The Horn Guys' page on the Best Brass pixie mute seems to strongly suggest that it would be just swell as your regular straight mute.

It's going to have be a hella big plunger to go over the base of even a tenor Crown straight, much less a bass Crown straight.OneTon wrote: ↑Sun Jan 07, 2024 12:18 pm I don’t have a proper reference for it and I don’t know where I read it. There were a few sites out there that suggested people would use a Thomas Crown straight mute in a small bore tenor bell in lieu of of a proper pixie mute, with a plunger over the bell. I don’t know is my search included Al Grey or not. That at least works. A smallish tenor mute might work with a plunger in lieu of a pixie mute in a bass trombone. I am afraid I would have to take a tuning slide out to remove a pixie mute from a bass trombone bell.
Not to muddy the waters, but ... My classic H&B fiber straight mute fits just fine in my bass bell (as it fits in my Olds Standard bell), and with a tuning slide pull of about 3/4" plays very well in tune, down to the D below the staff. After that it doesn't have a prayer.
I neglected to include that the subject Thomas Crown mute is a trumpet mute. It works in a tenor. It is always a pleasure to post on trombonechat.Dennis wrote: ↑Mon Jan 08, 2024 9:03 amIt's going to have be a hella big plunger to go over the base of even a tenor Crown straight, much less a bass Crown straight.OneTon wrote: ↑Sun Jan 07, 2024 12:18 pm I don’t have a proper reference for it and I don’t know where I read it. There were a few sites out there that suggested people would use a Thomas Crown straight mute in a small bore tenor bell in lieu of of a proper pixie mute, with a plunger over the bell. I don’t know is my search included Al Grey or not. That at least works. A smallish tenor mute might work with a plunger in lieu of a pixie mute in a bass trombone. I am afraid I would have to take a tuning slide out to remove a pixie mute from a bass trombone bell.
Besides which, any tenor straight will have to have the corks built up (or moved well down the cone) to fit in a bass bell.