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So, anybody ever get physical with an Ohm Walsh?

mamboni said:
Build your own Walshes from scratch for cheap: the sound will blow you away:music:. I have Walsh 5 Series 3 and the home brew loudspeakers come awefully close. Close enough for government work as they say.:D
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I like it!!! I have been thinking of a cool / fun project for my minty Utah 12" FR drivers. They have an odd shaped cone, like bell shaped. What is the idea behind this design. Is the cab on those sealed or ported?

380452667_HoHFp-L.jpg
 
For those who can get with the omnidirectional vibe, the Ohm Walshes are a real treat. I bought a pair of refurbed "Super 2's", and I thought that the price ($1300) was fair for what I got. I know that I could have found a pair for $200 or so...but I never would have known if the sound was as John and his engineers had designed the speakers to sound, so what good would that be? I applaud those who want to roll up ther sleeves and do it themselves, but given the unconventional design behind the
Walsh speaker, it just was never an option for me.

I guess that my feeling is if you are going to have a special piece of equipment, you should have it giving you its best. Whether it was EchoWars rebuilding my bastardized Sansui AU-919 (with modern parts that probably give it better-than-spec operation in certain areas), or buying rebuilt Ohm Walshes from the factory, I don't question either decision. I do own stuff that I think I bought right....and a part of the enjoyment of that piece of equipment is the joy of "buying it right". But when it came to the Ohms, I did not view buying the factory upgrade as some kind of "ripoff"...I viewed it as the price of admission.
 
The particular 10" paper cone woofer used called for a sealed alignment. Of course, this design will work equally well using a woofer with TS parameters appropriate for a ported box - I built a pair using 8 inch Pioneer woofers and ported and it was quite excellent. I gave that set to my son who gave it to a neighbor!

kfa888 said:
I like it!!! I have been thinking of a cool / fun project for my minty Utah 12" FR drivers. They have an odd shaped cone, like bell shaped. What is the idea behind this design. Is the cab on those sealed or ported?

380452667_HoHFp-L.jpg
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Mamboni, were you able to find an appropriate 10", or larger, driver that is appropriate for use in a vented cabinet?
 
Ohighway said:
Mamboni, were you able to find an appropriate 10", or larger, driver that is appropriate for use in a vented cabinet?
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No. But I haven't been tinkering with this design for several years. If you like, I can take a look at some of the available woofers on line and make some suggestions.
 
Sure, that would be great. And/or.... you could just give me a list of guidelines as to what I should be looking for, and I can do some dirty work hunting stuff down. Either or both works ! Thanks.
 
Your "Walshdriver" username sounds familiar. Did you used to head up a Walsh discussion forum several years ago?
 
Ohighway said:
Sure, that would be great. And/or.... you could just give me a list of guidelines as to what I should be looking for, and I can do some dirty work hunting stuff down. Either or both works ! Thanks.
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The ideal woofer for adapting to a Walsh bending wave operation should have the following properties:
1. low inductance low mass voice coil for extended high frequency response
2. powerful magnet
3. Low free-air resonance frequency
4. QTS ~0.3
5. Reasonable Vas
6. largest possible Xmax and power rating

Here's a neodymium woofer which is expensive and has most of the ideal properties. This driver has a highish Q cone with some FR peaks in the upper treble. However, one would apply viscoelastic and felt damping to the cone (mamboni-treatment) that would easily tame those "cone cry" peaks and yield a smooth response. I would mass the cone at the cone-surround junction to drop the Fs to about 40 Hz and sacrifice a few dB of SPL - this neodymium woofer is very very efficient. The driver Vas is quite small and the Qts is only slightly overdamped so that good bass down to 40Hz could be achieve in a ~3 cu ft box, vented. The power rating is an astounding 700 watts. This is an expensive woofer to be sure. But, with aforementioned modifications I am confident it could achieve spectacular performance to rival the Walsh 5 Series 3s which are monsters! I expect usable response to 4-5 kHz could be achieved, and a first order crossover at ~ 5 kHz to a 1" inch silk dome tweeter of premium quality, low Fs and generous power rating should be doable.

If I were to start a project to build a large kick-ass Walsh loudspeaker, cost-no-object, I might choose this fine neodymium woofer.

