"The Diminisher" is the alter-ego of Chicago musician David McDonnell (born 1976), who was a founding member of the trio Bablicon

Bablicon

Bablicon was an Elephant 6-related free-jazz band consisting of members of Neutral Milk Hotel and The Gerbils.The band was formed in 1996 when Dave McDonnell , Jeremy Barnes , and Griffin Rodriguez teamed up to write and improvise music...

, bass player Griffin Rodriguez informally assigned the moniker in reference to McDonnell's liberal use of the so-called diminished chord

Diminished chord

A diminished triad chord or diminished chord is a triad consisting of two minor thirds above the root — if built on C, a diminished chord would have a C, an E and a G. It resembles a minor triad with a lowered fifth....

 in Bablicon songs. When Bablicon informally dissolved in 2001, he began or joined a number of experimental jazz/rock projects, such as Michael Columbia and Icy Demons

Icy Demons

Icy Demons is an experimental music project started by Bablicon's Griffin Rodriguez and Man Man / Need New Body's Christopher Powell...

, and continued composing in Chicago.

In 2006, McDonnell released a solo album on the label Unsound Records, titled Imaginary Volcano, under the name of The Diminisher.

Now, The Diminisher teaches quietly at a Midwestern musical conservatory.