Acoustic treatment

Riaan

Hi everyone...since it's such a miserable rainy Sunday and everyone seems to be under their duvet's, please help me think about acoustic treatment for my little studio space which is nearing completion - it will be painted this week. To bring you in the picture: I've converted my old double garage and ended up with a 4 X 5 X 3.5 meter room with a ratio of 1:1.14:1.43. Total volume is 70 square metres, which is what I aimed for in the mistaken believe that a lesser volume would be useless in terms of acoustics. So this will be a one room studio which will also double as my study (i.e. place to hide).
In terms of soundproofing: The entrance will have a double aluminium sliding door, and the window similarly a sliding aluminium window on the inside. The slanted ceiling inbetween the exposed rafters is 2.5 cm Isoboard with a thick layer of Isotherm on top of that, below the asbestos-like roof plates. It's double brick walls all around. This will have to do in terms of soundproofing, and if anything still leaks in or out we all will just have to live with it, neighbours included.
Now the acoustic treatment: It obviously sounds like the Kango caves in there at the moment, much to my three year old girl's delight. The reverb time will improve with some carpets/ruggs and thick curtains at the entrance and window, and with some furniture.
It would have been great to get an acoustic expert to measure RT60, room modes and whatever else, and recommend treatments, but I'm afraid it's all going to be DIY and that by somebody who has zero experience, minimal background knowledge but a few books and an internet connection, and significant budgetary constraints... ☹
Bass traps for the corners will be my first project. How does one determine what type, what dimensions?
Some panels against the wall will be next. How many, what type if the exact Sabins needed is a thumbsuck? And where to place them?
Or am I nitpicking too much here?

Riaan

I tried to post some pics, but it says "upload folder full"

AlanRatcliffe

You are nitpicking a bit, but it's easy to do so with acoustics. I did that with my last studio, but the latest one is more of a music room and I haven't even put up any of my acoustic tiles - I have a stack of them piled up in one corner as an impromptu bass trap. The only thing I would have done different is your ceiling - the exposed beams are connected to the asbestos plates? If so, they are going to transmit sound directly to and from the roof. Covering them with the isoboard (preferably suspended) would have provided a much better STC.

Clutter is good. Once you get furnishings in the cavernous quality will mostly disappear. If you get enough stuff in the room, everything acts as a diffusor, basically obviating the need for mid and high frequency control. What is going in the room, BTW?

You will need to make sure that the short reflection points from your nearfield monitors have some absorption (don't forget the ceiling!), but that's the only essential thing if you've got some clutter. Once you've recorded some stuff with mics, you're going to get a better idea of whether you need more absorption or not.

The bass trapping is a different story. There's no need to go tuned unless you have a particularly nasty standing wave - which shouldn't be a problem given your room ratios. So, all you need is some broadband bass trapping. From what you said before, you're not pushing the volume and you don't have a drum kit or large bass amp, so that should be plenty. The easiest/cheapest way to approach this is to mount some rigid fibreglass across your corners, just the two corners behind your monitors should be enough - about four panels. If you want a bit more bass absorption, you could make some tube traps for the other two corners. Tube traps have the advantage of being moveable, so you could store them and only bring them out when you need them.

One thing you might want to invest in for a one room studio is an SE Electronics Reflexion Filter:
http://www.soundonsound.com/sos/jun06/articles/reflexion.htm
http://www.eqmag.com/article/se-electronics-reflexion/Oct-06/23512

Riaan

Hi Alan, thanks! Yes, with hindsight that ceiling wasn't such a great idea - I realised that yesterday when I clearly heard the rain falling on the roof ☹ But I may still cover the exposed beams with isoboard, I've actually been thinking about that purely from a cosmetic point of view and it's also possible to construct a hanging ceiling should it be necessary.

I will probably fill the place with all sorts of bits of furniture and stuff rather quickly...that's what usually happens! There will be a large table/desk customized for the DAW, monitors, keyboard and maybe a small rack. In terms of furniture there will be a couch the size of a single bed, another desk and PC for admin/work things and lots and lots of books. Guitars will be hanging from wall mounted hooks.

