*L* 'Contraption'...I can agree with that observation....a friend calls them 'steampunk', which I kinda like... 
They're a different animal...an omni that can actually sound good is rather rare; most are high-dollar and not seen or heard (or heard of) much. Rather habit-forming, at least for me and some others 'out there'.
For a DIY 'under development' (sic), I'm enjoying myself and seeing how far I can go with it and keep it from absorbing too much 'loose change' in the process.
If you look back in this forum, I posted a 'how to'. Gives one something to do with the 'orphans' that seem to show up in that cardboard box in the corner some of us have....
They're a different animal...an omni that can actually sound good is rather rare; most are high-dollar and not seen or heard (or heard of) much. Rather habit-forming, at least for me and some others 'out there'.
For a DIY 'under development' (sic), I'm enjoying myself and seeing how far I can go with it and keep it from absorbing too much 'loose change' in the process.
If you look back in this forum, I posted a 'how to'. Gives one something to do with the 'orphans' that seem to show up in that cardboard box in the corner some of us have....
Well, if you're reasonably handy and have or have access to some tools, they're an interesting object to make. And one of the best aspects of making a pair of them is that if you 'break' them, you know how to fix them. *L*
You wouldn't be the first person in the EU to perhaps 'give it a go'. Two guys from (I think) Norway downloaded the 'how to'. It'd be interesting to know how it went for them (I think they were brothers, or related in some fashion...similar names...)
If you try, use speakers that have a high rating for power handling. It will allow higher spl, since there's a higher physical 'load' to the voice coils that creates heat. My first pair died from 'cooked coil disease', but I'm recycling the cones for a current pair.
They can be played reasonably loud, but they're not disposed to generate the spl you get with a typical speaker. They can 'rock', but in a 'genteel' fashion. The neighbors won't complain.
You wouldn't be the first person in the EU to perhaps 'give it a go'. Two guys from (I think) Norway downloaded the 'how to'. It'd be interesting to know how it went for them (I think they were brothers, or related in some fashion...similar names...)
If you try, use speakers that have a high rating for power handling. It will allow higher spl, since there's a higher physical 'load' to the voice coils that creates heat. My first pair died from 'cooked coil disease', but I'm recycling the cones for a current pair.
They can be played reasonably loud, but they're not disposed to generate the spl you get with a typical speaker. They can 'rock', but in a 'genteel' fashion. The neighbors won't complain.
...kinda like this...
https://www.youtube.com/watch?v=XQ7z57qrZU8
...if you get my drift...
(Four of them in surround will surprise you...trust me....*G*)
https://www.youtube.com/watch?v=XQ7z57qrZU8
...if you get my drift...
(Four of them in surround will surprise you...trust me....*G*)
A 'wild hair'...
...by any other name or location....
Based on the result of my experiment in post #278, I've decided to eliminate any 'voids' beneath the cones of the 'in progress' V.4 3-way's 'upper mid' & 'lower mid' segments. There will be a space for their surrounds to mount and allow free movement, but no appreciable cavity that could be considered an enclosure. I'd like to see if the trapped air within the cone/surround/base plate will act perhaps similar to 'acoustic suspension', damping any vertical movement of the cones. Since two units 'butt to butt' seem to have no effect on the response, perhaps any enclosure isn't necessary or even desirable...
Worth a shot...
Secondly, I'd like to appeal to Glorocks or anyone else that may have access to an Ohm A or F to measure the diameter of the cone as best as possible at the intersection of the angle change in their cones that Glorocks mentions in post #252, the potential 'mechanical crossover' between the cone materials. I'd like to use that diameter to generate an upcoming set of cones to explore the limit of a 'pure' Walsh driver, one not attempting to generate any 'low' frequencies beyond the 'desired' limits of a cone surface acting in a 'distributed mode' as is sometimes applied to a Walsh driver and the way the cone vibrates....
