Discussion in 'Acoustics (Live Room, ISO Booths)' started by Jason Morris, Mar 19, 2018.
The New AT5047 Premier Studio Microphone
Process of elimination, gotta love the scientific method! Things are coming together here.
So, I'm still delving down the HVAC rabbit hole. I think I have a little more understanding of certain things.. But to be honest there are so many variables floating around that I get a little lost in all of it.
The past day or so, I have been trying to figure out what I want to do about silencers.
As I think I mentioned, isolation is very important to me. I am shooting for 60db, and want to do whatever I can to hit that target.
I read on John Sayer's forum that in order to get really good isolation, Im better of putting a silencer on each leaf penetration.
But because of the lack of space in my drum room, I have very minimal area between my leafs for silencers.
So I am thinking about options.
One option is building a small silencer that can fit between the existing ceiling joists. That would put me at roughly 14" x 7 1/2" x 3' or so (i could go longer if I wanted)..
I could only feed that with a 4" duct (12.56 sq in.. I think) . The channels in the silencer would be 4x4 (16 sq in), and it would come out the vent at 4 x 8" (32 sq in).
I think that fits the requirements for doubling the cross section at the output of the silencer.
I guess my question is.. am I starting off with too small of a duct to begin with? I have seen other posts where people with similar spaces to mine had used 4" duct.. but that doesn't mean they did it correctly.
What do you think?
Its easy to get dizzy, especially since all the variables depend on each other. Thats one reason why you'll find me referring to rod/the book so often. simply because ive used his methods, know what to expect, and i know they work. so it takes alot of variables out.
Last i remember HVAC you were saying you thought a ductless mini was the way to go, since your existing A/C wasn't cooling the upper floor very well. it made sense for the studio's systems to be independent, for for civil reasons, and for ease of installation, since modifying existing things can be troublesome from a construction POV, and practical one, since its not currently working to a satisfactory level. add sweaty drummer in airtight room to the equation, and who knows. The other consideration in your case, is that it may be cheaper to add a couple $200-400 blowers to the upstairs rooms, and hook them up to your multi split. Most multis handle between 3-5 blowers depending on the BTU's of the condenser unit.
the difference in price between a multi split system, and single blower mini split system, base cost isn't a whole lot different. Multi splits start to smoke mini's as soon as more than one room is involved from a cost vs benefit stance.
Silencers aren't necessary in every design. if your using ducting, you want to incorporate 90 degree turns in it, so sound has a difficult time propagating. basically what that silencer box does. If ducting size is your issue, you just box in the ducts. usually thats what the wall/ceiling junction is used for, as well as bass trapping.
now with that said, beyond basic needs, and budget requirements, the HVAC details like box locations, ect, aren't ready to be dealt with. basically you've got to make a call as to what type of system your going to use, specially if ducting is involved. Multi split, or modified existing. once that is weighed up generally, cost vs benefit, thats what you plan for in the rest of the plans. I personally like the Daiken systems, and my cousins multi, is working flawlessly, in the studio, and other main rooms of the house, going on 5 years now. The installers didnt balance the load properly at the panel, so we had to address some noises that weren't there previously, as the A/c was installed after the studio was built. (live and learn from your first try).
anyway, considering how unobtrusive the retro-fit was, very unobtrusive (couple small holes, and flexible tubing.) i have no doubts its the simpler way to go for most studios. They are reliable, predictable, quiet, hugely energy efficient, easy/cheap to expand to capacity, and doesn't have complicated zoning, duct routing, and space requirements that a ducted system does. To be honest, i cant see any good reason to try and modify, zone, duct, and spec out, your existing system. a simple btu calc based on your rooms sizes, and you select your blowers and condenser. thats literally it. Zoning and Ducting, are not concerns with this type of system.
Overall, first variable to eliminate is the floor plan, and layout. thats most important. that determines where your wiring runs needs to be, your lighting, and your acoustic treatments. all those depend on the floor plan. then the actual Hvac runs/plan will be incorporated into it, once that is settled.
