I will leave it up to the good readers of this thread to form their own opinions on this matter, after making a couple of final remarks from my side (following the bold numbering added to Thorsten's reaction):
Ad 1) A good read on this one is http://www.firstwatt.com/pdf/art_cs_amps.pdf
For a special case of loudspeakers, that is speakers that are electrically overdamped, current drive may be beneficial. However, as Nelson Pass also mentions, most speakers are designed to be driven by voltage.
ad 2) One of the first sentences I learned in German was from my father: nicht ägern, nur wundern. I will apply that wisdom here, whilst hoping for your understanding that not all on this site are prepared to share to the same degree their autobiography as argument in a technical discussion
ad 3) Some pictures to look at:
Eckmiller - Google zoeken
Do I see dome tweeters %$#!!! The 'solution' to place dampening material around the basket has not caught on. I can see at least two potential problems with it. Firstly, it would increase basket reflections back to the cone considerably. One of the nice things about the newer generations of drivers are baskets optimized to prevent those reflections. Secondly, flow resistance as you call it is not a linear phenomena. It is an impendance that rises with frequency, just to mention one thing, another is that the medium causing the impedance will be set in motion by sound waves.
vac
Hi,
I would suggest that reading Hawksford/Miller on distortion reduction in dynamic speakers (see Malcolms pages) is a better choice, but it is less "popular science" and more "hard science" then Nelsons justly popular paper.
Mills, P., Hawksford, M., “Distortion reduction in moving-coil loudspeaker systems using current-drive technology,” J. Aud. Eng. Soc., 37(3), 129- 148
Past that Esa's book (from the thread I linked a few posts up - buy at amazon) restates much of what I found in 1980's and earlier german literature on the concept and gives a good overview (though I am rather disagreeable with Esa's contention that current drive is the whole or indeed any of "Tube Amplifier Secrets" a notion he seems to be wedded to.
All electrodynamic speakers are driven by current, only current and nothing but current. The motional force is determined by BL, essentially usually shown dimensionless, but actually stating Tesla/Meter or more unambigous Newton per AMPERE, not VOLT.
So if a Speaker is designed to be driven by voltage it must have an absolutely linear impedance with signal levels, frequency, excursion etc. et al. or the very fact that it is designed "contra naturam" (that is against nature) will create massive levels of UNNECESSARY distortion.
You actually on the original Eckmiller see a 2" Dome loaded by phaseplug/compression chamber and the woofer cone acting as waveguide.
The Eckmiller is this:
Eckmiller O15 at AK-Audio
Some of the others that come out in your search (including the one with the 50mm Alu Dome) are later successors, with modifications that may or may not be improvements.
The one with the 50mm Dome HF was quite common in East German Studios, so I am quite familiar with it. In fact, I have even owned it in the late 80's. IIRC the two overlapped metal mesh's acted as phase-grid, avoiding the HF cancellation one would expect from such a large dome, or so I was told by old man Schulz himself.
For anyone interested in more on the subject of the original Eckmiller drivers here are some 60 Years + old articles on the real thing. You need to read german as these are picture scans from a german publication, the rest may stare in amazement and befuddlement at the pictures concluding these drivers to be total oddballs:
Eckmiller O15 (Radio Mentor Vol. 9/10 1943)
Eckmiller O15a dyn (Radio Mentor 07/1950)
Eckmiller O15 (Funkschau Vol. 1/2 1944)
Sadly the extensive purge of east german audio tech in Radio/TV Studio's as well as that of the associated publications following the "Anschluss" in 1990 leave me with nothing on the east german systems, except what is in my head.
It "caught on" in the late 30's and has been in use continously in german studio monitors until past the early 90's (in the form of the Schulze TH315 Driver) and is now found in a modified form in the MEG Cardioid Monitor Speakers (they are cardioids at all frequencies), so with a practical and beneficial use of the principle for over seven decades I find the "not caught on" comment singularly ill informed.
For the rest, you can invent problems until the cows come home from whever they do when they are out and about, have fun, unlike you I actually KNOW these system in both theoretical AND practical sense - I'm outta here...
Ciao T
I would suggest that reading Hawksford/Miller on distortion reduction in dynamic speakers (see Malcolms pages) is a better choice, but it is less "popular science" and more "hard science" then Nelsons justly popular paper.
Mills, P., Hawksford, M., “Distortion reduction in moving-coil loudspeaker systems using current-drive technology,” J. Aud. Eng. Soc., 37(3), 129- 148
Past that Esa's book (from the thread I linked a few posts up - buy at amazon) restates much of what I found in 1980's and earlier german literature on the concept and gives a good overview (though I am rather disagreeable with Esa's contention that current drive is the whole or indeed any of "Tube Amplifier Secrets" a notion he seems to be wedded to.
All electrodynamic speakers are driven by current, only current and nothing but current. The motional force is determined by BL, essentially usually shown dimensionless, but actually stating Tesla/Meter or more unambigous Newton per AMPERE, not VOLT.
