HEy, I like this thread!
Walsh drivers are a principle. The general principles are fairly well documented. Specific Walsh driver implementations realize the principles differently.
The principle involves a downward firing driver where the sound is emitted 360 degrees in the horizontal plane via the rear of driver.
So I have read that basically any open back cone shaped driver can function as a Walsh driver. But only those that are well designed and tuned will sound good. Also making one that is full range and robust as well as being even remotely cost effective is a trick that few if any have ever mastered. I would expect only a highly skilled engineer or technician could actually accomplish this. I know of only one these days that makes the claim (see Dale Harder's "My Walsh Dream" virtual system published here on Agon).
What is not well documented and also happens to be the magic sauce is how to design and tune a driver to function well as a Walsh driver. The shape of the cone, materials used in regards to rigidity and density along different portions of the cone (to realize the wave bending aspect of a Walsh driver) would seem to be important ingredients.
To do it well, even for a limited range Walsh driver, would seem to require understanding of the principles and a lot of testing involving trial and error and tuning to get the desired results, I would expect. Could be quite time consuming R&D type work! Not for the faint of heart looking for optimal results for sure! Or maybe you get lucky and happen to stumble onto a driver that works well out of the can (ha, ha, no pun intended)?
Those who know how to do this well are generally not prone to make their intellectual property public, so I do not know if there is such a thing out there as a quality Walsh driver design spec that one can attempt to realize themselves rather than start from scratch.
I have seen an internet thread or two on the topic on other sites where DIY'ers share their experiences, but I was not able to discern much I would bank on there.
Audiogoner Mamboni is the one I know of that might have the most practical experience with commercial Walsh drivers as well as DIY versions.
Another approach I would recommend is reverse engineering.
In other words start with a quality working Walsh driver design, and reverse engineer the specs to create one yourself based on your observations and any measurements possible. |
OF course any good speaker including omnis and the newer OHMs can sound mediocre if not set up well. Personal tastes aside, the same speakers can sound absolute top notch if set up optimally.
Like most things, it all depends...
Also worth mentioning that Dale Harder's website has perhaps the most information I have seen anywhere regarding what goes into creating a quality Walsh driver. Pretty daunting.... |
Glo,
Sounds like a rational plan.
I suspect many who are fond of the older generation (near) full range Walsh drivers and wide range DDDs in particular tend to be enamored more so with the Walsh driver top end sound.
The newer OHM CLS drivers take the opposite approach, using a conventional tweeter/super-tweeter crossed over to the Walsh driver at as high afrequency as possible, at ~ 7-8 Khz AS I recall.
I gotta say though that I find it hard to understand how anyone could not be impressed with the overall smoothness and detail including the top end that at least the newer OHM CLSs are capable of delivering. I say capable in that I find the limits so far depends on what's upstream more so than the speaker itself. I have heard major differences from absolute top notch to just so/so depending on the specifics of whats upstream feeding my OHM series 3 CLS speakers. The ARC tube amp with teh newer and pricey West German 12AX7 tubes ARC now is providing, the carefully matched BEl Canto Class D amps, and either somewhat humble phono or digital sources I use currently are in that top notch class IMH and also maybe somewhat biased opinion.
If you do it successfully for modest cost, maybe approach John Strohbeen to see if the Walsh tweeter might be utilized in the 2-driver CLS configuration maybe? That might be interesting! |
"I think that "stuffing a pillow" behind the driver as Ohm is presently doing is not the way to go."
I think this is the standard configuration provided to enable speakers to go closer to rear wall than full omnis otherwise and allow the speaks to fit into more peoples rooms like other speakers more easily.
That may be why they pass on the omni/walsh style tweeter. I'd like to see it though if possible in order for the dispersion characteristics to be similar top to bottom regardless of whether full omni or not.
I imagine cost management is a factor in the decision making process as well. The tweeter they use sounds very good. A "custom" Walsh style tweeter would likely add cost. Maybe a premium model of some sort with a separate Walsh tweeter might fly and still come in for a lot less than GErman Physiks, mbl, and their ilk.
But I also suspect that the niche high end market is not something OHM is really all that interested in, at least in the US, although they have started to market overseas in GErmany and elsewhere I suppose where their products can compete with the mbls of the world in a larger market for much less I guess.
