Construction Started...

Sorry it's been so long, haven't had a chance to work alot lately or at least it seems like I haven't gotten much done when I do. :? I hope to do a lot in the next couple weeks so, hopefully I'll have better pictures soon. My vocal booth is about ready for cloth and slats and then my ceiling absorbtion goes in. I know it's hard to tell anything about these pics but I hope to start my control room slat panels next week, maybe they'll be better, hope everyone is doing good. Steve hope your cold is on the mend by now. Check back same bat channel. :D Arthur

Had a question about the ceiling, I've seen in several pictures that a layer of thin mil clear plastic sheeting is tacted to the ceiling over the insulation before the cloth goes on. Is there a reason for that or just to keep the insulation from falling out? Does it affect the absorbtion level? Just wandering if someone could clear this up for me. Thanks. Arthur

Yeah, I've mentioned this here and there but it's not in the REFERENCE section as far as I know; A lot of times, using enough fberglass to take care of bass trapping, mids, flutter, etc, causes too much high freq absorption; a thin layer of plastic over parts of the absorbent can keep the highs from being over-absorbed. John's had good luck with this in more than one studio. Also, sometimes it's a real bitch getting rockwool into cavities over RC without major "shedding" - I've suggested to a few members with this problem that they first put the batts into plastic garbage bags (one over each end, taped together) and it's helped solve that problem. If, for some reason, that made the room TOO bright, you could always cut away the front of the plastic AFTER the rockwool is installed - My thoughts on this are that you can get all your calculated absorbent in place WITHOUT the cloth facing, then listen to the room for a while (with music playing :? ) and if it's already too dull, start adding plastic (NOT at first reflection points, if it's a CR) until the room sounds just a LITTLE too bright; If you then add a cloth cover, the cloth will take the room back to more absorbent at highs, and the end result should be just right. Hope that helped... Steve

OK, that makes total sense. That's why you're the man, I know I'm gonna owe you more than lunch after all your help. :lol: Arthur

Arthur, Congrats on starting your construction. Could you briefly describe your HVAC scheme? I am struggling with what to do with my space. I will be sharing the system with the rest of the house. It looks like you may have constructed a special box or something. Were your ducts wrapped already or did you do that? What did you use for flexible ducts? I tried to find a previous thread on this and couldn't. I apologize if you have covered this already. Thanks

Hi PhiloBeddoe, Yea, the HVAC stuff took a little to figure out, rather it took a little time to get my service guy to figure out. Luckily he was a friend so I didn't have to pay him for all the research time, plus I think it was a challenge since he'd never done anything like this before. Since my room is totally underground and didn't think we'd have too much trouble heating and cooling it, he thought it OK to tie into my main system, plus it was big enough to handle it. My main concerns were to keep the air transfer noise to a minimum and keep as little sound transfer from my studio back through the rest of the duckwork. Here's how we attempted that and I'll let you know how successful we were when I get the music up and running. First we just used regular insulated flexible ducking for the pipes, we just made a few extra turns than would have been normally. Once he figured out how much air flow we needed for each room, we used large enough pipe for the feed and return. Then we built a load box for both sides out of duckboard, the load box or catch box serves a couple purposes, to slow down the air flow and kill most of the sound that enters it. Since duckboard is compressed fiberglass it seems to work well. Then we just feed each room out of the load box by using extra long feed lines. My returns I did the same way except something extra I added, we built a filter cage on the end of the return box and located it outside the studio in the garage, that way when I change the filter all the dust is left outside the studio. So far everything seems to be working like I wanted it to, I have plenty of air movement but it's at a volocity that doesn't give that 'whoosing' sound, plus I have send and return in both rooms, which should keep the vocal room comfortable, I also made another sound catch out of the duckboard where they enter the rooms. I hope all this make sense, if not let me know and I'll try to clarify. Hope you have good luck with it. Arthur

Here's another picture of the return box...

Thanks, that's a perfect description. I think it's a good idea to get a pro involved to size the ducts and make sure your system has enough capacity. Yes, please let us know how it performs.

Steve, Got a question about the bezel for my soffits, my brother-in -law came up with something I think will work great for the bezel, he's a truck driver and he pick up a ton of this stuff, he called it "Fanalic Board"? I can't find any info on it and I can't reach him for the info, but it's super dence stuff, a 4x8 sheet probably weighs 200 pds or more, I can't pick it up. It's used in armered trucks, it's like a super laminant but you can cut and rout it like plywood. My question is... I have a door on one side of my studio close to the soffit, I done a work around for the slot walls, but I can make the bezel for the soffit a little bigger if I can hinge about 3 or 4 inches of the bezel so it will move out of the way when I need to get to the door. Do you think it will effect anything, and what effect will it have since I'm only doing it to one side? Since it's not atached to the speaker does it more or less just become a reflective surface? Hince with the extra denceness there is less chance of vibration? Thanks for you time. Arthur

