Last year, I was asked by a client if they could improve the deficient sound isolation between their hotel rooms by installing an acoustic wall paper.

Although I had never seen information on acoustic wall paper, it immediately brought to mind acoustic paint. "Can we put some type of acoustic paint on our walls to reduce the noise level in this room," a client will ask. It's not a frequent question because most of my clients are aware of basic architectural acoustics concepts. When I do get the question, I have to explain that a coat of paint on the wall or ceiling of their room will not increase sound absorption. A coat of block sealer might reduce the amount of sound passing through a CMU wall, and a coat of a vibration damping compound might reduce the level of sound radiated by a thin vibrating panel (think sheet steel), but there is no paint which absorbs sound. Actually, the application of paint to a porous sound absorbing finish, such an acoustical ceiling tile, can reduce the amount of sound absorbed by that finish. For that reason, I recommend that acoustical ceiling tile be dyed by the manufacturer. Some sound absorbing finish materials can be painted with a careful application of a dryfall paint.

To get back on subject, there is a relatively new product that I would consider to be acoustic wallpaper. The product is called SoundCoustic and is sold by SoundTech Inc. of Grand Rapids, Michigan. The SoundCoustic product is slightly less than 1/4" thick and is applied in a fashion similar to wallpaper. It provides decent, but not stellar sound absorption in the 1,000 and 2,000 Hz octave bands and advertises a noise reduction coefficient (NRC) of 0.35. This acoustic performance is not nearly as good as a typical fabric-wrapped acoustical wall panel, however, SoundCoustic is not intended to be used in the same manner as an acoustic wall panel. It is intended to be used as an alternative to paint, wallpaper, or fabric wall coverings. Where acoustic wall panels may typically cover only a portion of the wall area in a room, Soundcoustic may cover all of the wall area. This larger coverage area means that, for basic sound reverberation control, the same end result can be realized even though Soundcoustic's absorption coefficients and NRC are relatively low.

The company lists hospital patient rooms as one of the types of locations where SoundCoustic has been successfully used. As an acoustical consultant that works on a lot of hospital projects, the potential application that most interests me is on the corridor walls of in-patient nursing units. Much of the noise that disturbs patients is either generated in the corridors or must pass through the corridors in order to reach patients in their rooms (patient room doors are almost always left open). Noise from staff talking on phones at nurses stations, noise from televisions in nearby patient rooms, and from other sources must all travel through the corridor before intruding into patient rooms. Covering corridor walls with a finish such as SoundCoustic could significantly reduce the transmission of noise into patient rooms.

Returning to the question that I received last year, could covering the walls of those hotel rooms with acoustic wallpaper have reduced noise transmission through those walls and enabled them to meet the Field STC 45 required by the building code? No. No sound absorbing finish would increase the amount of sound blocked by those walls. It may have resulted in a slight reduction in the level of noise heard by guests in adjacent rooms, but it would not have helped the partition meet the code requirement. With that said, if you are designing a hotel with guest rooms that will have wood floors and gypsum board ceilings, you may want to consider a sound absorbing product such as SoundCoustic for the walls. It won't increase the party-wall STC, but it will result in less reverberant guest rooms and possibly a small reduction in the noise heard in adjacent rooms.

For more information on SoundCoustic, have a look at the SoundTech website (www.soundtechinc.com/soundcoustic_000.html). And remember, Soundscape Engineering LLC is an independent acoustical consulting firm. We do not have ties to any manufacturer. We sometimes inform our clients about acoustical products that we believe they may find of interest or wish to use on current or future projects. If you are interested in using the product described above, please be sure to conduct your own, thorough evaluation.

If you are in need of noise measurement, vibration assessment, or acoustical consulting services, you can contact me through the Soundscape Engineering LLC website (http://www.SoundscapeEngineering.com).