http://stores.ebay.com/honeycombandmore?_trksid=p2047675.l2563
Alum honeycomb, cheap. This is what I've considered for a DML. Laminate kevlar on this, perhaps....
One of the sources is not far from me, but when I called them direct they ('he', actually) said he didn't know anything about it being on EBay. Perhaps an 'employee sideline' with their drops? Could be, could be...one pauses to contemplate resourcefulness...
Alum honeycomb, cheap. This is what I've considered for a DML. Laminate kevlar on this, perhaps....
One of the sources is not far from me, but when I called them direct they ('he', actually) said he didn't know anything about it being on EBay. Perhaps an 'employee sideline' with their drops? Could be, could be...one pauses to contemplate resourcefulness...
...and then there's this...
https://www.washingtonpost.com/news/wonk/wp/2016/05/04/the-price-of-legal-pot-is-collapsing/
Alligator tears...
https://www.washingtonpost.com/news/wonk/wp/2016/05/04/the-price-of-legal-pot-is-collapsing/
Alligator tears...
...and today's "Subwoofer Test". Nail it down.
GoPro hitched a ride on a rocket and the video is incredible | TechCrunch
I hope it doesn't 'drop out' on you as badly as it did for me...
GoPro hitched a ride on a rocket and the video is incredible | TechCrunch
I hope it doesn't 'drop out' on you as badly as it did for me...
The patent I cited above says:
"The front and back facing skins of the panel of the preferred embodiment are fabricated from an aramid polyamide such as Kevlar or Dupont Nomex, which exhibits, simultaneously, a high Young's modulus for rapid dispersion of sound waves through the panel, exceptional energy dissipation characteristics for superior damping of large vibrational excursions, and very low self-noise (the latter two properties are indicated by the skin—as well as the core—having a high “loss factor” as discussed herein). In addition, these materials exhibit superb tensile strength to withstand bending and flexing during sound reproduction, particularly at higher volumes, without cracking, notching, or creasing. The aramid polyamide skins are secured to the core with a flexible adhesive with good damping characteristics such as, for example, water based acrylic, rubber cement, or a silicone adhesive. "
"The front and back facing skins of the panel of the preferred embodiment are fabricated from an aramid polyamide such as Kevlar or Dupont Nomex, which exhibits, simultaneously, a high Young's modulus for rapid dispersion of sound waves through the panel, exceptional energy dissipation characteristics for superior damping of large vibrational excursions, and very low self-noise (the latter two properties are indicated by the skin—as well as the core—having a high “loss factor” as discussed herein). In addition, these materials exhibit superb tensile strength to withstand bending and flexing during sound reproduction, particularly at higher volumes, without cracking, notching, or creasing. The aramid polyamide skins are secured to the core with a flexible adhesive with good damping characteristics such as, for example, water based acrylic, rubber cement, or a silicone adhesive. "
Finally went and really looked over the patent you've cited, rshe...it's interesting that the authors denote what's basically a 'high end' cardboard over aluminum honeycomb. But it does make sense...alum h/c is light and extremely rigid when 'faced', esp. with alum skins, but certainly doesn't exhibit any internal damping qualities....which is referenced not only in the h/c selection itself, but also in the adhesive used to apply the skins to the h/c. Skin application in a DIY situation would require a bit of experimentation to find the adhesive that wouldn't drive one to distraction...potentially.
Silicone, at least the ones we normally have access to, tend to 'skin over' rather quickly...applying a uniform coating to a fabric (Kevlar or Nomex) would (off the top of my head) need to be silkscreened onto the fabric, with the panel placed onto it immediately. And repeated for the opposite face just as quickly before the screen 'blocked' due to the silicone setting up, due to exposure to air....
Rubber cement might be a little more forgiving, if thinned; but then there'll be a trade-off on 'too thick/too thin' re the strength of the bond created. And then there's the 'fume factor', unless you're a fan of 'huffing'...which I doubt, since you're trading posts in an intelligent fashion (and not rambling like me...*G*).
W/B acrylic....now, that would be better for screen application, as you could clean the screen and not have to trash it out on any particular 'go' at a build. But one would have to source a suitable compound and play around with the 'thick/thin' ratio. So there's an avenue one could traverse...
Backing up or into the rubber cement issue...I use a 3M VHB transfer film in my Walsh's, which is a variant of a type of r/c. It's available in thicker versions and in sheet or roll forms, which get a bit pricey. But once it's down, it grabs like a chinese finger trap with no exit strategy. Trying to take it apart destroys the parts....been there, broke stuff trying. And it doesn't stink. It will stick to you quite happily....or anything else it gets near....
