Walsh 200, Secrets of Home Theater and High Fidelity, J.D. Moretti

By J.D. Moretti • Ohm Speakers • 8/1/96

Yo! Speakers with casters. Now THAT I am used to. The woof, woof, woofers that I have for my bass guitar in our Jazz ensemble are all on casters, with the amp sitting on top. Of course, the Ohm 200s look a LOT nicer, with the Rosewood veneer. All my guitar woofers face outward, but the Ohm speakers use a design called the Walsh, after the man who invented it. The main driver sits on top of the cabinet, facing downward, and is surrounded by a metal perforated can (see photo). The tweeter is mounted on top of the woofer magnet. In the case of the 200, you can see the can by removing the “grille” which surrounds the can, but with the Omni, the enclosure is continuous all the way to the top, above the drivers, and the sides of the top have openings, but the can is still there, inside. The 200 is ported on the bottom, where the single set of gold plated binding posts are also situated. The Omni uses a passive radiator instead of an open port, and there is one set of binding posts on the bottom. The 200 came with casters, and this made it SO easy to move them. The casters can be removed if you like the spikes instead (they are underneath the casters), but I really liked the casters. This also made it easy to connect the speaker cables and move the speakers so that they did not sit on top of the wiring. The Omnis didn’t have casters or spikes, but rather, the enclosure was slotted along the bottom. This did not allow me to connect big cables, since the slots were not high enough to allow the cables to pass underneath. I would suggest that the factory make the slots larger for those big, thick, heavy cables that us woofy mongers like. The enclosures are 3/4” MDF, veneered in the case of the 200s, and lacquered in the Omnis.

The Walsh design is such that the main body of sound, up to about 8 kHz comes from the inverted driver sitting on top of the cabinet. The idea is that the sound radiates in a 360 degree pattern from the perforations in the can. The tweeter, on the other hand, is highly directional, and is pointed towards one corner. This means that there is a left and right speaker, and if they are facing with a flat side horizontal with respect to the listener, the tweeter is actually pointed at a 45 degree angle inward. This is a VERY unusual design, one that I have never seen before. The effect is one of a very large sound stage for the lows and mids, but the tweeter is not so scratchy because it is not facing straight out. I like this effect, because, as you know, I am a bass hog.

I thought my wife was not going to like the looks of the 200s because of the box-like grille on top. But she loved them! More importantly (to me), she liked the sound. The 200s are big on the bass, and I mean deep and powerful. I was kind of surprised that the 10” driver could put out so much. The Omnis were tighter on the bass, and not quite so powerful. They both had very focused treble, which sort of threw me off guard, since the mids are so open, like you might find with a ribbon speaker. Definitely something you have to get used to. The Omnis might make good rear speakers when digital surround really takes hold. Neither model had any boominess, or nasality. As I mentioned, the high end is slightly laid back, due to the direction that the tweeter is facing.

Frequency Response Test Results (These data represent tests in a real room with furniture, not anechoic tests or simulations, and thus, may be somewhat different than you might experience in your own listening room of other dimensions and contents):

Ohm 200; Left speaker, grille on, 1 meter, on axis with tweeter:

20 Hz 74.0 dB 500 Hz 88.3 dB
25 Hz 74.6 dB 800 Hz 80.7 dB
31.5 Hz 75.3 dB 1 kHz 81.1 dB
40 Hz 84.1 dB 2.5 kHz 82.4 dB
50 Hz 93.8 dB 5 kHz 82.0 dB
63 Hz 97.3 dB 8 kHz 82.8 dB
80 Hz 90.5 dB 10 kHz 88.1 dB
100 Hz 87.3 dB 12.5 kHz 89.5 dB
125 Hz 75.7 dB 15 kHz 94.5 dB
160 Hz 92.9 dB 18 kHz 92.2 dB
200 Hz 94.2 dB

Ohm 200, left speaker, grille on, 13 feet, on axis with tweeter:

20 Hz 73.9 dB 500 Hz 77.9 dB
25 Hz 78.8 dB 800 Hz 77.6 dB
31.5 Hz 86.6 dB 1 kHz 80.4 dB
40 Hz 75.0 dB 2.5 kHz 75.7 dB
50 Hz 72.4 dB 5 kHz 77.5 dB
63 Hz 87.0 dB 8 kHz 78.9 dB
80 Hz 87.3 dB 10 kHz 79.0 dB
100 Hz 85.0 dB 12.5 kHz 74.4 dB
125 Hz 78.8 dB 15 kHz 69.7 dB
160 Hz 80.2 dB 18 kHz 79.7 dB
200 Hz 86.8 dB

Ohm Omni, Left speaker, grille on, 1 meter, on axis with tweeter:

20 Hz 63.1 dB 500 Hz 80.8 dB
25 Hz 64.9 dB 800 Hz 90.3 dB
31.5 Hz 66.7 dB 1 kHz 81.7 dB
40 Hz 70.9 dB 2.5 kHz 75.0 dB
50 Hz 85.0 dB 5 kHz 81.5 dB
63 Hz 91.7 dB 8 kHz 65.8 dB
80 Hz 89.5 dB 10 kHz 78.2 dB
100 Hz 86.2 dB 12.5 kHz 82.7 dB
125 Hz 80.2 dB 15 kHz 75.7 dB
160 Hz 79.6 dB 18 kHz 68.3 dB
200 Hz 84.1 dB

Ohm Omni, left speaker, grille on, 13 feet, on axis with tweeter:

20 Hz 69.1 dB 500 Hz 87.6 dB
25 Hz 77.5 dB 800 Hz 80.8 dB
31.5 Hz 84.3 dB 1 kHz 80.6 dB
40 Hz 75.6 dB 2.5 kHz 78.2 dB
50 Hz 67.8 dB 5 kHz 72.4 dB
63 Hz 88.1 dB 8 kHz 77.4 dB
80 Hz 91.9 dB 10 kHz 73.6 dB
100 Hz 88.2 dB 12.5 kHz 75.4 dB
125 Hz 80.8 dB 15 kHz 69.0 dB
160 Hz 69.1 dB 18 kHz 62.9 dB
200 Hz 89.5 dB

As you can see, the frequency response is all over the place, probably due to the multi-directional sound bouncing off the walls. I heard some harmonics below 200 Hz, especially below 50 Hz. Although this raised my eyebrows somewhat, one has to keep in mind that sine waves really stress a speaker to the limits. Never-the-less, deep end harmonics are not audible with all speakers that I have listened to. The designers should make them sine wave clean if they can, in future models. Music wise, they were fine.

In sum, the Ohm speakers, with their “Walsh” design, are very unique. If you are into an open sound stage, yet focused highs, these should definitely be auditioned.

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