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 4 responses by michaelhwolff

Well I made the jump. I purchased the Karl Schuemann ulitmate monitors. Luckily, Karl lives in the same state as I and after a couple of e-mails, he came up my way for business. Much to my delight the trip agenda also included stopping at my house and setting up a pair of his monitors.
When I first saw the monitors I knew this was going to be a love-hate relationship. Not conventional looking at all, however, close examination reveals some of the finest craftsmanship I have ever seen. A wrap of the nuckles on the side of the speaker are similar to the feeling that one gets when knocking on the bumper of a HumVee (solid). Finish is jet glossy black, beautifully done.
Now the sound, well I wrote Karl a check that night. I have never heard a speaker like this. I constantly was opening my eyes to verify that there were speakers in the room.
Quick,,,no fast,,,what the heck, just can't describe how quickly these babies handle the music.
Anyway all in all, I got em and am very happy with them. If you get a chance at CES this year, stop and listen. They are an amazing monitor.

Best Regards,
Michael Wolff
Yep, they ugly at first.. But, after a while you really don't mind, and actually look good from the front on thier custom Sound Anchor stands. I assume that Karl designed that shape as an alternate to the "box". He also does not port his speakers. I forgot to mention that Karl is simply a superb person. He even stayed for a sub sandwich dinner. I did get the bombs, and yes they are breathtaking in sound.
See you all at CES

Regards,
Thanks Howard,
And when you get here, I will have your IC's and speaker cable ready for you. I figure it will give you time to hear some of the run of the mill stuff. LOL

Michael