Are Ohm Walsh Speakers the Poor Man's MBLs?

Very good questions!

"(I)t seems that a lot of Omnis do no(t) limit the tweeter (Deuvel and Morrison come to mind) . "

"Does limiting the tweeter from being full omni help the coherence but hurt the imaging? "

No. I think coherence is mostly due to sonic waveforms being in phase at all frequencies top to bottom. Crossovers and multiple drivers present an extra challenge in accomplishing this I believe. A single Walsh driver that covers a wide frequency range has an advantage here I think.

"Does it also make it easier to place by letting it be closer to the rear wall? "

In general, yes. However there are other ways to accomplish this otherwise with any omni driver.

OHm Walsh speakers accomplish it by design with acoustic dampening material inside the cage and around the drivers that attenuate SPL of sound from the omni Walsh driver in the wall facing directions.

I believe it is possible to special order CLS Walsh drivers from OHM that do not use the acoustic dampening material to attenuate sound in wall facing directions if desired. This would be more mbl and German Physiks like in radation pattern and resulting effect on optimal location of speaks relative to walls. I think OHM may use this approach for some of their Walsh A/V surround sound speakers, but I am not certain.

So the tweeter being limited has only the benefit of increasing placement options. Does it in any way degrade the sound? Is there a price to be paid in sound quality for the ease of placement?

"So the tweeter being limited has only the benefit of increasing placement options. "

I believe increasing placement options for most users is the intent of OHMs design decision to attenuate the omni sound levels in wall facing directions. The tweeter being omni or not would not matter because I would assume they would/could be damped easily as well if desired.

There are several benefits of the more conventional tweeter used in the OHM Walshes compared to the original OHM Fs and As, which, other than the GP Unicorn, are the only designs I know of using only a single wide range Walsh driver:

1) lower cost
2) greater durability
3) higher SPLS possible without damaging the driver

The disadvantage is that the conventional tweeter does reduce sound stage size somewhat. I can hear this when I adjust the tweeter levels on my F-5s. The soundstage expands slightly and becomes more transparent at lower tweeter levels and appears to shrink somewhat and become less transparent at higher tweeter levels. At any level, soundstage and transparency is extremely good however.

Another disadvantage which does not really matter much in my opinion is that you will hear a slight but noticeable roll-off of the very top end if you stand behind the speakers. Coherency is not affected however which means you can listen from almost anywhere with mostly just a change in perspective in relation to the instruments and recording tracks within the soundstage.



" Is there a price to be paid in sound quality for the ease of placement? "

I think the price to pay might be the depth of soundstage at least compared to mbl, as Marty suggested.

Never heard Morrison or Dueval so I cannot speak to those, though I've heard good things about both. Both use more conventional drivers compared to OHM, mbl, or GP, but in a unique configuration for their omni sound, I believe.

Marty,

Have you tried listening near field with the 100s?

I have found I am able to percieve front to back soundstage better and more in line with what I heard with mbl listening just a couple feet or so in front of the speaks as opposed to my normal listening position 8-10 feet or so back with theF-5s in my larger room.

My listening location is more near field normally in my smaller room where the 100s are also and I can notice a similar effect there.

Map,

I haven't. I want to be clear, the front to back imaging from the Ohms is very good, relative to most speakers that I've heard. In this respect, the little ProAc Tablettes and MBLs are more striking, great fun and really dramatic, but not essential to me. The Ohm 100s image really well, but can't do what I'd call "audiophile parlor tricks". Maybe I'll pull the 100s out into the room for an experiment, but, more likely, I'll just live with 'em the way they are.

Marty