Pedal B♭ and Jingle Bells

Last week I was practicing pedal B♭ on trombone:

Pedal B♭1 is an octave lower than B♭2, the lowest of harmonics in the first position. It is not particularly difficult to play B♭1. I found that the less I think of how to play it, the easier it is for me to hit it. The key is to relax my mouth as much as I can.

Today in Duxford we were playing the trombone duet of Jingle Bells. Just like last year, except this time I was playing the funky bass line (featuring, you may have guessed, pedal B♭1). I wrote it down with LilyPond. The only new embellishment here is glissando. (I say, there is no point learning trombone unless you get to play glissando.)

• To link two notes with glissando, put \glissando between them, for example
  c2 \glissando f2
• If these two notes are separated by the forced break \break, add the line:
  \override Glissando #'breakable = ##t
• Default glissando is represented by a straight line. Add a touch of style in the following fashion:
  \override Glissando #'style = #'zigzag

Here goes:

And the LilyPond file:

% ****************************************************************
% Jingle Bells (duet) in Bb major
% ****************************************************************
\version "2.12.3"
\header {
 title = "Jingle Bells (for two trombones)"
 composer = "James Pierpont"
}
\score {
<<
  \new Staff
 {
  \clef bass
  \key bes \major
  \override Glissando #'style = #'zigzag
   d4 d4 d2
   d4 d4 d2
   d4 f4 bes,4. c8
   d2. r4 \break
   ees4 ees4 ees4. ees8
   ees4 d4 d4 d8 d8
   d4 c4 c4 d4
   c2 \glissando f2 \break
   d4 d4 d2
   d4 d4 d2
   d4 f4 bes,4. c8
   d2. r4 \break
   ees4 ees4 ees4. ees8
   ees4 d4 d4 d8 d8
   f4 f4 ees4 c4
   bes,1 \bar "|."
 }
  \new Staff
 {
  \clef bass
  \key bes \major 
  \override Glissando #'style = #'zigzag
  \override Glissando #'breakable = ##t
   bes,4 f4 f,4 f4
   bes,4 f4 f,4 f4
   bes,4 f4 f,4 f4
   bes,4 a,4 g,4 f,4 \break
   c4 f4 f,4 f4
   bes,4 f4 f,4 f4
   c4 f4 f,4 f4
   c2 f,2 \glissando \break
   bes,4 f4 f,4 f4
   bes,4 f4 f,4 f4
   bes,4 f4 f,4 f4
   bes,4 a,4 g,4 f,4 \break
   c4 f4 f,4 f4
   bes,4 f4 f,4 f4
   c4 f4 f,4 f4
   bes,2 bes,,2 \bar "|."
 }
>>
}

See photos of trombone @ Shutterstock.