OHM does do full omni versions for surround sound systems normally I believe where the sound absorbing materials inside the can are omitted. |
Eldartford,
I'd say you are correct in terms of how a properly designed Walsh driver operates.
My understanding though is that Lincoln Walsh invented the principle, but never implemented a specific commercial design himself, though he was involved early on with the first early OHM products, something that no other makers of Walsh drivers can claim.
SO when I read that any conventional driver can be configured to operate as a Walsh driver (though most likely not a good one unless the principles of designing a Walsh driver are applied and realized properly somehow), I find it hard to argue. The quality of the resulting sound produced in the end based on applying the principles is what matters.
I read about people implementing their own "Walsh" type speakers using otherwise conventional drivers, but have never heard any, so I could not comment on the results achieved.
If it walks like a duck and quacks like a duck, it's probably a duck, but still not all ducks are created equal! |
Hi Dale.
I'd much rather spend my time listening to Walsh speakers than building them.
Your speakers are on my short list of designs I have not heard that I would most like to.
Right now I am happy with what I have but always looking to explore new or future options.
I would make extra effort to go to Capital Audiofest this July if I knew you would be demoing your stuff!
I still have not heard anything that I can afford that would make me abandon Walsh style speakers for my tougher applications.
I do fear though that the expertise to make the technology work well in a marketable manner is so limited that it could fall totally by the wayside someday. That would be very sad! |
Hi Mamboni.
Great to hear from you. It's been a while!
Mamboni's writings on the various audio sites about the newer OHMs and Walsh drivers in general was largely responsible for my giving the latest generation of OHM Walsh speakers a try a few years back when I was in major upgrade mode.
I auditioned everything under the sun with price no object including large dynamic designs, the latest Maggies, Quad Electrostats, Magico, Gallo Refs, and others before deciding to try the newer OHMs in house first. It took me awhile as well to get everything dialed in just right in my main listening room as well but I am still so glad I did!
Mamboni's postings on the DIY site regarding DIY Walsh speakers are the most extensive, practical and best thought out technically that I am aware of. Anyone looking to DIY a pair of Walsh speakers should start there.
|
"Living presence indeed! You need a Walsh to get it."
Yes, would have to agree.
I just received the 51 CD MLP box set and am in process of ripping to music server. I am looking forward to quite a treat!
If you take a good MLP recording to the limit with OHMs or similar wave bending Walsh speakers in general, you are sitting pretty for pretty much everything else IMHO. And it does not have to cost a small fortune to accomplish either! I really do not know of any other way to accomplish that practically?
THe wave bending and how that enables a single driver to function wide range coherently and with 360 degree dispersion so efficiently is the key it seems to me.
When I consider the physics behind this, it makes a lot of sense in terms of getting the most possible out of a dynamic cone driver.
Lincoln Walsh was worlds ahead of his time! Not sure anybody else has come up with a better way yet even after all these years.
In my mind John Strohbeen and OHM are one of the best kept secrets out there in the high audio world. Other than the sound of the speakers these days, nothing about OHM screams "high end".
I find the whole thing quite fascinating and I admire John Strohbeen immensely as a guy who is obviously brilliant but knows how to keep his ego in check and just let his products and customer service speak for themselves. |
I'm not thinking of building any in the near future but very interested in learning from what others have done. |
Not sure how many DIYers in general hand out in these parts.
Frazeur I am doing well. Getting to listen to a lot of good music and work out 6 days a week amid all the rest. My wife and I will have a 25th anniversary coming up and kids are doing well in school. That's the jist of it. Best always! |
FWIW their was a DIY room at the last audio show I went to (no Walsh speakers unfortunately) and I came away thinking how silly the DIYers sound made many very expensive offerings there seem. I'm surprised but happy they were allowed there. The DIY stuff hit way above what one might expect but was certainly not pretty. Lots of pretty impressive looking gear as a whole there though.
The thing I like about Audiogon is that it sets a high standard for home music and sound quality. Where it becomes interesting then is all the different recipes out there for good sound at all price points. |
Fraz, the one significant enhancement with my OHMs recently was placing the 100s in my family room on Aurelax Subdude platforms to minimize interaction with the suspended plywood wood floors under the carpet there. That totally transformed the sound in that room by getting bass interactions with the floor under control. Inexpensive and definitely worth a try when called for.
My big F5s sit on solid concrete foundation. The 100s upstairs now sound more like those I have set up fairly optimally downstairs. |
