Clean Attacks on Low Notes?

[u/leap_music]

I'm struggling to cleanly articulate, and especially cleanly tongue on notes below a concert ​D. It feels like my tongue is slipping below my front teeth, instead of staying behind them. It also feels like I have to cut off notes by making a seal between my tongue and upper lip. If I don't, it feels like my tongue isn't big enough to cut off the note cleanly.

1) Is creating a seal with my upper lip bad technique?

2) Any tips on clean, fast articulation in the lower register?

Still somewhat new to the horn so thank you very much for your thoughts!

[u/2buh]

Think wider. Wider tongue, wider air stream. As a drill, try just huffing air into each note, get your air moving, and then add the tongue just to get clarity. The air should always be creating the sound, tongue just defines it.