John Sayers' Recording Studio Design Forum Archive

Hi Ron,

Firstly, I would definitely trust Stuart's advice over my own, and I am only advising you based on a mere freckle of experience compared to Stuart, so I am just sharing some observations I have made while researching this topic.

I too will struggle to source Homasote, in fact, unless I fly over to the states and get lucky enough to find enough of it for my space and then pay for a shipping container to export it over to me in the UK then it will be impossible for me to find any here!

I've mentioned this in another thread but some people in the past on this forum (and with John's blessing) have used those fiber underlay boards that are put under laminate flooring. They're usually green and come in a few different thicknesses. It may not share all of the same qualities of Homasote, but in my mind, it would hold it's shape well enough once hung to provide a good base to stick the insulation on to, it's light, easy to cut and it's dead cheap.

Also, bear in mind that Philip Newell uses heavy ply for in the innards of his hangers, it's a more expensive option than the fiberboard but might be cheaper than the homasote and certainly easier to find. If you can support the weight of it then you could try that?

Another design used by John Brandt is instead of hanging the baffles, you build the waveguides out of MDF which are attached directly to the framing at angles and then the light fluffy insulation is placed inside. There's a couple of advantages to this: MDF is easy to find and work with and the weight is supported by the floor and walls. The main difference in the design is that the waveguides no longer hang, so they are not free to move, and I suspect this ability to move freely is what helps them to dissipate energy. Though I have never personally tried it, I do trust John's methods, he has a very good reputation as a studio designer and is very well respected by other acousticians.

So those are my thoughts; If you can find homasote and can afford it then that would be the number 1 choice, but if you can't then (like me) you are forced to find another solution.

Thank you Paulus87, I will take it into account.

Well, I’m back after 3 months of caregiving for an elderly father in all my spare time. Got some help with that and am now able to put some time in again to move forward on the studio.

I drew up the plans, finally, on the whole front end soffit area. Here is the view showing the framing, bass traps and insulation (in gray). Following advice, I changed the hangers to be ½” homasote and 2” fiberglass. All of the gray insulation is Roxul safe-n-sound. Another view without framing: …and another view of the complete unit: (pay no attention to the grill colors, still to be determined)

The speaker enclosures are pretty-well lined with Roxul. The middle bass trap sections aren’t so deep and I didn’t find room to line the back with Roxul because the hangers would loose so much depth. Any thoughts on that? The total depth of the middle frame to the wall is 11 3/16”.
Hoping to hear some good comments, please!
It sure is exciting to be back at it again!
-Ron

"Nudge - Nudge"
It's been a couple of weeks since I posted. Any time available to answer my questions?
Grateful for your time -
-Ron

Still hoping to get an answer after 3 weeks since March 18th. Is there a concern about the bass trap sections above and below the control room window? It's only a little over 11" deep and I have it filled with hangers. Is it a problem that the back wall is not lined with Roxul like I did behind the speaker areas?
I'm gathering materials to get going on building the whole front end and want to be confident on the design.
Please comment. I would be most grateful.
-Ron

Ron,
Personally I would line the back wall but take a look over at John Sayers page. He shows it lined

http://johnlsayers.com/Recmanual/Titles/Acoustics3.htm

T

Tom,
Thanks for the reply. I took another look at John's drawing and I see what you mean. It will take off a lot of material from each of the hangers, but I guess it's for the best. I see that it also shows another layer covering the whole front too except for a space at the bottom (I assume for ventilation). I'm wondering about how important that is too.

Hey, I see you're just around the corner from me. I would love to see your studio! What are the chances some time? I work in Lake Oswego.
-
Ron

Hey Ron,
You are invited any time. Shoot me an email ... tom@lost-studios.com

Not sure about another layer in front of the hangers. If it helps or hinders
But the gap is for ventilation if you are using active monitors
Peace
T

Thanks Tom!!!! I will shoot you an email soon!
-Ron

I see that it also shows another layer covering the whole front too except for a space at the bottom (I assume for ventilation). I'm wondering about how important that is too.

Right. That actually sits in front of a wood panel (eg, MDF), which is a continuation of the front baffle of the soffit. The insulation in front of that helps with reflections coming back from the rear face of the desk, the console, video screens, etc., as well as other things.

But the gap is for ventilation if you are using active monitors

Actually, it's for passive monitors too. Speaker drivers are very, very inefficient at converting electrical power into acoustic power. To put out 120 dBC SPL, you are producing about one acoustic watt. A good speaker with decent efficiency might need a few hundred electrical watts in order to produce that. A very high efficiency spekaer might manage to do that with just 100 watts of electrical power... guess where the rest of that power goes? Right. Heat. That "missing" power ends up as heat inside the driver, which is then dissipated inside the box, and into the box, and some even radiates out through the cone. It doesn't cause much temperature rise when the cabinet is sitting on a stand, out in the open: you wouldn't even notice that the cabinet is very slightly warmer than air temperature. But when you enclose the cabinet inside a soffit, with insulation all around too... well that heat can build up. So you still need ventilation. It's probably not a big deal at all if you have smallish speakers and mix at low volume all the time, but if you have big speakers in there, or you like to monitor loud most of the time, then it can be an issue. I always play it safe, and put in vents. It costs basically nothing to do that... compare that against the cost of replacing your fried speakers...


- Stuart -

The speaker enclosures are pretty-well lined with Roxul. The middle bass trap sections aren’t so deep and I didn’t find room to line the back with Roxul because the hangers would loose so much depth. Any thoughts on that? The total depth of the middle frame to the wall is 11 3/16”.

Stuart, do you care to comment on my previous question? Is it better to loose depth on the middle-lower section in order to put about 1.5" of OC 703 to line the back wall or just leave it as is (unlined) and have a little more depth on the hangers?
-Ron

Darn! I keep replying late to your posts! Sorry about that.... I'm tracking a ton of threads at once, and sometimes one or two slip through...

Anyway, I agree with Tom: you do need a couple of inches (at least!) of insulation on your walls, behind the hangers. Also on the floor and ceiling, above and below the hangers. Part of the way hangers work is to redirect the sound waves away fro their original path, into the walls behind where they can be partly absorbed, then partly reflected back, but at a different angle, where they will hit the hangers once again.. So you need thick absorption on the walls, yes.

- Stuart -

Hey, thanks Stuart. Thought you were off building a studio in some remote place! As you can see, I haven't been on the forum for a bit - for a good reason: I've been building the left and right speaker soffits in between life obligations.

I will line the back wall with insulation.
* Would Roxul 3" safe-n-sound work too in places, or must it all be OC 703?

I need to download REW soon and start the learning curve. I expect it will be necessary to buy a suitable mic. I need to research that.

Here's a photo of the soffit progress. I haven't framed in the spaces between yet.

Ron,
Opposed to buying a mic you can borrow mine if you want.
It has one use and one use only
Let me know
T

Wow! Thanks, Tom! How very nice of you!
Even tonight I was going to email you about visiting your studio.
I'll fire you an email now...
-Ron