I think this is the guy I mentioned earlier. I'll check with my brother , as he is the one who told me of these mods.
I was going to suggest the same thing. Rather than modify the existing frame spokes, why not just remove half of them ? Make a 6 or 8 spoked basket a 3 or 4 spoked basket and massively reduce the immediate reflection ? Treat the remaining spokes inner surface with felt to help reduce their reflection.
What makes a driver a "bending wave transducer" ? Mounting it in a Walsh-type fashion and firing it into the cabinet ?
Anybody ever try and run their Walsh style speakers with the cone firing upwards, away from the cabinet (reverse polarity) ? Seems like it would be more correct . Every other speaker fires the driver away from the cabinet.
Not that I completely dislike multi-way speakers, but I believe the Walsh F's were the better way to go. Full range omnidirectionality (not just bass/midrange with directional treble), no crossovers, and massive bass.
When set up with compatible electronics, they are quite a treat !
I wonder if the Walsh speakers modified by the guy listed above fix the shortcomings of the original.
I guess there's at least one way to find out........
...........Blake
Nihilist said:
Hi Nihilist,
The guy's name is Dale Harder, he has joined a Audiogon discussion and provided in-depth descriptions of the original Ohm A & F designs along with his own restorations+modifications. Dale also makes brand new improved versions of those drivers. Read all his responses in that Audiogon discussion for more info.
Blake, darkmoebius and others
Dale Harder is the real deal. He has been repairing, rebuilding and making brand new Walsh Ohm F and A drivers for 30 years! I have spent a couple of hours with him on the phone. This is the man you want to have rebuild your Ohm F's. He no longer calls them Ohm anything, at least for his new production, out of deference to Ohm, who he has worked with in the past.
He has forwarded to me some high resolution pictures and I have put them up on my google photo site, along with the rest of the pics of the EnABL process, as applied to alleged pistonic direct radiators.
http://picasaweb.google.com/hpurvine/NewWalshDriversFromDaleHarderPlusSomeOriginalAllMetalOhmFS
The workmanship looks to be really excellent. Makes me very very jealous!!!!!!!!!!!!!
And, yes, of course I am discussing the EnABL process with him. After all, it was a pair of Ohm F's that launched that funny pattern. EnABL was originally intended as a proper termination for Walsh drivers. That it also properly terminates pseudo pistonic drivers, just shows that Lincoln Walsh knew exactly what he was talking about.
Bud
Dale Harder is the real deal. He has been repairing, rebuilding and making brand new Walsh Ohm F and A drivers for 30 years! I have spent a couple of hours with him on the phone. This is the man you want to have rebuild your Ohm F's. He no longer calls them Ohm anything, at least for his new production, out of deference to Ohm, who he has worked with in the past.
He has forwarded to me some high resolution pictures and I have put them up on my google photo site, along with the rest of the pics of the EnABL process, as applied to alleged pistonic direct radiators.
http://picasaweb.google.com/hpurvine/NewWalshDriversFromDaleHarderPlusSomeOriginalAllMetalOhmFS
The workmanship looks to be really excellent. Makes me very very jealous!!!!!!!!!!!!!
And, yes, of course I am discussing the EnABL process with him. After all, it was a pair of Ohm F's that launched that funny pattern. EnABL was originally intended as a proper termination for Walsh drivers. That it also properly terminates pseudo pistonic drivers, just shows that Lincoln Walsh knew exactly what he was talking about.
Bud
Mamboni speaker
It occurred to me while watching this thread that this - Mamboni’s DIY omni - may be just the ticket for a great mono speaker. I’ve been looking for something that would provide great sound for 78’s and mono LP’s, and provide it over a wide area. No beaming speaker wanted for this. The one difference I think is that here an omni tweeter, or tweeter array, would be desirable in this case.
