Is this the ultimate 2-way speaker design?


The Epos M12/M15 design that is. A hot-rodded version is the Verity Audio Parsifals. Both use polypropylene mid drivers which "eat detail" but add more body and weight to the sound than paper. Possibly bigger perceived dynamics as well. Both also let the mid driver roll off naturally above 5,500Hz.
The Epos uses a single bass/mid driver which rolls off without a crossover at 5,500 Hz. A single capacitor cuts off the tweeter below this frequency. Obvious advantages I see are:
1) no crossover in the vocal range of 100-500 Hz.
2) No crossover on the 3kHz region where the ears are most sensitive.
So there is no phase shift. Sound is time and phase aligned up to 5,500 Hz. Unlike a 1st order x-over, the speaker will sound good everywhere, not just in the sweet spot. The speaker should be very un-fussy about placement. Reviewers describe the huge soundstage and natural, seductive sound.
Maybe someone has the chart which shows which instruments play at what frequencies but I think 5.5 kHz is above the basic harmonics of most instruments. Most single driver (Jordan JX-92s and Tang-band W3-871s) designs get rough above 5kHz and beaming is also a problem because a larger driver is needed to reproduce the lower frequencies. So a tweeter solves these two problems.
But most designs use a crossover to do the job of integrating the 2 drivers. Crossovers eat power (an extreme example is the inefficient Thiels require with their complex 1st order x-over) and mask detail. So the beauty of the Epos design is one can use a low powered amp. Crossovers also reduce the dynamic range of a speaker. Reviewers have said the Epos is very transparent and even changes in cables are readily obvious. This is at least in part due to the absence of a crossover. So the Epos act as a sort of an active speaker. Except there isn't even a crossover before the power amps.
Most low powered amps sound better and of course, cost less. This is just my experience but higher power amps tend to sound harsher (bipolars vs. mosfets) and when an amp designers attempts to boost the bass, the high frequencies get harsh. Nelson Pass tried to resolve this with his XA amps.Off the subject, but 4 ohm speakers which require a high powered amp better have a pretty sweet high end IMHO.
Downsides to this design are limited bass extension and they cannot be played very loud without losing bass.If you turn up the volume they probably get shrill as the treble takes over in relative volume level. I also wonder, can a single mid/bass driver reproduce the detail compared to separate mid and bass drivers? How fast can a single driver move before it gets congested and starts smearing detail? Also there are probably higher levels of distortion, especially in the bass. Companies like B&W place a premium on low harmonic distortion (although there are other disortions than this!) and relatively high volume levels. So I can see why they don't make a design like this.
Maybe I'm showing my ignorance here but I would be interested in other's comments and their thoughts on what makes the best 2-way speaker design.
cdc

Showing 2 responses by boa2

Thanks, Michael. I'll definitely have to hear that speaker cable as well.
Howard
Congratulations, Michael. I'll be over to listen on one of my upcoming trips to Seattle. You lucky man!
All the best,
Howard