Ohm Speakers, thoughts?

Sean, I examine it, question it, go into it and find out on my own whether what I read makes sense to me and so far, it does not.

I agree with you on...how could reasonable SPL's be achieved without suspension. But on the other hand "with suspension", what is the cause of increased SPL's? You said yourself that the wave alone could not achieve the necessary SPL's. So I wonder if the sound being emitted from the cone is a mix of wave transmission line and conventional piston action? I do not know what else could be responsible for the higher SPL's.

I looked at the Ohm 5 Mk-2 again and there is no longer any back damping. It is omnidirectional now except for the tweeter. The can measures 9 3/4" high and the bottom 1/3 of the can is omeni, 360 degrees.

Sean, how far from the back wall did you position your F's?

Warning! Ohm posting that failed to, well post. (Sorry, some of this was written 2 days ago and I am trying to catch up.)

This is a recreation of what I think I said:

Line:

Jamscience, now we can argue over...'Is John actually marketing what he had patented .

No way, no, no, NO! And my Mom says you can't make me! ; )

BTW, I think someone just put up a pair of 4XO's on eBay.

Lngbruno:

What was the MSRP of the F’s back in the mid to late 70’s?

According to Ohm:

Production Period 1972 - 1984
Nationally Advertised Price originally $900 - $3995 per pair

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?

IMHO it is the cost associated with building them.

I am not a lawyer or a telephone sanitation engineer, so please excuse any mistakes I may make and feel free to correct them.

The patent ran out in 1989 (20 years if you keep up with the maintenance fees). (I personally believe it should be 42 years) :) If I understand correctly, once a patent is up, anyone can create that object according to the patent. If you modify it in any way, you have to apply for another patent or risk having someone or corporation competing with you using your modifications.

I have a problem with Ohm's excuse of running out of craftsmen to build these speakers. People can be trained to produce just about anything. It's just a matter of time and money. I also realize that it does cost a lot more to have something built by hand instead of by automation. John Strohbeen's patent refers to the cone and voice coil in the original Walsh patent as being expensive to manufacture. My take on this (and this is only opinion) is that the bottom line was being eaten up and to justify continuing to produce a "Walsh" speaker, a new design was needed to be equal in performance but less costly to make. Whether they succeeded is a matter of opinion.

Why does Ohm still use the Walsh tradename? IMO because they own the trademark indefinitly (as long as they pay the maintenance fees) and because of brand recognition. At least German Physiks had the cojones to name their driver by the inventors name; DDD (Dick Dipole Driver) yet give credit to Lincoln Walsh. Ohm could just as easily name their driver the SCD (Strohbeen Coherent Driver) or even the STD (Strohbeen Transmission-line Driver). OK, maybe that last one might be a marketing mistake!

Sean:

This type of design would have to be hand built using custom parts i.e. minimal off the shelf componentry. As such, it would be a relatively large economical undertaking for someone to attempt as compared to starting up a speaker company that uses off the shelf parts. On top of that, the market for such an item isn't all that big in the grander scheme of things, hence the lack of anyone jumping in with both feet.

Having said that, i can see this type of thing taking off if someone were to build "one off" products out of their garage. That is, IF they could achieve the type of results that we know this design to be capable of AND doing so with a high level of consistency. I have thought about this myself, but not too seriously. Sean

Maybe after creating a new prototype, an ingenious mechanical engineer could build a machine for mass producing these speakers (or at least cut down on some of the handwork. Of course one would have to charge outraegous amounts of money for these. (maybe in the range of $15,000 - $40,000) I don't know if there would be a market for such an expensive speaker? Would anyone buy a $40,000 speaker? ; )

When I hit the Lotto, I'll be giving you a shout!

Sean and Jamscience, thank you for your very informative posts.

Sean, I purchased the Ohm F's in early 1975 while I was working on Long Island (Huntington). When I auditioned the speakers, the gentleman who was fielding questions at the Audio store was from Ohm. I can't recall his name but he seemed like the #1 guy. I remember the price of the speakers was not in outer space and were a little more than the Bose 901's. My friend bought the Bose around the same time I got the Ohm F's and couldn't believe how stupid he was for purchasing something that sounded so inferior to what I had. To add insult to his injuring himself by self inflicted dope slaps upside his head, the F's were a couple hundred more (rememebering the details are foggy due the fact I was just out of college and hmmmmmm...maybe using some party substances at the time. LOL) I'm sure I am not alone in this aspect of youth. Regardless, I loved those speakers with or without being under the influence.

Based on what Jamscience stated about the patient (my cousin is an attorney for the US Patient Office and she had already stated as much this past weekend), then there is hope some very creative and gifted person will look at this design again and give it a whirl. I think, even built by hand, these speakers wouldn't be as expensive as was stated above. Remember, a well connected in the bizz person is going to have connections for some if not all the parts. Case in point, look at where the Von Schweikert line of speakers are being made, plus many many others.

Line: You've lost me in terms of "where do the extra spl's come from?". What "extra" spl's are you talking about? Sean
>

The difficutlty of manufacturing a Walsh driver is something that I believe could be resolved by good reengineering.

In my former life as an aerospace engineer, we worked closely with a university lab who were the primary designers of very sophisticated military electromechanical equipment. Our company's part of the design job was to refine their original designs, which often disregarded little details like "how do you make it?". The term used is "producability engineering" and it appears that the Walsh driver design never had the benefit of this kind of engineering.