Ohm Walsh 4 Refoam Questions

sealy said:

So now we know Ohm's dirty little secret, conventional drivers in the place of Walsh drivers. Small wonder they advise against opening the cans. The diagram is a bit misleading in that the taper of the cone leads one to assume that it is a somewhat truncated version of the Walsh driver, which is obviously not the case. I guess if the speaker sounds good, who can argue? Nevertheless, I am disappointed that Ohm has so obviously economized on the components. They certainly haven't shirked at charging a premium for their product. I have opened up many European and Japanese brands and have never found evidence of the same kind of cost-cutting. Sign of the times, I suppose.

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I don't think that's really fair. It's not as though they're buying Fostex woofers from Madisound.

They are using traditional cone drivers, but I doubt they're using an uncustomized, off-the-shelf part.

Granted, it's clear that Ohm takes full advantage of the relative invisibility of their drivers, but it's not as though no work went into it.

I've seen pictures of what the Walsh 3 driver can looks like on the inside, and it doesn't detract from how good the Walsh 3 sounds.

It's normal to be a bit disillusioned by these pics, but, disillusioned so hard that you no longer believe your ears?

If you think about it, all Walsh really did was observe a behavior of woofer cones that was less than ideal in their existing application, and engineered a solution to make it work in our favor instead.

Yeah, the full-range walsh driver is a damn work of art, but this isn't half bad either.

I had forgotten that I'd posted in this thread many moons ago. My Walsh 4's are back from the ohm factory and singing quite nicely. I drive them with an adcom gfa 555II and I'm very pleased with the results. I really don't care what the 4's look like inside; mine sound damn good to me.

That's the spirit. Ericj's description is Lincoln Walsh's insight boiled down to the essence.

There's another reason a conventional-looking wooferoid serves perfectly well for the second-gen Walsh drivers: Take a look at the Ohm F. Titanium cone bonded to an aluminum cone bonded to a cardboard cone. The top part acts as a tweeter-- as it did, inverted, in the Infinity Monitor. The aluminum's the midrange and the cardboard's the woofer down to frequencies whose wavelength is too big to fit on the cone. So replace the top part of the F's cone with a conventional tweeter mounted so as to be directional but time-aligned. Replace the bottom part of the cone with a ported enclosure. What have you got left?

This is also the strategy adopted by the DDD driver in the German-Physiks speakers-- they have actual cone woofers doing the bass, the bloody cheats.

If you want to see what's inside your Ohm can...

I'm still not sure what sort of goo Ohm used to stick the cans down over the driver assembly, but it's not that difficult to pop the can off, no prying required, at least not on my Walsh 3. This should apply to the Walsh 4 can, which I believe is the same size as the 3's.

How is the Ohm Can constructed? The Walsh driver proper sits with its face (well, it would be a face on a nomal woofer) facing down into a box, and this face is hidden by a perforated and foam-lined steel disc. A similar tall cylindrical cap (the visible part of the Ohm Can) slips over the "bell" of what on a normal woofer would be the stamped-steel basket, specifically the flared part just before the flat section that mates with the mounting gasket of the cabinet. In this case, the Walsh "woofer" is riveted to an extension of this flared section. This was probably done in order to give the extra bits some breathing room. The cap's a close fit, enabling Ohm to make a secure unit by painting around the base with some sort of mastic or rubbery glue. Nothing locks the cap down; there are no screws, locking tabs or spot welds. If you can soften the goo/glue, the cap will simply lift off.

Cabinover in post #21 used X-Acto knives to cut away the Ohmgoo. Not having very good luck with knives and guessing the goo was contact cement, I took a disposable horsehair paintbrush and painted around the base of the can several times with lacquer thinner; this softened the goo a little. Then I noticed short strips of the goo were detaching themselves and that I could pull bits of them off and rub off much of the rest.

In any case, I sort of broke the can across my tum the way you'd break a stick across your knee, working it a bit at a time around the circumference. No damage to anything, no bent metal.

Anyway, turns out the Walsh 3 driver isn't a conventional woofer at all but a driver built like a fullrange, with a very thin paper cone and a curved profile, but with a strangely heavy surround. Interesting.

Since my speakers are Walsh 3s, and this is a Walsh 4 thread, I've moved the photos that were briefly here over to ericj's thread about his Walsh 3, in this post.

