While it may seem fairly ordinary and not necessarily an extended technique, the Wah-wah or "Harmon" mute produces some pretty interesting filtering effects. I also happen to think it is generally underutilized.
It's probably most famous as the old "sad trombone" cliché:
However, played slowly, the harmon operates as a high-pass filter and beautifully isolates high formants in the sound, much like overtone singing:
The amazing composer / soloist Mike Svoboda has written a great concert etude that explores many aspects of the Wah-wah mute. Here is one of my favorite parts:
This etude is one of an entire book of concert etudes written by Mike, where each etude explores one extended technique. The book is a must have for any composer interested in writing for brass + all creative trombonists, and you can find it here. For those of you who don't know Mike, he is, as I mentioned above, amazing. He worked for many years with Stockhausen and Frank Zappa, and now widely performs as a soloist in a number of contexts, and is very busy as a composer. On top of that, he directs an incredible contemporary music program at Musikhochule Basel in Switzerland. Mike was my teacher when I lived in Germany, and I'm very grateful I had the chance to study with him.
In addition to solo repertoire, I have found the harmon to be especially useful in blending the trombone with instruments of a higher timbre. Below are a few examples written for trombone and violin by some of my friends.
Ian Dicke's Musa is a work for trombone, violin, and Max/MSP. In Ian's words: Using the electronic music programming language MAX/MSP, the amplified violin and trombone signals are delayed and looped over a collage of sampled sounds culled from the rich legacy of the Bossa Nova canon. Among the voices is the legendary Brazilian singer Nara Leão, who is often cited as the “Muse of Bossa Nova.”
While trombone/violin/computer is surely not the ensemble of choice for many composers, Ian deftly finds common timbrel ground between the muted trombone, violin, and samples of Nara Leão.
Ian is an Assistant Professor at UC Riverside and is currently on a Fulbright Fellowship in Sweden. Along with fellow composers Steve Snowden and Robert Honstein, he directs Fast Forward Austin, a great new music marathon event / new music organization. He's one of my favorite composers and also owns some excellent cowboy boots.
In this clip of Musa, Ian uses the harmon to compliment the timbre of the violin:
In this next clip, Ian uses the harmon to mimic the timbre and shape of the sampled vocal line:
There are still many more examples of nice harmon writing, so I'll talk a bit more next time about some new work by Ethan Greene and Pierce Gradone. Thanks for reading.