelton resilient mounts fixed to timber joists at 600 centres, and 24mm resilient channel.
Again, 2 x 13mm soundchek plasterboard sheets with Quietwave membrane in between is used to finish the ceiling construction.
Bradford SoundScreen R3 insulation batts are used in the wall and ceiling cavities.

Room1.JPG

Quietwave1.JPG

The floor is 12mm solid spotted gum timber glued to concrete slab.
The door is a 48mm Sontron 42 acoustic door by Spence Doors (Melbourne, Australia), with Raven seals.

There is one 2600mm (w) x 550mm (h) double glazed laminated highlight window at one end of the room made, I hope to position my monitors and desk etc against this wall. The window now has a roller blind covering it, so it would be difficult to cover with any treatment.
There is also a 2000mm x 100mm track light running lengthways in the centre of the ceiling.
The room is finished with a water based paint in a mat finish.

Window.JPG

Door.JPG

I am quite happy with the soundproofing qualities of the room, although I have not done any real testing with a DB meter yet.
Naturally, the room is full of echo as it is at the moment.

Regarding acoustic treatment, I have considered going with a room kit such as the Primacoustic London 12, because it seemed to be a good fit for my room size, but cannot find many user experiences with this product:

http://www.primacoustic.com/london12.htm

I have also looked at Real Traps, which look good on paper in my opinion, but are quite expensive:

http://www.realtraps.com/products.htm

Then there is the option of building my own traps/treatments , but I am at a loss as to where to begin for a room of my spec, placement, density, whether diffusers or broadband traps are required etc.

So, my question is, given the information above, and a budget of $1000-1500 AUD, if you were asked to acoustically treat my room, what products would you use and how would you use them?
How many base traps would you use, and where would you place them?
Would you use diffusers on the rear/side walls, or some other treatment?
What about the ceiling, would you use any treatment there?
Would you leave the window as it is?
What about the floor?

Bear in mind I want to keep some liveliness in the room for acoustic guitar tracking if that is possible.

I’d really appreciate your help and any advice you may have.

Cheers,

EssyJ

[Soundman2020]

Hi there "EssyJ", and welcome to the forum!

Several comments and questions on your post, in no particular order:

"The layout of the room was designed with the ‘live end, dead end’ theory in mind,"

That was a design concept from about 30-something years ago, which has longs since been discarded and replaced with more modern concepts. The problem with LEDE was that it did not live up to its billing, and turned out to not be a pleasant environment to work in. More modern extensions of LEDE include RFZ and CID, which are similar to LEDE in some ways, but very different in others. You might want to consider those alternatives. However, after looking at your photos it seems it is too late for that.

The room dimensions (in millimetres) are:
4600 (length)
2800 (width)
2600 (height)

You are not gong to be happy with this, I'm sure, but it is what it is. Plugging those dimensions into a popular and well respected room mode calculator, the result is this:

-----
Room Dimensions: Length=4.6 m, Width=2.8 m, Height=2.6 m
Room Ratio: 1 : 1.07 : 1.76
Nearest Known Ratio:
- "24) A worst case scenario calculated by RPG" 1 : 1.075 : 1.868
-----

In other words, that room ratio is not good at all. It is not near any known good ratio, and is very close to a bunch of bad ones. You didn't explain why you chose that ratio, but you probably should consider changing it.

The wall construction consists of Green Glue resilient channel clips fixed to timber stud, and 24mm resilient channel.

Hang on a sec: If you used Green Glue Noiseproofing Clips, then why did you also use resilient channel? Those clips are not meant to be used like that, and neither is resilient channel. The GG clips are supposed to be used with ordinary hat channel, not with resilient channel! And resilient channel is supposed to be used all by itself, without any clips.

But that isn't the biggest issue here: looking at your photos, I strongly suspect that those metallic things running up the edge of your studs is what you are talking about. If so, then you have a huge problem. GG clips with hat channel CANNOT be installed vertically up the studs. Neither can resilient channel. Both of them can only be installed HORIZONTALLY, across the studs.

