New studio in Hawaii, beginning questions

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

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mpr3
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Joined: Wed Jun 25, 2003 7:50 pm
Location: Kaneohe, Hawaii

New studio in Hawaii, beginning questions

Post by mpr3 »

Hello, thank you very much for this site and all its wonderful information. I have learned alot, but the more I learn the more questions I have concerning the construction of my studio. Before I start hammering away with questions, here is my preliminary studio information.

I will soon be leasing a 1200 sqft. space Oahu that is in between a jeweler and an auto repair shop. I will be doing exact measurements tomorrow and will post the space in the Studio Desgin forum. The building is constructed out of concrete blocks (not sure if there are gaps) and the immediate acoustic impression from inside is that things are pretty quite even with a mechanic next door.

I will be using this space to make a living recording a wide variety of music from local hawaiian to loud punk rock. Thus far I have been operating out of my house that has depended upon Auralex foam to control acoustics, and so it is very important for me to get this space 'right' since I know all to well what a bad room sounds like.

My build budget is $15,000. It will consist of one decent size control room, one main live room and an overdub room for vocals, amps, etc. All construction will be done by myself and a very skilled carpenter/eletrician whom I will hire. He has never done work that demanded attention to acoustic and noise isolation details, so over the past few weeks I have been printing alot of the information found here and through the SAE website which we will use as our main construction reference.

Here are my first set of questions. I apologize if they seem spread out, these are just on the top of my mind atm:


1. How do you avoid a parallel ceiling and floor? Is it OK if the main ceiling 'leaf' is parallel to the floor when using horizontal clouds? The ceiling design and contruction are the most difficult for me to grasp. Any recommendations?

2. I like John's slat resonator wall design: insulation - 2 x drywall - RC - 2 x 6s filled with insulation - fabric - wood slat resonators, but can this be used on most of the walls in both studio and tracking rooms? Regardless of the aesthetics, is that too much slat resonator? The reason why I like it is because it is easy to construct and produces both great isolation and absorption ratings. I know that the front of the control room will have a solid wood finish, but what can you recommend for alternative wall treatment for everything else? More drywall?

3. I notice in most of the drawings I have seen here and on John's site, the console is located some distance off the fron wall, further away from the monitors than what I have been used to. I prefer to mix on mid field monitors (K&H 0300Ds) http://klein-hummel.com/e/produkte/o300 ... 300d_e.htm through a smaller footprint desk (DMX-R100), so I am wondering if I need to retain this distance inorder to achieve the best acoustic performance out of both the room and the monitors? Since control room space will always be an issue, I would like to maximize its usage if possible.

I could go on and on, but that is enough for now. Thanks again for such a wonderful resource of information. I can't imagine doing what I am about to do without this site.
giles117
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Post by giles117 »

I Love those monitors. My Mastering Engineer uses them and the detail is nothing less than spectacular.

The Imaging is beyond awesome.

Bryan Giles
knightfly
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Post by knightfly »

First, when using a craftsman that hasn't built sound proof construction before it's usually best if they've built BOATS :=) Seriously, what I meant by that is that EVERYTHING needs to be hermetically sealed in sound proof construction, then controlled openings ONLY, which are designed to NOT seriously compromise that careful construction.

On to your questions -

1 - Not enough info to answer this one yet - we need to know whether you're intending a Reflection-Free Zone room for control room, whether you will build an inner shell with angled walls, whether the roof will support wire hangers with a heavy ceiling suspended (using special isolators) or if you intend to support the ceiling on the inner walls, etc...

2- Slat resonators are a great way to absorb low mids and mids without sucking the highs out of a room, but in your case those concrete block walls will be stiff enough that you'll not get the degree of built-in bass trapping commonly contributed by drywall on studs - this means that you'll need to reserve some area for serious bass trapping as well. You'll want to reserve areas that are prone to early reflections for absorptive treatment, in order to avoid phase cancellations and imaging problems.