Think or bass traps and the 'acoustical treatment wall' as you locations to run stuff. they're only needs to be a couple penetrations thru the actual iso walls. most things can be hidden between the iso wall and acoustic treatment.
Normandy's HVAC is so quiet i can't hear it, even with my ear up to the gigantic air supply and return duct in the ceiling. dead balls silent. its also got huge ducting, im guessing 18-24" off hand, and a completely isolated electrical, so the lights don't dim when it kicks in, and there are no clicks or pops in the audio chain. the whole system is properly isolated and grounded, as well as plenty of electrical headroom, for consistent performance. It's downside is the extremely inefficient operating of the system, which costs several hundred dollars a month. granted the blower is from the 70's, before energy star ratings.
Guess what kind of system Tony, the owner had me spec out for him, after our first summer there? yup. multi split. So i hope that tells you something helpful as your sort the variables, and dependent relationships. its good to know your options, and make your mistakes on paper. eventually you'll feel informed enough to make a call your confident with.
to sum it up. i know the modified existing system CAN work, and i know the multi split WILL work. likely with far less effort, thought, and money, short term and long term. Theres like a 10 year warranty on the condenser, and 3 years on the blowers. blowers are easy to replace, they just hang on the wall like a picture, no holes, and are affordable (relative to A/c's in general.
Just fyi- 4" ducting would generally be way, way too small. That would require a high velocity blower, and be noisy.
lol maybe ill go sell Multi Splits if i get sick of the music biz.
Thanks again for chiming in. Yeah, I didn't mean to imply that I had changed my mind from a split HVAC system. I'm still planning to go that route.
When I am talking about ducting I am speaking only about the fresh-air supply/return for whatever HRV/ERV/AEV I end up going with.
I was really just trying to come up with the best way to hide these potential silencer boxes inside the leaves, so that they won't take up any of my precious square footage in the room itself.
ANd my biggest concern is with cutting holes in my walls and letting sound leak OUT, ruining the isolation of my walls.
Yep, I have come to the conclusion that a soffit or two is just going to have to be used, and it won't be the end of the world.
I am still a little unsure of what I need for CFMs for my room.
Rod's book gives as a 'rule of thumb' 15 CFM per person.
90% of the time its just going to be me, but maybe once in a while, I will have 2 - 3 other people in the room, so 1-4 people would be 15 - 60 CFM.
That's easy, and the cheapest AEV should more than handle that.
But then I read other posts where it is suggested that I need 10-12 air changes per hour.
So, if I am doing the math right, 1119 Cubic Feet * 10 air changes per hour = 11190 Cubit Feet per hour. Divide that by 60 and I get 186.5 CFM.
That is a considerably more costly air exchanger unit.
But then I ALSO read that only some portion of those 10-12 air changes per hour need to be FRESH ( I think it was 2 ).. which leads me to believe that this 10-12 changes per hour stuff I was reading was when doing a traditional HVAC system, and wouldn't necessarily apply when doing a mini-split and an AiR Exchange unit.. in my case ALL of the air I brought in would be fresh air right? So if 100% of the air I bring in is fresh, do I really need 10-12 per hour?
So do I just go with Rods rule of thumb (which is what I want to do, as its way easier) or do I try to figure out how to get 10 Air changes per hour into this tiny room? I mean, I breathe a lot, but I cant believe I breathe 11190 cu feet of air every hour.
See.. this is me going down the rabbit hole again. Have I mentioned that I tend to be an "over-thinker"?
ok cool. are you positive you need silencer boxes? i don't remember rod mentioning me needing one for the home theater build when i spoke with him, but its possible i have forgotten, or missed it.
this is essential. i used a free app for my phone and it gave me info based on the room size. i think diaken had one, im not sure, its been a while, there is a bunch of free ones. you can also call someone at an HVAC company who sells the multi split system your interested in, and they'll help you size it. the sound isolation and activity levels, as well as noise, are the main concern of the studio. not to keep brand naming, but Diaken had the most options of blowers, and the best sound ratings, and efficiency ratings of all the major brands that i checked. best or right up there in each category. i checked mitibishi, and some brand with an F i csnmt remember msybe fujitsu and friedrich. Daiken cuz its swiss designed (i believe).
