Enhancing the Sound of Music

Nov 1, 2000 12:00 PM, By Michael Sankey

Schools need well-designed rooms with the proper acoustics for effective music instruction.

For students to learn about music, they have to hear it clearly. They need to be able to listen for the differences in intonation, dynamics, articulation and balance. These critical listening skills can be developed only in a proper acoustical environment - one that has the correct balance of absorption and diffusion.

Such a room must be designed to scatter sound as well as control excessive loudness. Unfortunately, music facilities in many schools have been designed by architects who have little or no knowledge about acoustics. Hundreds of details make up a properly designed music space, but a few considerations have become absolutes. If you are planning or renovating your music areas, make sure you don't overlook these considerations.

Plenty of space The most important place to spend your acoustical dollars is in the cubic volume (length by width by height) of your music suite. Reducing this space can make your room unresponsive and excessively loud. This failing is nearly impossible to correct later.

As a health issue, a room with properly designed volume sharply reduces sound-pressure levels. High sound pressure over time can be a factor in hearing loss. If a school must make sacrifices, do not reduce the cubic volume of rehearsal or performance spaces. Often, a district can take funds out of equipment budgets and permit more of the construction budget to be used on creating volume and other important acoustical considerations.

Avoid building concrete tiers. They dramatically reduce cubic volume, which increases loudness. In contrast, portable tiers do not reduce the cubic volume because the space beneath the risers adds to the room's total cubic volume. Portable tiers also allow instructors more flexibility in room arrangement and use.

Shaping up Room shape is another vital component in creating an effective music suite. A rectangular-shaped room, with one splayed (angled) wall, provides the best and most economical scenario for acoustical treatments. Parallel walls are not recommended because they cause flutter echo, which is a buzzing or ringing background sound.

When music room walls are parallel, a school can add acoustical panels to diffuse and absorb sound. These wall treatments will reduce or eliminate the flutter echo. A splayed wall will also help alleviate the flutter echo.

Avoid square- or cube-shaped rooms. They create additive wavelengths called "standing waves," which overemphasize particular frequencies and lead to an abnormally loud sound. The rectangular shape alleviates the problems caused by square rooms.

Don't be deceived by features that appear acoustical. Grand theaters with curved walls, balconies, columns, pilasters, curtains, sloped floors and ornate moldings function as a complete and sophisticated acoustical environment. Isolating only one element of these theaters can be disastrous. For example, domes and curved walls create hot spots of concentrated sound. This type of construction also is more expensive and adds little, if nothing, to the acoustic quality.

Isolating noise Allocate adequate funding for the HVAC system. A noisy mechanical system can destroy your carefully planned acoustics. When HVAC supply vents run continuously from room to room, they carry not only air but also unwanted sound. Insist on HVAC systems that employ branched supply-air ducts and isolation dampers at all major pieces of mechanical equipment. This will reduce sound travel through air ducts.

Sound isolation will help eliminate sound transmitted between rooms. Even small gaps can have significant effects on a room's sound isolation. Within a 24-square foot area of wall, only 3/4 of a square inch of cumulative air gap will reduce the effective sound isolation by 80 percent. Construction drawings should call for full-height (floor to roof deck or floor deck above) walls with an airtight seal and a minimal number of doors and windows.

Consider installing sound-isolated, modular practice rooms that can be reconfigured as the music suite needs change. Often, practice rooms constructed during general construction do not provide proper sound isolation or privacy for a rehearsing student. Sound isolation is not a major cost and should not be overlooked.

Acoustics are important not only to the music department, but also to the entire building. Poor acoustical design of areas such as libraries, classrooms, offices, corridors and lunch areas can affect the usefulness of the entire building. In most cases, acoustics is a matter of design knowledge, not dollars.