It's unlikely that there ever will be a drumkit, but then again you never know! Nor a large bass amp, though I probably at some point will get a bass guitar but that will be recorded DI - I will at most get a subwoofer for the monitors. My guitar amp is only 30 watts. At times there may be two of us jamming, each with an amp, but it will mostly be just me. Other real instruments may be some classical ones - violins, flute/recorder, etc. or classical guitar. A number of my colleagues at work are classical musicians and I'm planning on bullying and blackmailing all of them into collaborating with me on a few ideas in a yet to be defined genre of music... ?

But I will in all likelihood end up going the software modelling route for my guitars and the loudest equipment will be the monitors. Speaking of which...there were some KRK's and M-audio's recently on Gumtree, in the R3K to R5K range. Any recommendations? For the time being, my hi-fi speakers (Infinity) will have to do until I start expanding my equipment.

AlanRatcliffe

Suspending the ceiling will work best by far. Otherwise if you join another layer of isoboard directly to the joists, it will just transmit sound directly to them and this directly to the roof.

One thing I forgot to mention is that your sliding doors will work to add a little bass trapping to the room.

I have a pair of KRK's myself - the V8 Series 2's. I actually preferred them to the Genelec and Mackies in higher price brackets. Other than spending an absolute fortune on a pair of much more expensive Adam Audios or Tannoys, I couldn't be happier. The KRK Rokit series are great value for money and have a better bass end than most "budget" monitors in the same range. Infinitys are good HiFi speakers, but you'll notice a big difference in clarity and less "hyping" when you get a pair of decent powered monitors.

If you are going to get a sub, look at the 6" or smaller monitors first. Otherwise, try get something like an 8" and you won't need the sub unless you move into dance oriented stuff. Also, if you are planning on going surround at some point, start with smaller monitors (like 4" or 5") with a sub, then add in your surrounds and middle channels when you can.

Mr-M

+1 on the KRK V8 V2s. Really nice monitors and have AB'd them with several monitors from EVENT and Genelec in stores and they were my favourite. I like 'em alot but can't justify the cash. I'll stick with my trusty EVENT TR6s, which are really good fro the money (I prefer them to the KRK Rokit 6s).

A friend has Mackie HR824s in his studio which really impressed me, but of course I haven't tried them next to the KRKs. I'd take either of them if I had the $. ;D

Another mate of mine has ESI Near 05s that sound surprisingly very good, especially for under R3000. Quite impressed with them considering they are entry-level 5-inch powered monitors. Might be a good option for a first set of monitors.

AlanRatcliffe

A friend has Mackie HR824s in his studio which really impressed me, but of course I haven't tried them next to the KRKs.

I did. Very nice and detailed, but with a touch more forwardness in the upper end than I prefer. Also, the slightly tighter low end on the V8s really did it for me. I'd been using Alesis Monitor Ones for years (the passives - which are still going strong, hooked up to my Wife's PC), so the added and tight low frequencies were my main focus.

Mr-M

Alan Ratcliffe wrote I did. Very nice and detailed, but with a touch more forwardness in the upper end than I prefer. Also, the slightly tighter low end on the V8s really did it for me.

I didn't really notice the upper end forwardness of the Mackies (we're talking months apart on hearing them) although I did find them very detailed as you said. But if you put it that way, I'd also go for the KRK V8s then if I had the $.

Riaan

Suspending the ceiling will work best by far. Otherwise if you join another layer of isoboard directly to the joists, it will just transmit sound directly to them and this directly to the roof.

So I decided to go for the suspended ceiling. Took me a few weeks to do, having had to save up first and do the work all by myself over free weekends. Finally completed it this weekend! The ceiling now only is in contact with the joists through the wires that suspend the framework. For good measure I added a 5 cm layer of fibreglass (pink aelolyte) on top of the suspended frame, and installed a 3 cm thick layer of Isoboard on the underside of the suspended frame. I think the extra effort will be well worth it in the end, and the ceiling looks cool too! And the whole thing survived a fierce Cape storm this weekend without collapsing on my head... 8)

AlanRatcliffe

Riaan wrote So I decided to go for the suspended ceiling.
<snip>
And the whole thing survived a fierce Cape storm this weekend without collapsing on my head... 8)

Ahh. brilliant. If your weather this weekend was anything like ours, then that ceiling has more than proved your construction abilities.