...and we'll call this 'V.5'. A single 'partial full-range' driver, just to see what occurs.
Any and all help, thoughts, comments, or even a thoughtful 'discouraging word' will, of course, be appreciated....
...by any other name or location....
Based on the result of my experiment in post #278, I've decided to eliminate any 'voids' beneath the cones of the 'in progress' V.4 3-way's 'upper mid' & 'lower mid' segments. There will be a space for their surrounds to mount and allow free movement, but no appreciable cavity that could be considered an enclosure. I'd like to see if the trapped air within the cone/surround/base plate will act perhaps similar to 'acoustic suspension', damping any vertical movement of the cones. Since two units 'butt to butt' seem to have no effect on the response, perhaps any enclosure isn't necessary or even desirable...
Worth a shot...
Secondly, I'd like to appeal to Glorocks or anyone else that may have access to an Ohm A or F to measure the diameter of the cone as best as possible at the intersection of the angle change in their cones that Glorocks mentions in post #252, the potential 'mechanical crossover' between the cone materials. I'd like to use that diameter to generate an upcoming set of cones to explore the limit of a 'pure' Walsh driver, one not attempting to generate any 'low' frequencies beyond the 'desired' limits of a cone surface acting in a 'distributed mode' as is sometimes applied to a Walsh driver and the way the cone vibrates....
...and we'll call this 'V.5'. A single 'partial full-range' driver, just to see what occurs.
Any and all help, thoughts, comments, or even a thoughtful 'discouraging word' will, of course, be appreciated....
my ears preferred the sound with the cones running in "free-air", in contrast with directing the internal sound into an enclosure, despite other issues that created.
G
I will see if my friend still walks the planet and has his Ohm's in the garage.
Ohm published a white paper that discussed the patent and also gave some hints about the transition to "piston" operation in the LF band, as well as the titanium to aluminum thing. My copy is long gone, but there may be some historically minded affectionado out there who hung on to one. Should note that this wasn't part of the regular dealer tear sheet line-up- you had to call Ohm to get a copy (at least I did).
I do remember that the "A" was billed as having a 18" diameter annulus, and that the later "F" had an annulus diameter of 12".
Always thought it amusing that several other manufacturers copied the truncated pyramid enclosure look (ESS AMT for one)
Ohm published a white paper that discussed the patent and also gave some hints about the transition to "piston" operation in the LF band, as well as the titanium to aluminum thing. My copy is long gone, but there may be some historically minded affectionado out there who hung on to one. Should note that this wasn't part of the regular dealer tear sheet line-up- you had to call Ohm to get a copy (at least I did).
I do remember that the "A" was billed as having a 18" diameter annulus, and that the later "F" had an annulus diameter of 12".
Always thought it amusing that several other manufacturers copied the truncated pyramid enclosure look (ESS AMT for one)
The 'A Team' to the rescue...
Thanks, both of you. I'd like to take this opportunity to express my appreciation for your continued interest and support. If you ever think of something by which I might reciprocate in some fashion within my means, please feel free. It's been great to have y'all and others (who know of whom I infer) to continue to look in on this forum and keep me on the 'straight and narrow', since I'm obviously prone to wander. *G* 5's, guys...
I hear you, Gary...it comes down to a 'preference' sort of thing. I tried 'free air', but the sound from the underside of the cone has a 'megaphone' quality that kept reminding me of Rudy Vallee warbling to a audience. Whenever I placed a unit onto a surface, the sound from the cones' exterior seemed to 'firm up' vs. when they're on a column. That, and putting a pair 'base to base' seems to exhibit that as well. That's why I'm opting to go 'baseless' as much as practical with the V.4s'...IF I can ever get a 'roundtoit' applied to them. It's great that AP (our company) is busy, but free time becomes like CA water...
I hope your buddy is still admiring daisies rather than pushing them too, Glo.
Notwithstanding his garage contents...just because, for his sake...
