Brett said:
I would love to, but as our company (one of them) is also doing work in the exact area..and we are getting ready to publish product... I would likely be beaten to death by my business partner-with a $10 badly built Chinese woofer. (Here lies Ken: Done in by a badly executed Vifa copy)
~~~~~~~~~~~~~~
About 12 years ago, I came up with a filter circuit for crossover design that does some interesting things with transient distortion issues. I will not explain it further, but will state it is not patentable due to it being entirely passive in nature. It will be published in the form of being used in our loudspeaker designs, and I will impart the information to the DIY crew at that time of product finally being issued. It has been frustrating to hold onto it all this time, as I do much prefer an open source situation...but that is the way of such things.
The circuit looks quite retarded on it's own, and beyond the pale with regards to electrical insanity..but it works and solves the issues at hand, when you really go out of your way to understand the core issues of fundamental electrical function itself.
About 3-4 years back, I remember a thing about a Kimber crossover thing-a-majig that was doing the rounds..where those who wanted to see the circuit (after hearing the speakers) had to sign an NDA to see it. I thought to myself that this was foolish on the part of the folks who signed the NDA...as if it was passive, patents where not enforceable and an open ended NDA was a good way to trap one's self in a small corner where they would be forced to submit to the Kimber considerations as a defacto licensing situation. I suspected the circuit was similar to mine.
SNIP
Not a big fan of the R-word. People with mental retardation and learning disabilities tend to be extremely alert to their situation and how it differentiates them from others. Best to just not use it, like saying "that's gay" to mean "That's stupid" is not about gay at all, but makes that association. Retarded and stupid are two very different things.
Oh, and I use associative phrases like those sometimes too, it's very common in our culture, but that doesn't make it a good way to speak/post.
Oh, and cheesy to tease the bracing scheme, then say you won't post it. I'm REALLY sure that a bunch of DIYers looking at a 50 year old picture would effect the sales of a completed product
The bit about the chinese woofer was funny though.
KBK said:
Not a big fan of the R-word. People with mental retardation and learning disabilities tend to be extremely alert to their situation and how it differentiates them from others. Best to just not use it, like saying "that's gay" to mean "That's stupid" is not about gay at all, but makes that association. Retarded and stupid are two very different things.
Oh, and I use associative phrases like those sometimes too, it's very common in our culture, but that doesn't make it a good way to speak/post.
Oh, and cheesy to tease the bracing scheme, then say you won't post it. I'm REALLY sure that a bunch of DIYers looking at a 50 year old picture would effect the sales of a completed product
The bit about the chinese woofer was funny though.
Sorry for keeping coming out with this site but maybe you'll find this interesting. The RF-C805 widerange driver uses a balsa wood cone. I wonder how this shows on a distorsion measurement. The motor seems very interesting: 4.5 kg of copper in the field coil. Interesting to see the iron rods closing the magnetic circuit. I've seen this used in goto LF units, with alnico magnets.
Here is a picture:
And one with a fieldcoil tweeter:
Enjoy!
Here is a picture:
And one with a fieldcoil tweeter:
Enjoy!
Boy, those drivers are really "out there", aren't they? Nice steam-punk/retro-future look, have to admire that. If I ever manufactured or licensed the Karna amplifier, the 1930's Bell Labs esthetic would be the way to go.
Interesting 20's/30's style spider, and the cone is certainly unusual, to say the least. Have no idea at all how it would measure - hard to tell from looking, except that the dissimilarity between the inner and outer cone implies some kind of mechanical crossover, like the Ohm Walsh and MBL speakers. Getting these mechanical crossovers right is not trivial, and would take a lot of trial and error with instrumentation and auditioning.
Hmm - speaking of which, I wonder if Great Plains Audio will re-introduce the Altec Biflex, from all accounts a very sweet-sounding widerange loudspeaker.
Interesting 20's/30's style spider, and the cone is certainly unusual, to say the least. Have no idea at all how it would measure - hard to tell from looking, except that the dissimilarity between the inner and outer cone implies some kind of mechanical crossover, like the Ohm Walsh and MBL speakers. Getting these mechanical crossovers right is not trivial, and would take a lot of trial and error with instrumentation and auditioning.
Hmm - speaking of which, I wonder if Great Plains Audio will re-introduce the Altec Biflex, from all accounts a very sweet-sounding widerange loudspeaker.
chrismercurio said:
Heck no. Ken Kantor would never have what I've got for a signature. Too out there for most folks.
I share what I can. For example, I said 'please go stare closely at the surround/cone termination on a Robin Marshall designed woofer'. This would be a 80's -late 80's Monitor audio driver, and the Earlier Epos drivers. (more than about 4-5 years old, he sold the company a while back). Now, how does it serve me, to tell you how to look to find a properly done cone/surround termination. It does me no favors. But I like to share, and well...Robin did it right! And how many of you would know to look there?
And in saying that..it can end up being, within a year..all the rage in Chinese sourced drivers. Except they won't even know what they've copied or why. This, in turn, kills more Euro and US manufacturing market. This is the kind of thing that makes it difficult to be 'open source', as much as some would like to be.
thanks for the tips!
