[Aom-Uom]

dave,
great, I hope you succeed!  In my understanding, to reduce ringing at low frequencies some vibration energy must be diverted necessitating constant voltage drive.     

[Aom-Uom]

Hi,
bidirectional output can give superior imaging, spatial clarity and ambiance, but speaker placement is critical, an improper ratio of directly radiated and reflected sound creates a diffuse, disorganized sound field.

[face]

Since no one driver can do it all, there's no perfect speaker.  Crossovers are necessary until then.  Lesser of two evils.

I seem to remember hearing a pure class a amp or two in my day.  A lot of them tend to be romanticized, and sacrifice bass grip, dynamics and slam. (single ended types etc) Oh well, they are good for those intimate cold winter days sipping brandy in an easy chair listening to baroque. At least you have no need to start the fireplace going for heat.

Although I don't completely agree, this is one of the funniest posts I've read on here. 

[lonewolfny42]

I seem to remember hearing a pure class a amp or two in my day.  A lot of them tend to be romanticized, and sacrifice bass grip, dynamics and slam. (single ended types etc)

Then you need to hear a KR Audio amp....they don't sacrifice anything...

http://kraudioproducts.com/Kr/ProductMain.aspx?CatID=14

[planet10]

dave,
great, I hope you succeed!  In my understanding, to reduce ringing at low frequencies some vibration energy must be diverted necessitating constant voltage drive.   

I don't see why. You just need to start with a driver with low mechanical Q and then flatten the impedance curve. Or have the FR (under voltage drive) droop just enuff to complement any rise in the impedance. The hard part if finding a suitable driver in a world dominated by voltage drive. I have found a driver that looks to be a good starting point.

dave

[Aom-Uom]

Dave,
the primary reason for employing voltage drive is to provide electrical damping. Mass, voice coil resistance and compliance are motional impedance parameters. System Q is the ratio of motional impedance to electrical, mechanical and acoustical losses at resonance. The resonance frequency depends on mass and stiffness. There may be considerable problems in achieving a sufficiently small mass/stiffness ratio for the desirable mechanical damping at low frequencies. The current induced by the back EMF does much harm in the amplifier. My goal would not be only a slightly increased output impedance, rather MOSFET output stage with no feedback.