By the way, I haven’t seen any posts from Mamboni for a while. His initial input started a flood of ideas, Bud’s, for instance, which have carried over into other threads and forums. I’ve been curious about his feelings on how these DIY speakers compare to his new Ohms. He wrote early on that they (his DIY pair) give about ninety percent of what his Ohm 5S3’s have to offer. For the cost that is fantastic, but my curiosity is in what specific ways they differ, whether it’s mainly the bass, and/or midrange detail, and so forth. A great DIY project, no matter. This project- the stereo pair - will shove some other projects off my list. A mono speaker will move next to the top.
It occurred to me while watching this thread that this - Mamboni’s DIY omni - may be just the ticket for a great mono speaker. I’ve been looking for something that would provide great sound for 78’s and mono LP’s, and provide it over a wide area. No beaming speaker wanted for this. The one difference I think is that here an omni tweeter, or tweeter array, would be desirable in this case.
By the way, I haven’t seen any posts from Mamboni for a while. His initial input started a flood of ideas, Bud’s, for instance, which have carried over into other threads and forums. I’ve been curious about his feelings on how these DIY speakers compare to his new Ohms. He wrote early on that they (his DIY pair) give about ninety percent of what his Ohm 5S3’s have to offer. For the cost that is fantastic, but my curiosity is in what specific ways they differ, whether it’s mainly the bass, and/or midrange detail, and so forth. A great DIY project, no matter. This project- the stereo pair - will shove some other projects off my list. A mono speaker will move next to the top.
Thanks for the suggestion. I didn't try an email because somehow it felt like it might be a little intrusive if the good doctor is no longer interested in this thread. I will definitely be trying this clone myself, but it will be about a year off. As in a lot of DIY speaker projects, when you can't find one to listen to yourself, it's nice to hear what others compare them to, how they differ, where they're better, weaker, and so forth. It can keep the expectations down to realistic levels - all this, of course, in the context of different tastes and hearing.
The reason this project appeals to me so much is twofold: first, I think that for parties and casual gatherings where you want everyone to enjoy the music without playing musical chairs, mono is the way to go; second, for playing stereo, these speakers, along with a few others - Jordan array, Beveridge electrostats, to name two - would have the widest sweet spot of what is out there. I want to keep the narrow sweet spot systems as either office or desktop affairs for my own personal listening.
I'm thinking that one of these, placed near (but not in) a corner with lots of sound-absorbent material behind it may make a great mono speaker. If not, it would still be one side of a great stereo system, so no harm, no foul.
Maybe activity on this thread will pick up again. I'd like to hear how c2cthomas is doing with his speakers, but I think he has gotten tied up over on the enabl thread. There seem to be some angry people over there - not c2cthomas, though.
Take care and thanks
The reason this project appeals to me so much is twofold: first, I think that for parties and casual gatherings where you want everyone to enjoy the music without playing musical chairs, mono is the way to go; second, for playing stereo, these speakers, along with a few others - Jordan array, Beveridge electrostats, to name two - would have the widest sweet spot of what is out there. I want to keep the narrow sweet spot systems as either office or desktop affairs for my own personal listening.
I'm thinking that one of these, placed near (but not in) a corner with lots of sound-absorbent material behind it may make a great mono speaker. If not, it would still be one side of a great stereo system, so no harm, no foul.
Maybe activity on this thread will pick up again. I'd like to hear how c2cthomas is doing with his speakers, but I think he has gotten tied up over on the enabl thread. There seem to be some angry people over there - not c2cthomas, though.
Take care and thanks
Hi berm,
I'm here! A little worse off for wear at the moment but I'm healing up quickly and might be able to help you out a bit.
I made my speakers using a ESS AMT 1 for the mid and high frequencies - and let the Pioneer 10 inch woofer run full open to as high as it can get (around 5 -6 kHz). Very wide open sound field and is a nice speaker to listen to from just about anywhere in the room (I have mine about two feet out from the back wall and 3 feet from the side walls). In fact I often leave them playing music and listen to them from my home office around the corner and down the hall! The wide sound field also works very well for Home Theater.
