Ah, but the box is a big deal. I'm a DIY speaker builder, but for musical instrument rather than hi-fi use. The box is an integral part of the electromechanical system that determines the response (and to some extent power handling) of the speaker at low frequencies. The box may be a plain box whose volume is its main parameter, or may contain other structures such as resonant ports.
Most woofers are designed so they have to be in an appropriate box in order to be useful. Without access to the process for designing custom woofers, the DIY'er has at our disposal two main variables for tailoring low frequency response: Woofer choice from off the shelf models, and box design. And there are some tradeoffs to manage, such as low frequency response and box size, so that there's no ideal box design for all uses.
Me, too. Just when speaker design seemed to be a solved problem, with a small set of uniform solutions, up springs the concept of co-designing speakers and musical instruments.
What frequency range/instrument are you working with? And what architecture/horns/boxes/tubes/drivers?
Sorry, I left town right after posting that. I'm a bassist, so it's 40 Hz up into the midrange, with not that much going on in the tweeter zone. So far my designs are just lightweight "pro audio" drivers in ported boxes. Nothing sophisticated, but I just want to be in control of how my speakers work.
Interestingly enough, I think that the electric bass involves a sort of de facto co-design, because the bass acquired its "classic tone" during a time when speakers were relatively low performance, i.e, having -3 dB points far above the lowest fundamental. To this day, speakers with that tone quality tend to be preferred by bassists, which is a fortuitous circumstance because it liberates us from dragging around huge boxes capable of actually reproducing that E fundamental at full strength.
