- Resilient channels are not needed with lightweight (20
gauge or thinner) non-structural metal studs.
Wood stud + resilient
channel = metal stud.
- Never trap the resilient channels between layers. Use resilient channels to isolate all
of the sheet rock from all of the framing. A hat channel is not the
same thing as a resilient channel, and has no useful acoustical
channels are not needed on both sides of the wall.
- Batt insulation inside the wall is almost always a good
idea. There is nothing magic
about "sound deadening batts" -- regular R-11 or R-19 fiberglass is fine, depending
on the wall studs used.
Insulation should substantially fill the cavity.
- Dissimilar sides of the wall or window is generally a
good thing. Think "1 +
- Solid material (such as a shear plywood layer) on the inside
of a double stud wall will drastically reduce the overall sound rating,
often from STC 60 down to STC 46.
Yes, adding more material reduces the sound rating!
- Triple glazing is worse than double glazing for noise
reduction. Thin vinyl
interlayers improve R value, but don't count as a third pane. Float glass and laminated glass are
- Think "water tight" when sealing sound rated
walls or enclosures. Anywhere
that water would leak out, sound will leak too. Leaks are very important -- 1% open area lowers the STC
rating by 15-20 decibels.
- With an open plenum above the ceiling tile, you get STC
30-35 room-to-room, regardless of wall type or ceiling tile type. Penetrating 6" above the grid
or adding batts on top of the ceiling tiles does absolutely nothing.
- "Sound deadening board" doesn't. Never has, never will. It has absolutely no useful
- An acoustical "boot" is more than just an
elbow. It is 12” of duct plus
an elbow plus 4 feet of internally lined duct. External duct insulation is thermal only - it does
nothing for noise.
- Inertia bases under mechanical equipment do not help
with either noise or vibration. They are not a substitute for an adequate
- Plastic waste/drain piping in residential construction
will almost always be a noise problem, even with remedial treatment. Adding pipe wrap and appropriate
isolators is very labor intensive.
Cast iron pipe will almost never have noise problems.
- The supply side of a ventilation system seldom presents
a noise problem. The return
air side almost always needs noise control, because of the shorter more
- Active noise cancellation works best in confined areas
and for specific low frequency tones. Cancellation won't work for broadband noise in three
dimensions, such as a portable generator or traffic noise.
so it was more than ten.....)