But give him my regards and thanks if he's still 'up 'n about' and willing/able to contribute.
I'll go poke around the net and the A & F forums to see if any of the 'true believers' have a copy of that document. Thanks for remembering it, it'd be another puzzle piece for me to consider. I'm wondering if anyone at Ohm currently could produce it, but I suspect that would surely be a long shot. They've strayed so far from the original design that the original is likely buried so deep in their files that only hungry roaches are enjoying the content for all the wrong reasons...
And, yeah...the As' seem to enjoy a preference among the fans. I wonder...(out loud, live, now)...if the smaller diameter of the cone base, the 'down-scaling' of the overall size...allowed efficiency to improve, at the cost of reduced bass response. The 'mechanical crossover' should also scale down in diameter (Today's' "leap of logic" *L*)
"Will somebody PLEASE keep Jerry AWAY from the particle accelerator? Thank you." (*LOL*)
I used to own a pair of ESS AMT 1B's...I know of which you speak. I own a pair of Heils' from them...love my ribbons, but fascinated by the Walsh. What can you say.... The pyramids were never good at sharpening razor blades anyway. *L* Too truncated, I guess....*smirk*
Well, happy Sunday, and 'see y'all later.
Thanks, both of you. I'd like to take this opportunity to express my appreciation for your continued interest and support. If you ever think of something by which I might reciprocate in some fashion within my means, please feel free. It's been great to have y'all and others (who know of whom I infer) to continue to look in on this forum and keep me on the 'straight and narrow', since I'm obviously prone to wander. *G* 5's, guys...
I hear you, Gary...it comes down to a 'preference' sort of thing. I tried 'free air', but the sound from the underside of the cone has a 'megaphone' quality that kept reminding me of Rudy Vallee warbling to a audience. Whenever I placed a unit onto a surface, the sound from the cones' exterior seemed to 'firm up' vs. when they're on a column. That, and putting a pair 'base to base' seems to exhibit that as well. That's why I'm opting to go 'baseless' as much as practical with the V.4s'...IF I can ever get a 'roundtoit' applied to them. It's great that AP (our company) is busy, but free time becomes like CA water...
I hope your buddy is still admiring daisies rather than pushing them too, Glo.
Notwithstanding his garage contents...just because, for his sake...
But give him my regards and thanks if he's still 'up 'n about' and willing/able to contribute.
I'll go poke around the net and the A & F forums to see if any of the 'true believers' have a copy of that document. Thanks for remembering it, it'd be another puzzle piece for me to consider. I'm wondering if anyone at Ohm currently could produce it, but I suspect that would surely be a long shot. They've strayed so far from the original design that the original is likely buried so deep in their files that only hungry roaches are enjoying the content for all the wrong reasons...
And, yeah...the As' seem to enjoy a preference among the fans. I wonder...(out loud, live, now)...if the smaller diameter of the cone base, the 'down-scaling' of the overall size...allowed efficiency to improve, at the cost of reduced bass response. The 'mechanical crossover' should also scale down in diameter (Today's' "leap of logic" *L*)
"Will somebody PLEASE keep Jerry AWAY from the particle accelerator? Thank you." (*LOL*)
I used to own a pair of ESS AMT 1B's...I know of which you speak. I own a pair of Heils' from them...love my ribbons, but fascinated by the Walsh. What can you say....
The pyramids were never good at sharpening razor blades anyway. *L* Too truncated, I guess....*smirk*Well, happy Sunday, and 'see y'all later.
yes, and I spent a fair amount of time trying to address the "megaphone effect" with some degree of success.
G
You're project looks amazing, by the way. Dale Harder has a white paper on the web that actually gives a lot of info up.
Also, I found a German HiFi archive site that has some tidbits. Problem for me is, every time I try to add the links here, they vanish before I can post. PM me your e-mail address and I'll send along what I have so far.
I assume you have read the patent- although the PO lost some of the information, there is a lot of information there that you can easily miss.
