F-attachment

The F-attachment enables us to play notes between the bottom of the bass staff and pedal "BB-flat." But as the sounding tube lengthens the positions get farther apart and the adjustments required to play in tune become greater. Here are handslide placements for these low notes with valve engaged:

"E" - tiny bit flat 2nd position
"E-flat" - half way between 2nd and 3rd positions
"D" - sharp 5th position
"D-flat" - 6th position
"C" - very flat 7th position
"BB" - not possible without maximum extension of F-attachment tuning slide; even then it must be "lipped" down. Most bass trombones have a second valve attachment which is added primarily to get this one note.

Trombonists often use the F-attachment to play "c, B," and sometimes "B-flat" (all in the bass staff). Here are handslide placements for these notes with valve engaged:

"c" - first position
"B" - flat 2nd position
"B-flat" - quite flat 3rd position
"A" - 5th position

Tuning

There are two basic ways to tune the F-attachment. I use both depending on the demands of the music.

1. If you want to be able to play low "F" (just below the bass staff) in 1st position with the valve:

Get low "B-flat" in tune with the handslide 1/4" to 3/8" out from the bumper, or with handslide just touching the spring if your handslide has a spring bumper. Then play low "F" with the valve engaged and the handslide all the way in. Adjust the F-attachment tuning slide until you achieve a solid, perfect fourth between these two notes. It is quite easy to bend the pitch of these low notes with your embouchure; so be careful to place the notes where they naturally want to sound. Make all adjustments with the valve's tuning slide. Use a tuner to be most precise. When low "F" is in tune in a "tight" 1st position, you are done. With this system you will need to place these 1st position low notes as follows:

"c" - first position with valve engaged, ½" to ¾" out from bumper
"B-flat" - 1/4" to 3/8" out, no valve
"F" - all the way in with valve engaged

2. If you want to be able to get low "C" (whole step above pedal B-flat):

Tune 2nd space "C" so it can be played with the F-attachment engaged and the handslide in "tight" 1st position. You will have to pull the valve's tuning slide out to do this. Then you will be able to play the low "C" with F-attachment engaged and the handslide in the longest 7th position possible. You will not be able to use the valve to play low "F" in first position though.