Ventilation

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.

Moderators: Aaronw, sharward

newnes
Posts: 1
Joined: Wed Apr 16, 2003 5:03 am
Location: Calgary, AB

Ventilation

Post by newnes »

Hello. I'm currently building a small project studio - 540 sqft, 2 rooms, in my attached garage. I've already finished the interior wall framing, insulation and electrical and I'm stumped trying to find an effective, yet affordable hvac solution. I've already picked up 2 radiant electric heaters, and it's only crazy hot around here (Calgary, Canada) for a few weeks so, at this point, I'm mostly concerned with ventilation. My questions are this:

1. Does anyone have any experience with heat recovery ventilators as seen here:
http://www.nu-airventilation.com/produc ... html#nu145
http://www.lifebreath.com/life.htm

2. Portable air con units like the one below claim they provide fresh air, however with only an exhaust fan, how is that possible? Also, are these units anywhere near quiet enough to operate in a studio?
http://www.fedders.com/catalog/applianc ... d_port.htm#

3. I'm familiar with John's window air con design as seen in this thread:

http://www.homerecording.com/bbs/showth ... ht=heating

How much fresh air does this actually provide and how would this work in a multi-room studio?

I've been quoted $3000 CAN for a cenral a/c system and similar for a split-system which still wouldn't provide fresh air. I'd like to keep my hvac under $1500 CAN, if anyone has any creative ideas, please let me know.

Thanks for your time,

Craig Newnes
knightfly
Senior Member
Posts: 6976
Joined: Sun Mar 16, 2003 11:11 am
Location: West Coast, USA

Post by knightfly »

1 - No direct experience with either of these particular brands, but of the two, the Nu-Air sounds like it comes closest to being usable. It has centrifugal, or "squirrel-cage", blowers, which are a lot quieter than axial (propeller) types - it also provides a slow mode, so you could get a larger than necessary unit and slow it down. Keep in mind, that the noise caused by moving air is roughly proportional to at least the 5th power of the velocity of the air. This means that a small reduction in air speed gives a large reduction in noise created.

2 - It's NOT; and, NO. Portability means small, and that's the opposite of what works for quiet HVAC. You need large, and slow - unless you're willing to shut it off during recording, which can be a real pain.

3 - This would depend on the size of the unit and whether the ducting restricts air flow below what the unit can put out. When ducts are oversized, you can get more air through them with less velocity, which is what you need in order to reduce noise. Also, each turn in the duct reduces sound transfer, and lining with absorbent further restricts sound transfer.

For a multi-room studio, if the AC unit is large enough you can get by with one - however, you will need to run separate, non-straight, absorbed ducts to and from each room ALL THE WAY BACK to the AC unit, which should be mounted in rubber, preferably on a separate slab, and connected to the ducting with FLEXIBLE ducting. All this keeps your hard work of sound-proofing from being wasted. Without doing this, you will have short air paths between rooms that are supposed to be isolated.

From what you've described, I think you'd be OK with something like one of the Nu-Air units, following the installation ideas above - I don't know what those cost, but if you use flex-ducting and install most of it yourself, leaving enough flex duct to keep from having straight lines, you should keep costs down as much as possible.

Oh, location of registers within the rooms is important too - they should not be near mix positions, or where mics are likely to be placed. they should also NOT blow across the space between speakers and the mix engineer, that can cause all kinds of wierd sound effects at least partly due to doppler effect. The aerodynamics of grille work also affects noise level, although I don't have any particular brand or model recommendations as of yet.

If you're REALLY short on budget, you could "roll your own" from the beginning - check suppliers such as Grainger, or McMaster-Carr, for a large centrifugal blower, mount it on junkyard-obtained auto engine mounts in a small, separate shack outside the studio, put a motor on it that has half the RPM called for, hook it to your home-made ducting with large flexible ducting, following the techniques above - you should be able to do this for parts cost of well under $1000 CAN... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
Post Reply