History on ohm A's and F's.

Spike,

Is it also possible that the cassette recording was audibly distorted, oversaturated or something along those lines?

In general, cassettes were never a great medium for capturing low distortion recordings with good dynamics.

OR maybe a combo of cassette recording distortions combined with OHM F overdrive?

Csommovigo,

How do the GP Unicorns do with high SPLs compared to the Ohm Fs or As?

Also how much do they cost?

I participated in some exchanges here on A'gon threads with Dale Harder a few months back, but not recently.

He seems most knowledgeable regarding what it takes to get a pure Walsh driver like those found in old A's and F's operating properly and has shared that info in the form of a guide both here on Agon and on Ebay. It is an extremely challenging task to accomplish in practice, as I understand it. I have also seen ads he has posted for both Ohm As and Fs here on Agon that he has completely refurbished for $5-6 grand (about the same price as a pair of new Ohm Walsh 5's) and they looked very nice. Would love to be able to hear them someday.

The closest things to Ohm As and F's today design wise are probably the larger and extremely expensive German Physics designs and Ohms own Walsh line based on the CLS driver.

I have heard most all Ohm box speaker designs from that era but never As or Fs so I cannot comment on their sound other than saying that many who did hear them remain dedicated.

Newer Walsh CLS speaks are definitely easier to drive (though the larger models still require very good amplification to do their best), are easier to locate relative to walls and are less problematic and more reliable overall.

The newer Ohm CLS speaks have better specifications on paper, but I have heard some Ohm F fans state that they do not think the newer Ohms have the same "magic" as the Fs.

Pedrillo,

One other thing of interest is that Ohm's website indicates that newer Walsh 5 speakers, like those like the F5s in my system, can be set to sound identical to original Ohm As using a certain combination of the 4 range level adjustments on the Walsh 5 cage.

My experience with most assertions on the Ohm site is that they are usually on target, for what it is worth.

I tried this with my system and found it a bit bass heavy in my larger 30X20 L shaped listening room. I've used similar settings in that room most recently but with the relative bass levels lowered somewhat.

In the current 12X12 main listening room I currently have the F-5s in (where I have access to best speaker cables, etc.), I lower the bass even further otherwise my fixtures will start to vibrate and I might well be driven out of the room at even moderate to higher level SPLs.

The weight, dynamics and overall impact the Walsh CLS speaks provide though when properly matched to room size is an exhilarating experience you will most likely never get with electostats or planar designs which may otherwise sound similar.

The Ohms and Maggies are the only speaks I can afford that I ever found endearing when set up properly with classical music but the Maggies alone cannot touch the Ohms in regards to overall power and impact.

Audiofeil,

Have you heard Walsh 5 series 3? What electronics have you heard with them?

I'd be curious for a comparison between 5 series 3 and properly functioning Fs if you've heard both.

Jtwrace,

No,unfortunately never heard MBL, so I can't compare the sound.

I can compare the two designs however to some degree.

They are similar in that both are inherently omnidirectional using a single yet supplemented wide range driver.

The Ohms however are physically damped/attenuated in the wall facing directions by default to enable easier placement near walls, so their measured sound dispersion pattern is not purely omni-directional.

Also the Ohm Walsh wide range driver reside on top of the cabinet like larger MBL and German Physik for that matter and is supplemented on the high end by a directional super tweeter and ported to extend the low end, whereas I think the large MBL wide range driver is supplemented on the low end by a sub woofer.

Larger German Physiks, which use their own derivation of the Walsh design, are also supplemented like the MBLs on the low end by a sub woofer, I believe.

All these designs will claim a high degree of phase coherency from top to bottom.

Ohm claims that their near full range design produces most of the most important frequency range that most people over 40 can truly hear via the wide range Walsh driver used. The theory is that we lose our ability to hear the highest frequencies recorded in music as we age.

Ohm As and Fs utilized a single Walsh driver for all frequencies but rolled off at ~17Khz, according to the specs on the Ohm site.

Ohms and German Physiks use different derivations of Lincoln Walsh's original driver design (look up "Lincoln Walsh" on wikipedia for more info here). I am less familiar with MBLs omni design but from what I have read on their site it is a more radically different breed of omni design.

One a'goner here whose opinions I respect recently referred to the Ohms as "Blue Collar MBLs", which is probably a fair description in that Ohm Walsh speakers range in cost from $1000 to $6000 depending on target room size and finish, whereas big MBLs cost over $25000 as I recall, so some might consider the Ohms to be "giant killers" and all that goes with that designation.

Ohm is located in Brooklyn NY, USA. MBL and German Physiks are imported from Germany.

