What to do about sound leakage WITHIN a space?

Greetings Folks, Well I'm back after a few month delay, been pottering around as a freelancer and teching and putting the studio on hold as I continued to look for the right space. I've found a space now that I've taken over that for many reason I'll list is RIGHT, before I get onto the MANY wrong!!! RIGHTS 1. The space was built a studio and has operated as one for 2 years with an established client base and I've taken it over on a 3 year lease, so too late to back out now... 2. It is situated in a creative complex called the 'Old Castle Brewery' housing 30 other businesses in the creative arts i.e graphic designers, animation studios, video production companies etc and I'm the only studio, so the potential for work from within the building alone is nice. 3. Isolation from the outside world is great as the studio is situated in the cold storage unit of the Old Brewery (it was a working brewery built in 1899, and was partitioned up/out in the early 1980's) with 3 walls of 1m (3 and half feet) of brick, with a single window. There is one neighbor on the other side of me where there is heavy set drywall (the thinner wall on the plan below) and even with the current status of the studio walls (which I'll get to under WRONGS) are happy with the noise or lack of, generating from it. 4. The actual studio layout seems to be quite solid with lots of care being paid to the HVAC system. Which has a fresh air duct that brings in fresh air, a mini split cools it, the air is then drawn into the rooms through baffle boxes and extracted out of each room through another baffle box to the outside world,much as described in Rod's book, totally isolated from each other. Here is the layout (all measurements are in millimeters): 5. There are no parallel walls though the windows are a 3 leaf design, which I'm not sure is a good thing but sealed up nice and tight. Here is pic of the control room. Okay... so I have a 'nice' space, in a creative complex, no neighbors to worry about... what is WRONG then... Well in a nutshell I'm worried about the sound from WITHIN the unit! As you can see from the plan above the studio is built within the space, it comprises of a control room, live room, machine room and vocal booth. It has a cinder block shell (not a good thing I know as it is effectively a double leaf) in which an isolated wooden frame provides the framework for the inner rooms, the cinder block looks like this. But essentially there is a lounge/kitchen area as well as passage running alongside the structure and noise generated here travels into the studio rooms due to the lack of a ceiling covering the area between the cinder blocks and inner wooden framework. In the pic below you can see the cinder block wall, with the inner wooden frame with an airgap between the cinder block and inner room, stuffed with isolation... problem is only the INNER roof is sealed off so sound comes over from the adjacent areas, filters through the gap between the walls and can be heard in the studios. Also it seems that the previous owner only has a SINGLE layer mounted to the frame and it constructed of 'thinnish' OSB/Particle Board, and while it is sealed up with all the joints being caulked and the all the doors sealed it is no match for the noise coming THROUGH the walls. I took off the I/O panel to show you what it looks like with the room. To give you an idea of HOW bad it is I took in my MacBook today, opened up Itunes and played a rock song at full blast, which isn't very loud on a Macbook, but according to my Radio Shack SPL meter it was putting out 76dB's C weighted... I then moved into the all the rooms, sealed the doors and the isolation was miserable as I was reading 55dB's with the same C weighting... so in my book it means the walls are only providing about 21dB's of isolation... even a standard double leaf dry wall with no insulation (a simple wall) provides 33 dB's according to Rod's Book.... OUCH! So what to do... I'm bound by the cinder block structure as it would be too costly to remove it as it is cemented together and the room design doesn't look bad and sounds pretty good as you can see in the layout above. Within these parameters I am able to do a few things. Firstly I think adding more mass to the internal walls will help somewhat. I'm just wondering if I should remove the current OSB and replace it with 2 fresh layers of drywall or just add another layer of dry wall to the existing OSB (anyone know if Drywall has a better STC than OSB???). The other thing I'm wondering about is how I should go about preventing the sound coming over the top of the cinder block and filtering in through the wall cavity.. should I construct a new roof, and if so any idea how? I'm open to ideas and thoughts, right now I'm just a little overwhelmed by how BAD it really SOUNDS (isolation wise), while it LOOKS pretty good... I'm bound by the lease so I need to get it working as best I can within the parameters above and have enough finances to spend a month or 2 doing so. As I shared the neighbors aren't complaining, I'm more worried that the musicians sitting in the lounge area having a modest conversation will end up all over the recordings. The previous owner/builder solution was to get people to keep quiet... I'm just hoping to there is a better solution. Thanks in advance folks for any advice offered. Cheers Matt

