Attic Shaped Studio

#241

endorka wrote:Source of the post... after the light bulb went on in my head ...

The moment of enlightenment; the connection between the science of acoustics and the creativity needed to accomplish the task at hand. We all need the light bulb to switch on at the right moment.

#242

Starlight wrote:Source of the post
endorka wrote:Source of the post... after the light bulb went on in my head ...
The moment of enlightenment; the connection between the science of acoustics and the creativity needed to accomplish the task at hand. We all need the light bulb to switch on at the right moment.

And sometimes - many times - it seems to arrive just in time. "When the student is ready, the teacher will appear."

Spent the morning crawling about the roof eaves verifying the planned duct runs were realistic. Decided to go for a longer route of flex duct with very gradual turns rather than a shorter route with sharp turns. Did some tidying up in there, and used the circular saw to trim back the tongue and groove floor around the front knee walls to allow for a double layer of OSB + plasterboard. Previously there was just plasterboard. Also did several other small but necessary jobs preparing to fit the silencer.

I was going to cut the outlet hole on the silencers with my router, but bought a 150mm holesaw instead to save time. Glad I did.

Finally opened up the duct liner Gareth sent - it is excellent quality. There will be more than enough for this job.

After fixing it all in place and placing one of the side layers on, my wife & I did a test; one of us talking loudly in to the duct end while the other listened at the other end of the room. Even though we were both in the same room the difference is marked. It's pretty hilarious actually, does indeed sound like someone behind a wall.

Cheers!
Jennifer

#243

Nice work. Glad the duct liner survived the courier.

It’s a shame there’s no pic of you and your wife testing the sound level reduction. I should imagine it would be quite amusing

#244

Cheers Gareth. We tested it again after I assembled the silencer properly today, and the effect was even more pronounced

It's been a very long but productive day. More detail later, in the meantime you might enjoy this sequence of photos;

#245

I love the lines of caulk as they emphasise the attention to detail and how airtight all the seams are. Good work.

#246

Starlight wrote:Source of the post I love the lines of caulk as they emphasise the attention to detail and how airtight all the seams are. Good work.

And there are so many of these lines several times on every join to do the stepped "bank vault" seal properly. Three I think, for the two layers. The combined length of seams on the silencers and built in bass traps must be epic. I anticipated using a lot of sealant, but not that much!

I reconnected all the studio electronics in the wee small hours of last night & tidied up this morning for a session today, acoustic guitar and vocals. The client is a regular so was fine with the work in progress aspect. The room sounded really good, even if it looked a bit rough!

I scheduled the session a month or so ago, assuming the work would be finished by now. Therein lies the lesson - you will always underestimate the time required to build a studio, and the amount of sealant required to do so.

#247

And the money....!

#248

An update about the exhaust silencer build at the end of last week.

The intumescent grill that faces in to the room has to be attached in a very specific manner to preserve the fire rating. Brackets and screws of particular dimensions and type were detailed in the fitting instructions. The gap surrounding it must be filled with intumescent sealant. This grille is 200x200mm, not large enough to get the airspeed to under 300 feet per minute at 6 air changes per hour. No matter though, it is only a way to get air through the wall, there will eventually be a larger register here as part of the soffit.

Bench test of the inline fan before final assembly of the silencer. It worked really well. At low fan speed there was very little sound at the grille, just a very subdued turbulent gurgling if you put your ear up close to it. Plenty of suction too, enough to grab a sheet of paper from a few inches away and hold it against the grille.

The question solved here was how to attach the side panel so the front edges of it are on the same plane as the panel on the other side. Essential to ensure it will fit flush against the wall OSB board. The answer was to make a small section of temporary wall from an offcut of OSB, and assemble with it in place.

In the room ready to fit - see previous post

#249

Your silencer reminds me of this Star Wars craft. I bet yours will be quieter!

#250

Yes! I knew it was like something but couldn't think what! :yahoo:

#251

I took a day off on Saturday for R&R. Sunday I finished the plasterboard on the rear knee wall. It now has one layer of 18mm OSB and one layer of 15mm acoustic plasterboard all over. Green Glue between them.

Sealed up all the edges too, quite a job. You can see there is a thin layer of some sealant spilled over on to the plasterboard in some places. I tried to wipe it off but obviously didn't do it well enough! I plan to skim plaster this area so will likely sand those spills to roughen them up for better adhesion. Any other recommendations about what to do for this welcome of course.

Cheers!
Jennifer

#252

The sealant will have an adhesive quality so I don't think you have anything to worry about. It will have a different porosity to the plasterboard so a primer or undercoat would help the top coat look smart.

#253

Starlight wrote:Source of the post The sealant will have an adhesive quality so I don't think you have anything to worry about. It will have a different porosity to the plasterboard so a primer or undercoat would help the top coat look smart.

Cheers Starlight. In the past I've used the Zinsser BIN Primer/Sealer for this, it works well.

#254

Yesterday (Monday) I spent beefing up the studs forming the left knee wall with methods inspired by those Stuart uses for hanging heavy doors. This is where the exhaust silencer goes. Although constructed correctly and fine for a small bit of plasterboard, the existing stud wall was too weak for the silencer. The vertical stud on the left of these photos was only 20x50mm cross section. All studs were nailed and a bit wibbly wobbly.

It took a bit of work to figure out how it fits in the house structure. The wall to the left (with the room door in it) has its own studwork - sole plate, top plate & verticals. The plasterboard is attached to this, not directly to any of the joists or rafters. The last (short) vertical ends before the first vertical of the roof truss, and does not touch it.

In contrast, the wall to the right that extends out to the balcony is formed from several sheets of plywood that are directly attached to the rafters / roof truss. So although the existing studwork might look a bit funky, it was done in a manner that preserved the "leaves". My reinforcements keep this system.

First up, remove all old knee wall studwork. Then brace the diagonal corner of the main wall with a sheet of OSB. In this photo it looks like the OSB is touching the roof truss but it is not.

A smaller brace at the bottom corner.

New 89x38mm stud in place. Consistent with previous studwork, it does not touch the rafter above the sloped part, therefore will not become a vertical load bearing element.

The stud on the right is part of the roof stucture "horizontally" by virtue of being attached to the structural plywood. Therefore I reinforced this one horizontally with a nogging to the roof vertical. Again, the stud stops short of the rafter so no vertical load from the roof is imposed.

Overall view. The studwork is now very solid indeed.

#255

"Liftoff! We have a liftoff."

It's floating a couple of inches above the ceiling below.

Just temporary bracing to test and allow fitting of the proper OSB layer. I'll cut the bottom half to go around the grille, and the top half to go above that.

The studs are solid, OSB braces holding up well but bending a very small amount. Having the full OSB board will help, and I'll add a noggin below the silencer for extra support just in case.

Cheers!
Jennifer

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