Salem Oregon conference center studio

[Guit-picker]

Continued from last post. (I was worried about size limits with so many photos).

Photo 10: After mudding, taping, texturing and paint:

10A_20170827_205639.jpg

Photo 11: One example of electrical wiring as it enters the room through short conduit. Sealed on each layer of drywall and inside conduit:

11A_20170826_133640.jpg

Photo 12: Detail of surface-mount plate mounted to the conduit and into stud:

12A_20170826_133601.jpg

Photo 13: Finished surface-mount receptacle:

13A_20171008_191046.jpg

Photo 14: Preparing split window frame for glass:

14A_20171228_120001.jpg

Photo 15: Put a layer of Rockwool in the crevice then covered it with a layer of compressed fiberglass wrapped in black felt. Doors are in process of being mounted too:

15A_20171228_115937.jpg

Photo 16: Glass installed on both windows. One side is 3/8” and the other side is 5/8”. Same thing on each door pair:

16A_20180105_103501.jpg

Photo 17: Flooring is now in progress for three of four rooms. The control room must wait until the soffit speaker area is built first. The quality of this flooring is very good according to the experts I’ve got contact with. One thing of concern is that the short ends on this particular brand CANNOT be taken apart without breaking! This can be bad if there is a problem and you have to undo the floor up to the error point. That whole section will be trashed. I learned there are better brands that don’t do that. This is “lifeproofRigid Core Luxury Vinyl flooring” from Home Depot. That being said, we haven’t had that issue yet:

17A_20180512_162908.jpg

I seem to have lost my pictures of the door seals. I’m using GM type “K” automotive trunk rubber seal. We are in the tedious process of adjusting the door stops in the fine line between “leaky” and “so tight you can’t shut the door”.

That’s about everything I can think of. I hope this is helpful and/or inspires! I welcome comments!

[Soundman2020]

It's looking pretty good! How is it sounding?


- Stuart -

[Guit-picker]

It's looking pretty good! How is it sounding?

Sounds like an echo chamber! Ha ha! I was really jazzed when the glass went in and we shut the doors (as they are at this point) and shouted as loud as possible. Pretty amazing! When I was in the vocal room and my friend was 4' away in the large recording room (facing 90 degrees away), I was trying to get his attention. The door was shut and I was yelling at him and couldn't get his attention. Had to pound on the glass.

Another great relief is that it is really hard to hear the ventilation fan when it is full on. It is actually a bit louder when in slow speed. I was really concerned whether the fan noise would be a problem, but I could not think of a way to really test the quietness until the walls and doors and windows were in. I am very satisfied and relieved, to say the least!

Next is the front soffit area. I will be digging into details on the forum and will start some drawings. Prepare for a few questions soon! Thanks again, Stuart, for all your help and patience with me!

[Guit-picker]

I was planning on using my Roland DS-90 speakers since they are front ported. The bass roll-off only goes down -3dB. Do you think this is a lost cause right from the start?

[Soundman2020]

I was planning on using my Roland DS-90 speakers since they are front ported.

Porting is not an issue. It is entirely possible to soffit-mount rear-ported speakers. So don't limit your speaker choices to front-ported only.

The bass roll-off only goes down -3dB.

That's probably fine. And if it isn't enough, then there are ways of dealing with that. An external cross-over, for example. Or my famous-but-secret "digital tuning" method....

Do you think this is a lost cause right from the start?

Not at all! Pretty much ANY speaker (with few exceptions) will benefit greatly from being soffit-mounted, as long as it is done right. IF the Rolands are all that you have, then they can work fine in there. But if you have some extra cash to spend, you could move up to something more befitting of that beautiful room... Top class speakers to match the top class workmanship...

- Stuart -

[Guit-picker]

Okay, that's a relief! I'm really liking the Barefoot approach, which will allow for easier speaker upgrade down the road. I've been struggling to get some good "homework" time, researching the forum on soffit details. I've got to get some drawings started to get the ball rolling. I'm supposed to be sleeping now, but my eyes are "glowing in the dark"!
Thanks!
-Ron

[Soundman2020]

I've been struggling to get some good "homework" time, researching the forum on soffit details. I've got to get some drawings started to get the ball rolling.

Take your time with the design: soffit design is not something you should rush. Actually, STUDIO design is not something you should rush! But soffits especially.

If you need to have your speaker easily replaceable, think about putting it in some type of "tray" that can be bolted in firmly, but also easily removed if needed, to switch speakers. Make the "tray" much larger than the speaker, so you can upgrade to any other size in the future. That's what I did for Studio Three originally with their Genelec's, and it paid off when they wanted to upgrade to the Eve SC-407's a couple of years later.

http://www.johnlsayers.com/phpBB2/viewt ... 923#p40923

- Stuart -

[Gregwor]

I'm really liking the Barefoot approach, which will allow for easier speaker upgrade down the road. I've been struggling to get some good "homework" time, researching the forum on soffit details. I've got to get some drawings started to get the ball rolling.

I'm in the middle of designing my soffits as well. I'm trying to isolate the speaker from an enclosure with Sorbothane, then isolate that box from the wall as well. In order to get the isolation frequency low, like floating a floor, you need extreme weight. I'm trying to emulate weight by strapping down the enclosure.

If you need to have your speaker easily replaceable, think about putting it in some type of "tray" that can be bolted in firmly, but also easily removed if needed, to switch speakers.

I was having a hard time picturing in my head how to make a module that I could replace for speaker changes. I suppose some T-Nuts under a divider would allow for easy replacement of modules.