Mileage may vary as to quality of components used but they are a fairly quick and easy build and will allow the use of less costly components while still producing some good to great sound for the investment. Lot's of things to play around with and tweak on! For use as a mono speaker you may well be on to something!
Please feel free to ask questions if you wish. In my present state of recovery I'm a bit limited as to the amount of time and effort I can put into things but I'll help out where I can.
I'm here! A little worse off for wear at the moment but I'm healing up quickly and might be able to help you out a bit.
I made my speakers using a ESS AMT 1 for the mid and high frequencies - and let the Pioneer 10 inch woofer run full open to as high as it can get (around 5 -6 kHz). Very wide open sound field and is a nice speaker to listen to from just about anywhere in the room (I have mine about two feet out from the back wall and 3 feet from the side walls). In fact I often leave them playing music and listen to them from my home office around the corner and down the hall! The wide sound field also works very well for Home Theater.
Mileage may vary as to quality of components used but they are a fairly quick and easy build and will allow the use of less costly components while still producing some good to great sound for the investment. Lot's of things to play around with and tweak on! For use as a mono speaker you may well be on to something!
Please feel free to ask questions if you wish. In my present state of recovery I'm a bit limited as to the amount of time and effort I can put into things but I'll help out where I can.
Hi,
I'm happy to hear you're doing better. I didn't expect a response so quickly, and I'm feeling a bit guilty. I won't be able to start this until I finish up some estate stuff, sell my home, and find another - really bad timing in this market. That will be a while yet. I was looking at putting together a Cornwall clone for mono, or some sort of speaker that reflects off the wall like Cockcroft's designs in the old Speaker Builder magazine. Then I saw this, and it looked more interesting and probably better for the purpose, and there was the extra input from you and Bud too. I'm really looking forward to this one. With luck, maybe my financial situation and time demands will change sooner and I can get on to this.
I hope your brain isn't reeling too much from following that thread on enabl. It's a shame people had to dial up to near flame level there.
Berm
I'm happy to hear you're doing better. I didn't expect a response so quickly, and I'm feeling a bit guilty. I won't be able to start this until I finish up some estate stuff, sell my home, and find another - really bad timing in this market. That will be a while yet. I was looking at putting together a Cornwall clone for mono, or some sort of speaker that reflects off the wall like Cockcroft's designs in the old Speaker Builder magazine. Then I saw this, and it looked more interesting and probably better for the purpose, and there was the extra input from you and Bud too. I'm really looking forward to this one. With luck, maybe my financial situation and time demands will change sooner and I can get on to this.
I hope your brain isn't reeling too much from following that thread on enabl. It's a shame people had to dial up to near flame level there.
Berm
Hi berm!
I'm not familiar with Cockcroft's designs - guess I'll have something to go look up and check out now (I love doing that sort of thing). I was around when Dr. Bose started bounding things off of walls with the 901's and I'm not a big fan of trying to fill a room full of sound from such small speakers. Speakers that work by reflection off of walls period (without any direct source of audio being projected outward) I would approach with some caution as I find them to be tiresome to listen to for extended periods of time. My brain wants to know where the source of the sound is coming from and it is always looking around for it and won't rest until it has located it.
BudP's EnABL thread is just a little "spicy" - and I'm rather used to wondering around on the "bleeding edge" of things technical - so I find the debate to be of interest. There are those that get a bit heated at times but they are simply voicing their beliefs, experience, and knowledge about something that has not been defined very well and thus is difficult to get a handle on - a bit like grasping at shadows. The nice thing about EnABL is that you can try it out for just a few $$$ and a little bit of DIY effort and then make your own determination about things.
Let me know when you have your situation in hand - and good luck with selling a house in L.A. in the present market
I'm not familiar with Cockcroft's designs - guess I'll have something to go look up and check out now (I love doing that sort of thing). I was around when Dr. Bose started bounding things off of walls with the 901's and I'm not a big fan of trying to fill a room full of sound from such small speakers. Speakers that work by reflection off of walls period (without any direct source of audio being projected outward) I would approach with some caution as I find them to be tiresome to listen to for extended periods of time. My brain wants to know where the source of the sound is coming from and it is always looking around for it and won't rest until it has located it.
