The practice of using objects to alter the sound of an instrument has been around for several hundred years. Mutes made of wood, cardboard, metal, and plastic are commonly used today. Other materials, such as glass, rubber, cloth, and gourd, have also been used as a mute, though much less frequently. Modern composers often look for new and creative ways for instruments to produce sound. John Cage’s Concerto for Prepared Piano (1950-1), as well as his many other works for prepared piano are a well-known example of this practice. Cage asks the performer to use nuts, bolts, rubber, bits of plastic, cardboard, and many other objects to change the piano’s sound.
For brass instruments, there are many techniques which can be used to alter the sound of the instrument, but the most common by far is placing a mute into the bell of the instrument. The use of glass as a mute has been very limited so far with only a few orchestral uses. In addition, some early jazz musicians, such as Bix Beiderbecke, have been said to have used straight mutes made from glass.
This passage from György Ligeti’s compostion Aventures (1962) is a rare example of using glass as a mute in an orchestral setting. The instructions on the right are translated: “Use a large glass vase with a small opening (with a short, small neck) to mute the sound. Play into the vase very smoothly and steady. Hold the note for as long as your breath lasts but do not start again.”
In his book, Extended Techniques for Horn, Douglas Hill mentions the glass mute stating that it produces a “hard, less vibrant sound than a straight mute,” which is “not frequent but is an effective variation on the normal mute sound.” The type of object Hill specifically refers to is a 12 oz. glass soda or beer bottle. Using different kinds of glass objects will produce different qualities of sound. Soda and beer bottles, which are thicker and use a lower quality glass do not resonate as easily and tend to sound very similar to standard straight mutes, but with a ‘brittle’ quality to the sound. Other objects, such as flower vases or various types of wine glasses, which are thinner and made from higher quality glass resonate more easily and produce a timbre easily distinguished from a straight mute. The timbre from these objects tends to be lighter, clearer, and hollow.
Finding a suitable object to use as a glass mute will take a little effort and experimentation. Glass soda or beer bottles are easy enough to find and can be simply held in the bell of the horn. Cork can be applied to the bottle as well so that it can be used just like a standard mute. For this, 12 oz. soda bottles work better because they are (usually) much closer in shape to a standard straight mute. Replacement mute corks are easiest and are sold by many music shops, but plain cork from a hardware store along with some glue will also work well. Other objects, such as flower vases and wine glasses can be found at most any department store. A third option is to go to a professional glass blower to have a mute custom made.
Composing For the Glass Mute:
There is little difference in composing for glass mutes compared to standard mutes. As with other mutes, glass mutes do not speak well in the lower ranges of the horn, and are most effectively used in the upper half of the horn’s range. Anything above a written middle C (in F) should be fine. Always give a few seconds before and after a muted passage to allow a performer time to prepare the mute. This is especially true for glass mutes as they are more fragile and cannot be changed quickly. To indicate the use of a glass mute in music, simply write “glass mute” above the passage. This should be clear enough, though adding a footnote or performance note would be helpful since glass mutes are an unusual request. As with any other mute, write “open” at the end of the muted passage.
The glass mute would be best used in a chamber ensemble or in a setting with sparse orchestration. The horn does not project well when muted and the unique sound would easily be lost in a thicker instrumentation.
Thanks to Cody J. Staudt for help with the German translation in passage from Ligeti’s Aventures.
Hill, Douglas.: “Extended Techniques for the Horn: A Practical Handbook for Students, Performers, and Composers.” Warner Bros. Publications U.S. Inc. 1983, 1996.
Smith, Nicholas E.: “The Horn Mute: An Acoustical and Historical Study.” Univeristy of Rochester. Rochester, New York. 1980.