Matt, this isn't as bad as it looks at first. For one thing - the block walls do not act as 2 leafs - but rather as one.... so you still have a 2 leaf system What I would do here is this - first i would take advantage of the fact that those block walls are open at the top - which means you can fill them with sand without a problem - and sand is a great mass and a excellent damper.... will help cut LF transmissions real well. BTW - I would remove the wires I see running down int the block walls and slip some conduit down there to protect those wires... Then I would fill the very top course of the wall with concrete - and set a 3/8" anchor bolt about every 4 feet - let them stick up 2". Then I would add a 2x6 plate on top of the wall - and frame in a wall up to the underside of the ceiling above...... Let the new wall sit flush to the inside face of the block. Now - go inside of the wall (over the top of each room) and install 2 layers of 5/8" drywall - caulkk and tape nicely - let the bottom lap over the block a couple of inches and set into a bed of caulk. Once you're done all of those - do the same with the outside face..... make sure to fill the cavity with insulation. This way - the sound traveling up and over will be stopped by the new wal - and will then have to climb over the ceiling above and back down- which wil increase your isolation quite a lot. Then I would test again to see the gain - If these rooms sound great the way that they are - it would only be as a last resort that I would consider adding any more mass to the inside of the rooms - because the more mass you add - the more it will change the room - especially at low frequencies........... you'll wind up adding a lot of room treatments if you take that route....... Sincerely, Rod

rod gervais wrote:

Matt, this isn't as bad as it looks at first.

Rod, Thank you SO much for responding and thanks for your book! It has been very helpful getting to grips with... I actually loaned it to a friend planning a studio and it has been so well thumbed I need a new copy as it is falling apart and vu/laminate coating it peeling off the cover!

rod gervais wrote:

For one thing - the block walls do not act as 2 leafs - but rather as one.... so you still have a 2 leaf system

This is great news, I was just worried with the air gap between the blocks would constitute as 2 leaves, but filling them with sand sounds like a great idea and 2 become one so to speak with added mass! I think I should triple check with a structural engineer on how much weight the floor can take, but a since was the old cold storage unit and has a unit height of 7,5m (25 feet) and is set ona cast concrete slab I'm fairly sure it will hold the added weight.

rod gervais wrote:

What I would do here is this - first i would take advantage of the fact that those block walls are open at the top - which means you can fill them with sand without a problem - and sand is a great mass and a excellent damper.... will help cut LF transmissions real well.

Cool, got that one loud and clear!

rod gervais wrote:

BTW - I would remove the wires I see running down int the block walls and slip some conduit down there to protect those wires...

Will look at addressing this as well.

rod gervais wrote:

Then I would fill the very top course of the wall with concrete - and set a 3/8" anchor bolt about every 4 feet - let them stick up 2".

Okay if I read right you mean pack in all the cinder block holes with sand and then fill the top row with concrete with the 3/8" anchor bolts every 4 feet jutting out 2" above the wall? Right now what the pics above don't show is that the cinder block is not all the same height due to the fact the control room ceiling slops from around 2.40 meters at it's lowest point up to around 3.71meters, so it looks like this from the roof. Should I raise the lower side up to make it a single height all round?

rod gervais wrote:

Then I would add a 2x6 plate on top of the wall - and frame in a wall up to the underside of the ceiling above......

Forgive my ignorance but what is the plate? Is a 2x6 wooden structure mouted to the 2" bolts that I set into the top row of cinder block?

rod gervais wrote:

Let the new wall sit flush to the inside face of the block.

Okay... you lost me there :?

rod gervais wrote:

Now - go inside of the wall (over the top of each room) and install 2 layers of 5/8" drywall - caulkk and tape nicely - let the bottom lap over the block a couple of inches and set into a bed of caulk.

