Recording - November 2015 - 14

property was well within legal limits, but the
neighbor was hypersensitive to it and was
pounding on his door every day. So you could
say all day long to that neighbor, "Well, it's
legal," but if you have an unhappy neighbor...
It's going to be a headache no matter what.
It's a headache. It's hard to live with an irate
neighbor. To help avoid this type of problem,
selecting the right location for your studio can go
a long way. If the studio is in a very quiet neighborhood and all you hear at night is a cricket, it
will not only be more difficult to meet the noise
code, but any noise produced will be more evident. If the studio happens to be in a noisier environment, such as being close to a freeway, any
noise that does leak out of the studio will tend to be masked.
When it comes to intrusive noise coming into your studio that
is sporadic, such as a plane flying over, it might make the most
sense to just live with it, and do another take, versus the cost to
fix the isolation problem. Choosing a good location, one that
doesn't have lots of exterior noise or sensitive neighbors can
make your studio a much more enjoyable experience.
Once you've assessed this, though, and with the mindset of
doing the most one can do without breaking the bank, what
are some of the things that
you can do, or you can recommend people to do, to achieve
good isolation?
When you're trying to figure
out a location for your studio, it's
ideal to have it on the ground
floor of the house, what's called
the slab-on-grade, the ground. It
is much more difficult to have any
level of isolation if you're on the
second floor, because the second
floor acts as a diaphragm and
connects to the outside walls, so it
becomes difficult to do anything
about that without spending a
fair bit of money. Additionally,
you just can't add weight to a
floor of a house without risking
severe structural issues.
Then there are two areas that are the absolute weakest links:
windows and doors. A room that has fewer windows and fewer
doors, particularly to the outside, would be better. If you're concerned about adjacent rooms or other parts of the house, then
of course try to find a room that may be farther away from the
bedrooms or other areas that you might be concerned about.
When you're adjacent to something, it's difficult to fix. In a typical house of fairly typical construction, the STC of an interior
wall might only be about 33 dB.
STC?
Sound Transmission Class. It's the amount of energy that gets
lost by going through this material.
So you want a lot of STC?
The higher that number the better. The STC value is a single
number that does not give you any meaningful information
about low frequency or high frequency attenuation, so it has its
limitations, but it is a valuable reference. A typical exterior wall
in a house has a STC around 36, where a typical window might
be 20-30 and a door as low as 10-25. So you can see that's
a huge weak link between the wall value and the doors/
windows. What you need to do is fix those two components.
14

RECORDING November 2015

There's one company out there that actually
makes windows that are designed to attach to the
inside of the window frame; it's basically attached
over the existing window so what you end up with
is your window, a little air space, and the new
window you've attached to the inside, and it's a
relatively inexpensive solution which is easy to
install. (www.soundproofwindows.com)
To get a higher level of performacne would
require replacing the existing window with a fixed
piece of acoustic glass, preferably 9/16" thick, leaving the maximum air space possible, and installing
another fixed piece of acoustic glass in the interior.
Acoustic glass performs much better than regular
plate glass. It is made by laminating two pieces of
glass together with a plastic interlayer.
Doors are the other huge weak link; a common problem with interior doors in a house, typically hollow core, is that they're paper-thin;
they do almost nothing. You'll only get an STC of about 10-12 with
these doors! The best solution is to replace them with 13/4" solid core
doors and good quality perimeter seals. An inexpensive solution is
Pemko S88 seals and a Pemko sound rated door sweep. Exterior
doors can suffer from the same problem. Many exterior doors have
"panels" which make portions of the door very thin. They should also
be replaced. And if you want to take it one step further, remove the
casings around the door, and fill any open cavities with acoustic
sealant, then replace the door casings. The object is to make it as airtight as possible.
Excellent. I was just thinking, as
I was hearing a little bit of
noise coming into where we
are right now, from people
around the house... I was wondering if you ever say to people, "This room is nice, except it
happens to be right next to the
kitchen or your kid's room"?
Absolutely. It's very difficult, so
if you can, find a room that is farthest from rooms that you have
any concern about regarding
noise intrusion. The baby's room,
bedrooms, any room with a
potential for the occupants being disturbed by the noise.
What about basements?
They're excellent, because most of them are subterranean or
partially subterranean, so it's the best of all worlds; the floor is
slab-on-grade underground, most of the walls are underground,
so you really have a high level of isolation. Even with a very
modest amount of work on the ceiling, you can produce very
high levels of isolation, very inexpensively.
If there is living space directly above the basement, I would
recommend removing the drywall of the basement ceiling, filling
the stud cavities with fiberglass, and installing Kinetics Noise
Wave hangers directly to the bottom of the ceiling joists, then
installing two layers of 5/8" gypsum per Kinetics Noise specifications. This approach completely decouples the new ceiling
from the existing ceiling joists.
The Kinetics Noise Wave Hanger is something I would highly
recommend. It produces virtually the same level of performance
as actually using springs to hang the new ceiling, but it's a fraction of the cost and it's pretty easy to install. You install these
Wave Hangers, attaching them directly to the bottom side of
those joists, and put two layers of gypsum dry wall on there.
When you're done, you'll have a very good, reasonably affordable ceiling.

http://www.soundproofwindows.com

Table of Contents for the Digital Edition of Recording - November 2015