Do both lips buzz?

[rmb796]

Hi Everyone,
When I play I am quite sure that both my upper and lower lips buzz, with most of the work being done with the upper lip. On lower notes my lower lip seems to be more involved.
I had a teacher once tell me that the trombone is a "single reed" instrument with the bottom lip firm against the teeth. I am a bit confused.
Thanks for your thoughts.

[harrisonreed]

One lip should be dominant, depending on your embouchure type.

[imsevimse]

When you play real low and use a raised emboushure then only one lip vibrate. I use this technique below pedal G on a small tenor, below pedal F on a large tenor and below pedal Eb on a bass trombone. On a normal emboushure both lips vibrate to make a nice sound. I have never heard anyone say different.

/Tom

[Doug Elliott]

I often describe lip vibration as a "single reed" because from the middle range on up, one lip is far more active than the other, and from the middle range down, the other lip gradually becomes more involved. For a downstream player the top lip predominates in the mouthpiece and is doing most of the vibrating. For an upstream player it's the opposite. In the low range they're nearly equally vibrating.

[rmb796]

Makes perfect sense. Thanks Doug and everyone for confirming what I am experiencing. Whew!!

[Basbasun]

Well, both lips vibrate, in the same frequency, but different amplitude. What you describe is the most common, for some, not many, the opposite is true.

[Wilktone]

You can see what this looks like in slow motion in Lloyd Leno's film.

[Basbasun]

Thank you Dave, I have looked at those many times, very good answer to the OP.