A very challenging design.

[princeplanet]

Some of you may remember my posts about designing a 2 room studio totalling approx 70m2 on the top floor of a 7 storey office building. Yup coming up to 3 years now. Long story, but coming to the end of a long trail of red tape, so I'm opening up the discussion again and thought I'd start fresh.
I see that traffic around here is not what it used to be, so I'll share information and data commensurate with interest shown. Let me begin with the existing layout: (sorry, you need to rotate the PDF's):

7th Floor Layout.png.pdf

The dashed lines indicate structural beams beneath the existing 125mm concrete on bondek slab. The diagram below outlines the studios area to be floated along with a description of permissible loads from the SE

ROUVALIS beams outline.png.pdf

OK, Here are 2 different CR orientation options:

2 room north CR descrptive.png.pdf

... and

East CR alt 4.png.pdf

Of the 2 options, I heavily favor the "wide" control room (north facing). If someone asks, I'll happily divulge the reasons why, but happy to get the thoughts of others.

I guess my real questions are about the requisite isolation through the STUDIO floor- will the proposed design be enough to mitigate the usual rock drums and bass amp sound through the floor? (the other rooms on the same level as the studio are not noise sensitive). Ambient background on level 6 is around 40dB, so it drums are 115dB, I'm needing 75dB attenuation through a floating floor composed of 150kg/m2 compressed cement sheet floating on engineered rubber mounts with a 100mm insulation filled gap.

Another main concern is with the bulkheads (310mm x310mm) that run overhead along the wall corners as indicated by the dashed lines below:

Accurate Blank.png.pdf

How do I rest the heavy ceiling on the walls (can't hang it off the existing ceiling) and go under and around the bulkheads? Here's what I mean:

building inside the bulkhead.png.pdf

OK, I can go into a lot more detail and also ask a thousand other questions, but I'll wait to see if anyone shows interest.

Cheers!

[Gregwor]

Yikes. This one is intense. First off, acoustically speaking, I like control room layout # 2. I would ditch the huge console/desk though which would allow a symmetrical layout.

As for whether or not you can achieve 75dB of isolation, I'm guessing that you won't get that much. This is purely because of structure borne transmission as you won't be able to build a true floating room due to weight limits.

Regarding holding up the ceiling with the bulkheads in place, you'd have to ask a structural engineer about that because both options look sketchy to me.

Glad you're back at it though!!!

Greg

[princeplanet]

Yikes. This one is intense. First off, acoustically speaking, I like control room layout # 2. I would ditch the huge console/desk though which would allow a symmetrical layout.

As for whether or not you can achieve 75dB of isolation, I'm guessing that you won't get that much. This is purely because of structure borne transmission as you won't be able to build a true floating room due to weight limits.

Regarding holding up the ceiling with the bulkheads in place, you'd have to ask a structural engineer about that because both options look sketchy to me.

Glad you're back at it though!!!

Greg

I'm surprised you think it's "intense", why? As for the 75dB TL, yeah, a little ambitious, but what do you mean when you say I can't build a true floating floor due to weight limits? Can we talk about what densities and gaps you feel are needed to stop drums and bass through my floor?

[John Steel]

Hello & howdo' Princeplanet?
I have been following a build of JSRSDF member 'Purelythemusic' who is in Bristol in the West of England. If I remember correctly, he was aiming for 70dB of transmission loss and figured out that the only practical way to get close to this was to build separate foundations for both the inner & outer leaf of his studio, set in heavy clay soil on the ground. Don't base a law suit on this, but I would guess it's going to be tricky achieving the same amount of isolation within an existing structure, especially 7 stories up (not to mention the practical difficulties involved in simply dragging all that mass up there). Perhaps there's either a better place to build or a more environmentally suitable spec for your project in that location? Good luck and best wishes, John.

[princeplanet]

OK, so not getting too much advice here, but I'm happy to bring to this thread advice I'm receiving from some local studio designers.

One very well known guy says I can achieve all the isolation I need by floating a total of 44mm particlboard over an air gap of only 60mm filled with 60kg/m3 insulation. He claims the walls and ceiling also can be made of the same particlboard materials (1 19mm plus 1 x 25mm patricleboard). Spacing at 450mm. His theory is that stiffness is more important than mass. When asked if it will suffice to block out heavy drums and bass, he responded that a second "piggy backed" floating floor on top of the first one would do the trick.

Now, you guys can have a field day tearing holes in this claim! It flies in the face of all the commonly accepted practices. And yet, he has been around for 40 years and has designed studios for all the major TV and radio stations as well as a ton of recording studios. I've spoken with some of his clients, especially the ones that have built on upper levels, and they all say his ideas have always worked!

His floating floor mass is only 30% of the mass I was prepared to use. Sounds too good to be true, right?

[John Steel]

OK, so not getting too much advice here . . .

My intention is to be as helpful as possible. If you are confident that your goals are achievable by following your designer's advice I would not presume to know better. BTW, did you ever check out the 'Purelythemusic" thread?
http://johnlsayers.com/phpBB2/viewtopic.php?t=21612
Best wishes and good luck, John.

[princeplanet]

OK, so not getting too much advice here . . .

My intention is to be as helpful as possible. If you are confident that your goals are achievable by following your designer's advice I would not presume to know better. BTW, did you ever check out the 'Purelythemusic" thread?
http://johnlsayers.com/phpBB2/viewtopic.php?t=21612
Best wishes and good luck, John.

I appreciate your advice John, and yes, I did check out that thread, some interesting ideas going there for sure. Still, I wish I could find a thread where someone built an upstairs drum room and managed to keep the sound from the lower neighbouring rooms...

[Gregwor]

Have you reached out to John to see if he'd be interested in helping you out? He's in Australia so he would be the best guy to talk to.

As for your local designer's ideas, I'm skeptical for sure. I'd ask him to provide you with his calculations because I'd LOVE to hear/learn that we can achieve high isolation values like that using less space and material. That along with three leaf low frequency isolation would change everything I know!

Greg