BudP's EnABL thread is just a little "spicy" - and I'm rather used to wondering around on the "bleeding edge" of things technical - so I find the debate to be of interest. There are those that get a bit heated at times but they are simply voicing their beliefs, experience, and knowledge about something that has not been defined very well and thus is difficult to get a handle on - a bit like grasping at shadows. The nice thing about EnABL is that you can try it out for just a few $$$ and a little bit of DIY effort and then make your own determination about things.
Let me know when you have your situation in hand - and good luck with selling a house in L.A. in the present market
Hey berm - have you checked "The Pencil" thread? It's another nice omni design by "Juspur" 
I would consider using a Neo 3 without it's backplate for the tweeter
as this would be similar to my AMT 1's and help to have a more "airy" top end - YMMV.
I would consider using a Neo 3 without it's backplate for the tweeter
as this would be similar to my AMT 1's and help to have a more "airy" top end - YMMV.
Juspur said:An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Drivers: Peerless 832873 and Morel MDT-40 (tweeter).
Cross-over is just a 2. order Linkwitz Riley for the tweeter at 6 khz, 1,8 uF in series + 0,39 mH in parallel - Because the Peerless is ultralinear and has a natural rolloff at 6 kHz with 12 dB/octave rolloff
The enclosure is 10 liter, 71 cm tall, 12,1 x 12,1 cm internal.
The port (on the back of the speaker) has Ø 5,7 cm, length 10,5 cm.
The "tweeter-protector" on top is just a pencil-holder turned upside down
The costs is about US$ 500/euro 300 total for a pair. It's easy to build, and don't take up much space (except the sound, which is very spacious
The sound is fantastic - very dynamic, slam-bass, and a very natural soundstage. This is a speaker, where I don't skip music, but listen to music, I previously wouldn't have - THE PENCIL simply plays MUSIC... Try it, build it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Regards, Jesper
Hi,
Yes, the market here is tough, but I'm hoping the location is desirable enough that we won't be having too much difficulty.
Cockcroft's designs surprised me. The most popular one, and the one I built, was the "Simpline", using a mass loaded (with several small lead shot) glue-coated (like Dave of P10' mods) Radio Shack 1197 as the main driver. It was about a two-foot long tube, heavily stuffed with the one end open and the driver at the other end, with a mild shaping circuit. It leaned against the wall at about a 20+ degree angle, so that all the sound from the mid frequencies up came off the wall used as a reflector. Many speakers have done this, and it's not at all like the Bose model, as the speaker is not using late reflections mixed with the earlier direct arrival sound of a forward facing driver. Ronc uses a reflector in one of his horn designs, there is a Lowther that uses the same principal, and others like the Allison Four that use an upward-facing woofer against the wall.
A newer design by Cockcroft is here, on Dave's (of Planet 10) site:
http://www.t-linespeakers.org/projects/cockroft/index.html
It stands up straight rather than leaning, but the idea is similar, and the mod he does to the 1197 is the same. It was such an easy build (the Simpline) I did it just for the heck of it, and was really surprised. Cockcroft calls it a transmission line, but I think the Simpline functions more like an aperiodic. It is very open sounding, somewhat like an open baffle, and the soundstage is very large, not at all what you would expect from a four-inch driver. The limitations are that it is very inefficient, and it lacks dynamics in the lower registers. But hey, it's a four-inch driver, it's an easy build, and it's cheap. Also, as a Simpline - a square mdf tube leaning back against a wall - it's pretty ugly. Cockcroft apparently designed a version with a 6 1/2" woofer in Glass Audio, which I never saw, but would love to try. I think this configuration would be particularly suited to drivers with rising response and beaming problems, as the reflected sound - the only sound you hear from the midrange on up - would probably have absorbed some of the excess treble and spread out the rest into the room, giving a more even sound dispersion. At least that seems logical to me.