This is likely what he's referring to - http://www.usplastic.com/catalog/catego ... e%5Ftest=1 I'll have to consider your other questions when I have more time... Steve

Steve, about the bezel issue... Like you said before unless it's a tried and true method don't do it, since I don't have the time nor effort to go back and fix it if it don't work I've decided to forgo the extra width on the bezel and just give my slanted walls a few more degrees of angle. Thought that might save you some brain cells, sure has saved some of mine. I would like to know what you think of the Phnolic board idea, the board I have is 3/4" thick. Thanks again for your help, I know I couldn't have gotten as far with all the great advice and BTW I do intend to make a donation to the forum for all the help. Arthur

Arthur, I've yet to find real numbers as to what phenolic weighs - can you weigh a panel and post size and weight figures? Beyond that, I'm not sure about resonance - seems like the stuff might tend to resonate pretty strong, but that's just a wild guess... Steve

Steve, The Phenolic boards that I have are 3/4", 4x8 sheets and they weigh about 150 lbs, the best I could measure with bathroom scales which the wife didn't appriciate :roll: but that's all I had to weigh them. Here's the link http://www.wilsonart.com/productlib/techdata/laminate/SolidPhenolCore.pdf for the company who made them. Some type of resin laminate. though I would have loved to put the whole sheet up for my bezel my deminsions will be 38"x88". Why do you think it might resonate? Am I missing something? It seems to be a lot more dence than plain 3/4 laminate plywood. I should have more pics in a couple days, I'm about finished framing for all the insulation and the floor goes down next week. Thanks again. Arthur

"Why do you think it might resonate? Am I missing something? It seems to be a lot more dence than plain 3/4 laminate plywood" - Density isn't the only property that affects what a material does acoustically - for example, 1" plate steel weighs 40.82 lbs/sq.ft., or just over 1300 pounds for a 4x8 foot sheet; if you hang it from a cable and hit it with a soft mallet, you still get an audible response from it. So even the phenolic, which apparently weighs twice what a 5/8 gypsum panel weighs, and a bit over twice what 3/4 plywood weighs, will likely still have a resonance that's within the audible range. Baffle extensions should NOT resonate - so these will need to be damped no matter what material you use, unless that material is 12" thick depleted Uranium or lead... Steve

Thanks Steve, I do understand that almost everything has a resonate frequency, my point was, all the post about the bezel talks about how it needs to be out of something of high density, so I guess I'm just confused, again :? What am I supposed to use? If I bolt the bezel to the soffit frame I understand it's still going to have some resonance at some frequency, but wouldn't any material? So if the density of the material is higher wouldn't it be an advantage? Maybe the density of my head is the disadvantage :lol: Thanks for helping me understand this. Arthur

Arthur, you're right - density IS your friend; but so is low resonance - all I'm saying is that your baffle extension should NOT also be a "passive radiator" its only function should be to extend the baffle so it forces the woofers into "half space" mode. Beyond that, it should be dead enough NOT to sympathetically vibrate, which means that it needs to be damped. This generally takes mass, as well as some degree of limpness - I'm not positive, but I think this is one reason using heavy plywood seems to work so well - it's just my gut feel, but I think the separate layers and glue of the 1-1/8" flooring plywood help minimize quite a bit of ringing. The ringing is what I'm a bit worried about - what little I've handled phenolic (much smaller pieces than yours) it just seemed like it would ring quite a bit. You can find this out fairly simple - take a piece of 2x2 about 6" long, rip it diagonally to make two triangular pieces 6" long, set them on the floor about a foot closer together than the side of one of your panels, have a helper help you set the panel on these so there are only two "knife edge" support points, then balance the panel so it only takes a light touch to keep it standing verticall, and tap the panel in different locations with a rubber mallet - if you hear ringing at any frequency, it needs to be damped. Bolting it to a frame would lower the resonant frequency; how much I don't now. Gluing heavy rockwool batts to the rear would also help. I'm really not trying to be an alarmist here; just pointing out things I would look at before committing to anything new and different... Steve

Thanks Steve, I understand compleatly what you're saying about trying new things, it's funny I just said that three post above but why I didn't referance it with this subject beats me. It must be the density of my head again. :oops: I will try the rubber mallet trick and hook my RTA up so I can test exactly what it comes up with. Do you think I should cut the 4x8 sheet down to the size of my bezel first? Again thanks... Arthur

