Ohm Speakers, thoughts?

Jamscience, thanks for the patent info. and picture.

One thing I would like to say, is that the cans are not diffusion cans, they are as transparent too sound as grill cloth is.

Jamscience: Thanks for all the research and leg-work. I have to agree with all of the points that you brought up. That's one of the reasons why i've "harped" so hard on the fact that these units are NOT actual Walsh drivers. This can be seen on the Ebay photo's that you provided for us. All i can say about that one is that if they had shown the other side of the speaker i.e. where the crossover network is attached, most people would be appalled.

As a side note, these drivers do appear to have some type of a "plastic" based cone material as Line described above. This would lead me to believe that they are the original equipment as supplied by the manufacturer.

As to the basket design, Ohm used two different baskets on the F's that i'm aware of. One has very "skinny" flat metal rails with wood glued to them to damp their resonance. The other has much wider "U" shaped metal channels with wood glued inside of the channel. Common sense would dictate that the thinner rails would cause fewer problems so long as resonance induced ringing was controlled. I have a set of each and to my ears, the thinner flat rails sound better than the wider "U" shaped channels.

As far as the Ohm G goes, i think that it is a Walsh driver by basic design, but i'm not sure about the flare rate on the cone. It obviously has a LOT less surface area than the Ohm A or Ohm F Walsh drivers. The "standard" cone driver that you see in the G cabinet is a passive radiator, not a driven woofer. I've never seen one of these in person though, so i'm kinda sorta guessing on this one based on photo's / technical info that i have.

As far as treble response goes, the internal factory wiring in the F's did a number on that. I would recommend plugging your speaker cables directly into the Walsh driver itself, which bypasses the internal wiring. I could NOT believe how much the 2 - 3 ft of internal wiring could demolish the sound after hearing the difference. I also have some Walsh "tweeters" that Infinity made, but i've never tinkered with them.

Once again, thanks for the legwork and sharing this info : )

Line: The info from the German Physiks website that you quoted sounds more like the design ideas behind the Manger driver than the Walsh design. How someone that manufactures a Walsh based product could confuse the design and description of operation is beyond me. Then again, they are a German based company and maybe something is getting lost in the translation.

As to your comment about the cans NOT acting as diffusors and being acoustically invisible, i almost had to laugh. Just placing a very thin layer of felt on the baffle around a midrange and / or a tweeter can cause major differences in reflections, diffraction and frequency response. This is VERY measurable in most cases and easily audible.

If you don't think that surrounding a driver with a perforated metal screen and placing it directly in the firing path between one's ears and the drivers would make any audible difference, you should think again and / or have your hearing checked. I don't mean this to be rude, but that screen also has grille cloth material in it, making an even bigger difference at high frequencies. Sean
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Line, Sean,

Your welcome. As I stated before, I am just searching for the truth.

Line:

One thing I would like to say, is that the cans are not diffusion cans, they are as transparent too sound as grill cloth is.

Sorry, I have to agree with Sean on this one. I know of no grill (cloth or metal) that does not affect the sound in some way. (of course I have not heard all speakers with and without grills; I could be wrong, I could be right!) ; )

Sean:

As far as the Ohm G goes, i think that it is a Walsh driver by basic design, but i'm not sure about the flare rate on the cone. It obviously has a LOT less surface area than the Ohm A or Ohm F Walsh drivers. The "standard" cone driver that you see in the G cabinet is a passive radiator, not a driven woofer. I've never seen one of these in person though, so i'm kinda sorta guessing on this one based on photo's / technical info that i have.

Yes, the Ohm G does use a Walsh driver but is not a "true" Walsh loudspeaker since it uses the energy from the concave part of the driver to power that passive radiator. (I am being a stickler to the original parameters of the patent)

I also have some Walsh "tweeters" that Infinity made, but i've never tinkered with them.

I almost bought a pair of Infinity's with the Walsh tweeter back in '76. I wish I had, it would have saved me money on a Transcriptors Skeleton turntable! (They were both part of a system I was pondering at the time)

If anyone is curious about the Walsh Loudspeaker, I encourage you to take a look at the patent (see previous post). There is a lot of technical information there but there are also things such as:

" A single very large coherent-sound loudspeaker might be built to serve a stadium of 100,000 listeners with high quality music and voice. It might have a vertically oriented conical diaphragm with an angle of 60 to 80 degrees, a diaphragm diameter of approxmately 60 inches and a height of 60 inches. The diaphragm might be of a composite aluminum and elastomer to substantially attenuate 16,000 c.p.s. waves in a vertical distance of 3 to 6 inches, and 4,000 c.p.s. waves in 12 to 14 inches, to obtain good diffusion of sound vertically. It would inherently have uniform diffusion in all directions horizontally. Its frequency range might cover 60 to 16,000 c.p.s. and it could handle well an electrical input of 500 watts with extremely low transient effects and other types of distortion. Its uniformity of response might well be about 1 db over the rated frequency range."

I would love to see this become reality! Any takers?

Also, any takers on my question; is it ethically, morally, politically... correct to keep calling the line a Walsh speaker?

Very nice information being posted. Thank you.

Question - What is preventing a Manufacturer from building an authentic Ohm F again?

Is it the licensing?
Is it the technology?
Is it the patent?
Is it the cost of producing them correctly?
What is it?

It has been approximately 30 years since they first appeared with such great potential, but later proven to be flawed. Why hasn't someone taken today's computer based designing techniques and applied them to this speaker in an effort to make them a reality. IMHO, there would be a viable market for them in 2-channel as well as HT.

I would definitely put my name on the list of future owners if they weren't priced ridiculously. Heck, when I purchased them in 1974 I was just out of undergraduate preparing to go to graduate school. IOW, I was flat broke but had the foresight to scape enough coins together to purchase them. I now have a coin jar spilling over. LOL

Lngbruno, I believe that Ohm has claimed that their original technicians have all retired and that they could not find suitable replacements. German Physiks have done just what you have suggested. The German Physiks speaker line does deviate slightly fom the original Walsh description. Most are augmented with additinal woofer/sub-woofer(s) with added cross-overs. Some use mulitiple Walsh type drivers. Most would consider their offering on the expensive side.
All in all, I agree with you complelety. While I haven't actually heard them in decades and I don't trust my memory of those experiences, the Walsh drivers still look like the most promising design to date. I would imagine that they may even be more relevant today than yesteryear.