History on ohm A's and F's.

Hello Darkmoebius, all...

Thank you for inviting me back to the discussion . I am a little disappointed that I was basically ignored on my last posting of the 23rd, so I just stayed out of it.

Furthermore, It upsets me that some people just refer to me basically as the “repair guy”, when I produce a brand new and fully viable line of Walsh “style” drivers known as the TLS series. www.hhr-exoticspeakers.com

True, I have remained closely akin to the original designs, but where else can you find a true single driver capable of covering the audio range without crossovers, ports, and supplemental drivers of any kind.

Note: I also have full carbon fiber cones and high energy Nd magnets system on the drafting board, but they are a ways off yet.

Anyway, my frivolous comments are as follows…Bending wave schmendig wave…piston schmiston…it’s just a matter of semantics at best. So what if the GP vc is elastomerically connected or mine is hard fixed. I can do that with silicone. Bottom line, the vc still controls the movement of the cone and the cone is launched forward in a bending wave fashion or a pistonic fashion depending upon the wavelength. Additionally, the mass of the vc controls the upper end and transient response. GP still uses an Aluminum edge wound vc same as mine. And both drivers are made of Titanium foils exactly the same size. T/S parameters still apply as well.

I agree with Mapman, The old design “F” and “A” or my new design TLS remain full bandwidth drivers while GP avoids the issue of drivers being destroyed by overdriving them by utilizing a separate bass driver and crossover system with a Helmholtz resonator and an MDF box. The bass on my drivers simply blows away the GP series in all but the best of their line. (this is not my sole opinion, but as supported and reported to me from other listeners)

I applaud DDD and all they have accomplished, but the True full range Walsh “style” speaker is FAR from dead.

Can you overdrive and crush my drivers like a bear can…Yes, you can. Can you overdrive and short out the best electrostats? Yes, you can? Can you overdrive the best ribbons of the day such as Apogee or Analysis? Yes, you can. Finally, can you launch a 15” or 18” piston driver across the room? Yes, you can. Just short out the amp or drop your needle on your record and see what happens.

As far as ear deafening sound, 98db in a small 300 sq ft room is quite loud, with peaks going far above that. What more can you ask of a single 12” driver or an 18” driver. At a price point of $8.5K or 16.5K vs. A Wilson Alexandria with 6 drivers, some of which are 13” and 15” and at more than 6 ft. tall. Or, the MBL Extremes requiring a huge room and sub station to drive them at a price point of $200K. They are all still multiple driver systems with huge crossover networks and they SHOULD play louder than a single 12” driver. I don’t know about you, but I would rather have the resolution and engaging sound rather than ear destroying volume levels especially in a smnall room.

One of my clients, proceeded to utterly destroy a brand new set of TLS-I’s with no less than a 600 sq. ft. room and a pair of 1KW amps… Geee…go figure and they were amazed when I refused to cover this on warranty.

This unfortunate event has led me to “choke” design a new series of Walsh “style” subs with 15” and 18” drivers crossing a roughly 50 Hz utilizing active crossovers. So it will relieve some of the stress placed on the full range drivers and volume levels will soar. But, am I happy with using a crossover or compromising the time and phase coherency of the original drivers… NO! I am not. Still this is quite a feat and requires an extreme amount of engineering.

No, these are not available yet…soon, but they are not cheap and they are not small.

Also, I would like to mention that my drivers incorporate subsonic filters that roll of quickly to help protect the low end excursions. Still, no loss of performance here.

Here again Ladies and Gentlemen, it is all about what you can afford to spend, your actual rooms sizes, system and WAF. I do not want to get into any kind of a “pissing contest” nor would I ever belittle any one else and their experiences. I think we are all very fortunate to live in an age when so much is possible and so much has been accomplished technologically. It is all about one thing, Enjoying music, and this love has brought us all together. How much better can it get!

Sorry for my ramblings, if I failed to answer any questions, please ask me here directly. If I know the answer I will gladly post it, if not, I will give it my best to look for it.

Good listening to all, Dale

Dale,

98db in a 300 sq ft room from a single full range driver sounds pretty appealing to me!

This is as good or better than the original As and Fs, right?

Considerably better.
My measurements were made in the far field at 10 to 12 feet from the pair. 95db to 98db was routine.

These volumes were with less than 10 watts average on my system. Though I can not accurately measure the peak demands.

I use Antique Sound Labs DT-200 Hurricane mono blocks that have been highly modified. IMHO, these tube amps are pretty dynamic and have lots of head room. The Walsh drivers sound very open and articulate on these. I find that tubes are a good compliment for speakers. More so than anything but the best SS amps.

BTW,for those who don't know, I forgot to mention that I am also a rep for Piere Sperry's Mapleshade products. Mapleshade is a great producer of fantastic CD's and a wide selection of some very fine accessories including plinths, wood bases, equipment racks and ribbon cables. Pierre also gives away an enormous amount of FREE set-up and tweak info. www.mapleshaderecords.com

Dale

I don't know how many Ohm A's and F's were sold, but due to the power requirements and various other reasons, I doubt they were exactly ubiquitous. Let us remember that the OHM Walsh A's and F's are now over 35 and 25 years old respectivley. Furthermore, due to their unique design, I would think it would be fair to reason that some may have compromised by less than qualified repair efforts. I seem to recall that both Dale Harder and Bill Legall of Miller Sound have made claims that they have solved some of the issues re: the OHM A's and F's, including the alleged reliability issues. I'd imagine that many speakers of that era might need some maintenance. According to the Ohm web site, it was not failure rate that made them abandon the true Walsh drivers, but rather an inability to replace the skilled labor force that had been lost. The original titanium DDD driver was reputed to be somewhat delicate as well.
I will admit that I am not the least bit qualified to make an accurate assessment, but it appears to me that the new OHM's appear to me to be much more similar to a pistonic dynamic driver than to a true Walsh driver. Perhaps, it's just me, but I find Ohms web sites use of audio buzz words to be confusing if not indeed misleading.
I don't mean to condemn the German Physiks offerings. That the lower frequencies, that most consider to be percieved as omni-directional in nature anyway are passed on to another driver may appear to be less elgant, but doesn't perturb me. The newer carbon fiber drivers appear to be a very good evolution. If I could personally justify the expense of these designs, they would certainly be at the top of my short list.
I can't help but wonder if either or both German Physiks or Dale Harder could manage to use a sub that maintains time and phase coherence in the same way that some manufacturers of more traditional cone and dome speakers have, with their Walsh inspired concepts. Or better yet, develop a larger perhaps differently tappered Walsh like driver to be truely full range? And while your at it (Ha!) let's not forget the dynamic contrasts that allow for appropriate loudness are an integral part of music, for both headbangers and "serious" music afficandos.
I sincerely encourage those who choose to pursue the development of these types of speakers, and I would like to to especially encourage the development of ones that could be afforded by the masses. Good luck!

Dale,

I would absolutely love to hear a set of your speakers. I think that the promise of the Walsh concept has not yet been 100% fulfilled, but I remain a big fan of the concept (which is why I became the importer for German Physiks).

Where are you located?