Just a thought...well, more than one, but....*L*
Yours? *S*
Silicone, at least the ones we normally have access to, tend to 'skin over' rather quickly...applying a uniform coating to a fabric (Kevlar or Nomex) would (off the top of my head) need to be silkscreened onto the fabric, with the panel placed onto it immediately. And repeated for the opposite face just as quickly before the screen 'blocked' due to the silicone setting up, due to exposure to air....
Rubber cement might be a little more forgiving, if thinned; but then there'll be a trade-off on 'too thick/too thin' re the strength of the bond created. And then there's the 'fume factor', unless you're a fan of 'huffing'...which I doubt, since you're trading posts in an intelligent fashion (and not rambling like me...*G*).
W/B acrylic....now, that would be better for screen application, as you could clean the screen and not have to trash it out on any particular 'go' at a build. But one would have to source a suitable compound and play around with the 'thick/thin' ratio. So there's an avenue one could traverse...
Backing up or into the rubber cement issue...I use a 3M VHB transfer film in my Walsh's, which is a variant of a type of r/c. It's available in thicker versions and in sheet or roll forms, which get a bit pricey. But once it's down, it grabs like a chinese finger trap with no exit strategy. Trying to take it apart destroys the parts....been there, broke stuff trying. And it doesn't stink. It will stick to you quite happily....or anything else it gets near....
Just a thought...well, more than one, but....*L*
Yours? *S*
Offers like this make me crazy(er than usual)....
https://www.audiogon.com/listings/f...15-2016-05-02-speakers-07924-bernardsville-nj
Now...this is being offered on the website of a dealer in SC....but can't/won't be shipped to the US. Huh? Really? And the 'depreciation' on something that's less than a year old? And it's now a '9'? REALLY?!
I think I'll just keep playing around with my DIY 'garbage', thenk u vedy mulch....
I guess I'll never be a 'high end audiophile' when I grow up. *mock sigh*
https://www.audiogon.com/listings/f...15-2016-05-02-speakers-07924-bernardsville-nj
Now...this is being offered on the website of a dealer in SC....but can't/won't be shipped to the US. Huh? Really? And the 'depreciation' on something that's less than a year old? And it's now a '9'? REALLY?!
I think I'll just keep playing around with my DIY 'garbage', thenk u vedy mulch....
I guess I'll never be a 'high end audiophile' when I grow up. *mock sigh*
That's what struck me...14 decimal 000 euro = $15.97. Replace the decimal with a comma, $15, 973. Absolute Sound's review lists the pair @ $13,500. My local tax (7%) would stick another $943 onto it. Euro taxes I suspect are higher for 'luxury goods', which this definitely qualifies. However, a +/- 50% depreciation in 7 months?! Damn! They must be as common as household flies or you can't get rid of them....an audio 'tar baby'....
Posting the price in US dollars for something that won't get shipped to the US is just funny weird strange too...
I can understand the poster not wanting to get involved with shipping to the US. I wanted to buy a type of table saw manufactured in Norway. They won't ship here, either, and that was from the company itself. It's apparently a major pain in the tush, unless it's a car that can be rolled into a regular shipment via freighter. 'Small stuff' ends up going via FedEx or UPS worldwide via air, and the cost is stratospheric....
Must be a posting for the individual that's going over to pick up a BMW or Porsche and is going to toss the GP's into the back seat.....
I can hear the discussion @ customs now.... "Those? Oh, they're for the car's stereo. It's the latest thing there/here in the states..."
Or, just another example of waiting for a sucker that was born yesterday...there's a lot of that going around, Still.....*shrug*
Posting the price in US dollars for something that won't get shipped to the US is just funny weird strange too...
I can understand the poster not wanting to get involved with shipping to the US. I wanted to buy a type of table saw manufactured in Norway. They won't ship here, either, and that was from the company itself. It's apparently a major pain in the tush, unless it's a car that can be rolled into a regular shipment via freighter. 'Small stuff' ends up going via FedEx or UPS worldwide via air, and the cost is stratospheric....
Must be a posting for the individual that's going over to pick up a BMW or Porsche and is going to toss the GP's into the back seat.....
I can hear the discussion @ customs now.... "Those? Oh, they're for the car's stereo. It's the latest thing there/here in the states..."
Or, just another example of waiting for a sucker that was born yesterday...there's a lot of that going around, Still.....*shrug*
...and I'll Definitely keep on doing what I'm doing. Other than my precious and precocious time, I don't think I've spent more than $200 on all of the parts and necessities for ALL of the units I've made. And my time? Does one put a figure on one's 'hobbies'? If I could, I might be skating up to that $7K figure...and I'd be putting a premium on my spare time to do so...and including the time I've spent trolling the web for info...