That I think has been done already, IF I'm understanding you correctly, whcih I may not be?

rod gervais wrote:

Once you're done all of those - do the same with the outside face..... make sure to fill the cavity with insulation.

Okay... lost again...

rod gervais wrote:

This way - the sound traveling up and over will be stopped by the new wal - and will then have to climb over the ceiling above and back down- which wil increase your isolation quite a lot.

Lost again I'm afraid... sorry :?

rod gervais wrote:

Then I would test again to see the gain

Once I fully understand what I need to do I'll do it and recheck... right now I'm not fully understanding it all... but I will in time!!! Any reference so something similar in your book, I can always try look it up.

rod gervais wrote:

If these rooms sound great the way that they are - it would only be as a last resort that I would consider adding any more mass to the inside of the rooms - because the more mass you add - the more it will change the room - especially at low frequencies...........

They sound pretty good, I mean the previous owner/builder scored a few movies in there and won a couple of awards for his sound design and seemed to be happy.. the weird/freaking thing is I actaully watched one of the movies he scored on a plane to the UK and a few weeks later I took over the studio as he needed to move back Stateside... what a random set of events! The only thing I'd like to do is raise the ceiling height of the live room as it is currently only a paltry 2.3 meters and I'd like to add some height for a 'bigger' sound when tracking drums. Thank you again for your thoughts and comments, I'd love you to expound on them if you have time, I'm committed to going ahead with your direction! Cheers Matt

TRY THIS:

Rod, THANK YOU SO MUCH!! That makes it a lot clearer, I guess why I was getting confused was because I was privet to information I didn't share and that is that the actually UNIT's, i.e the total spaces celling is not flat but has these convex/concave mounts in them that look a lot like the drawing below. I also have to deal with refrigerator pipes (I can't cut them out/off sadly) if going to full celling height of the unit and AC ducting as shown below. Would it be unwise (other than the increased cost) to raise the exterior frame as you have done in the drawing and then lay another 2-3 layer dry wall on top of the frame, obviously I would need to add further bracing to the frame to support the new roof? I guess the other option would be to go to full roof high as you have shown and the just caulk between the convex/concave structures? Again, I can't thank you enough, you have settled my stomach more than any amount of 'Tums' could do and this is starting to look a lot more manageable. Cheers Matt

UP, I would do it just like I drew it and caulk against the poly diiffusors they have at the top- you should be able to shim the iso-brackets so they still work. AND, you don't have to do the outside wall - just the other 3 sides - just make certain that you don't touch the outside wall - you want to caulk against it - no hard connections at that point. Rod

Thanks Rod, I'm metting with a contractor tomorrow and have asked the landlady to get me the info on the load bearing stat for the floor. I'll report back soon! Cheers Matt

Ok... Im the original poster, under my original username... seems I didn't report back soon at all! I took some of Rod's advise and we ended up ripping out the whole ceiling and raising the height so it now graduates from 2.25m to 2.53 which has given me some extra height. We ended up NOT filling in the walls with sand as it was too costly and the landlords were skeptical, but we DID end up putting in a new celling taking it right to the edge of the frame where it meets the cinder block, putting in a double 20mm dry wall and caulked it in. It did WONDERS! I now have drummers banging away at all hours of the day/night and had only once compliant in a year of business from my neighbor below me who could hear the low muffle of a double kick when I recorded a heavy metal band... but other than that, nothing! And leakage within the space has been drastically minimized. I retuned and tweaked the control room and live room and am pretty happy. Getting a bit of build up around 300Hz in the live room and have posted a thread here about that: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=10597 Thanks again to Rod instilling confidence and the advice! Cheers Matt

Matt, I'm happy things worked out for you. Rod

Rod, I owe you a beer or 3! You instilled the confidence to help me get through it and while I'm still addressing minor issues in the live room the place is 1000 times better than when I first moved in a year ago. Kudos for all your hard work and time spent here, oh and everyone, go buy Rod's book, it is the rulebook for studio construction! Cheers Matt

rod gervais wrote:

Matt, I'm happy things worked out for you. Rod