So if a Speaker is designed to be driven by voltage it must have an absolutely linear impedance with signal levels, frequency, excursion etc. et al. or the very fact that it is designed "contra naturam" (that is against nature) will create massive levels of UNNECESSARY distortion.
You actually on the original Eckmiller see a 2" Dome loaded by phaseplug/compression chamber and the woofer cone acting as waveguide.
The Eckmiller is this:
Eckmiller O15 at AK-Audio
Some of the others that come out in your search (including the one with the 50mm Alu Dome) are later successors, with modifications that may or may not be improvements.
The one with the 50mm Dome HF was quite common in East German Studios, so I am quite familiar with it. In fact, I have even owned it in the late 80's. IIRC the two overlapped metal mesh's acted as phase-grid, avoiding the HF cancellation one would expect from such a large dome, or so I was told by old man Schulz himself.
For anyone interested in more on the subject of the original Eckmiller drivers here are some 60 Years + old articles on the real thing. You need to read german as these are picture scans from a german publication, the rest may stare in amazement and befuddlement at the pictures concluding these drivers to be total oddballs:
Eckmiller O15 (Radio Mentor Vol. 9/10 1943)
Eckmiller O15a dyn (Radio Mentor 07/1950)
Eckmiller O15 (Funkschau Vol. 1/2 1944)
Sadly the extensive purge of east german audio tech in Radio/TV Studio's as well as that of the associated publications following the "Anschluss" in 1990 leave me with nothing on the east german systems, except what is in my head.
It "caught on" in the late 30's and has been in use continously in german studio monitors until past the early 90's (in the form of the Schulze TH315 Driver) and is now found in a modified form in the MEG Cardioid Monitor Speakers (they are cardioids at all frequencies), so with a practical and beneficial use of the principle for over seven decades I find the "not caught on" comment singularly ill informed.
For the rest, you can invent problems until the cows come home from whever they do when they are out and about, have fun, unlike you I actually KNOW these system in both theoretical AND practical sense - I'm outta here...
Ciao T
Hi,
And I bet if I made speakers that used drivers made with very poor magnet systems (non-linear, high compression) but had bass and midrange cones made from say super stiff "Ceramikum", which ring like bells and which even "infinite slope crossovers fail to tame and added even stiffer "Diamondilium" Tweeters and used an Enclosure made from super hard "Corriolian", threw a texbook 2nd order crossover using Mundorf Capacitors and Chokes (cheapest series, not the good stuff) at it, which of course would not work properly and spend even more money on advertising and hence sold a pair of 100K US, I'd be selling a fair few...
What do you think?
Ciao T
And I bet if I made speakers that used drivers made with very poor magnet systems (non-linear, high compression) but had bass and midrange cones made from say super stiff "Ceramikum", which ring like bells and which even "infinite slope crossovers fail to tame and added even stiffer "Diamondilium" Tweeters and used an Enclosure made from super hard "Corriolian", threw a texbook 2nd order crossover using Mundorf Capacitors and Chokes (cheapest series, not the good stuff) at it, which of course would not work properly and spend even more money on advertising and hence sold a pair of 100K US, I'd be selling a fair few...
What do you think?
Ciao T
"Felted cellulose composite"
I have yet to find a mid-base made from something other than paper that I like. I even prefer my old paper Peerless subs over the new metal version. Easier to use well. Maybe exotics have a higher potential, but if I can't realize it I will stick with paper. Marketing has now moved to exotic paper: bamboo, reed, and so on.
I have no doubt you are quite right.
This world has ceased being about the essence of the matter at least 15 years ago.
Ever since then, it has been far more important how something APPEARS to be, not how something IS. We are becoming more and more superficial as a race day in, day out.
And everybody and their dog have some hard hitting "science" to prove just their point. Theories are a dime a dozen. So are PhDs. Most of whom have probably paid their $400 to an Internet university for the PhD.
Frankly, I don't give a damn about any Internet PhDs. They would have been hilarious if they were not so sad.
Testemony to human vanity and gutter standards.
Thorsten, I am not under the impression that you know who I am and what theoretical AND practical knowledge I hold. Let's keep it that way and stick to arguments.
vac
Agree Bro , just take a look at Willie nelson before he got involved in the High end ...Bizniz ..
Willie Nelson -Hit Medley On The Grand Ole Opry(1965). - YouTube
Willie Nelson -Hit Medley On The Grand Ole Opry(1965). - YouTube
Didn't he write his thesis in a psych ward ?
(best experience to enter the audio business)
Ummm....well only to the extent he was working with psychiatric cases, although few diagnosed as such. The degree was in Social Psychology, but required an essay and a lot of life experience. And then there was a check
But although there were times I couldn't have imagined saying this, I miss Sid. "Don't it always seem to go That you don't know what you've got 'till it's gone..." (Joni Mitchell, Big Yellow Taxi)
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