As it happens I was looking at the surround of the bass driver in a ES 11 just 2 days ago, since I had always admired the sound from those, although not without reservation. I must say that they didn't strike me the way they did 15 years ago - I heard no particular magic this time.
What I saw was a lightweight inverted rubber roll surround, but I am not schooled in surround esoterica, so probably missed the essentials.
Russell
As it happens I was looking at the surround of the bass driver in a ES 11 just 2 days ago, since I had always admired the sound from those, although not without reservation. I must say that they didn't strike me the way they did 15 years ago - I heard no particular magic this time.
What I saw was a lightweight inverted rubber roll surround, but I am not schooled in surround esoterica, so probably missed the essentials.
Russell
Hi SunRa,
They continued with the idea, have a look at the current M22i:
M22i zipped hirez photo
Cheers,
Mike
They continued with the idea, have a look at the current M22i:
M22i zipped hirez photo
Cheers,
Mike
Thanks for the picture Mike!
However I don't get it what's so special with this surround. It seems to me that the suspension is still glued to the cone. For example in some Hartley woofers the surround and the cone are the same body. This is said to greatly reduce the edge artefacts.
I've also seen this on a paper cone. The surround was formed from the edge of that cone.
I'll try to post a picture later.
However I don't get it what's so special with this surround. It seems to me that the suspension is still glued to the cone. For example in some Hartley woofers the surround and the cone are the same body. This is said to greatly reduce the edge artefacts.
I've also seen this on a paper cone. The surround was formed from the edge of that cone.
I'll try to post a picture later.
KBK said:A Simple question..simple answer.
Why is field coil superior to all other 'dynamic' style (magnet, basket, cone, etc) drivers?
It's and old civil engineering thing. '3 to 15' it's called. Let's see who 'gets it'.
KBK, I'm afraid the "3 to 15" reference is a little too obscure. Why?
Well, I'm married to a Civil Engineer who went on to work for the US Army Corps of Engineers in the Portland District for 20-plus years, and she had no idea what it meant - and Karna is a pretty sharp cookie, with a background in biochemistry, civil engineering, and a mainframe computer systems analyst. Is it some kind of regional or national reference?
Nick,
Do You have dimension drawings Yours 15" and new 18" drivers?
Something like this:
http://profesional.beyma.com/ingles/pdf/18P1200Nd.pdf
Can You send drivers to Poland?
Best
C
Do You have dimension drawings Yours 15" and new 18" drivers?
Something like this:
http://profesional.beyma.com/ingles/pdf/18P1200Nd.pdf
Can You send drivers to Poland?
Best
C
mechanical resistance
I don`t remember anyone ever mention the importance of low mechanical resistance (Rms) while choosing the bass drivers, only magnets, voice coils and cone types. Aluminum VC formers seem to slow down bass transients considerably, as well as lack of venting the magnet/coil structure.
From my experience, low mechanical resistance plays a very important role for the "subjective" speed of woofers. The higher the Qms or lower the Rms, the better or livelier is the reproduction of bass transients. That of course among other factors, but I`ve never encountered any woofers with low Rms to sound detailed in the bass.
Only Tony Gee from Netherlands seems to pay attention to it:
http://www.diyaudio.com/forums/showthread.php?postid=806812#post806812
example of extremely low Rms 15" :
http://oem.ciare.com/it/296/346/prodotti.php
I don`t remember anyone ever mention the importance of low mechanical resistance (Rms) while choosing the bass drivers, only magnets, voice coils and cone types. Aluminum VC formers seem to slow down bass transients considerably, as well as lack of venting the magnet/coil structure.
From my experience, low mechanical resistance plays a very important role for the "subjective" speed of woofers. The higher the Qms or lower the Rms, the better or livelier is the reproduction of bass transients. That of course among other factors, but I`ve never encountered any woofers with low Rms to sound detailed in the bass.
Only Tony Gee from Netherlands seems to pay attention to it:
http://www.diyaudio.com/forums/showthread.php?postid=806812#post806812
example of extremely low Rms 15" :
http://oem.ciare.com/it/296/346/prodotti.php
I am presently using two of these vertically mounted on an 18" wide board.
http://profesional.beyma.com/ingles/pdf/SM115N.pdf
The 2008 version of this LS has more normal close folds in the cloth surround, so it looks different to the manufacturer's photo in their PDF.
I have the tightest/cleanest bass yet when driven using this circuit with a 500VA 2x 40V toroidal trafo, 1000uF capacitor and another choke circa 2.2mH in series with the driver. No resistor in series with the 6.4mH choke; one ohm in series with the capacitor.
My amplifier is 1 ohm capable so I have no worries there.
Other drivers likely to sound good with this circuit, especially larger ones.
Cheers.......... Graham.
http://profesional.beyma.com/ingles/pdf/SM115N.pdf
The 2008 version of this LS has more normal close folds in the cloth surround, so it looks different to the manufacturer's photo in their PDF.
I have the tightest/cleanest bass yet when driven using this circuit with a 500VA 2x 40V toroidal trafo, 1000uF capacitor and another choke circa 2.2mH in series with the driver. No resistor in series with the 6.4mH choke; one ohm in series with the capacitor.
My amplifier is 1 ohm capable so I have no worries there.
Other drivers likely to sound good with this circuit, especially larger ones.
Cheers.......... Graham.
