Would the "booster" magnets perhaps be to force the main magnet's flux into the desired gap? Since they would have to be the same polarity as the main magnet, this would be exactly the same as having a larger magnet with a shaped pole-piece...
By the way, I'm campaigning to outlaw the following words in marketing copy or newspapers:
Booster
Revealed
Quantum
Perfect
Invention
There may be others...
By the way, I'm campaigning to outlaw the following words in marketing copy or newspapers:
Booster
Revealed
Quantum
Perfect
Invention
There may be others...
How about innovation? It's the word Micro$oft likes to overuse, even though there is none to be found at that particular monopoly.
BTW, on http://www.transmissionaudio.com/pages/738785/index.htm where they compare other speaker technologies, under ionic/plasma they list the low quality RF-driven corona discharges, but do not mention the Plasmatronic's superior technology. Somehow I doubt they'll bother to correct the omission if I prompted them.
Re: Titanium...
Price, though.
Beryllium. Almost as electrically conductive as aluminum, but is lighter and stiffer.bear said:Titanium is unsuitable for a practical ribbon. The mechanical properties - it is tough - don't buy you anything in the electrical department. It is also *heavier* than aluminum, iirc.
If you plug into the ribbon equation, you find that you need two things more than anything else: light weight ; lowest possible resistance. That and flux.
As the mass increases and the resistance increases the efficiency goes right out the window, quickly.
Thus aluminum - almost as good as copper in the conductivity, but one heck of a lot lighter... silver? Too heavy. Gold? too heavy,
too soft.
Bummer, eh?
_-_-bear
Price, though.
Can't recall exactly now, but I think I remember that even Berrylium (not just the oxide) is scary toxic...
The ultra HF tweeter from TAD uses a Berrrylium diaphragm, afaik.
Don't have the requisite table in front of me to check the conductivity... I'll have to take ur word on it.
Certainly possible but other than TAD no one has tried it.
_-_-bear
The ultra HF tweeter from TAD uses a Berrrylium diaphragm, afaik.
Don't have the requisite table in front of me to check the conductivity... I'll have to take ur word on it.
Certainly possible but other than TAD no one has tried it.
_-_-bear
woody said:
My (apogee) ribbon tweeters go down below 300hz and they
have been doing so since the beginning of the 1980's so that's nothing new. The bass ribbons go down to 30hz for both my small ones and big apogee's. The homogenity, clarity and low level detail is still unmatched.
Undtill recently the problems has always been finding a good amp to match them. But class D amps seem to work perfectly.
To see how the apogee bass is mounted look at this DIY rebuilt of a Scintilla; Scintilla rebuilt project
For people interested in the latest evolution from the original apogee design look at this:
Scroll down to blast-off
I hope Guido and Graz are ok with me posting this link.
Hi Eric and Apogee fans,
Purchased 80” high Full Range Apogees with broken midrange ribbons. They came with the standard passive bi-amp crossover that went between the preamp and two power amps. It had 6db slopes at 320Hz to the bass panel amp and to Mid+Tweeter ribbon amp which then drove a standard 6db passive crossover at 10KHz using an inductor to the midrange ribbon step-up transformer, and a capacitor+padding resistor to the tweeter ribbon.
The bass panel is ~2 ohms, 2” wide midrange ribbon ~ 0.1 ohm, and 0.5” wide tweeter ribbon ~ 1 ohm. A transformer brought the midrange ribbon up to 4 ohms, and a series padding resistor balanced the power to the tweeter ribbon.
Currently bi-amping using active 48db LR8 crossover at 80Hz from the bass panel amp and a DIY direct-drive ribbon amp, and a 12db passive crossover at 5Khz between the mid and tweet ribbons. The original 15 micron thick ribbons were replaced with 5.4 micron ribbons, which almost tripled efficiency and resistance which makes direct drive easier. The midrange ribbon now covers the entire vocal range, which is the key to a great speaker, and there is no set-up transformer to create phase shifts. The 48db slope at 80Hz sends less bass power to the ribbons than the original 6db at 320Hz. The 25W Class-A ribbon amp uses +/- 12V driver supply with +/- 8V output supply to drive the low impedance, also keeps the circuits simple and heat low.
Purchased 80” high Full Range Apogees with broken midrange ribbons. They came with the standard passive bi-amp crossover that went between the preamp and two power amps. It had 6db slopes at 320Hz to the bass panel amp and to Mid+Tweeter ribbon amp which then drove a standard 6db passive crossover at 10KHz using an inductor to the midrange ribbon step-up transformer, and a capacitor+padding resistor to the tweeter ribbon.
The bass panel is ~2 ohms, 2” wide midrange ribbon ~ 0.1 ohm, and 0.5” wide tweeter ribbon ~ 1 ohm. A transformer brought the midrange ribbon up to 4 ohms, and a series padding resistor balanced the power to the tweeter ribbon.
Currently bi-amping using active 48db LR8 crossover at 80Hz from the bass panel amp and a DIY direct-drive ribbon amp, and a 12db passive crossover at 5Khz between the mid and tweet ribbons. The original 15 micron thick ribbons were replaced with 5.4 micron ribbons, which almost tripled efficiency and resistance which makes direct drive easier. The midrange ribbon now covers the entire vocal range, which is the key to a great speaker, and there is no set-up transformer to create phase shifts. The 48db slope at 80Hz sends less bass power to the ribbons than the original 6db at 320Hz. The 25W Class-A ribbon amp uses +/- 12V driver supply with +/- 8V output supply to drive the low impedance, also keeps the circuits simple and heat low.
I'm not really convinced there's anything worth looking at here. Maybe once I see a review, or hear them in a hifi shop.
I agree with previous posts that he brushes off other technology. On one part of the page it says something to the effect of: "It took a year to find a vendor that met our quality standards. This makes me believe it's a "catalogue manufacturer." ie: He looks through catalogues to find parts, and throws it together.
The only way I could think of to increase the impedance of a ribbon driver is to have sandwhiched layers of aluminum and mylar. Then the individual layers could be wired in series.
I agree with previous posts that he brushes off other technology. On one part of the page it says something to the effect of: "It took a year to find a vendor that met our quality standards. This makes me believe it's a "catalogue manufacturer." ie: He looks through catalogues to find parts, and throws it together.
The only way I could think of to increase the impedance of a ribbon driver is to have sandwhiched layers of aluminum and mylar. Then the individual layers could be wired in series.
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