*Ahem* Not including, of course, the time I've spent hanging around 'here', filling your eyeballs and polluting your minds with my errant chatter. *L* This I do for grins 'n giggles...
*Ahem* Not including, of course, the time I've spent hanging around 'here', filling your eyeballs and polluting your minds with my errant chatter. *L* This I do for grins 'n giggles...
Here's something that might make you happier, a pair of OHM F speakers for sale near me. Newly refoamed. Asking $1500. I'd buy them but I have nothing powerful enough to drive them. Maybe someone else can use them?
Ohm Walsh Model F Speakers
Ohm Walsh Model F Speakers
They certainly look in good condition...and as the old saying goes "sounds great @ 200, blows at 201". Driving them with a lower wattage amp would be an intelligent move anyway to keep one of trouble and/or temptation to court same....*G*
There's no easy way to determine what the condition of the interior treatments of the cone interiors unless the seller was willing to let you inspect same. I believe the wing nuts in image 3 would allow one to do that, but he'd have to be a generous soul to let one do so IMHO. An audition would be the minimal requirement with a variety of selections to discern if they're still 'up to snuff'. But they're still ancient...I know my parts don't work as well as they used to, and we've still got some 'onboard automatic repair functions' in our favor.
A refoam is probably the least invasive operation one could perform on them, but I'd hope some care was taken to try to match the characteristics of the original surrounds...
I'd be tempted too, but lack the disposable cash to be enthralled any more than being a 'lookie lou'...and even then the distance involved (NC>CA>NC) would make for a helluva 'road trip', esp. the drive back. I'd be a basket case on return. *L* The bed of a Dodge 4wd dually would not be a kind thing to subject them to, and we haven't even talked about the weather in betwixt.
We can get a great deal from Budget on a rental with unlimited mileage, but they'd still freak at the odometer setting and not want to talk to us anymore. *L*
I wouldn't trust shipping them to typical OTR freight services, even insured. Although the seller seems to be a dealer in the various 'n sundry older audio, most balk at packing for shipment....lack of facilities to do so, and it's a real pain to crate an irregularly shaped object like it is...
But...if one really wants to own an icon...as it is...one does what one must to do so, and logic and sense be damned by lust. *G*
Thanks for the link, though. *S* It's nice to see a pair that look like they were well loved, and treated nicely over the decades. I'd bet the owner passed away, and the widow couldn't bear to have them about...too big of a reminder. Just guessing, but it would explain them...
There's no easy way to determine what the condition of the interior treatments of the cone interiors unless the seller was willing to let you inspect same. I believe the wing nuts in image 3 would allow one to do that, but he'd have to be a generous soul to let one do so IMHO. An audition would be the minimal requirement with a variety of selections to discern if they're still 'up to snuff'. But they're still ancient...I know my parts don't work as well as they used to, and we've still got some 'onboard automatic repair functions' in our favor.
A refoam is probably the least invasive operation one could perform on them, but I'd hope some care was taken to try to match the characteristics of the original surrounds...
I'd be tempted too, but lack the disposable cash to be enthralled any more than being a 'lookie lou'...and even then the distance involved (NC>CA>NC) would make for a helluva 'road trip', esp. the drive back. I'd be a basket case on return. *L* The bed of a Dodge 4wd dually would not be a kind thing to subject them to, and we haven't even talked about the weather in betwixt.
We can get a great deal from Budget on a rental with unlimited mileage, but they'd still freak at the odometer setting and not want to talk to us anymore. *L*
I wouldn't trust shipping them to typical OTR freight services, even insured. Although the seller seems to be a dealer in the various 'n sundry older audio, most balk at packing for shipment....lack of facilities to do so, and it's a real pain to crate an irregularly shaped object like it is...
But...if one really wants to own an icon...as it is...one does what one must to do so, and logic and sense be damned by lust. *G*
Thanks for the link, though. *S* It's nice to see a pair that look like they were well loved, and treated nicely over the decades. I'd bet the owner passed away, and the widow couldn't bear to have them about...too big of a reminder. Just guessing, but it would explain them...
Some progress
After and amidst a long hiatus (work related, same old same old...), the V.4 upper radiators are partially completed. You'll pardon the 'test mount'...one does with what's at hand...
All 4 functioning as hoped, a 'broader' midrange and the highs extended. A rather cursory analysis with the calibrated mic and the RTA agrees with what my less calibrated ears tell me.
Unfortunately, the lower 'main' radiators will be waiting in the wings for awhile. One has to remind oneself that patience must be a virtue, as any other description sounds like an agonizing wait.