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-680&ctab=2#Tabs
http://www.partsexpress.com/pdf/294-680.pdf
 

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Fascinating stuff. What Walshy behaviors do the different available cone materials exhibit? Does paper ripple better than polypropylene, or does the self-damping of poly-p work to the Walsh's advantage? Ohm's used both and seems to've settled on poly-p.

And why does a conventional woofer need to be mass-loaded near the surround?
 
They need some tweaking to sound the way the dome drivers did, but yes, you can stick a monopole Heil (this one was from the socalled Performance Series) right on top and its unshielded magnetic field leakage will make it cling tightly.

In comparing one with the Heil to another with the dome tweeter on its special corner baffle, I think I see why they did it that way. They wanted a uniform hemispherical response, thus the small dome. The baffle cuts this hemisphere in half, and the cutoff is sharp. The controlled treble doesn't bounce off the floor or the ceiling and holds up when you're standing at the opposite speaker. So the Heil is not ideal, but it can be made to work, and the sensitivity works out to about the same, so the 3's elaborate crossover can get the sound into the right neighborhood.
Ohm Walsh 3 with PS type Heil-1.jpg
Ohm Walsh 3 with PS type Heil-2.jpg
 
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Interesting. Why not follow the original omni-directional design(sort of) and install a big Heil tweeter rather than designing a baffle to limit dispersion in the highs? That way, a larger woofer with a lower cutoff frequency can be used? Granted, not everyone would have the right room to put them in. The low frequency cutoff with the neodymium woofer seems rather high. The original Walsh radiator has always seemed to me to be the pinnacle of Ohm design. Yes, it had its limitations it terms of being power hungry as well as a narrow window of power application. But to this day, I have never heard its equal in terms of presenting a realistic sound stage. Surely the big Heil could go a long way towards restoring some of that original magic.

As a matter of fact, you've given may have given me the right project to put my Heils to good use.
 
sealy said:
Interesting. Why not follow the original omni-directional design(sort of) and install a big Heil tweeter rather than designing a baffle to limit dispersion in the highs?
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Why not, indeed. This particular project was simply to get a 3 with a blown tweeter (which the seller did not reveal/notice) back into operation, but sure, if you toss both dome tweets, the sky's the limit. It is worthwhile to narrow the dispersion vertically (something the big Heil would be terrific at), and who knows, it might be good to go omni with the highs, because 1) they don't "drive the room" the way the lows do, and 2) you can always jam a stuffed Sylvester the Cat doll into the rear of the Heil, as EchoWars did, to control the pattern. So I say go for it.

sealy said:
That way, a larger woofer with a lower cutoff frequency can be used?
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You must be talking about the DIY Walsh. --Yeah, sure, do it!
 
Ok then, I will! Here's my plan: 12 in. Eminence woofer, downfiring, 4 in. metal-cone mid range, down firing, big Heil driver for the highs. Box size: about 4 cu. ft.
 
FWIW the glue used to hold the cans on IS contact cement.

sealy said:
Interesting. Why not follow the original omni-directional design(sort of) and install a big Heil tweeter rather than designing a baffle to limit dispersion in the highs?...
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John at Ohm has experimented with Omni-directional tweeters, but, while a full-omnidirectional speaker is interesting and potentially good in some regards, the benefits/trade-offs of going with the dome tweeter setup as it is on modern Ohm speakers are a better fit for most people / listening environments. The tweeters are angled in and this "cross firing" is one part of the "secret sauce" that make Ohm's special.

dragon said:
...I've heard that they crush them. They want you to buy new ones I guess.
Wouldn't it kill you to see a mess of A's & F's being smashed. Ahhhhh! :tears:
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The original models with the three part Titanium/Aluminum/Paper cones had a real Achillies' Heel : power handling. So... mostly what they did with those trade-ins was use the "pots" to build newer 2-way (woofer and tweeter) model Walsh-5 speakers with MUCH better power-handling than the old fullrange Walshs.

I had a pair of the then current top model for several years (~ 1999 - 2003). They could play as loud (louder than) I wanted without strain. My amp wasn't any high-end affair, just an Onkyo TX-DS787.
 
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Fascinating stuff! I wish the thread would continue. I'd love to know if any of these proposed projects came to fruition.
 
So, Anybody Ever Get Physical With Ohm Walsh?

Can't say that I have... (Well, OK, there was this one time, but I was pretty-drunk..... ).
 
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