DIY Soundproofing

[marlowem]

Hello

Any suggestions for soundproofing a small home studio?

[jackfrost]

egg shell cartons?

had a friend back in college who did this.

[makinao]

Preparing a room for sound work involves two stages.

First, "soundproofing" a room means isolating the inside of the room from sounds coming from the , as well as isolating the outside from sounds originating from inside the room. This involves making the walls as rigid as possible so that it will not vibrate when sound hits it. Rigidity is achieved in a number of ways, one by making the wall as thick and dense as possible. This is expensive and is sure to turn any any household inside out. Another way is to seal off air leaks so that sound in the air is halted. This means putting rubber seals on your doors and windows, so that when they are closed, they close TIGHT like car doors. There are other methods, but these involve even more civil works than those I just mentioned. So I'll pass on them. Assuming you can't do any major construction, but are allowed to choose the room to work on, go for a room that has at least concrete walls, solid core doors, and small, sealable windows. This leads us to the second stage..........

"Tuning" a room is very different from soundproofing. Tuning "tames" the acoustic characteristics of a room. What most people are looking for is a room that has a combination of "liveliness" and control. If a room sounds tubby or has undersirable echoes or reverberation, the cheapest solution is put in 1) semi-filled cabinets to control low frequency boominess, and 2) heavy but absorbent materials like drapes, carpets and upholstered furniture to absorb high frequencies. Egg cartons are so thin and porous that their effect is minimal, and they look dreadful. You also might want to arrange the cabinets and furniture asymmetrically to help minimize the dreaded "standing" waves (google it for a better explanation).

All studios, even commerical ones, are always a work in progress. Things get re-arranged whenever some kind of anomaly is noticed. So just keep working on your room, keeping in mind the two concepts of soundproofing and room tuning.

[nemo]

old matresses maybe?anything that is "dense" will dampen the sound hehe so cguro if you're going makeshift use matresses with eggshells?...then there are the professional solutions of course

[makinao]

old matresses maybe?anything that is "dense" will dampen the sound hehe so cguro if you're going makeshift use matresses with eggshells?...then there are the professional solutions of course

If you are planning to set this up in the bedroom, beds are actually great for absorption. I'm not quite sure if putting eggshell cartons on top of a bed would be comfortable to sleep on though

[marlowem]

Thanks guys!

I always thought eggshell cartons didn't actually work 'cause the neighbours still complained XD

[Tarkuz]

I hope you will find this info useful.

It's a misconstrued belief. The original "eggtrays" were strips of cardboard, about 4" in
width and are formed to have some sort of a square container inside, much like the old
soda boxes. People found out that by putting these on the walls, they have the ability to
"break-up" certain frequencies - much like Schroeders - and they help in making the
sound of the room good. The old eggtrays are different from the ones used as eggtrays
today (Reference: look at Everest "How to Build a Small Budget Recording Studio From
Scratch," Chapter 16, "Bits and Pieces of Acoustical Lore.")

Since entering the acoustics arena in the seventies, we have heard many stories over and
over. One of these is that the acoustic foams are no more than a fancy packaged version
of egg cartons.

After listening to this many times, I decided to include them to be tested with some
commercial products at Riverbank Acoustical Laboratories. I recently discovered these in
my "attic" files and have reproduced them here.

Egg Cartons do, indeed, have acoustical value. They measure NRC - 0.40.

However, the graph tells the rest of the story. While commercial products exhibit a smooth
curve, there is a "pothole" in the acoustical road with egg cartons.

Another thing to consider is flammability. Take an egg carton outside and put a match to
it! Then ask yourself, "Do I still want this on my studio walls?"

Q What's the difference between soundproofing and acoustic treatment?

Acoustic treatment, in the context of a recording studio, generally deals with the acoustic
quality of the room from a listener's point of view. In other words, if you monitor in a
control room that has been designed using the correct acoustic treatment, what you hear
is likely to be more accurate than the same recording played back over the same speakers
in an untreated room.

Soundproofing, on the other hand, is specifically designed to increase the degree of
acoustic isolation between the studio and the world outside -- cutting down on noise that
leaks into or out of the studio. Sound isolation works the same both ways, so there's no
difference in approach to keeping sound in or out.

Q I've heard that sticking egg boxes or acoustic foam to walls will help soundproof a
room. Is this true?

Egg boxes can make a marginal improvement to some aspects of a room's acoustics by
breaking up reflections from hard surfaces, but they are virtually useless for
soundproofing. The same is true of lightweight suspended ceilings, acoustic foam and
even Rockwool (Rockwool tends to be used for acoustic treatment or for damping out
resonances inside partision walls. All these materials have their uses, but they're mainly
for acoustic treatment, not for soundproofing).

Q Where can I obtain more information on this subject?

There are past articles on the SOS web site (enter Soundproofing or Acoustics in the Search
facility at www.soundonsound.com/search), and a couple of my own books are available
from the SOS bookshop (01954 789888), including Creative Recording II and Basic Home
Studio Design. These are good if you want a practical rather than mathematical guide to
the subject. For a more detailed, technical approach, there are some excellent books from
F. Alton Everest, including The Master Handbook of Acoustics.

Q Are you sure I can't use egg boxes?

Quite sure!

Many musicians believe that soundproofing comes from foam, or egg-carton-looking
materials hung around studios. Unfortunately, this cannot be further from the truth. Any
foam you see in a studio is not there for soundproofing, but rather acoustical treatment.

Acoustical treatment is the process in which you attempt to deaden the acoustics of a
room via sound absorbing foam, bass traps, and all kind soft, porous materials. Anything
labeled as Acoustic Foam is for this purpose, not soundproofing. This is mostly the
treatment of resonance in certain frequencies and minimizing echoes. Each studio will
have it's own feel to it and that will all depend on the Sound Engineer's preference for
acoustical treatment.

Soundproofing is the process in which you attempt to reduce the intensity of sound
transmitted outside of a practice area. This is mostly accomplished in the walls and
insulation of the studio itself. The thing to consider here is the STC rating of a given
material. An STC rating describes how many decibels are lost in the transmission through
a given material. For example, if you had a wall with an STC of 40dB and you were playing
your drums at 70dB inside the room, outside of the wall you would measure a 30dB noise
level. Average walls have an STC of around 40-60, with brick and concrete walls on the
higher end of the spectrum. However, keep in mind - a soundproof room is only as
soundproof as it's weakest point.

Egg Cartons

I'm sure you've heard it, put egg cartons all over your room and you'll soundproof the
room! Sounds like an excellent idea, and hey - omlets are starting to sound better by the
minute. Unfortunately this is this most popular myths of soundproofing. The
soundproofing properties of egg cartons are effectively negligible. That's right folks,
you're better off putting a chair in the corner than lining your room with egg cartons. Now
what egg cartons do is provide acoustical treatment. Specifically, they lower the resonance
of mid to high range frequencies - such as cymbals. This can lead to a false sense of
soundproofing since the room will echo considerably less after installing egg cartons.

The reason this works it that the goal of acoustical treatment is to trap small pockets of air
inside a flexible container. This `traps' the frequencies and prevents them from reflecting
back into the room. This is also why acoustical treatment materials can sometimes be
called 'sound traps' or by their specific purpose such as `bass traps'.

[rosea]

@ makinao & tarkuz - thanks for the info, sirs, very interesting read!

[marlowem]

Very scientific read, thanks! So then, any practical suggestions? The room's walls are concrete, aside from the rubber seal-offs for the windows and doors what can I add to the walls that won't need major construction?

[masterjames]

Acoustic wall panels, some of them can be customized to have printed art,so i think this is the most practical