Caulk, sealer, mastic, silicone, etc....?

[qiktune]

Thanks for the input Bob, but the reason I'm here asking these questions is because I DON'T want to guess. I know what I need to do but unsure about which products I should use to achieve this. The opinion of the experts seems to change over time and as I'll only get one shot at this ( and being on a strict budget ) I want to know that I did the best I could with the knowledge I had.

Eg 1: 3 or so years ago it was a given that you would float a floor, no question. You'd do this by either constructing your walls ( decoupled from an existing structure of course )and then putting your floor in OR prepare a new concrtete slab and build on top of that....this was recommended for a build like mine and the ONLY way to get REAL isolation. NOW though, if you mention floating a floor in a case like mine it brings on aneurysms and guys start screaming "STOP!" in build threads.

Eg 2: Soffits. Ok, so the build threads I've read ( including Rod's book ) suggests that soffit mounting your speakers, in fact over on the Sayers forum it's the ONLY way to go. In the real world however, 90% of studios I've been in have their monitors on the meterbridge or independent speaker stands which tells me that it's not critical nor is it necessary.....but it is suggested otherwise. So do I soffit because they're the experts and telling me to do it or do I not because the studios I've worked in don't? In this case I'm going with the latter...it just works.

Don't get me wrong, I'm not bagging out John Sayers forum nor the guys on there. They give so much of their time and effort to help others realise their dream, I just get really confused about some things and know that if I come here and ask the Iced Vo-Vo brigade I'll get a real world, no BS answer.

[The Tasmanian]

I reckon if you can't mix a great sounding record with nearfields and midfields then you should give up.
So many many great records have been done without soffit's - and I personally feel they are a becoming a thing of the past (unless you spend big $).
Even mastering studios don't seem to employ soffit's these days - and surely these ME guys want the best monitoring money can buy.
Why is there so few studios with soffits?
Because you need to be prepared to spend so much of money and really know what you are doing to make them great. It can be a huge hole to throw money into - and a lot of studios who have done it hardly turn them on - unless they have employed a proper acoustic technician who has refined the room and the soffit's .
I know cause I have been asked to redo them after they have been installed.

And - I know some studios that have had to redo the soffits multiple times to get it right....
Also - speaker designs have come such a long way since the old days of soffit mounted speakers.
Remember - its all subjective. I know many a studio build that has had the "correct" acoustics employed - only to find that they need to get rid of some of it later when producers and engineers give them feedback on the lack of "real life" sound that the room permeates .

There is also nothing wrong with a floating floor - its the way the walls are built, and how they connect to the structure that really brings in all the problems.

[stosostu]

Qiktune, you're right, in acoustics there are any number of solutions to a specific problem, that is why I advise you to do the reading, take from it what you want and leave the rest. John Sayers board is great, a lot of good people trying to be helpful for free, BUT, I doubt that anyone who really knows how to design and build a studio is going to design one for you completely free, if they are that good they'd be in demand from studios that will pay big money for their services. On the other hand, no one knows exactly what you want like you do, no one really understands you budget and whether you would rather spend more on one great mic, or use a cheaper mic and spend the dough on more soundproofing. All studios, even at the highest level, have to compromise in one way or another. I recently visited the brand new studios of the SA Film Commission and had a lengthy discussion with the acoustician about the compromises they had to make, and they are spending our tax dollars, not what is left over after the household bills are paid. Another important point he made was that what is right on paper, may not work in practice. After having the entire studio designed by the best acoustics companies from here and overseas, he was telling me about things they now have to do to overcome problems with the acoustics.

So, IMO, your best bet it to read the two books I suggested, ignore the stuff on major studios, and even mid range, from what you've said that is not what you are building. Once you have the basics then apply that to your particular circumstances, if you have specific issues run them past the folks here or a John Sayers, but do your own design to meet your requirements. Then build it. There will probably be issues, hopefully not major if you've done the design work based on good basic princples, but once it is built you can fix these by making refinements, adding some absorbtion, reflection or refraction, or just work around it. It will not be Studio 1, Abbey Road, but it probably will be what you need and that is the important point here.

It is impossible to get a design that will have no problems, as the SA FC example shows, but you can minimise the problems by understanding the basics and applying them.

To address a couple of the issues you raised. Floating floors are usually outside the budget of a small studio and are often not necessary. If you are building and a concrete raft floor, like most garages and a lot of modern homes, then the coupling through the floor will be less than you will be able to achieve in walls and doors etc. A concrete raft is also closely coupled to mother earth, which is a great acoustic absorber. Build your rooms on the 'room within a room' principle ensuring that there are absolutely no points of contact between them. If possible use the staggered stud method of wall construction. Ensure that you only have double leaf walls, triple or more leaves will reduce isolation. I know this seems counter intuitive but it is true. A double leaf wall will have a Mass, then an Air Gap (which can be filled with rockwool or similar) and then the second Mass. The more dense the mass on each side the better, two foot thick stone walls would be excellent, but a double layer of plaster board (gyprock or whatever it is called where you are) is more practical and in a home studio, usually sufficient. Ensure that both the mass layers are airtight, this is the MOST IMPORTANT thing and this is where the Firesound caulk comes in. You need something that will make an airtight seal but still resonate in a similar way to the plasterboard and exhibit similar absorbtion coefficients, hence Firesound rather than other products that may or may not do the job. The thing with Firesound is that it was designed and has been tested and proven to do exactly what we require in studio building, other products haven't. They may work, but you won't know until the studio is built and if they don't it's a crap job to have to tear it down and start again

