SOUND ON SOUND

[Thomson_Thomson]

Hi all,

Long time reader and first time poster here.

I am currently in the design phase of converting my garage in to a small studio and have a few questions regarding acoustic panels so here goes.

Most of the panels that I have seen have the side walls in direct contact with the wall of the room. Would it be more efficient to put the panels on legs with rubber feet and allow a gap in the back of the panel? I think this would help with potential vibration noises.

Would the gap I mentioned have any impact on absorbed sound waves? i.e. They would be absorbed one time and anything remaining would bounce out the back as opposed to a box design that would absorb at entry then absorb again as they rebound out the front.
I have made a drawing of a potential design. Note that this is only one idea for now and I have a few different sizes in mind.




Regarding corner traps, would it be beneficial to simply plasterboard diagonally across the corners and put acoustic panels spanning the width of the diagonal sections and tuned for low frequency absorption?
Like this -


The other two corners will have soft furnishings and storage in place.

As I am still in the design phase, I would really appreciate any sort of feedback, positive or negative.

Thanks

T

[blinddrew]

Hi Thomson_Thomson,
Not sure about everyone else but those images aren't showing for me. Most folks host on imgur and link to the thread.
However in principle mounting your absorbers away from the wall will increase their effectiveness at lower frequencies.
A quick Google will find you a table for frequency absorption material depth vs effective frequency but you can work it out from first principles: to be fully effective the depth of the material has to be at least a quarter of the wavelength of the sound. A quarter wavelength being the first anti-node for that frequency.
At 20Hz that wavelength is 17m, so you can quickly see how managing bass frequencies in project studios is so difficult. Adding 4.25m of absorbers isn't going to leave much space in my downstairs room! :)
You will probably also have gathered from this that you want your corner pieces to be the full depth of the corner. Or at least place your absorbers across the corner with free air behind them.

[Music Wolf]

For the corners I would recommend 'super chunks'. i.e. triangles of Rockwool stacked floor to ceiling to fill the corner and faced with Cara fabric stretched across a wooden frame.

For the walls I suspended my absorbers from the top corners and then spaced them away from the wall with a cardboard tube at the bottom. No need to fix the tube, the weight of the absorber will press it to the wall and hold it in place. I get an additional 40mm gap this way.

[Thomson_Thomson]

blinddrew

I have tried to use Imgur but unfortunately I am currently working on a boat in the Atlantic, just off the coast of West Africa and my work's spam filter has blocked any sites like that. Luckily, Google Photo works.
I'm not sure why you aren't seeing them as I tried on a few different devices first to make sure that they were coming through on preview first, before I posted.

I see what you mean with the gap, it would have to be enormous to make a noticeable impact. What I could do is just make a couple with legs and a couple without and swap them around to see if I hear a difference. It's no issue just to whack the legs off if they aren't making any impact.
The problem then is that there would be no air gap whatsoever without legs, even internal to the box frame.
I just came across this article by Primacoustic. An interesting insight there. http://www.primacoustic.com/broadway-panels/science/

Music Wolf

Ok, so plaster boarding the corners wouldn't be worth while and it would be better to make them 90 degrees with corner wedges instead?
The void space behind the plaster board would be insulated anyway but I figure that because it will be double skinned with a bond between the two layers, all that the insulation is doing in there is helping to keep the sound from escaping to the outside world.

[Wonks]

You may be linking to the page the photo is on, rather then the photo itself. Click on the picture, so only that is displayed, then right click and you should get the option to copy/save the image location and that should work.

You'd normally expect to see .jpg or .png etc. at the end of the web address for the image to work. Otherwise, check that the pics are set for public viewing.

[Thomson_Thomson]

Right, I think I’ve found a workaround for the images.
It depends where I am on the vessel.
If I’m in the office, I can’t access Imgur via wired network as it passes through the corporate spam filter.
If I’m in a recreational area, I can connect via public WiFi where the filter rules are a bit less strict.
I’m off shift now and away to go to bed but I’ll get them uploaded tonight when I wake up.

It looks as if the google pics don’t work on mobile devices and only pop up on pcs. I definitely copied the URLs correctly.

Never mind, watch this space.

[blinddrew]

blinddrew
I see what you mean with the gap, it would have to be enormous to make a noticeable impact. What I could do is just make a couple with legs and a couple without and swap them around to see if I hear a difference. It's no issue just to whack the legs off if they aren't making any impact.

I think you may have slightly misunderstood point, it's not that it won't make an impact when close to the wall, it's just that the range of frequencies that are affected* will be smaller. A 2khz frequency has a 17cm wavelength so the quarter frequency distance is 4.25cm, so you'd expect a 5cm panel to be effective. Mounting that same panel 5cm from the wall will extend its effectiveness down to about 900Hz - which is obviously including a lot of useful frequencies. So even relatively small gaps can have a worthwhile impact.
Make that 10cm panel, 10 cm from the wall and you're providing good damping right down to 450Hz (and limited affect beyond that).