Interesting. This is the first I heard of Huff and their exotic driver speaks. Nice that they are US made apparently. Price wise, they appear to live somewhere between the Ohm world and German Physiks.

So where can one go to on the east coast to actually hear them?

By the way, I would not consider Ohm CLS drivers to be "exotic".

The technology is unique and affordable, perhaps, but if you were to look inside the cage, the actual driver is butt ugly THBOMK. Thank God it is hidden! Its like that episode of Star Trek where that ambassador guy was so ugly he lived in a box and if you opened the box without the protective glasses, you went insane (even Spock)!

Aktchi:

My comment was meant to apply to speakers that I have actually owned and tested over the years in my own house, not necessarily to any that I have ever auditioned or heard. There may well be others out there, but nothing I can think of offhand that I would consider over the Ohms.

$2800 B&W floorstanders (P6) and $2500 Dynaudio Monitors (Contour 1.3 mkII) are two that I own or have owned and tried.

I lost all interest listening to classical with the B&Ws after the Maggies. Though they had good weight and slam overall, they were never convincing with classical. Pretty good with other more rhythmic forms of music though.

The Dynaudio monitors, though fantastic for their size, are not totally convincing with large scale works including classical either.

I also still have a pair of Triangle Titus 202 monitors mated with a sub which does a very respectable job with all classical music forms.

Also I would include original Ohm Walsh 2's from the 80's that I owned for years....respectable but not great with classical.

The newer Walsh CLS series 4 drivers beat out all of these in every type of music, but for classical in particular.

There is no sense of missing anything in a performance of a large scale classical piece with any of the Walsh series 3 drivers in a properly matched size room.

"Even Spock???"

Yes, even Spock!

Although as I recal he felt better by the end of the episode.

I think it (the episode) was ironically called "Is There in Truth No Beauty?".

With the Ohms, I would say there is truth and still some beauty as long as you don't open up the "cage".

Dale, thanks so much for your (one of the most I have seen) detailed accounting of how the Walsh driver works.

I've always considered the Walsh driver a truly a unique and vastly under-appreciated piece of engineering work IMHO despite my limited understanding of the physics and engineering behind it.

I'm glad there are people like you, Strohbeen and the others out there devoted to keeping it alive and moving forward to the benefit of music lovers everywhere!

I think saying the Walsh speaks including As and Fs are pistonic is an accurate statement.

Regarding efficiency, though I would not doubt the DDD driver is more efficient than the original Walsh A or F drivers from 30 years ago, I think comparing a full range driver like those on the Ohm A and F to a limited range driver that does not cover the low end like the DDD is an apples and oranges comparison.

I think the Ohms were both bending wave and pistonic using a voice coil and foam surround.

Sounds like the drive mechanism for the DDD is different as described by Csommovigo as like "striking a bell", but honestly the exact difference is not clear to me.

The difference in basic operating principle between the DDD driver and the Walsh driver on original Ohm F and As is not apparent to me. The drivers are different sizes and cover different frequency ranges for sure, but both seem to operate similarly in principle in a manner one might chose to describe as pistonic or not...not sure what difference it makes because it appears to be the same. Whether pistonic or not, the bending wave principle for producing the sound appears to be the same.

I would also add the the Walsh portion of the newer Ohm CLS drivers also operate on the same bending wave principle.

That doesn't mean that old Ohm Walsh, newer CLS and GP DDD drivers necessarily sound the same. I am certain that they do not just like three different conventional cone driver designs that operate on the same basic principle sound the same.

On all counts?

Maybe.

Csommovigo,

Sounds like a reasonable accounting of the similarities and differences to me. Thanks.

IS it accurate to say that the different designs all operate on similar principles despite the fact that the implementation of each is significantly different, for better or for worse?

One other question I had was is it accurate to say that the lower frequencies with all of these designs are produced "pistonically" while the upper frequencies are produced by bending waves?

If so, then the Ohms must rely less on wave bending because the upper frequencies (>~14000 khz, I think) are produced by the separate tweeter whereas for most of the GP speakers, the low end (pistonic range) appears to be handled separately .

Still, other than the on e GP model I think, the Ohm Fs and As are the only speaks that use a single driver for the full range.

An advantage of wide or full range is the elimination for the need of a separate crossover device and a more "coherent" sound overall.

"Curiously - to say that the DDD is a variation of a Walsh driver (as described in LW's patent), in a fashion, to say that the Blackhawk helicopter is a variation of a drawing of a flying machine by DaVinci. While the DaVinci is certainly elegant and inspired, the GP actually works, and works with predictable precision and reliability."

This part is a bit biased I suppose.

Has GP's DDD driver solved the robustness issues of the original FULL range Walsh drivers on the A and F?

