We are always glad to welcome newcomers to the bass clarinet family. Remember, before he started fooling around with metal instruments, Sax first devoted his skills and aspirations to the perfection of the world's most desirable instrument.
My one favorite bit of advice to a new or returning bass player, based upon over fifty five years of manipulating bass clarinets of one style or another (along with about fifteen years of teaching in the bargain), is to have your instrument looked over by a technician once you have it in your hands. More frustration results from playing un (or poorly) regulated bass clarinets with microscopic leaks from pads on the lower joint than from any other issue with the instrument.
The lower joint on basses played off of pegs tends to take much more abuse than anything else on the horn. The saucer-like lower pad cups are exposed to contact with chair edges as well as the human leg, and it only takes a slight bump to cause a tiny little leak around one pad edge to start the process going. The leak acts as a unplanned "register vent" when you attempt to ascend above the break, and you find yourself playing notes that have never been heard before.
Once you do get the horn carefully regulated, guard it like the crown jewels. Don't let others borrow it - this is hard in a school situation where you might be playing a shared instrument, but as an adult you are much more likely to have your own instrument. Watch out when you set it down across the case when putting it away.
My second bit of advice is to worry less about mouthpieces at first (particularly as they are much more expensive for the bass), and more about the reeds that you use. There is a tendency for players to want to use harder reeds (3 and 3.5) on all clarinets, but I have learned over the years that you get a richer tone and better overall response by sticking to something in the 2.5 range.
(I've even moved to a pretty extreme mouthpiece (a Selmer G lay) in order to play out in a modern ensemble situation. Most won't want to go that far (if for no other reason than the mouthpiece expense involved) but it is one solution open to you.)
My third bit is to avoid the neckstrap if at all possible and play the instrument exclusively from a peg. For some players, there is no good way to get the neckstrap/peg combination to work right.
The last piece that I'll offer up is to look into a neck or neck pipe that will allow you to play with a more "clarinet-like" mouthpiece angle. The "tenor saxophone" angle bass clarinet necks force players to either angle the instrument in the mouth, or to adopt a very "unclarinet-like" embouchure. Charlie Bay and others (plus one of the manufacturers) offer a neck that gives you this advantage.
Oops - one more thing:
I would avoid like the plague any of the older Leblanc professional model horns, and stick with the traditional "linked register vent" instruments from Selmer and Buffet. These are the horns with the long, exposed rod on the back of the instrument that runs from the lower joint to the upper. This style of instrument has the two vent opening properly situated for the easy transitions from Bb to E in the clarinet register of the instrument.
It may be that you are stuck with the horn that you've got, and that it is most likely a student instrument with the "all on the upper joint" register mechanism. If so, you will just have to make do. But, if you are choosing a horn, try to go with one with the long rod on the back.