Rod has never been wrong to my knowledge with anything stated in the book. just follow along each section, it can seem to be alot, and the details matter, but its fairly straightforward and easy to follow a bit at a time. Again, HVAC is my weakest area of knowledge regarding studio building and design, i just havent had to deal with it much in my experiences as i said in earlier posts. im always happy to learn as much as possible.
its only over-thinking if you are under-achieving as well.
I haven't forgotten about this place!
I'm still working on things slowly but surely. Man some of this stuff takes a long time. The process of beefing up the existing structure, moving what I can, cutting around and caulking the things I cant move.
It takes forever. I can't wait to finally get around to building a freaking wall. :/
I ordered a pair of MOTU AVB interfaces for testing out the audio-over-ip stuff.
Since about 90+% of my recording is just me recording my own stuff, having the preamps in the recording area with me is appealing.
I'm also intrigued by the idea of just running a few cat6 cables rather than a whole snake and then soldering the connectors to each end.
I'm not sold on the AVB stuff yet, and if it doesn't work out, its back to Sweetwater with the stuff, but the idea is too good to not at least try.
Has anyone here successfully wired up a studio with just cat5/ cat6?
Audio over ethernet seems to be the next best thing. The bandwith permit so many connexion and control that it will be a good choice in the future.
If it's ready now is a good question.. Please keep us inform of your progress. It's always good to be informed of tech developpement
if you use a pre-soldered snake (like a store bought one) you can tape the ends of the wires/connctors to the snake so they'll fit through a smaller hole than they would otherwise. cut and solder is better, but thats a decent workaround ive used.
awesome! your perseverance is commendable! these are the things that make it work well, and the days that you feel extra satisfied about when your jamming out!
not yet. im on that bandwagon though. cat cabling is going to undoubtedly be part of, or all of the future of a/v wiring.
its a tough call. Dante is arguably more well supported [future compatible], but AVB does video. either way, MOTU makes decent stuff, and my experience with it (about 3 years) is its very reliable. im hoping to see some sort of unified Dante/AVB agreement or format, which would make things easier for customers and designers alike. Congrats on your new purchase and for your hard work. much respect sir.
Finally started building some walls....
This room is going to be tiny. :/
Awesome keep up the good work.!
OK, so in the process of beefing up my subfloor/ceiling, I dealt with a couple of ducts that feed the dining room above my recording space..
I ended up ripping out the 6 inch flex duct and put in 2x12 rectagular duct.
So above my head from top to bottom I have
2 layers of 5/8 Drwall
1" duct liner
Yes, I used duct liner on the OUTSIDE. I know thats not the right use of it, but it was what I had on hand, and it did what I wanted, which was to give the ducts something to 'squish' into .I wasn't sure how else to deal with the ducts as the bands that join them together make them irregular. They would not sit tight against the drywall.2x12 duct
1" duct line
2 more layers of 5/8 Drywall
Battened into place with 1x2
Acoustic caulked gaps.
This only exists on two bays. The rest of the bays are just 2 layers of 5/8 drywall as typical.
In order to preserve my ceiling height, I got a bit creative with the line that feeds one of those bays.
I used a 2x12 section, turned sideways, then frankesteined some ductwork to create an elbow that would join up properly.
Everything is taped up and sealed, and it is passing air to the room just fine.
Now that I have completed my epic preamble, I can get to the point.
What is the best way to build the inner leaf wall around that section of 2x12 that I turned sideways?
I can just build inside-out like I have done with the other walls, and pull that wall away from the duct by a half inch or so, but thats going to make the already small room even smaller.
OR maybe build a 'normal' wall, but use 2x6 (or 2x8 maybe?), and notch around the duct?
