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Old 9th June 2004, 08:47 PM   #11
BrianGT is offline BrianGT  United States
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Quote:
Originally posted by Nappylady
Anyone know a supplier of black holes and flux capacitors? I searched at Parts Express and couldn't find any....
Parts Express sells Black Hole products:
Click the image to open in full size.
http://www.partsexpress.com/pe/pshow...number=268-886



I used a box of it to line the walls of my latest speaker project:
http://www.briangt.com/gallery/focal-raven-tl

I hope I don't have response problems with the cone being sucked into the speaker.

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Brian
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Old 10th June 2004, 06:23 AM   #12
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Putting fun aside, there are indeed possibilities to make a box look larger (acoustically) than it actually is.
And I am not talking of the usual stuffing. Cerwin Vega once used a bag inside closed boxes that was filled with something that is more compressible than air.

There was also an article in JAES dealing with something like that. Maybe I can find it.

OTOH why bother, we just have to tame our SOs first and size won't matter anymore.

Regards

Charles
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Old 10th June 2004, 02:45 PM   #13
Bill F. is offline Bill F.  United States
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Quote:
Putting fun aside, there are indeed possibilities to make a box look larger (acoustically) than it actually is.
Here's one that strikes me as very practical. No special gasses, just activated charcoal...
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Old 10th June 2004, 03:18 PM   #14
amo is offline amo  United States
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Bass: Nine 12" woofers loaded in three parallel chambers. Each chamber consists of three woofers firing in a pressure driven configuration. The rear drivers reduce backpressure on the baffle-mounted drivers, simulating a free air resonance while simultaneously increasing linearity and power handling. The rear drivers are vented out the back of the enclosure through 4" ports.
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Old 10th June 2004, 03:46 PM   #15
Bill F. is offline Bill F.  United States
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Quote:
The rear drivers reduce backpressure on the baffle-mounted drivers, simulating a free air resonance while simultaneously increasing linearity and power handling. The rear drivers are vented out the back of the enclosure through 4" ports.
Uhh, lemme see if I have this right... a monopole system in series (phase reversed) with a 4th-order bandpass system? And sharing an enclosed volume?

Assuming the driver phases are lined up (probably wouldn't be because of the different loads, but...) so the rear drivers unload the fronts for a sorta free-air effect (+ resonance contributions of the enclosed air column), depending on the tuning of the rear ports, you'd move from a net reflex alignment to a sorta dipolar radiation patters, prolly with some cardioid characteristic?

Since you'd get cancellation killing efficiency below the tuning of the rear ports, it ain't exactly a panacea...

What's the goal of such a goldbergesque device?
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Old 10th June 2004, 03:54 PM   #16
amo is offline amo  United States
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I do not pretend to understand how this works, but it is quite fascinating. These are well over USD 100,000 each, and are supposedly some of the very best studio monitors money can buy. Entire audio spectrum, at any level, with impecable pulse caracteristics, etc etc etc. But I guess at 800 pounds of granite each, the "small box" is defeated. Here are the rest of the specs:



-Frequency response is from -4dB @ 13 Hz to well beyond 24,000 Hz. -Efficiency is 87dB. -Impedance is 7 Ohms, nominal. Minimum impedance is 5 Ohms. -Tweeter: Two 1" cloth domes stacked back to front. Each tweeter has a large-diameter vent on its pole piece and a big aperiodic damping chamber that imitates an infinite baffle loading. Stacking them doubles the size of the pole piece across the same driver surface area, increasing linearity and power handling, while having no effect on frequency response. The tweeters are manufactured on a special production line under laboratory conditions. -Mid-bass: Twelve 6" polypropylene, double-magnet driver, with a 3" voice coil diameter. Extremely rigid structural physics and the piston-like action of this driver produce exceptionally quick transients and a complete absence of coloration. These drivers are run full-range in four independently tuned transmission lines. Each transmission line contains three drivers in a pressure driven design, mounted front to back. The rear drivers reduce backpressure on the baffle-mounted drivers, simulating a free air resonance while simultaneously increasing linearity and power handling. -Bass: Nine 12" woofers loaded in three parallel chambers. Each chamber consists of three woofers firing in a pressure driven configuration. The rear drivers reduce backpressure on the baffle-mounted drivers, simulating a free air resonance while simultaneously increasing linearity and power handling. The rear drivers are vented out the back of the enclosure through 4" ports. -Enclosure: The extremely heavy enclosure becomes slightly wider as the speaker gets deeper on the bass enclosure and slightly narrower on the high frequency section. This minimizes parallel wall interactions, while increasing rigidity and stability. -Internal wiring is manufactured by Transparent Audio. -Single Cardas rhodium binding posts. -The crossover for the tweeter is hard wired. We utilize Hovland MusiCaps and Vishay resistors. -Damping material or stuffing is Acousta-Stuff, a nylon polyamide loose bulk fiber that is tri-lobal (instead of round) and multi-directionally crimped so that the strands interlock to form a very cohesive mass that does not require support and will not settle. -The grills are made of an extremely transparent material that is stretched over a thin steel frame. They attach via magnets that are buried under the surface laminate, allowing the speakers to look as finished with the grills on as with them off. -Black Italian granite is utilized. -Special designed castors are permanently mounted to the base and are an integral pert of the design. -The footprint is 15" wide on the baffle, 18" wide on the back panel. It is 36" deep, and 76" tall -Net weight, per loudspeaker, is 790 pounds.
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Old 10th June 2004, 10:11 PM   #17
rnoble is offline rnoble  Australia
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OK here's a thought.

Assuming that you can travel through time as well as space to get to another universe. And considering that black holes have an infinite amount of magnetic force you could hook up your coil to the black hole and time it's release to when it went black, leaving you with an infinite magnet with infinite excursion!
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Old 11th June 2004, 10:12 AM   #18
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Since you're travelling through time, why not attend the actual recording event, live, as it happened?!!! Going back to see Elvis in the sixties would be awesome, and the tickets would be unbelieveably cheap.
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Old 11th June 2004, 10:23 AM   #19
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... or go back into the 50's and discover Elvis.
Talk about a goldmine!
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Old 11th June 2004, 12:36 PM   #20
KT is offline KT  United States
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["IIRC then black holes are black because of gravitation pull and past a certain point anything within distance of it will be sucked in beyond saving. Therefore I conclude that you're going to need a good gasket, and you may experience some response problems with the cone being sucked in a little."]


Would this be referred to as "BH Offset?"

KT
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