I compared the sound to a modded Fried Beta, which I thought only a slight notch or so below the L/S3 5A, and it was an easy choice for the Simpline. AT this point, I'm amazed that more people don't at least try their speakers upward facing against the wall, particularly if they are hot-sounding.
People drop the name Bose whenever reflected sound is mentioned, but remember that Bose uses a combination of direct and reflected sound in a specific way. Others, such as Olsher's Samadhi designs, may use reflected sound, but I think you will find a vast difference in how they sound and the soundstage they present. Don't think Bose here.
Sorry for wandering so far off topic here, but I think those little Simplines of Cockcroft are vastly under-rated by people who have never tried them. I may try my hand at more speakers based on Cockcroft's designs, but first I think this Walsh clone looks very good for now - and MJK's little open baffle too. The wealth of great new projects floating around now is killing me. How do you decide? Where does it stop?
Take care
Berm
Yes, the market here is tough, but I'm hoping the location is desirable enough that we won't be having too much difficulty.
Cockcroft's designs surprised me. The most popular one, and the one I built, was the "Simpline", using a mass loaded (with several small lead shot) glue-coated (like Dave of P10' mods) Radio Shack 1197 as the main driver. It was about a two-foot long tube, heavily stuffed with the one end open and the driver at the other end, with a mild shaping circuit. It leaned against the wall at about a 20+ degree angle, so that all the sound from the mid frequencies up came off the wall used as a reflector. Many speakers have done this, and it's not at all like the Bose model, as the speaker is not using late reflections mixed with the earlier direct arrival sound of a forward facing driver. Ronc uses a reflector in one of his horn designs, there is a Lowther that uses the same principal, and others like the Allison Four that use an upward-facing woofer against the wall.
A newer design by Cockcroft is here, on Dave's (of Planet 10) site:
http://www.t-linespeakers.org/projects/cockroft/index.html
It stands up straight rather than leaning, but the idea is similar, and the mod he does to the 1197 is the same. It was such an easy build (the Simpline) I did it just for the heck of it, and was really surprised. Cockcroft calls it a transmission line, but I think the Simpline functions more like an aperiodic. It is very open sounding, somewhat like an open baffle, and the soundstage is very large, not at all what you would expect from a four-inch driver. The limitations are that it is very inefficient, and it lacks dynamics in the lower registers. But hey, it's a four-inch driver, it's an easy build, and it's cheap. Also, as a Simpline - a square mdf tube leaning back against a wall - it's pretty ugly. Cockcroft apparently designed a version with a 6 1/2" woofer in Glass Audio, which I never saw, but would love to try. I think this configuration would be particularly suited to drivers with rising response and beaming problems, as the reflected sound - the only sound you hear from the midrange on up - would probably have absorbed some of the excess treble and spread out the rest into the room, giving a more even sound dispersion. At least that seems logical to me.
I compared the sound to a modded Fried Beta, which I thought only a slight notch or so below the L/S3 5A, and it was an easy choice for the Simpline. AT this point, I'm amazed that more people don't at least try their speakers upward facing against the wall, particularly if they are hot-sounding.
People drop the name Bose whenever reflected sound is mentioned, but remember that Bose uses a combination of direct and reflected sound in a specific way. Others, such as Olsher's Samadhi designs, may use reflected sound, but I think you will find a vast difference in how they sound and the soundstage they present. Don't think Bose here.
Sorry for wandering so far off topic here, but I think those little Simplines of Cockcroft are vastly under-rated by people who have never tried them. I may try my hand at more speakers based on Cockcroft's designs, but first I think this Walsh clone looks very good for now - and MJK's little open baffle too. The wealth of great new projects floating around now is killing me. How do you decide? Where does it stop?