It doesn't seem so to me since it is not full range and does not deliver the low end. Unless I'm missing something, the DDD solution appears to be to avoid the problem, ie separate the low end off to another driver to avoid the stress and wear issues associated with delivering the low end "pistonically" along with the upper range that is delivered via wave bending all with the same driver, as I believe was done with Ohm As and Fs.

For newer Ohm Walsh speakers, they've elected to deliver the low end via the wide range (still not full range) Walsh-style driver. The rational Ohm provides is that most of what most people can actually hear (up to 14000khz or so) is delivered via the single driver and that preserves a lot of the benefits of the original Walsh driver design while avoiding the inherent fragile nature apparently of the full range Walsh driver design.

Spike,

My educated guess is that the Fs were starting to be overdriven at that point, which as I understand it was common and easy to do with the Fs, and their acknowledged achilles heel that Strohbeen tackled by switching to the CLS design with Walsh driver not as wide range as the F Walsh driver.

I may still have a similar cassette recording of Babylon sitting around. I'll have to give it a play on the latest and greatest Walshes from OHM and see if I hear anything. I have not noticed the sonic artifact you describe on any CLS OHMs I have owned, however.

"Next: The Peter Dicks driver parts ways with the Ohm driver in several ways. First of all, it was modeled more accurately."

There is no doubt that modern (1980s and later) Computer Aided Design (CAD) technologies would provide a means of producing superior drivers, Walsh style included.

These tools were not around when Walsh conceived of the Walsh driver nor when Gersten attempted to actually realize the design. So practically, the concept was ahead of its time in terms of the ability for a manufacturer to realize it optimally. The tools and technology needed simply either did not exist or was cost prohibitive.

Credit goes to Dick and GP for applying the newer technologies needed to the problem practically once they became available. Credit also goes to John Strohbeen, though he took a different approach in the interest of value, robustness and good sound.

Apparently though, nobody has yet figured out a way to make it work in a robust and reliable manner in a single full range driver though. All modern designs either punt and introduce a second driver or are still somewhat fragile in the same way as the originals.

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?

YEs, I'd really love to understand the pistonic/wave bending thing in more detail in regards to the CLS Walsh driver.

OHM CLS must be doing some wave bending in the mid range and up, though clearly not at the very top end where the super tweet works. The cls high end response extends beyond 16-17Khz which I think is approximately where the F ended.

I'm assuming wave bending is at least part of what propagates sound outward horizontally from the rear of the downward firing cone as opposed to up/down (pistonic) using the cabinet to tune the low end, but I do not know for sure, just how smooth, dynamic and "coherent" the resulting sound is, particularly in the mid-range. The very generalized diagrams I've seen on the OHM site showing how the CLS driver works seem to indicate this.

Lewis,

There is a transition from wave bending at higher frequencies to pistonic at lower, I believe.

Not sure I'd call it a "crossover" necessarily. Not sure to what extent that transition is audible or discernible to the human ear. Maybe others might know more?

The F driver had three separate sections covering different frequencies with different materials comprising each section. I believe I've heard reference to the 2 cut-over points between sections referred to as the physical equivalent of an electronic crossover, similar function, totally different technology/approach.

Also it is not clear to me the exact specifications in regards to at what frequencies and to what extent at each the driver operates pistonically versus bending wave.

I think it would be accurate to say that the modern Walsh drivers used by OHM operate more in the pistonic mode than wave bending in that wave bending is associated with higher frequencies I believe and the modern OHM CLS Walsh drivers use a supplementary tweeter. German Physics DDD drivers on the other hand operate at the high end of the frequency spectrum supplemented for the most part by conventional woofers, I believe, which is an opposite approach.

Getting a single Walsh driver to do it all or as much as possible without destroying itself at high SPLs would seem to be the name of the game in general.

Dale did chirp in on this thread earlier regarding his designs and German Physiks specifically and his comments are worth repeating here.

Though their Walsh driver designs all vary, I suspect what he says regarding how each are similarly voice coil driven regardless of resulting pistonic or bending wave propogation of sound applies to the OHM CLS as well, but this is just my assumption based on what appears to be similar physics and design elements in play in the case of each.

Dale said:

"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."

IMHO, each vendors Walsh design varies based on targeted market.

GP targets the very high end audio market.

Dale Harder is a champion of the concepts of Lincoln Walsh's driver and is a champion of carrying the original OHM designs into the future with a focus on quality and value.

OHM has always and continues to focus on providing the best sound possible as cost effectively as possible to the masses.

Spike,

Which Marley live recording?

Were the Fs possibly being over-driven? It was not hard to do this with Fs from what I have heard.

If the source was vinyl in particular, was it possible that low frequency noise (rumble, etc.) was present? That might contribute significantly to a problem as you describe if so.