Harder makes a point about the aluminum alloy being special. Thinking about it, if you reverse the math in the patent, you should be able to determine the velocity of the propagating wave based on the angle of the aluminum portion of the "cone". The sound propagation velocities in various aluminum alloys and tempers are often stated in the manufacturer's specs.
Young's modulus may be another consideration, but one step at a time.
The titanium is another question, but back then there wasn't a lot of choice in alloys as there are today.
Back in the day, I talked a rep in to giving me a sample of beryllium foil to play with but quickly gave the idea up when some Feds showed up at the door with a book of regs and forms that rivaled the LA phonebook in thickness to fill out. I knew the stuff was nasty, but had no idea how closely the Fed watched it. I gave them the foil and they left. I did, however keep the wire. Be could well be the ultimate voice coil material, but I digress.
Also, I found a German HiFi archive site that has some tidbits. Problem for me is, every time I try to add the links here, they vanish before I can post. PM me your e-mail address and I'll send along what I have so far.
I assume you have read the patent- although the PO lost some of the information, there is a lot of information there that you can easily miss.
Harder makes a point about the aluminum alloy being special. Thinking about it, if you reverse the math in the patent, you should be able to determine the velocity of the propagating wave based on the angle of the aluminum portion of the "cone". The sound propagation velocities in various aluminum alloys and tempers are often stated in the manufacturer's specs.
Young's modulus may be another consideration, but one step at a time.
The titanium is another question, but back then there wasn't a lot of choice in alloys as there are today.
Back in the day, I talked a rep in to giving me a sample of beryllium foil to play with but quickly gave the idea up when some Feds showed up at the door with a book of regs and forms that rivaled the LA phonebook in thickness to fill out. I knew the stuff was nasty, but had no idea how closely the Fed watched it. I gave them the foil and they left. I did, however keep the wire. Be could well be the ultimate voice coil material, but I digress.
Mind meld in progress, please stand by.
"In the end, I piped it outside..." Just kidding, Gary. What seemed to work for you? It'd be interesting to try it out on one of mine, just to see what happens.
...and Thank You for the kudo, Glo. 'Amazing' might be a little premature, as I can hear their weakness. Physically I like the 'look', but even it is still a bit crude. Always room for improvement...
I've got HHRs' site address, I'll go snooping again for those tidbits.
I've considered alloys. The potential issue could be the availability of a thin enough gauge for use of the desired alloy...especially in a small enough initial quantity to verify it's effectiveness.
I have read the patent, and Harders' commentary would seem to bear that point out. I'll analyse it and his white paper to contrast the info therein...
...and Youngs' modulus does sound like the 'deep end of the pool'; but I'll get there. Just got to get the right scuba gear together...
Any initial work with titanium will likely start with the 'backpackers' heat shield' material available online. Again, alloy/thickness/availability issues...
...."beryllium foil"....*L* They probably thought you were going to cook up a WMD in your garage, or the like. And then there's this: "Beryllium and its compounds are highly toxic, inhalation of the dust resulting in berylliosis, an inflammation of the lungs." Sounds charming....
"Your speakers sound great. Does your oxygen tank need changing?"
And it'd probably make terrific voice coils. I'll keep that in mind...
"Yeah, I can listen to Vivaldi or drive nails with an attachment...." *L*
You'll have to amuse us one day with that digression...sounds epic. *G*
"In the end, I piped it outside..."
Just kidding, Gary. What seemed to work for you? It'd be interesting to try it out on one of mine, just to see what happens....and Thank You for the kudo, Glo. 'Amazing' might be a little premature, as I can hear their weakness. Physically I like the 'look', but even it is still a bit crude. Always room for improvement...
I've got HHRs' site address, I'll go snooping again for those tidbits.
I've considered alloys. The potential issue could be the availability of a thin enough gauge for use of the desired alloy...especially in a small enough initial quantity to verify it's effectiveness.