Greetings Arthur In addition to Steve's cool advice..... Soffit walls need to be STIFF!!! To avoid the soffit wall becoming a passive radiator, you should decouple the speakers from the soffits/soffit wall with a resonant freqeuncy at least 2 to 4 octaves BELOW the lowest freqeuncy your speakers can emit. Genelec recommend a resonant freq of 2 to 8Hz. This is hard to do, but 10Hz is easily achievable. The speakers should be EXACTLY flush with the soffit wall. to prevent diffraction. Soffit mounted speakers not only give you an incease in bass levels ( compensated for by EQ ), but they also excite standing waves ( room modes ) more than free standing speakers, so you should heavily absorb the rear wall. I thoroughly recommend reading the Genelec papers on soffit mounting. here's the links http://www.genelec.com/support/soffit.php http://www.genelec.com/support/faq/faq20.php http://www.genelec.com/support/faq/faq19.php hth ;) Paul p.s. I've just finished building my soffits/soffit wall. See Paul's Studio Build Diary here....http://forum.studiotips.com/viewforum.php?f=1

Thanks Paul, I've been following your studio diary... WOW your soffits are amazing; I wish I could hear how it sounds when you're done. Your posts have been an encouragement to me as I journey on with my construction. I’ve read the genelec stuff, which was a big help. I guess I should have posted a floor plan but I’m not very good with the Smart draw program, so instead of taking the gray matter to learn something I would probably only use this one time, I just tried to take the floor plans from this great forum and adapt what would work for me on paper. It’s along the lines of the Garage Studio design with a 10x8 Vocal booth and 14x17 Control room. As far as acoustics, I have slats on the sides, Absorption on the ceiling, back 4 ft of the control room and the whole back wall is nothing but 8” to 10” of rock wool. I was hoping the phenolic board would work, it served a couple of issues for me plus it cost me nearly nothing which is always a plus. I still haven't given up on it but I need to do a little more investigating. I've been fortunate on several issues with my place; my wife has always been cool about my work so isolation hasn't been a major concern. It's funny how when your hobby not only is something you enjoy but it pays all the bills, hearing a little music in the house doesn’t become much of an issue. :wink: So I was able to for-go a few steps, I just want a place that I enjoy working in that sounds great, I get tired of giving other people my cash just for a place to work, then have the budget dictate the work instead of the music. All the great advice I’ve gotten has been a God send, but just the planning alone makes you really appreciate the hard work that goes into a great sounding room. I start my floor tomorrow, yippy. I haven’t gotten as much done as I’d have liked but I’ve gotten closer than I would have dreamed with all the help from everyone here. Thanks again. I look forward to following your diary; your pictures are incredible, thanks for taking the time to do them. Arthur

Arthur, not only should you cut to size for the test, but keep in mind that when you mount to your frame, you will LOWER the frequency of resonance by further increasing the overall mass - What I'm concerned with, (with nothing to back it up beyond gut feel and natural paranoia) is that the phenolic might have (for some reason) a really HIGH resonant frequency, so that (when attached to your frame) it will be at a REALLY audible frequency range. I'm not telling you that this won't work, I'm just suggesting caution when "blazing new trails" - that "limb" you whack off with your machete just might be the tail of a very large, pissed-off snake, or you could discover that the sap of the plant is a cure for cancer (sorry about the obscure crap, it's 5 AM and I'm not quite awake) Steve

My flooring is down, looks great and sounds even better.

Looking good. Is that prefinished HW or a lam? <it looks like real HW to me> ~R

Thanks ~R, It's a Laminent, sorry I don't have the brand; I bought it from a contractor friend who had a little too much for him but just enough for me. It's tongue and grove, 1/2" thick and can be resurfaced 3 to 4 times. It was a breaze to install floating and I got it at a great price, he said it normally goes for 8 or 9 bucks sq ft but he sold it to me just to get it out of his way for 2 bucks a sq ft. If I can find out the brand I'll let you know. Steve, I have a question about my rear wall, it's 14 ft wide 8" thick and I was going to make it compleatly absorbant with 3" of rockwool on the inside wall with 5" of air space behind. On each side next to the adjacent walls should I pack about 2' full of rockwool. IOW since I don't have room for corner traps should I put 8" of insulation 2' wide on each side of that back wall and then 3" on the remaining 10' in the middle all covered in cloth? I hope that makes since. :? Hope everyone had a great thanksgiving. Arthur

That sounds like it should work fairly well; you might need more bass trapping than that, if so you can hopefully utilize some ceiling/wall corners for more corner trapping... Steve

Thanks Steve, My ceiling is going to be angled at 6 degrees from just behind the mix position to the front with hangers in the space in front. The rear half ceiling will be cloth covered 2" rock wool flat. I was thinking about putting a ceiling corner trap along the whole back wall but do I need to seal that or just make it packed rock wool covered in cloth? The corner bass trap designs on here have slats on the front and since I only have about 10' from the back of my head to the rear wall, if I'm understanding everything correctly I don't need to make anything on the back wall reflective, is that correct? What do you recommind? Thanks, Arthur