Take care
Berm
Just saw your "Pencil" post. Wow. Again, where does it stop? My head may explode before I get one of these great designs built. It feels at the moment like I have a prime peephole into a harem. You know, great view, but just out of touch. Shortly, I hope, I can start on one - or some - of these.
Take care
Berm
Take care
Berm
OhioTanner said:" The wealth of great new projects floating around now is killing me. How do you decide? Where does it stop?"
(?)
In my case I'm designing around WAF, budget (so no expensive xovers - tri-amps, or $2,000 cables, etc.) and space constraints (which makes OB's a challenge for placement and speakers must be usable for HT and audio). A Thrifty Scott living in a small flat on a small stipend - or a collage student - those are the situations I'm designing around.
I wonder with the Pencil design whether having such a shallow cone is a good idea. It looks to have a lot shallower profile than the Pioneer 10 incher. It seems like it might exacerbate the problem you were having with the Pioneer - the high frequencies recessing when you sat down, until you remedied it by tilting the speaker some. I also wonder whether, with such a shallow cone, it may be functioning more like Olsher's Samadhi Ichiban than like the Walsh. I'd like to see what it would sound like if he merely inverted the cone so the front side faced toward the ceiling to compare it with the sound he is getting now. Beautiful build, though.
http://www.blackdahlia.com/samadhi/ichibanrel.htm
I think Ohm uses a rather deep cone to alleviate the problem. That was part of the earlier discussion on this thread too, wasn't it?
http://www.blackdahlia.com/samadhi/ichibanrel.htm
I think Ohm uses a rather deep cone to alleviate the problem. That was part of the earlier discussion on this thread too, wasn't it?
A note to owners of OHM F's.
I have been collaborating with Dale Harder for a period of time. Dale is the current mfg. of what was known as the OHM F and A. He no longer calls them that, out of deference and respect for OHM Acoustics.
They are drop dead gorgeous.
http://picasaweb.google.com/hpurvin...alAllMetalOhmFS
They are also improved, in so far as the original targets have been met, rather better than the original, drivers were able to. Attention to detail and an extremely precise manufacturing process sees to that.
The reason for the post here is to note that the collaboration will produce patterns for the OHM F drivers in existence today. Dale intends to apply an EnABL pattern, in stages, to his personal speakers, made with his own hands. I have those pattern templates and will make them available for brave souls who ask for them. PM me please.
They will become public documents once Dale has succeeded in controlling the F cones with them. I am confident, of course, but I won't be there to supervise, or actually apply the patterns. Which is what I really want to do.
Never the less, this will bring that over rated event, closure, to a 35 year investigation and return EnABL to it's roots, where it belongs.
Bud
I have been collaborating with Dale Harder for a period of time. Dale is the current mfg. of what was known as the OHM F and A. He no longer calls them that, out of deference and respect for OHM Acoustics.
They are drop dead gorgeous.
http://picasaweb.google.com/hpurvin...alAllMetalOhmFS
They are also improved, in so far as the original targets have been met, rather better than the original, drivers were able to. Attention to detail and an extremely precise manufacturing process sees to that.
The reason for the post here is to note that the collaboration will produce patterns for the OHM F drivers in existence today. Dale intends to apply an EnABL pattern, in stages, to his personal speakers, made with his own hands. I have those pattern templates and will make them available for brave souls who ask for them. PM me please.
They will become public documents once Dale has succeeded in controlling the F cones with them. I am confident, of course, but I won't be there to supervise, or actually apply the patterns. Which is what I really want to do.
Never the less, this will bring that over rated event, closure, to a 35 year investigation and return EnABL to it's roots, where it belongs.
Bud
Hi Jeff.
Here is a link to all of the EnABL picture albums. The OHM pics are fifth down the list.
http://picasaweb.google.com/home?tab=mq
Bud
Here is a link to all of the EnABL picture albums. The OHM pics are fifth down the list.
http://picasaweb.google.com/home?tab=mq
Bud