Nice work. Fwiw, duct liner can be used on the interior or exterior of the duct, with equally good results, assuming everything else is proper.
I'm in a rush right now, I'll take a look at your pics and question when I have a minute. One way or the other you just want to outline the duct with the new frames, maintaining the airspace. Wether it's a nottched header, or "chase frame" hanging diwn from the ceiling from isolation clips/channel, the idea is the same with regard to physical decoupling. In
rods book there is an illustration of a Chase frame boxing out a beam, and I believe one showing a protruding duct in the airlock. It's definitely in there because his plan in the book called for perimeter ducting all over the place.
Gotta run. I'll check back ASAP.
I would just build a soffit/Chase frame around the duct. Attach one side to the ceiling with iso clips, or channel, and then the bottom I part to the wall. Basically just outlining the duct with the continuous iso assembly. I'd space it off the duct 1" just to compensate for bowed framing members.
@Jason Morris @kmetal
I don’t know why my last post was deleted... but I’m sure it was simply due to error on my part, and my inability to get my fat fingers to type properly on an iPhone.
In the deleted post, I was just mentioning that both You and Kyle seem to be well-informed on this subject... certainly more than I could ever hope ( or even want) to be.
I had offered the suggestion that you may want to send an email to
Rod Gervais, who’s book on Home Studio Construction seems to have become the de facto “bible” on the subject.
To my knowledge, Rod has always been friendly and approachable for those who own his book and who may still have questions. Owning his book may also make it easier for him to point you in the direction of reference to help answer your question(s)...
That said, both You and Kyle seem to have a pretty good grasp on the intricacies of the subject.
I’m following this thread not because I have any future plans to build another commercial recording studio in my life ( 3 studios between ‘85 and ‘04 were more than enough for me, LOL), but because I do find the subject to be interesting reading... now... how much of what I am reading here that I actually comprehend is another subject entirely.
My question is about what the final decision is for the ceiling assembly, as I don't recall off hand, and an too lazy to fish thru the 4 pages of this thread.
You're not suggesting soldering XLR connectors to the Cat 6 for analog audio are you? There are several reasons that's probably not a great idea, however, there are numerous converters you can get to properly transform 4 channels of analog audio to a single Cat5/6 cable- and they work quite well. The Cat5/6 cable has to be shielded if you need to pass phantom power through it. I've used a couple different brands [ ETS InstaSnake / EliteCore ] on installations and they've worked very well for their given application. I haven't used one, but Whirlwind makes a nice looking version with both male and female XLRs for each channel so you can mix and match sends and returns easily. You can order the EliteCore with a variety of connector combinations. But if you're not adverse to soldering (and it doesn't seem like you are), you can always change XLR gender or add TRS connectors as needed.
AVB works fine and supports up to 192kHz 32-bit. DANTE is probably available on more high-end gear though.
I am doing an inside-out ceiling.
Oh no way! I have a pair of AVB interfaces that I have been using! Only drag is that if I want to change interfaces, I need to buy into either more AVB or Dante.
The way things are laid out in my studio and the finished portion of my basement, it wouldn't be the end of the world if I have to bring a snake in down the road, but who knows where things will be in a few years.
Maybe AVB or Dante will be more ubiquitous then. Or maybe I will have moved out and will be on my next studio build.
Are you doing it independently framed- resting on the wall headers, or mounting it with isolation clips/channel/suspension.?
Independently framed. The new joists will be 2x6, and will be about 1/2" away from the existing joists, running perpendicular to them.
Very good sir. You may want to plan on 3/4" or tbe standard 1" airspace to account for bows in the wood, deflection (bending) under load, and vibrations from rock and roll. Imho
I'm curious why your running perpendicular to the existing joists, instead of parelell, and tucking them in the bays of the existing ceiling as rod depicts in the book. This could save you nearly three entire width of the joist in ceiling height.
Forgive my fried brain, ive been comoaring computer chip and ram performance, and motherboard specs for a month straight.
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