Thanks for the question.
I need to clarify a bit of the perceived history here: When I switched from a large 7/8 size bass to a smaller one, we were talking about orchestral playing. It did not take any time to get used to a smaller bass, as far as playing orchestral music is concerned. At the same time I let the big bass go from my collection of instruments, I was adding Rabbath techniques. This is what took me a good two years to feel comfortable with (the "new" bent end pin, moving from being a sitting player to a standing player, using arm weight verses muscling, using new equipment that was smaller and lighter). My reasons for making this move were to actually gain greater facility and power in my playing. I believe I accomplished that, although it took many more than two years. So... to answer your question:
I believe that all basses need to be the correct size for the person playing. One should "size" the bass to the player, not the other way around. So, if you are, like me, not very tall, slight in frame, a smaller bass makes sense IN THE LONG RUN. As a young person, one can usually overcome a lot of the physical challenges any bass provides. But as you age (in your 40s+ particularly) the habits of form usage and angles of approach need to be efficient for your muscles and structure, so that you can play a long time without straining, or creating pain. Francois Rabbath is still playing as well as ever and he is 80! So, I aspire to play until I croak, and therefore had to assess the techniques that I was using, and the equipment (bass, bow, stool, etc) that I was using. If your bass is so large that you must pivot or (ack!) stretch to play a whole step in 1/2 position, it is likely the mesura is too long for your hand. However, by assessing your technique and making it close to my "forms-at-rest" philosophy, you can play larger basses easily. And if you are sitting or standing, those positions affect the angles that your arms approach the bass. For some, even German or French bow can have great impact on their ability to play for a long time. Well, to answer your question fully, it would take a close examination of you playing, assessing whether you were struggling or not to play this bass, whether you understand the demands that particular bass provides, etc. A big bass is not necessarily a bad thing, same for a small one. It IS important that the sound you WISH to create is coming from the instrument you chose. And of course the size and shape of the instrument will have an effect on your sound and what you wish to have (as 'your sound"). I hope this helps a bit, even though it is not a clear, black and white answer.
And one other (of many many) consideration: If the bulk of the music you play (say, perhaps, jazz) is being played in the lower pitched positions, then access to high positions may not be an issue, so a big-shouldered bass is okay. But if you are an aspiring Bottesini soloist, you need not only sloping shoulders, but an elongated fingerboard, low strings, and fat ego!
Best to you!
Originally Posted by dmitchell
You probably don't remember me, but I took the masterclass you held at the university back in 2005. For my performance, I played "Body and Soul", and John Clayton critiqued/advised me.
One thing you mentioned at some point during the multi-day event, and I wish I had asked more questions, was that you had switched from a bigger bass (a 7/8?) to a smaller one. I believe you said it took you a couple of years to make the adjustment. What I never got a chance to understand is what were the issues you were having with the larger bass that the smaller one solved? I'm asking because I do have a larger size bass, and am wondering if it's impeding any progress I might make.