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Old 5th April 2012, 04:33 PM   #3741
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Originally Posted by obeman View Post
B&C SPEAKERS

21IPAL
2500w (AES)
80 mm peak-to-peak
15..22mm linear peak
Flux Density 1.35
FS 37HZ

:O
Interesting...What is up with the 1ohm impedance though? Very odd. April Fools?
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Old 5th April 2012, 06:03 PM   #3742
obeman is offline obeman  Finland
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"IPAL"

Nomen est omen
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Old 6th April 2012, 01:07 AM   #3743
djk is offline djk
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"What is up with the 1ohm impedance though?"

Ever try and get 5KW into 8Ω?

A Crest 10001 does 5KW RMS (stereo) into 1Ω, 7.5KW on program material.
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Old 6th April 2012, 01:33 AM   #3744
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"What is up with the 1ohm impedance though?"

Ever try and get 5KW into 8Ω?

A Crest 10001 does 5KW RMS (stereo) into 1Ω, 7.5KW on program material.
Sure...Usually involving bridging an amp... but a 10001 weighs way over 100lbs and most amps aren't really happy with high power into <1ohm minimum loads. That is a lot of current demand. Sure most of the impedance will be over 2 ohms but the minimum will stlll be really low in a few spots and it would make me concerned with most available amplifiers running them hard into that type of load.

Last edited by Josh Ricci; 6th April 2012 at 01:36 AM.
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Old 6th April 2012, 07:42 AM   #3745
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You're right, most amplifier won't even run a 2Ω load, much less a 1Ω load. The Crest was designed to run a stereo 1Ω load (137 lbs).

A Crown MA5000vz will do 5KW into 1Ω in mono (77 lbs). The mono MA10,000 is rated at 9.4KW at 1Ω, and can drive as low as 0.5Ω (128 lbs).

McIntosh used to make an amplifier rated to drive a 0.25Ω load in mono, full power, all day long. We used to put them in dance clubs and drive eight 15s. It did weigh 128 lbs though.

The mach speed a vented box would require would seem to rule out a simple vented box, but the driver might have a use in a tapped horn.

http://www.danleysoundlabs.com/pdf/T...ec%20Sheet.PDF
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Old 6th April 2012, 10:38 AM   #3746
epa is offline epa  Netherlands
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cannot get a nice sim for a th ,for this speaker ,unless i use verry high compression ratio
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Last edited by epa; 6th April 2012 at 10:43 AM.
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Old 6th April 2012, 10:53 AM   #3747
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"cannot get a nice sim for a th ,for this speaker ,unless i use verry high compression ratio"

The Qts is almost too low to be usable.
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Old 6th April 2012, 12:42 PM   #3748
iand is offline iand  United Kingdom
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It really is a crazy driver, huge output but very hard to design any kind of box for because of the huge BL/sqrt(Re) (30% higher than the 18sound 21NLW9600 which is the previous champ) and Mms -- a Qes of 0.22 with Fs=37Hz says it all, really.

You'd get almost exactly the same maximum output, efficiency and Vd with a couple of good 18" drivers like the BMS 18N850V2, which might even cost less and would certainly be easier to drive and design suitable boxes for.

I think this driver is a case of seeing what happens if you push driver design to the extreme rather than than something with real advantages over existing solutions -- unless you want to drive massive currents into a 1 ohm load from a class-D amplifier (which can use efficient low-voltage output transistors), like the custom Powersoft module...
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Old 6th April 2012, 01:31 PM   #3749
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I see now that this is developed as part of a system for Martin and uses a custom Powersoft module. Im still trying to get a little more detail on how the IPAL system functions. I bet these would work well in a couple of cabs but judging from the cost of the 21sw152 currently the cost would be hideous. Extra power to make use of the extra displacement is not cheap either. Wonder if a k10 would run these ok?

This would make a hell of a car audio SPL competition burp sub.
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Old 6th April 2012, 02:59 PM   #3750
tb46 is offline tb46  United States
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Hi,

B&C 21IPAL in a TH, V-net=550 L, 4:1 throat compression, @ 5kW:

Regards,
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File Type: jpg B&C_21IPAL_TH_Input.jpg (33.1 KB, 356 views)
File Type: jpg B&C_21IPAL_TH_SPL.jpg (29.4 KB, 350 views)
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