John,
Behind the Iron Curtain the availability of western made drivers was minimal and priority came to mainstream PA Stuff...
In East Germany the biggest HiFi Woofer was 8"... In one of the Baltic Republics of the Soviet Union they made a 10" Driver that was a copy from a Sony Speaker... Some Pro Drivers where bigger but had very resonances.
At the time I owned also Schulze TH315 in Studio Boxes (12" Coaxials developed over time from the original Eckmiller Design) and boxes build from an EV Kit with an EV 15" Woofer, 8HD Horn and T35 Tweeter. But these all looked industrial and where in what was supposed be my Bedroom, but which was small mastering studio instead...
The active speakers where for my living room. Slim Towers, back full off heatsinks, Chip-Amp's for power. 😀
Ciao T
Behind the Iron Curtain the availability of western made drivers was minimal and priority came to mainstream PA Stuff...
In East Germany the biggest HiFi Woofer was 8"... In one of the Baltic Republics of the Soviet Union they made a 10" Driver that was a copy from a Sony Speaker... Some Pro Drivers where bigger but had very resonances.
At the time I owned also Schulze TH315 in Studio Boxes (12" Coaxials developed over time from the original Eckmiller Design) and boxes build from an EV Kit with an EV 15" Woofer, 8HD Horn and T35 Tweeter. But these all looked industrial and where in what was supposed be my Bedroom, but which was small mastering studio instead...
The active speakers where for my living room. Slim Towers, back full off heatsinks, Chip-Amp's for power. 😀
Ciao T
Some of the GE medical pressure transducers make decent DC - 3KHz microphones.
Sorry for the typo: of course, positive feedback by current. Yes, result is negative output resistance.
Fostex still makes a 31.5" woofer.
An externally hosted image should be here but it was not working when we last tested it.
$3,464 at Madisound.
se
From what I've heard those Fostex 31" don't really sell. You can't get one. Just a show piece. Would like to hear from someone who actually has one or has seen it in use.
Anything else than voltage drive of the dynamic speaker is a great nonsense
The road to hell is paved with good intentions - Wikipedia, the free encyclopedia
I have seen and heard one at a trade show in Tokyo in the middle of the eighties. It might even have been at its introduction. Very impressive. Even when not playing very loud, it would fill a whole trade fair hall with bass. Haven't seen or heard one since, unfortunately.
vac
Anything else than voltage drive of the dynamic speaker is a great nonsense
Agree for the most part, certainly for woofers it is most dangerous. At the high impedance peak(s) caused by the one (closed) or two (BR) fundamental resonance(s), voltage would sharply increase at the exact moment when excursion is already maximum and badly damped. Results like VC's bumping backplates or cones crumbling are likely. Hence my earlier question to Thorsten how many woofers he had destroyed in the time when he says he used current drive for all his drivers. There are some other additional good reasons not to use current drive with woofers, such as the effect it has on Qes.
Hawksford in his paper identifies some interesting properties of current drive though, such as flattening out Bl irregularities.
Please note that in practice all mid and high drivers in passively filtered more way system have current drive to some extent, since they are usually attenuated in order to line up with the sensitivity of the woofer. And some manufacturers seem to have calculated this into their designs. I have measured a fair deal of tweeters that slope down in the upper octave when driven by a pure voltage source, only to become straight by placing some resistance in front of them.
vac
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Although this is second hand, a speaker designer friend of mine told me that some of the best bass he's ever heard was in a system that used a pair of these. The enclosures were a simple truncated pyramid. It wasn't really an enclosure per se as the bottom was left open and the drivers mounted at the top. The bottom was held up off the floor by about 4 to 6 inches with some simple feet.
se
The old saying about there being no substitute for cubic inches is true enough, and can even be modified a little for audio to say that there's no substitute for square inches either. (Except horns, and they gotta be big.)
Thanks,
Chris
Thanks,
Chris
In specific cases, it may be tuned for the unique application. But in general, current drive of dynamic speakers may not be recommended.
best = most? 😀 The room rattlers at BA did pretty well. Dick Burwen uses 30' concrete horns which are part of his foundation. There was a French fellow doing this even bigger, lost the pics.
I have only one pair of 12" drivers in the concrete horn under my floor, it is more than enough for movies...
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