As Eric has pointed out in some of his (greatly appreciated) posts, for a studio the MTC (Music Transmission Class, or Machinery Transmission Class, depending on where you look) is much more practical a standard than the outdated (but prevalent) STC, which ignores everything below 125 hZ. Those concrete block walls are a good start for some decent Transmission Loss figures for low frequencies - For that, you'd likely be better off adding even more mass DIRECTLY to the walls (at least on the Jeweler's side) say, in the form of a couple extra layers of sheet rock laminated to the block wall.

Sound blocking at lower frequencies can get pretty involved - the stiff partition of the concrete blocks will block most sound, but will PASS whatever its resonant frequency is - to block that, it's my understanding that you would need to add a second frame, fill with insulation, and add a skin to that frame that has a DIFFERENT resonant frequency so that there is a barrier no matter WHAT the frequency is. Any construction here should stick to double leaf (total) walls, one leaf being the concrete block wall and anything that is laminated to it.

Again, Eric has been kind enough to attempt to educate us in this area, and hopefully will chime in here as well.

3. That's because John is a big fan of SOFFITED mid or far-field monitors - they avoid some of the problems caused by nearfields and sound bigger, while avoiding most of the console reflection problems of nearfields. If you have speakers that allow compensating for the baffle step in some way, it makes a lot of sense.

Generally, if you put your (free standing) speakers too close to a wall, you'll get an un-natural bass boost - if your speakers are back from the rear of the console far enough, you'll get reflections off the rear of the desk into the front wall and back to the mix position, so absorption is commonly used on the wall behind the console to help avoid this.

All stereo speaker listening layouts need to be symmetrical (including juxtaposition with room elements), and at least an isosceles triangle if not equilateral. Meaning, you don't necessarily have to stick to a layout where (the back of) your head and the center of your speakers form an equilateral triangle - some studios have used a 90 degree spread (instead of 60 degrees) with good results.

Beyond that, some experimentation usually works best. You'll find that moving your head forward and back, and/or moving the speakers, will change your perception of bass energy, sometimes by quite a bit. What you DON'T want is for either your head or the speakers to be located in a node or anti-node of the room - places that are 1/2, 1/3, 1/4, etc, of any room dimension are not good. Placing speakers so that the woofers are equidistant from floor and ceiling isn't good either.

In the case of mid-fields and a DMX board, you might benefit somewhat by building a custom desk that tilts the board slightly toward you, which could cause any early reflections from the board/desk to bypass your ears and instead hit the back wall. (Which, BTW, should be absorbed if less than about 12 feet from the back of your head)

We can probably get deeper into things once you've posted more info on dimensions, existing construction, etc - Before you start beefing up walls, you should run a sound check (after first warning your neighbors) with loud drums (live) while you're in the neighbors place with a meter. It never hurts to present a caring image to neighbors - goodwill can be worth more than any lawyer... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
mpr3
Posts: 11
Joined: Wed Jun 25, 2003 7:50 pm
Location: Kaneohe, Hawaii

Post by mpr3 »

Thanks for all the info Steve. As I now have all the measurements of the space, I am ready to set some construction details in stone. Here is the current floorplan and a very rough draft studio layout:

http://johnlsayers.com/phpBB2/viewtopic.php?t=378

First off, the floors will be floated with neoprene and the walls will be drywalled on the inside of the rooms. Unfortunately, with John's inside-out wall design I would not be able to apply proper caulking to the drywall as it hits the floor next to the wall base boards. There is just simply not enough room to get the caulking gun back there without applying the caulk before setting the entire wall leaf into place which seems difficult in attaining a good seal along the entire edge.

The ceiling leafs will all be parallel to the floor with drywall layers on the room side, resulting in drywall enclosed rooms with wood floorboards. I will add appropriate wall treatment (resonators, bass traps, insulation with clothe) once this stage has been completed. I realize that I should then use clouds to help offset the effect of a parallel ceiling and floor, most especially above the mix position. Is this correct? And if so, can you briefly describe the construction and layout of a typical cloud room configuration?

