Is there a cheap way to soundproof a room?

The quick answer is: Probably not, but you may already have a room that will accomplish your goal.

This question came to me from a trumpet player that was looking for a way to practice without disturbing others.

There are three principles we will draw on to understand the direction needed:

  1. Sound proofing is achieved via isolation and not absorption.  Most people mistake the zig zaggy foam they see on studio walls as providing isolation.  Foam has another purpose (absorption) and doesn’t really help much at all to keep sounds in or out of a room.
  2. Higher sounds (frequencies) bounce off solid objects like walls and floors and glass.  Lower sounds transmit through typical walls.  Therefore, the steps to achieve sound proofing are determined by the frequency range of the sound source.  Isolating a flute is much easier than isolating a kick drum because with a flute you can go into a typical bedroom and close the door.  An kick drum can transmit through the floor and ground to be heard a block away.
  3. The rigidness, thickness and spacing of the barriers (walls, doors, windows, air space) are factors in sound isolation.  Solid concrete walls will isolate more volume at a lower frequency than sheet rock because concrete is more rigid and vibrates less.  And sheet rock will be more effective than glass.

Let’s look at a few specific examples of how to isolate various sound sources for rehearsing.  I will list them from easiest and cheapest to most difficult.

Flute, clarinet

Since higher sounds will bounce off of walls and the energy of quieter sounds dissipates quickly, a flute player can typically attain practice isolation by simply going into a bedroom and closing the door.  If the bedroom is really close to those you don’t wish to disturb, you may need to go to a bedroom that is farther away.  A flute will not produce sounds low enough to transmit through typically constructed walls and doors.  Note that the slightest crack (like under the door) will allow sound to pass through.

Trumpet, vocals, violin

The volume produced by a trumpet or vocalist makes those sound sources a little more difficult to isolate.  But the relatively high frequency range still works in our favor.  The key is to dissipate the sound before it escapes to the ears of people nearby.  One tool we use in the studio to accomplish dissipation of loud sound sources is a room within a room.  The air between the rooms does a marvelous job of absorbing and further attenuating the sound.  It isn’t practical for most trumpet players or vocalists to build additional structure, but you may already have a bathroom or walk-in closet that offers the option to put two doors & walls between you and the family.  If that doesn’t work, practicing in the car will demonstrate how well this works.

Trombone, Tuba, Electric bass

Instruments that produce low sounds require a room within a room and also physical isolation from the floor.  A platform on foam can help.  In my studio, the floor joists were constructed on U-shaped thick rubber that prevents low notes from transmitting through the “floated” floor to the concrete below.

Auralex makes a drum platform designed to decouple the drums from the structure.  It’s not a magic bullet by any means, but can be the difference in how many neighbors you share your rehearsal with.

Publishing early to help a friend.  More to come.

If you have questions, I would be glad to try to help.