I have read the patent, and Harders' commentary would seem to bear that point out. I'll analyse it and his white paper to contrast the info therein...
...and Youngs' modulus does sound like the 'deep end of the pool'; but I'll get there. Just got to get the right scuba gear together...
Any initial work with titanium will likely start with the 'backpackers' heat shield' material available online. Again, alloy/thickness/availability issues...
...."beryllium foil"....*L* They probably thought you were going to cook up a WMD in your garage, or the like. And then there's this: "Beryllium and its compounds are highly toxic, inhalation of the dust resulting in berylliosis, an inflammation of the lungs." Sounds charming....
"Your speakers sound great. Does your oxygen tank need changing?"
And it'd probably make terrific voice coils. I'll keep that in mind...
"Yeah, I can listen to Vivaldi or drive nails with an attachment...." *L*
You'll have to amuse us one day with that digression...sounds epic. *G*
I think Harder's white paper gives the thicknesses of the metals in the "a". Something like .002 for the Ti and .003 for the Al. Too bad they don't use Al plates for small page offset printing anymore- I had pretty good luck with them in my experiments, although it might pay to make friends with a pressman at your local newspaper- they recycle the plates.
Yamaha sold Be domed tweeters in some of their speakers in the mid '70's. The Be was plated on a plastic substrate. I actually got the formula for the process from Kaweki Byrelco in San Diego- the process used organic chemicals that would have given cancer to dead people- really nasty sh*t.
Yamaha sold Be domed tweeters in some of their speakers in the mid '70's. The Be was plated on a plastic substrate. I actually got the formula for the process from Kaweki Byrelco in San Diego- the process used organic chemicals that would have given cancer to dead people- really nasty sh*t.
More on this 'n that...
Glo, here's a quick 'sketch' of the cone profiles per Harder's descriptions. Perhaps, if your bud is still breathing and in possession, you might only verify these dims.
Local paper is now being produced out of town....budget move...but I think I could work around the sourcing issue as needed.
....and Yamaha likely had the work done in China, so there's likely a lot of ugly health issues in some town in some province that thought they had a 'boom' but got f'd over instead. Same old story retold now, with the details of the cell phone manufacturing processes and how the workers are getting sick and getting f'd over, yet again.
"So sorry, Hiro, but you should have worn the masks and gloves that we didn't give you for your 6 day 12 hour shifts...."
I swear....I'm becoming allergic to civilization. For each tech leap we make, the price is getting really high for some. Welcome to capitalism, y'all. CYA if you can.
Glo, here's a quick 'sketch' of the cone profiles per Harder's descriptions. Perhaps, if your bud is still breathing and in possession, you might only verify these dims.
Local paper is now being produced out of town....budget move...but I think I could work around the sourcing issue as needed.
....and Yamaha likely had the work done in China, so there's likely a lot of ugly health issues in some town in some province that thought they had a 'boom' but got f'd over instead. Same old story retold now, with the details of the cell phone manufacturing processes and how the workers are getting sick and getting f'd over, yet again.
"So sorry, Hiro, but you should have worn the masks and gloves that we didn't give you for your 6 day 12 hour shifts...."
I swear....I'm becoming allergic to civilization. For each tech leap we make, the price is getting really high for some. Welcome to capitalism, y'all. CYA if you can.
Attachments
Heavier cones will be proportionally more difficult to tame down. A very light coat or two of thinned latex rubber cement applied to the entire interior (which also dampens high frequency ringing). Then, I cut narrow strips of furniture foam in to a wedge shape from 1cm to nothing, applied a coat of rubber cement and fixed them length-wise on the interior (fig.8 in Walsh patent). I also tried very light applications of dacron acoustic fill to fill the interior void. All low tech stuff, but worked fairly good unless over-done.
G
After wracking my brain, I suddenly remembered what Bud Purvine's damping technique is called. EnABL. Bud's user name here is BudP, and much of his wisdom makes a lot of sense.