I did want to mention a part I've seen in many exposed 2nd-gen Walsh assemblies, namely some small tubular parts that look like fat fuses covered with different colors of spaghetti, that coarsely-woven fiber tube material used to insulate leads and bare wires. Turns out these are tubular lamps, ie, incandescent bulbs, and they form part of the protection system for the speaker's drivers. Usually there's a vertical stack of two or three of these things. One of 'em may have a 13 uF electrolytic in parallel with it.

Anybody have a guess at what the capacitor's for? It's not connected to the tweeter. It's in parallel with the top "fuse".

Here's what my pal Don says about the capacitor:

when the lightbulbs light, they go high in resistance (duh)
that cap not only protects the lightbulb from burning out, it adds another section to the crossover at the time of high-current
probably shifts the corssover higher in freq
forming a current-variable crossover frequency
at the same time it kicks up the ability of the lightbulb to survive
those damn things die wayyy too fast to be useful as protectors
I'd have to see the rest of the circuit to know for certain, but it probably turns it into an 18db filter, from a 12db one

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That means Ohm was too clever for their own good. It moved the crossover point, it steepened the slope, and my Ohm 3's tweeter (not as clever by half) blew to protect the crossover anyway! Brilliant!

Thanks to your friend Don for seeing how the protection circuit works.

i wonder if the lightbulbs are dead and the tweeter isn't

No, sadly, I checked that right away. The tweeter blew to protect the light bulbs. Murphy's Law, y'know.

The bulbs are 0.2 ohm, by the way.

So Ohm Walsh owners, if your tweeter is blown, blame this clever protection system.

[whispers] I'm gonna stick some monopole Heil tweeters in mine, sho nuff!

My cut on the modern "Walsh" (whoops, I mean CLS) drivers is that they're both impressive and disappointing.

Impressive: They sound good. They're a very clever use of conventional components to emulate the coherent sound of the "true" walsh driver.

Disappointing: For the price that Ohm charges, they could (should) have used much -better- quality components. Some shoddy construction techniques, poor fit and finish in this price category. Frightening number of individual electronic components in the signal path (based on my Walsh 5's)

Premium prices should equate to premium components and construction.

Ummm...other than how a speaker "sounds", what else really matters?

Don't get me wrong - I understand why someone would be disappointed if they spent $1500-$3000 for a pair of speakers and if those speakers were taken apart, the "parts" would seem to be significantly less than the "sum"...but here's the thing:

For any business to stay around as long as Ohm has (unless they are a charity case), the revenues must cover the cost of goods sold, the cost of keeping the business going (plant, equipment, labor, other operating expenses, etc...), and have enough of a profit margin to keep the equity owners interested in continuing to operate the business. Ohm Speakers isn't Apple...they don't sell a gazillion iPhones. Honestly - how many speakers can they be selling? No advertising...no distribution network...right?

Let's say they sell 5 pairs of speakers a day...a blend of new and refurbs...at an average of $2000 of revenue per transaction (I think that number is high...if you want, you can raise the amount of transactions and lower the average revenue per transaction).

250 selling days x $10,000 per day = $2.5 million/year

So...given the "crappy" construction, what shall we say for raw materials? 20%? That's $500K. Cost of labor? Let's say John has 10-12 people working for him (could be more...could be less)...with benefits and health care, that's what - another $500K? Plant, equipment, utilities, and other overhead costs? Another $500K? Taxes - another $500K? And that leaves $500K for John...

Man...he's really getting rich on all of those cheaply constructed speakers.

We can flex a lot of these numbers, but the bottom line to me is that the guy is responsive (he personally responds to ANYBODY who calls), he cares about his gear, and he supports his product line like virtually nobody else out there. And since it is such a big part of his business operations, he does need to spend a buck or two on stuff that other manufacturers just call "discontinued operations" (and force the more technically-challenged AKers to run down EchoWars to sprinkle his pixie dust on our old gear).

I gotta say...the level of distain that some on this forum have for the "lack of quality" of Ohm's construction is baffling to me. If you don't like the speakers, that's cool. If you are turned off enough by your perception of the quality of the construction of John's gear, then don't buy it. However, the sheer number of people on this forum who own his speakers and love the sound that we get from them seems to suggest that there is something more to it than a travelling barker selling "wonder balm" - and I, for one, am glad that that John's business model has allowed him to stay afloat long enough for me to buy a pair of his speakers.

