TromboneChat

I found two online tutorial sites I like a lot. Both guys give good, clear tutorials, backed up with solid demos.

One is Keith Hilson of the Schmitt Music Trombone Shop channel on YouTube. It currently has 2.4k subscribers. He also does demos of trombones of interest.

https://www.youtube.com/channel/UCd7gtw ... IEuiO9n_zw

The other is Dion Tucker of the Chops Shop channel on YouTube. It currently has 320 subscribers.

https://www.youtube.com/channel/UCFSEbS ... C3XJPTY60Q

Both are good resource channels on YouTube. The Chop Shop might get a little bit more into the nuts and bolts for those who are looking for more detailed information, though Hilson does some great tutorial segments too!

I think this is the best explanation of liptrill on the trombone.