I think it would be worth your while to find his threads and read what he has to say.
I remember he had a lengthy and quite detailed explanation of his ideas- well worth finding and reading.
I think it would be worth your while to find his threads and read what he has to say.
I remember he had a lengthy and quite detailed explanation of his ideas- well worth finding and reading.
OK- I talked to my friend who has the Ohm's. They are still in his garage, but he is in such poor health (he's 87), he is unable to get them down off of the shelf and do any sort of measurements.
He couldn't talk too long, but it sounds like he wants me to drive up there and get them. (I know some of you are hating this).
I have been planning a trip to the coast in the fall to visit some old friends in SoCal- driving up to the Bay area is way out of the way, but I think I'm going to go for it. Been a while since I have driven the PCH, and it's been too long since I have had a puff watching the sunset over Monterey. Probably a last hurrah for me, but at least I'll finally get a look inside the buggers.
He couldn't talk too long, but it sounds like he wants me to drive up there and get them. (I know some of you are hating this).
I have been planning a trip to the coast in the fall to visit some old friends in SoCal- driving up to the Bay area is way out of the way, but I think I'm going to go for it. Been a while since I have driven the PCH, and it's been too long since I have had a puff watching the sunset over Monterey. Probably a last hurrah for me, but at least I'll finally get a look inside the buggers.
ROAD TRIP!
Ah, yes...winding that asphalt ribbon through the hills, dales, and valleys. I've driven it enough from LA/SF~SF/LA to have had memorized the better parts, and the segments that simply needed to be gotten through....*sigh*reverie*
Thanks G for the details...the only way it could be easier to accomplish is for you to do it with me watching. Kidding aside, I think I'll subject my V.2s' to that treatment and hear what happens. Can't say exactly when that will occur, as we're still in 'busy season mode'. I get to observe the delivery of 90+ yards of playground mulch tomorrow...and begin to install it Thursday. Since our Bobcat can only move 1/2 yard per trip, one begins to feel like some sort of mechanical shuttlecock midday....
Preparation for play involves work. There seems to be a logical disconnect in there, somewhere...
I'll go find some bud...waitaminute, that sounds...*smirk*
Sounds like a nice vaca to me, Glo, and we're all preemptively jealous on various levels, Yes. As for the Ohms...well, we also know what could be lurking beneath those cones. Can you say 'mixed blessing'? Only one way to find out....
I'd come with you, but we'd risk learning the little habituations each of us have that we don't experience here. It could get testy....
"If you play that cd again, I'm going to put you in the trunk and superglue the lock." *squeaking of gritted teeth*
Thanks, guys...*G*
Ah, yes...winding that asphalt ribbon through the hills, dales, and valleys. I've driven it enough from LA/SF~SF/LA to have had memorized the better parts, and the segments that simply needed to be gotten through....*sigh*reverie*
Thanks G for the details...the only way it could be easier to accomplish is for you to do it with me watching.
Kidding aside, I think I'll subject my V.2s' to that treatment and hear what happens. Can't say exactly when that will occur, as we're still in 'busy season mode'. I get to observe the delivery of 90+ yards of playground mulch tomorrow...and begin to install it Thursday. Since our Bobcat can only move 1/2 yard per trip, one begins to feel like some sort of mechanical shuttlecock midday....Preparation for play involves work. There seems to be a logical disconnect in there, somewhere...
I'll go find some bud...waitaminute, that sounds...*smirk*
Sounds like a nice vaca to me, Glo, and we're all preemptively jealous on various levels, Yes. As for the Ohms...well, we also know what could be lurking beneath those cones. Can you say 'mixed blessing'? Only one way to find out....
I'd come with you, but we'd risk learning the little habituations each of us have that we don't experience here. It could get testy....
"If you play that cd again, I'm going to put you in the trunk and superglue the lock." *squeaking of gritted teeth*
Thanks, guys...*G*