That's all for now. I am still working out the details of how I am going to array my monitors. Once I do I will share my plans here.

Once again, thank you very much for you assistance. :D

Mark
knightfly
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Post by knightfly »

Mark, you'll definitely need to do the cloud thing with parallel ceilings in order to avoid the flutter echoes that result from parallel surfaces - in fact, you may end up having to use clouds over the entire ceiling area, since any parallel surfaces will contribute to the problem.

Doing this could contribute to an overly dead room if you're not careful - if you're a math-oriented kind of guy, you could use the absorption figures for the material you plan to use, calculate the areas of each type of surface, and come up with RT60 values for your room at each frequency band - one of the problems with this approach is that it doesn't take into account the "edge effect" which causes smaller pieces of absorptive material to act as larger ones. Another problem with this is that RT60 values should vary with room size, so you can't just say that the control room should have an RT60 of .4 seconds - it's more important that the reverb time is even throughout the frequency range, so the room doesn't sound boxy from too much low mid reverb, or too bright because of too little high freq absorption.

Another, more time-consuming way is to do just the things you KNOW you'll have to do, such as clouds over the mix area and absorption anywhere you can place a mirror against and see either of your speakers in the mirror, then putting up the speakers and listening to several reference tracks (songs you're really familiar with) keeping in mind that speakers and speaker placement can play as much or more of a part in how things sound as wall treatment.

One other tool I've downloaded a demo for, but have yet to find time to play with, is ETF Acoustic's ETF software - check it out here -

http://www.etfacoustic.com/

As to the ceiling clouds, they would normally be made from at least 2" thick 700 series Owens Corning rigid fiberglas - if you have room to space them off the ceiling by a few inches, even better. One way to hang them is to use plant hooks, but if you use the kind that has a "toggle" on a bolt, it will cause soundproofing to fail due to the large hole you'd need to drill in the ceiling.

You would need to get the kind of hooks that give you both a toggle and a "lag" screw in the package, intended for installations where you know where the stud is located. Once you have located studs and installed plant hooks (using the "lag" screw option into framing members), you can measure distances and thread picture hanging (stranded) wire through the fiberglas panels, making a loop to hang on each hook - to keep the wire frim pulling through the fiberglas, you can slip a large fender washer over the wire loop where it goes thru the fiberglas, then slip some kind of pin or split ring thru the wire loop that is large enough to keep it from pulling back through the hole in the fender washer. You need to do this at all four corners of each piece, assuming you're using the normal 2' x 4' size of rigid fiberglas.

If you want a single, larger cloud, you can use two layers of 2" material, running the long dimension of the pieces at 90 degrees for the second layer, and gluing the two layers together. You would need to use support at about the same intervals, and make sure that the whole thing is supported by the "captive" fender washers so it can't fall.

For coverings, some people use a finer-weave cotton cover under something more aesthetic, such as a dyed burlap - as long as you don't restrict air passage by using something like plastic, you can control the shedding that is prevalent with fiberglas without affecting its acoustic qualities noticeably.

If you don't want the hanging hardware to show, you can mount it in a ways from the edges of the panels - then, AFTER the wires/fender washers are in place and wire loops are sticking out the BACK of the panels, you can cover the front and sides with your cloth/burlap, fastening with spray adhesive around the back of the panel, and THEN hanging the panels by the loops of wire sticking out the back of the panels.

I'm sure others have done this in other ways, maybe they'll share their experiences... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
mpr3
Posts: 11
Joined: Wed Jun 25, 2003 7:50 pm
Location: Kaneohe, Hawaii

Post by mpr3 »

Thanks for being so clear! I shouldnt have any problems making clouds now.