Soffits. Soffiting speakers has several advantages. Because the front of the speaker is flush with the 'wall' and the wall becomes an infinite baffle, then you don't have the defraction problems associated with sound reflecting from corners behind the speakers. The overall result of soffitting is improved bass response, which is often a problem in small rooms like home studios. This is all well documented on the web so I won't go into detail here. So, why don't all studios soffit their speakers? Well, probably many reasons. They may not think it is necessary, they may mix entirely on near fields, they may want the option of changing thier monitors regularly, they may have a huge room which doesn't lack bass response, they may be renting the facility and the landlord won't let them or they may think that a new Neumann is a better bang for their buck. Like I said above, every studio is a compromise.

Good luck with your studio, make sure that the compromises that you make are YOUR compromises, not someone elses.

[The Tasmanian]

Well said Bob - sums it all up nicely.

[qiktune]

Thanks guys.

I really only wanted to know if anyone here knew why there's been a recent shift in thinking as relates mass in wall construction as at the moment I'm completely focussed on geting the isolation aspect nailed.

[stosostu]

What shift in thinking regards mass in sound isolation are you referring too? Generally, the more mass the better and the lower the frequency you want to isolate then the more mass you need.

[qiktune]

Since you guys have all been so amazingly helpful to me I wonder if you can help me with the other question I have re insulation. I asked over at the Sayers site but things tend to get lost in translation since there are different products globally with either the same "name" or reffered to in the same way.

Filling up my wall and ceiling cavities with "pink fluffy stuff" is suggested but it seems that the pink fluffy stuff in Oz has a too low nominal density eg, Fletchers Pink Batts which are 8-10kg/m3. I've made a lot of enquiries but can't seem to find anything around the suggested 25kg/m3....beyond that it's Soundscreen which is 38kg/m3 and apparently too dense for a MSM construction. The idea being that I should use Glasswool for the exterior of the room and Rockwool for interior treatments.

Sometimes I just get so confused and think "hell with it" I'll just use the pink ( or yellow ) stuff that's all over ebay at the moment and completely fill the cavity with it rather than just placing it between the studs. Have any of you guys thought the same when building your rooms? Just get what is available and affordable and double up the materials that are cheaper...eg, lighter insulation in conjunction with an extra layer of gyprock.

[stosostu]

If you refer to the Bradford Insulation Acoustic Insulation Design Guide, page 15 for low frequency perfomance comparison, and on page 17, you'll see the STC comparison table for the various formats of wall with no insulation, glasswool insulation and standard rockwool and Soundscreen.

This can be downloaded at http://www.google.com.au/search?sourcei ... sign+guide

This document is another great source of information for your acoustic design, and, once again, its free. There is a whole section on recording studio acoustics from page 52.

Another great, free, resource on acoustic design is the Red Book, http://www.gyprock.com.au/downloads/dow ... 7_62e5.pdf

The table which starts at page C6 in this document lists the acoustic performance of a huge variety of wall construction methods and materials.

You are much better off refering to these documents than getting second hand information from the various sources on the web. Whilst people on these sites are generally well meaning, they are often misinformed or at least they have incorrectly interpreted what they have heard.

[qiktune]

Thanks for the effort and the links Bob.
I had a read of the Bradford stuff I thought may relate to my situation but their suggestions are based on an existing structure. Even the "ceiling/roof" section which I was quite interested in learning about advised to add sarking to underside of roof tiles, use rockwool between ceiling joists and then for added isolation throw their "Soundlagg" heavy vinyl blanket over the top of it. Hmmmm....

Kinda going around in circles here - all I need is advice on which products ie batts, I appreciate that you feel I need to understand "acoustics" before proceeding but the more formulae and numbers I read and look at the more confusing it becomes. Had someone told me when I was learning to play guitar that I should learn to read the dots first I would have given up on the spot, if you know what I mean

[The Tasmanian]

Brett - I know it all seems daunting, but It really is so simple at the end of the day.
Putting aside all the acoustic design stuff - all you need is density, and absorbent voids.
If it was me I would use the best batts I could get put them into any void you have, float a floor, use 2 layers of Yellowtounge as the floor basis - add some nice floorboards/carpet to some sections, build the walls standing on the floating floor, and use 2 layers of yellowtounge for the walls plus one layer of half inch fire rated plasterboard. .
Do not attach the walls to the existing structure - let them lean against rubber or neoprene
Done.
If you need to hang a ceiling then it gets tricky - but there exists neoprene ceiling hangers - and the same as the walls - 2 layers of yellowtounge and one layer of 1/2 inch fire rated plasterboard.
Done.
Then get onto the acoustic panels for diffusion.
Its not rocket science - its just mass and common sense.
All the above works - without fail.
I hope you are not renting though.............

[qiktune]

No, not renting

So in a nutshell....just f*$cking get on with it is what you're saying. I will, thanks Chris.

[EvLoutonian]

Hi Brett and Co.

Was interested to read through this post as I'm about to get onto the ceiling of my own recording space (two room) in the next week or so. (and wall cladding etc following after)

Brett, did you end up using any of these membrane type layers between your plasterboard layers?

Cheers,
Evan.