Two reeds for different registers? Nope, something's wrong...
An email came in that I wanted to share:
I would appreciate your telling me if I/The Bass Clarinet have a problem to sort out, or whether I can live with it as reasonably common for a doubler.
I play clarinet and soprano sax in a group, with occasional doubling on bass clarinet (selmer bundy low Eb, selmer bundy MP) .
1/ I find that when I want to stay a lot below 3 finger C (and especially in sharp keys) I am much more secure if I select a soft reed (1.5 or 2) unfortunately I then have to be very careful going into clarion.
2/ When the piece is largely in the clarion I need a 3 or 3.5 to get a decent sound up there, but using this strength makes me nervous if I dip down to low G and below.
3/ Fortunately I have 2 mouthpieces, so I can preload and switch. Solves it?
4/ I can usually get through at 2.5, but I don't really like my sound at either "extreme" so if I need to play in either clarion or chalumeau, I would rather swap reeds.
I guess part of this is an over-tight embouchure due to clarinet and soprano, and too little bass practice. Clearly I should try to make a reed work at both ends, could you recommend a strength I should work on?
My answer—but I would love to hear your thoughts in the comments:
Based on your "symptoms" there are a lot of things going on potentially. A few possibilities: your instrument is not in great adjustment and is leaking — even a little bit of leaking will cause a less-experienced player to struggle to get sound out of the instrument. The strength of the reed mitigates that somewhat, with a harder reed allowing for clarion work (which requires more air volume in some cases, especially with the leak), and a softer reed allowing for the chalumeau to speak more clearly and cleanly.
Another element in this is your mouthpiece—I think you owe it to yourself to get a better mouthpiece than the stock one that presumably came with the horn. There are many, many options, but one of my favorites, and also one of the least expensive, is the Vandoren B50 paired with a V12 2.5 reed.
Finally, practicing voicing might solve some of your problems as well, but only if you have an instrument and a mouthpiece and reed combination that is cooperating. Voicing exercises are available on the YouTube channel under the title of "How to NOT squeak on the bass clarinet"