Hilmar-at-Bose wrote about how low the B1 goes on the Bose Musicians Forum.
... before I answer the technical stuff, please let me try to clarify a few things. Many people think that a 5-string bass need a speaker with a frequency response down to 30 Hz or you wouldn’t be able to hear the low B “properly”.
That’s really not the case. The sound of the bass does not only consist of the actual “fundamental” tone (i.e. 31 Hz in case of the low B) but also many multiples of that frequency (i.e. 62 Hz, 93 Hz, 123 Hz, etc.), which are called the “harmonics”. In fact the amount of energy in the fundamental is relatively small as compared to the rest, so you really don’t loose much by keeping the response low at 30 Hz.
Furthermore, very low frequencies (say below 50 Hz) are not perceptually associated with “bass” or “thump” or “punch” but are much more like an indistinct rumble. We actually have analyzed the frequency content of a lot of recorded music and there is little energy below 50Hz and virtually none below 40Hz. The only type of content that uses very low frequencies regularly is movies. But there it’s not used for musical purposes but as a sound effect, e.g. explosions, starting rockets, a T-Rex stomping along, etc.
In live sound situations very low frequencies tend to make the sound very muddy unless it’s carefully designed fixed installation (as it is in theaters), so most live sound amplification gear will not go particularly low. For example an Ampeg SVT cabinet is only specified down to 55 Hz and most people would claim it does a very adequate job on a 5 string bass.
In fact our B1 goes actually deeper than most other bass cabinets. But it does stop at 40 Hz and does so very abruptly. You will not be able to get any usable energy out of the B1 or the Bass Line Out at 30 Hz. The reason for this is mainly protection. Most bass box designs cannot handle anywhere near the fully rated power below their port tuning frequency and there is no point in trying. They can’t radiate any appreciable amount of sound energy and it’s very possible to damage the driver.
Anyway, if you have a chance, why don’t you just plug in your bass into a double B1 system and let your ears decide whether there is anything missing or not?
Hope that helps