Planars/ Electrostats benefits over box speakers?

Jim, you've received lots of good comments, but one thing that hasn't been addressed which should be considered before embarking on one of these paths is amplification.

Maggies present fairly benign impedance characteristics to the amplifier, even though their impedance magnitude is in most cases nominally 4 ohms. However, they need a lot of power. If you still have and are planning to keep the Rogue Sphinx I recall that you were using not long ago, its 155 watt capability into 4 ohms (per Stereophile measurements) might be marginal (or worse) with a Maggie, depending on listening volume, room size, the dynamic range of the music, etc.

Martin-Logans, on the other hand, do NOT present benign impedance characteristics. As with many electrostatics and electrostatic hybrids, their impedance decreases to very low values in the upper treble region, typically reaching 1 ohm or even less at 20 kHz. With impedance phase angles that are significantly capacitive at many frequencies, which is much more challenging for an amplifier than the Maggie's mostly resistive impedance.

The impedance characteristics of an M-L will result in sonics that are particularly sensitive to the output impedance and other characteristics of the amplifier that is being used. The negligibly small output impedance of most solid state amplifiers (including the Sphinx) will interact with their decreasing impedance at high frequencies in a manner that will give greater emphasis to the upper treble, and perhaps the lower treble as well, in comparison with tube amps. And the tonal balance which will result with tube amps will tend to differ among different tube amps, due to their differing output impedances. And some amps will simply not be able to handle the very low impedance at high frequencies with any kind of good results.

In the absence of an audition, or specific and credible inputs from others, I would not assume that the Sphinx would be happy dealing with a Martin-Logan.

Good luck. Regards,
-- Al

I realize I'm probably simplifying and generalizing, but aren't companies like Magico, Wilson Benesch, BMC (and I'm sure others I don't even know about) utilizing steel or aluminum cabinets in an effort to build "box" speakers but with such inert cabinets that they eliminate the "box" from the sound? Not that they're trying to replicate panels, of course, but that they're trying to create dynamic speakers that offer the same absence of cabinet coloration that panels enjoy? Or am I barking up the wrong tree?

Bcgator, I believe that you are correct in describing what many companies try to do, by designing inert cabinets that allow the drivers to work most efficiently without adding cabinet induced coloration. However many companies discover in attempting this that in reality all cabinets have some inherent sound which impacts the speaker's performance. So what some then do is design a cabinet more like a musical instrument, which is tuned so that its resonance is musically coherent rather than of an objectionable nature. There is more than one way to design and engineer a fine speaker, and it often comes down to subjective as well as objective performance goals.

I recently auditioned Sphinx at my local dealer running magnepans. It was a very good match seemingly. The amp had no problem driving them to reasonably high volume. The room was moderately large.

I'm considering Sphinx for use with my smaller ohms which I have ab compared to magnepans at home in the past and think that to be an even better match with more muscle overall.

Can't comment on Martin Logan. Not much experience there.

I understand what you're saying Bill, I think Sonus Faber, just for one example, has that philosophy that the cabinet isn't just a holder for the drivers but an organic functioning part of what creates their sound signature. Thanks for the response.