[Guit-picker]

If you need to have your speaker easily replaceable, think about putting it in some type of "tray" that can be bolted in firmly, but also easily removed if needed, to switch speakers. Make the "tray" much larger than the speaker, so you can upgrade to any other size in the future. That's what I did for Studio Three originally with their Genelec's, and it paid off when they wanted to upgrade to the Eve SC-407's a couple of years later.

Thanks for your encouragements, Stuart. I hope to spin up Sketchup today. I had a drawing already started a while ago.

[Guit-picker]

Gregwor, Thanks for chiming in. I'll be watching your progress too!

-Ron

[Soundman2020]

I'm in the middle of designing my soffits as well. I'm trying to isolate the speaker from an enclosure with Sorbothane, then isolate that box from the wall as well. In order to get the isolation frequency low, like floating a floor, you need extreme weight. I'm trying to emulate weight by strapping down the enclosure

Yes, you sure can use mechanical "things" to strap down your speakers, and apply more pressure to the Sorbothane, thus improving the deflection, and the isolation. Barefoot did that with canvas straps, but there are other ways...

- Stuart -

[Guit-picker]

Here is the first-step drawings of my soffit area – borrowing (stealing) from Barefoot’s method. After reading some of the other posts…

Yes, you sure can use mechanical "things" to strap down your speakers, and apply more pressure to the Sorbothane, thus improving the deflection, and the isolation. Barefoot did that with canvas straps, but there are other ways...

… I came up with this idea of clamping down the speaker with sorbothane sandwiched between a plywood top and the plywood shelf underneath using threaded rod and nuts. My thinking is that canvas or nylon straps could loosen in time. I could be way off with this idea, but what do you think?
I was looking at the sorbothane “hemispheres” and temporarily drew them in (can’t draw hemispheres, so I drew them as disks). I’m not understanding their instructions for selecting the correct product and amounts just yet. My Roland DS-90 speakers weigh 15 kg. (33 lbs. 2 oz.). At this point I would like to know if I’m heading in totally the wrong direction.

Here is the rear frame assembly with the speaker:

Soffit_3_A1.jpg

Here is the front frame assembly added (not touching the back assembly):

Soffit_3_A2.jpg

Here is a closer detail of the speaker / sorbothane “sandwich”:

Soffit_3_A3.jpg

… and once more without the speaker:

Soffit_3_A4.jpg

I’m already getting the drift that there is not enough sorbothane here. What think ye?
Also, another question: Looking ahead at making bass trap hangars, what is the difference between Homosote and the cheaper 4’ x 8’ “Acoustic Soundboard” that Home Depot sells? Is the cheap stuff worthless for bass traps? I used the cheap stuff years ago and it had a heavy "cardboardy" odor to it - not good if it’s not buried under another layer of something!
-Ron

[Soundman2020]

… I came up with this idea of clamping down the speaker with sorbothane sandwiched between a plywood top and the plywood shelf underneath using threaded rod and nuts. My thinking is that canvas or nylon straps could loosen in time. I could be way off with this idea, but what do you think?

That should work quite well, actually. And definitely better than canvas straps. Finer control on the pressure, too.

I’m already getting the drift that there is not enough sorbothane here. What think ye?

You'd have to do the calculations, but yeah, I agree. Not enough, and not thick enough. Don't forget to take into account that the pads on the bottom have the weight of the speaker PLUS the pressure applied by the rods, while the ones on the top ONLY have the pressure applied by the rods...

what is the difference between Homosote and the cheaper 4’ x 8’ “Acoustic Soundboard” that Home Depot sells?

Not sure about that stuff: what¿s the density? Is it similar to Homasote?

and it had a heavy "cardboardy" odor to it

Better check the data sheet for that, and see what chemicals go into it. It sounds like it was off-gassing something unpleasant...

- Stuart -

[Guit-picker]

You'd have to do the calculations, but yeah, I agree. Not enough, and not thick enough. Don't forget to take into account that the pads on the bottom have the weight of the speaker PLUS the pressure applied by the rods, while the ones on the top ONLY have the pressure applied by the rods...

Yeah, that’s the part that I’m not sure how to figure into the equation. Here’s my current thinking:

I’m looking at a hemisphere that has a weight range of 5 – 10 lbs each. It is 1.25” in diameter and 0.625” tall. They say to expect 20 to 30% deflection when statically loaded.
The speaker is 33.125 lbs.
If the speaker only had absorbers underneath, five or six hemispheres should suffice bearing 6.625 lbs or 5.52 lbs respectively. When you add more on the top, I’m not sure if that will throw everything out the window, as far as correct calculations.

As we all know, under-loading as well as overloading will cause poor isolation. They say “Remember: A bad design can actually make things worse for vibration damping. Consult the factory if you are having problems.”

I think I will do just that. I will send them the proposed design and see what they recommend. I’ll post the results.
-Ron

[Gregwor]

It is 1.25” in diameter and 0.625” tall.

The thicker the Sorbothane, the lower the frequency.

They say to expect 20 to 30% deflection when statically loaded.

Using some rectangular chunks and some trial and error, you can torque down your lid with the ready rod to achieve the deflection required on both top and bottom. You might want to consider adding an oversized baffle on the front of your soffit so you can remove your speaker or change it out with ease. Some turnbuckles might be easier to adjust than nuts on the top and bottom. You could also further lower your frequency by mounting your entire assembly onto more Sorbothane pads and torque it down super hard onto your wall supports. What I'm suggesting is the speaker on pads, then your speaker mount on more pads. So two layers of pads.

Greg