If you did what I think you did, then not only do you not have any isolation happening there, you also have a very unsafe situation: The drywall is not supported correctly, and sooner or later something is going to fail. You are REALLY not going to like hearing this: If you installed the channel vertically up the studs, the way it looks in the photos, then all of that has to come off. It just isn't safe. You have to take the drywall off, take the channel and clips off, re-attach the clips correctly, oriented horizontally, throw away the resilient channel, buy proper hat channel, install the hat channel horizontally in the clips, then attach new drywall to the hat channel in the correct manner.

I hate to be the bearer of such bad tidings, but what you did there is no use, and has to be undone.

I have considered going with a room kit such as the Primacoustic
I have also looked at Real Traps, which look good on paper in my opinion, but are quite expensive:

Those are both possibilities, and in the case of Real Traps you'll find that Ethan Winer himself is a member of this forum and posts here occasionally. I'm sure if you asked him, he would recommend Real Traps products!

But DIY is a very real, and less expensive option.

How many base traps would you use, and where would you place them?

It is a small room with very serious modal issues (due to the ratio you chose), so it will need major bass trapping. I would put large superchunks in all of the vertical corners (floor to ceiling) as well as some of the horizontal ones. Your budget might not stretch that far, so the second option would be corner absorbers diagonally across all of those corners. Big ones.

The door in that one corner is a problem, but perhaps a superchunk on wheels would work there

Would you use diffusers on the rear/side walls, or some other treatment?

The room is way too small to be able to use most types of diffuser. In particular, numeric-based diffusers would be a bad idea in that room. Not nearly enough space for the artifacts to smooth over. I would go with a more conventional small-room approach, with thick, angled absorption spaced away from the rear wall, absorption at the first reflection points on the side walls, more absorption between the speakers and the front wall, and probably yet more absorption in smaller patches on the side walls, checker-boarded and staggered.

What about the ceiling, would you use any treatment there?

Definitely. You have a hard floor so you need a soft ceiling. At the very least I would hang a large hard-backed cloud with thick insulation over the mix position. Hard-backed in order to help break up some of the modes a bit, and at least 10cm of absorption under that (preferably OC-703), since it will be at your first reflection points o the ceiling.

Would you leave the window as it is?

It is fine, just as it is.

What about the floor?

It is also fine, just like it is, except that I'm not sure if you can glue that type of wood directly to concrete. I had heard that that's not the right way to do it, but I'm not to clued up on solid wood floor installation. Maybe Brien can comment on that.

Bear in mind I want to keep some liveliness in the room for acoustic guitar tracking if that is possible.

Then cover the bass traps with 6 mil plastic before yo put the cloth front on, and do the same for the ceiling cloud and some of the side absorbers, but not the rear absorber or first reflection points on the side walls.

I hope that helps a bit, but your biggest problem here right now is not the treatment: it is fixing the safety hazard that is hidden in your walls, due to the incorrect installation of the resilient channel.

- Stuart -

[khurrm]

I've often read that tightly packed fiberglass is worse than loose, fluffy fiberglass, but my experience has been the opposite. I live in a 1958 condominium with single, unfilled drywall 2 by 4 walls between the living areas and staggered-stud 2 by 3 walls with batts of fiberglass sandwiched between 2 layers of tar separating the bedrooms. It's no surprise that the 2 by 4 walls let a lot of noise through, but the bedroom walls were nearly as bad. One obvious problem was that there was an open gap under the bedroom walls (probably to isolate them from the floors) through which noise could clearly be heard; just puling off the baseboards and caulking the gaps helped a lot. Eventually, I also added a second layer of drywall, which helped some more. My neighbor's new baby still had no problem getting through this barrier, so I filled the space around the fiberglass with tightly packed cellulose and topped it off with cat litter and sand. That seems to have conquered the bedroom problem.

[Soundman2020]

I've often read that tightly packed fiberglass is worse than loose, fluffy fiberglass,

It's not how tight or loosely it is packed that matters. It is what the density is. Optimum density for MSM damping is about 30 kg/m3 for fiberglass, 50 kg/m3 for mineral wool.

And if you pack it too tightly, then you create flanking paths, which reduces isolation drastically.

- Stuart -

[Soundman2020]

UPDATE to me comment above: It turns out that khurrm was actually a spammer, who has now been permanently blocked and banned.

- Stuart -