Rant over. Thanks.

Yeah, what he said above. I also thought for a while that John's prices were high but have since changed my opinion after talking personally with him on the phone. Have I bought the parts I need or sent my 5s back yet? No, but the winter season is coming and we'll be headed to Brooklyn to hand deliver them soon. Then we can see NYC in all it's glory at the same time.

Ohm Walsh

Greetings!

Quick question.... Did you happen to notice a neon lamp in the crossover circuit. The other night in darkness I cranked my Walsh 2's pretty hard(105wpc) and noticed a orange glow from the upper can area on the left driver. Needless to say I'm spooked on cranking them up till I fiqure out what's up. Mabee a overload protection measure for the tweet?? Neons have been used as such before. Oddly enough Ohm says the 2's don't require any major service, unlike the 4's.

Thanks,
Samuel

That would probably be the lamp/protection circuit mentioned above Samuel.

cabinover said:

There is no way to see into the can really without taking the bottom cover off. If the bass is lacking they are due. If they bottom out, they are due. If there is any doubt they are probably due.

Having said all that, the only ones that people shy away from are the F models with that aluminumish cone.

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I don't shy away from the F's at all! The cone is titanium, aluminum, and paper, btw.

bs

motorstereo said:

I'd respectfully have to disagree with that. I've opened up many speaker boxes to be amazed at the good quality drivers, decent crossover, and heavy gauge wiring. I recently re-capped of a pair of older sp3500's would shame those walshes compnent wise for a quarter of ohms pricetag. Sometimes shortcomings in cabinet construction leads to better innards and vice versa. I've been inside the bottoms of my walshes and it's pretty poor workmanship if you ask me. After seeing the pics of the insides of the walsh's and having first hand experience owning a pair I'm sorry to say I've been had. The most I've ever dropped on a pair of speakers are these guys. If you spent $1,400 on these speakers I think you'd feel the same way.

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I'm with Cabinover on this one. Back when I was selling stereo's in college, speakers were always the high markup item. IIRC, electronics were marked up anywhere from 20% - 40%, and speakers were always marked up 60% - 70%.

The key to speakers has always, imo, been to use high quality components, and to assemble them in a way (enclosure) that results in a sum which is greater than the individual parts. But there is still a heck of a lot of profit in speakers..

bs

I gotta dig up a old thread. has anyone tried using a heat gun?

I'm sending my Ohm 4 to John while the guy is still doing it.

heres Johns email:

Hi Theoman,

Thank you for your ongoing support of Ohm speakers.

The Walsh 4/4XO grills are $130/pair and General Maintenance is $250/pair of driver. You can have both for $280 plus S&H with a copy of this email. We will contact you if we find any major problem that would cost more.

Good Listening!
John Strohbeen
President
Ohm Acoustics Corp.
76 Degraw Street
Brooklyn NY 11231
800-783-1553

Wow a 10 y/o thread still relevant and still stirring up emotions that the Ohm Co. is keeping industrial secrets. I was always under the impression the Ohm Walsh spkrs were not to be messed w/ by the common public. It seems once one knows something about the system it can be done. My own experience w/ Ohm was that I owned some large Ohm model L book enders. These were very heavy and when I pulled out the driver was all the weight. I never saw a magnet that big or heavy in any speaker. I got mine re foamed by a private party and did not include to put back the Ohm logo dust cover. I called Ohm (e-mailed) spoke to Evan and he said they do not send out just dust covers and I would have to ship both drivers,again very heavy and that was not happening. I also asked for a schematic for the Ls and again they refused saying we don't have any and the L went through many design changes. They were very eager to sell me a SBA a part that boosts sub drivers. I also said no and and told them that yes they did give me a history lesson but were no help in the parts dept. If you go on to their site all repairs request original units to be shipped to them w/ their logic being that they can measure both units for the same results. While Jon and Evan are very easy to talk to unless your uber flushed w/ cash your going to get no where fast w/ them. Just my opinion......Lew

I would like to revive this thread yet again, as I would like to draw it's attention to the moderators, that the links in the thread now take you to a phishing/scam/virus site.
Is it possible to remove them?

Jon