@deep_333 I am deep into control systems. I have been using room control and digital bass management since 1996 not to mention I design and build my own subwoofers. One of today’s excellent low distortion subwoofer drivers 12" and larger, used in adequate quantities for the environment have no need for servo anything.
@mijostyn Get the highest quality low distortion driver you want...It is still unrelated to the principles behind servo control. You are still asking an accelerated mass to stop passively/ring down without it, which may be good enough with a high quality driver. You are actively stopping it with servo control by letting it constantly track a setpoint.
@phusis Paul’s vid describes the free lunch that he got with initial use of crappy drivers. How about this....Get the low distortion high excursion bells and whistles driver. Now, stack/integrate several of them so they don’t have to move as much for said spl level. Now, add servo control on top of it...it is incremental. It could all be overkill at normal listening levels, but, maybe not, because it is still the highest distortion component in the chain, relatively speaking.
On a related note, I have some coupled cavity speakers, i.e. the physical bass drivers sit inside and are cavity coupled to external radiators (Acoustic filter/ clean bass). One might argue that it is a unnecessarily complicated design. But, the free-er lunch there was that you didn’t need very expensive drivers trying to hit a price point (the expensive driver that may or may not hit a performance requirement just because you kept spending up the wrong tree). I know because i also owned a cost no object conventional speaker design from that same designer...a few different ways to do these things/clean it up, i suppose.
