Originally Posted by Mike Dimin
Then there are different cab designs, like EA's Transmission Line which can provide up to a half octave below the fundamental resonance of the driver. It is more than just the driver in a sealed cab. If that were so, all cabs would sound the same. It is knowing how to tune a cab and how to design a cab that makes all the difference
Unfortunately transmission line cabs still suffer from the same restrictions as ported cabs in terms of Hoffman's "sensitive, low, small, pick any two". None of us can beat physics!
Originally Posted by naturalkinds
This is somewhat on topic...
Why, in general, would a four-string bass player -- with no need to play below E -- care about getting a cabinet with very low frequency response? I certainly see the prima facie appeal for someone who plays notes with lower frequencies, like a five-string player. What is gained by, say, me plugging into a speaker with very low frequency response, like an Acme? (Leaving out of consideration the other reasons I might be drawn to Acme in the first place, e.g., the three-way, relatively flat performance.)
This is rather complicated to get one's head round and curiously it's not so much tied into your string count (or more precisely the fundamental frequency of your lowest note) as to your desired tone. The reasons behind this emanate both from the bass guitar tone end of the problem (the tonal balance of the lower harmonics of the lower notes) and from the fact that all bass guitar cabs exhibit some degree of roll-off above low E fundamental.
My conclusions have been two-fold:
1. To get good solid tone from any bass cab it needs to be able to reproduce the second harmonic of your lowest notes without excessive distortion or compression (the amount of either that is tolerable depends on your tonal goals) at the required SPL. I believe that is the minimum requirement for bass to sound like a bass, so decent output at 82Hz and up for a 4-string, 62Hz and up for a 5-string, 55Hz for five tuned down to A, etc. This does not mean that the cab has to be flat at these frequencies because EQ is almost always available.
2. Some bassists (myself included) like to go for a bigger sound in the lows, more akin to the lows you hear from a bass guitar through a studio desk and fullsize monitors (the big scary ones sunk into the walls often with 15"+ woofers you see in top-end studios) or through a big PA system with proper subs. That doesn't necessarily mean they're going for an uber hi-fi sound as we're just talking about the feel and depth in the lows, not what's happening higher up. In more conventional rig terms these huge tones tend to result from big piles of cabs, whereby there is sufficient power handling and sensitivity to compensate for any roll-off in the lows to get greater weight to the 2nd and 1st harmonics on the lower notes. Many bassists will find this amount of bottom too big, often referring too it as "not tight enough". This sound/feel can be produced by smaller bass rigs with specialist cabs, such as Acmes (which were how I was introduced to this sound), the DIY fEarfuls or my own Barefaced 'Big Series' designs, all of which combine lower than typical tuning with woofers which reach lower at the expense of sensitivity (particularly with the Acmes) and with greater Vd (ability to move air) for a given cab size so they can support the SPL demands at these lower frequencies.
Whilst I owned my Acmes I exclusively played 4-string (though occasionally detuned or used synths and octavers) so although I didn't benefit from the extension below 41Hz most of the time I still benefitted from the near-flat response between 100Hz and 41Hz (and of course from the very clean clear sound higher up).
Playing 5-string exclusively now I find that all my Barefaced cabs can handle the low B perfectly well (see point 1) though only the Big Series cabs have the HUGE weight of sound that I like in an ideal situation but I realise that many bassists neither need or want that degree of extension.
It took me a long time to work all this stuff out, so sorry if I've rambled on too much!