2 mil aluminum cone, no interior treatment or damping. No plans for a surround...the only thing I could conceive of using for that would be have to be incredibly light, as the alum creases if you look at it hard. I have some dental dam latex that I might try on a test cone and driver, but adhering it to the cone without crumpling it will be a test of practical levitation....
...which means I'll have to try it...*G*
After and amidst a long hiatus (work related, same old same old...), the V.4 upper radiators are partially completed. You'll pardon the 'test mount'...one does with what's at hand...
All 4 functioning as hoped, a 'broader' midrange and the highs extended. A rather cursory analysis with the calibrated mic and the RTA agrees with what my less calibrated ears tell me.
Unfortunately, the lower 'main' radiators will be waiting in the wings for awhile. One has to remind oneself that patience must be a virtue, as any other description sounds like an agonizing wait.
2 mil aluminum cone, no interior treatment or damping. No plans for a surround...the only thing I could conceive of using for that would be have to be incredibly light, as the alum creases if you look at it hard. I have some dental dam latex that I might try on a test cone and driver, but adhering it to the cone without crumpling it will be a test of practical levitation....
...which means I'll have to try it...*G*
Congratulations Jerry, nice to see you making progress. All I have is a pile of drivers and electronics gathering dust in a box waiting for me to have time to enjoy a hobby. (jealousy showing through).
Came up with an open question or two that I've not been able to figure out via Google:
How does altering the spider and/or surround stiffness change the sound of your aluminum cones? My hypothesis is that for a Walsh-type driver one would want a stiff surround, to minimize excursion, and maximize the bending or transmission-line effect of the aluminum cone. The logical conclusion of that premise is a higher-wattage/low X-max coil pushing the aluminum cone against solid board. Perhaps this would work better fir some frequencies, but maybe not so well for others?
Your V.4's don't even have a surround for the Tweeters, so that shoots my theory down (but what happens at the loose edge? does the sound from the inside of the cone blend with the sound from the outside?). How about mids/woof's, would you recommend a softer suspension on the woofer surrounds and spiders for more excursion and lower frequency, or go stiffer than the mids and feed the woofers with more power?
On a separate train of thought: How are your splitting frequencies between your multiple drivers? (I may have missed this on earlier posts) 2 channel amp after active crossover, or single amp channel with passive crossover? I like the idea of active, less chance for clipping and distortion but it's definitely more work.
Keep up the good work, It's inspiring, and wish I could hear them directly!
Six - Minneapolis.
Jerry's busy right now (he and his company are headed south for a big job) but, I'm sure he will answer, when he finds the time.
In proxy; I would say a stiff termination would yield as much of a terminal wave reflection as a free ended termination would. It is frequency dependent but, highs are less effected because they are absorbed faster due to cycling time.
All 'speaker cones' exhibit bending wave radiation, it's just that Walsh configurations are better suited for coherent radiation.
Walsh cones (for their intended use) are only good down to their 'co-incident' frequency i.e, the frequency where wave velocity drops below super-sonic, that; being a function of frequency.
Not sure if I answered your question.
G
In proxy; I would say a stiff termination would yield as much of a terminal wave reflection as a free ended termination would. It is frequency dependent but, highs are less effected because they are absorbed faster due to cycling time.
All 'speaker cones' exhibit bending wave radiation, it's just that Walsh configurations are better suited for coherent radiation.
Walsh cones (for their intended use) are only good down to their 'co-incident' frequency i.e, the frequency where wave velocity drops below super-sonic, that; being a function of frequency.
Not sure if I answered your question.
G
Thank you, Cochleus - makes sense. I did not consider the wave reflection factor. Makes it even more important to establish the right degree of surround-compliance for a given frequency range.
Also, I wonder how one would go about determining the "coincident frequency" for a given driver (material, size, shape?). Seems like an important parameter for a multi-driver configuration.
I may not be able to tinker at this time, but I can't stop wondering about how these drivers work and how to tune them to sound as accurate as possible (minimizing distortion at their intended frequency range)
Six - Minneapolis
Yeah, some resistance at the terminus is important for the sake of reflections. In general, the higher the frequency the faster damping occurs because energy is absorbed with each phase cycling.
A simple way to establish a coincident frequency could be to just measure sound pressure level during a sweep with the driver in an 'open baffle' setup.
Below the coincident frequency sound waves do not radiate from the cone surface into the medium (air).
A simple way to establish a coincident frequency could be to just measure sound pressure level during a sweep with the driver in an 'open baffle' setup.
Below the coincident frequency sound waves do not radiate from the cone surface into the medium (air).