* Obviously this all assumes you're using a material that is effective across a broad band of frequencies, but you've already read about that. :)

[Thomson_Thomson]

Here are the images (finally!).

The first one shows the panel design. It's a narrow panel but there are plans for wider ones too.



The second one shows a birds eye view of the garage after the plasterboard has been applied. See how I've put the corners at 45 degrees but as discussed already, I might put these back to 90 degrees and put panel wedges in place instead.



Please can somebody tell me if they can see the images or not. Thanks.

[zenguitar]

Images are visable to me. :thumbup:

So while I will be of no use helping out, at least we can expect that those who can help will be able to see them :)

Andy :beamup:

[Thomson_Thomson]

Bravo!
:clap: :clap:
Much happier now.

[Music Wolf]

Hi

Yours looks to be a very similar layout to my own humble studio (also a converted garage). My door is central to the back wall I have a window on the front wall.

You'll see that I've also hung a panel above the mix position. Don't overlook the space above you or below desks. The problem with a small space - you need as much absorption as possible whilst having nowhere to actually put it.

[blinddrew]

Yep, images now visible, along with a very useful starting template from MusicWolf.
It's worth remembering that it is possible to overdo the treatment. Because any practical panels will have a disproportionate influence at higher frequencies, if you overdo it you'll just end up with a really dull sounding room.
So corner chunks and mirror points (as illustrated by MW) is your starting point. Then see if you need to do anything more.

[Thomson_Thomson]

I know what you mean. Lack of space is a bitch which is why I'm thinking long and hard before I start to put some intensive labour in to it.
It's not a big garage, 2.5x4.5M, and rather than removing the door and putting a window in, sealing it is the way to go.
Were you not concerned about load on the ceiling with that panel?
I like what you have done with your cables. It's much better to hang them than to have a box that resembles a snake's wedding.

Tonight I've been busy re-designing the corner panels, making them wedges instead.
Here's the idea.



I have made scale drawings too but they will probably need to be altered once the ceiling has been completed.

[Thomson_Thomson]

Blinddrew

I have made a rough sketch of a potential layout with panels too.
What do you think?

[blinddrew]

Looks promising. Start at the right hand end and move along as required. Though I'd definitely consider a cloud at the ceiling mirror point before moving further down the room.
Are you intending to record in there as well or is it just for mixing?

[Music Wolf]

Were you not concerned about load on the ceiling with that panel?

The cloud absorber is fixed to the ceiling joists.

I screwed eyelets into the joists and the absorber frame then fixed them with these. Same for the wall mounted panels.

[Thomson_Thomson]

I haven’t drawn the roof stuff on yet, except for the electrical layout (in another drawing).
To be honest, I was just going to experiment with foam panels until I got the desired effect but a cloud panel above is definitely food for thought.

The goal of this studio is to finally be able to reclaim my gear out of the loft which was put there to make way for my new born son last year. We had just moved in to our new house and the room that was earmarked for a music room is now his bedroom.

Initially I only wanted to play and do some small scale recording of my own stuff but a few friends in the know have shown great interest in this project and have convinced me to broaden my horizons a bit and take a few folk in for sessions.
This for me is quite exciting as I’ve never really recorded anyone else before and it will definitely be a big challenge at first. But without getting too carried away, the studio needs to be ready first.

That’s a good idea for hanging the panels. There are also heavy duty saw tooth picture hooks for the wall stuff too.

[blinddrew]

If you're planning to record in there, definitely take a gradual approach to adding treatment. You don't want to end up with a recording environment that kills all the top end, otherwise you'll end up adding a load of reflective surfaces back in.
A reasonably common approach is to have a 'live end' and a 'dead end'. The dead end is generally where your mixing will be done and you can record at the live end (or however far down the room gives you the best compromise).
At which point it's worth emphasising again that anything you do in a standard domestic sized room is always going to be a bit of compromise, but you should still be able to get very workable results out of it.

[Wonks]

You'll probably benefit from putting corner bass traps in in the two rear corners, but if you really need the storage and the coat rack in those positions, then you'll have to do without. Though you might consider trying to fit in some 1/2 or 1/3 height corner traps if possible. It all helps, as the bass end is always the area that's hardest to tame and suffers most from standing waves.

[Thomson_Thomson]

After some good advice from you guys, I've had a play around with the drawing again.

Side panels in the 'live end' have been removed and will be added after the room has been finished. It might even be worth making the side panels portable so that they can be placed when & where needed. This would also free up some wall space to hang guitars etc.

Coat stand removed. This was just there for aesthetics more than anything else.

Corner trap near the door added.

1/4 size corner trap above the storage area added. Storage is important and I really don't want to lose it. I could always panel treat the cupboard doors if they really need it

Cloud ceiling panel added to the 'dead end'. Exact placement position still TBD.

The two side panels in the 'dead end' have been left in but I fear that they may be too narrow (340mm) although it isn't a problem to alter the sizes. The heater would have to be moved a bit.