Question: since there will be RC on the ceilings, do you know if a normal eletronic stud finder will reveal the RC through 2 layers of drywall?

I guess I could try those magnetic ones, but that is alot of drywall to sense through.

btw, if you ever make a FAQ for this forum, be sure to copy and use your above description on how to make a cloud. :)

Mark
knightfly
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Post by knightfly »

Mark, I doubt if a "normal" stud finder would work thru double drywall - I just recently bought one of the newer "deep" ones from Home Depot, that does electric wires, deep studs, dead cocker spaniels (JK :=) but it worked on my wierd walls - my house was built by a moron (you could say it was also BOUGHT by one :=(( who did everything bizarre - there is one wall between two bathrooms that is a double stud wall (no reason, there's no pipes in it) with an extra layer of 3/4 ply under the sheet rock on one side, and no two studs spaced the same, etc... Anyway, the new finder had no problem thru 3/4 ply and 1/2" sheet rock; I think it cost about $35 or so.

One way around the problem you mention, is to put masking tape (use the more expensive blue stuff, doesn't rip off paper when you leave it on for more than 15 minutes) - anyway, put strips of masking tape starting at the end of each RC (on the ceiling) and run them down the wall a few inches. Do this on both ends of the run of RC and on each run, making sure that when you install the RC you get it STRAIGHT. Also, the end of the RC should lack about 1/2" from touching the wall, so that there is no hard connection between the wall and the ceiling. The sheet rock can go closer than that (about 3/16") then the acoustic caulk will fill the cracks.

On the OTHER two opposing walls, put masking tape where each ceiling joist meets the wall. Make notes as to which set of tapes is RC, and which set is joists.

Next, run a strip of masking tape clear around the room, about 3" down from the ceiling joists, and mark it every foot starting about 2" from the wall. Make sure your marks which run the same direction as the RC, do NOT, repeat NOT, coincide with ANY joists. This should give you a set of marks 12" apart that run along the RC, NONE of which are in line with a ceiling joist. These will be your marks for where to put drywall screws.

Offset the second layer of drywall by at least a foot one way, and preferably half a sheet the other way, so that NO joints line up. Use acoustic CAULK on the joints, NOT sheet rock mud. True acoustic caulk doesn't dry up and crack, mud will.

For the second layer, note where you put the first course of screws by your marks on the tape around the perimeter, and offset the second course of screws over by about 4" (be careful NOT to put ANY screws in line with your JOIST markers. You don't want to "short" the RC to the framing.

Probably one of the best things you can do if you've not done much (or any) drywall, is go to Home Depot and buy their book, just called "drywall" - it's about 5/16" thick, and has a ton of good info on do/don't stuff.

If you plan ahead, you can use the above marking system on each phase of construction so you know where everything is under the paneling - once you're finished with that phase, you can take off the masking tape.

Also, for the ceilings you should rent a panel jack - you won't regret it, especially if you're doing 5/8 rock, and DOUBLE especially if you use 4 x 12 sheets of 5/8 rock. That stuff can KILL...

On ceilings with double 5/8, I would recommend 12" centers on the RC rather than take the chance of "wearing" the ceiling.

If you're new to drywall construction and plan to do it yourself, start with the LEAST visible part that doesn't have to be sound proof - make your mistakes THERE, then do the rest.

Oh, yeah, get that drywall book. Gotta get some sleep, later... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
mpr3
Posts: 11
Joined: Wed Jun 25, 2003 7:50 pm
Location: Kaneohe, Hawaii

Post by mpr3 »

Yet again and again, thank you kindly!

I will be working closely with the drywaller and carpenters (no, they won't mind be barking orders at them:) and I will make sure they adjust their normal working methods to accomodate a sound-critical construction. I am printing out everything you and many others here on this forum have posted, high-lighting the essentials which I will go over with the workers.

I don't want to flood you with too many questions, so I will take a small break and be back with more in a few days. :twisted:

cheers!
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