Riaan-Combrink

Alan Ratcliffe wrote If your weather this weekend was anything like ours, then that ceiling has more than proved your construction abilities.

Can you guys believe I had to carry my PA, guitar, etc into and out of a club on Saturday night / early Sunday morning?!! Worst storm in goodness knows how long and there were still punters in the venue. Some guys don't know when to hang out at Club Duvet , for sure ?.

Riaan C

Riaan

Just a quick question about bass traps: How expensive are Auralex corner traps? Where can one get hold of them? Is it worth getting or would DIY bass traps constructed of wood and compressed fibre glass be as good?

AlanRatcliffe

Doing it properly with some wood and rigid fibreglass (Owens Corning Energylite 47.5 or Energylite 96) across your corners is actually more efficient at damping the bass, but doesn't look anywhere near as good as the Auralex, which is also damn expensive.

The Auralex LENRDS are about R2,500 retail for a box of four, or you can get the ATOM 12 pack with 12 LENRDS and 4 CornerFill cubes for about R7,000 retail. That's November 2007 prices, so check with them.

Owens Corning in Cape Town:
Tel: 951-1167.
Contact names:
- Bruce Murray
- Trevor Henwick
- John McEnvoy
- Marieta Foord

You can get Auralex products from Alec Surridge at True Sound Acoustics:
021 982 4915
021 982 4916
084 019 5111
truesoundATmwebDOTcoDOTza

Riaan

Thanks Alan. I thought Auralex was gonna be expensive...wow...so it's the DIY route for me then! Glad to finally get a contact for Owens Corning!

Alecsu

Hi Riaan
Alec here from TrueSound Acoustics, just joined and already I'm plugging my products. Please talk me through what you need and maybe we can be of assistance. Quite a few people have said that our products are expensive but we have alternatives and even do custom application products. And as to the expense, unfortunately it comes down to the Rand, as I'm sure you are aware, secondly, what most people don't realise is that all our products are fire retardant to some degree. In terms of people's insurance this plays a major role if anything happens. Building your own traps out of the wrong materials, and I'm not saying Rockwool or the like is the wrong material, but I know of local guys manufacturing foam based panels that are not flame retardant and if your insurance were to find out about this there will be issues.

I've known Alan for many years and he uses a couple of things that I import, Let me see if I can be of assistance, if not, then there was no harm done.

cheers
Alec

AlanRatcliffe

Hi Alec! Welcome - and thanks for joining.

<admin_hat>: please note your affiliation with TrueSound in your signature.</admin_hat>

Nice to see you here, hope you're going to hang around a bit - there's quite a few metal players around here. Post an intro in the Introductions Board and they'll come crawling out to greet you.

The Auralex Mopads I got from you work a treat, BTW. ...and I must still get an SE Reflexxion Filter from you sometime.

deanBailey

Alec pretty much build my studio from scratch, and it's doing it's job nicely ?

Riaan

[quote]Alec here from TrueSound Acoustics, just joined [/quote] Hi there Alec, sorry I only saw your post today. Welcome to the forum! Yes, I'm in the process of completing my "guitar room"/home studio. It's been quite tough, as I had a limited budget and did all of the finishing myself, including a suspended ceiling. It's just been painted, and I've put up some guitar hangers - see pic. The foresight that I'm know for, and that serves me so well in other spheres of life, once again did not fail me and you'll notice more hangers than guitars....hehehe! As far as the acoustic treatment is concerned, I'll get to that in the next few months only. I still got to move the rest of my stuff in there and build some bookshelves, cupboards etc. In the meantime I'll save... I'll contact you - would it be possible to come and do an assessment in Worcester?

FatBoy

Riaan my man, I can already see some UBER jam night happening in that there room. I know you've been working on it for quite some time, I'm sure it will all pay off in the end, it's looking great so far!! Nice guitars by the looks of things, and yes, one can never have too many hooks ? Good job dude!!

Riaan

Thanks Fritz - yes, it would be great to have a jam in there sometime. Maybe we should have a kind of GFSA housewarming jam with dop & tjop once it's completed. Only challenge would be to get the Cape Town folk to venture so far out of civilisation... ?