Speakers and power - explain this bit....

[Mr. Foxen]

My band makes bad sounds. I blew up my cab. I touched a 9 volt battery arcross my speaker lead to check the speakers were in phases and all move in same direction. Oh noes, DC into my speakers making them suck inward. But then I touched it across the other way and they went outwards, so now its AC and they are all good.

[alexclaber]

[quote name='bass_ferret' post='314113' date='Oct 24 2008, 08:13 PM']The 21inch woofer is not a myth. It was an architectural hifi driver made for the US market by Electrovoice.[/quote]

I was actually referring to the Whappo Grande made by AccuGroove which uses the Beyma 21" woofer. It does indeed exist but their -3dB @ 22Hz and -6dB @ 19Hz frequency response claims are more than an octave different from reality!

Alex

[crez5150]

Plenty of big speakers around.... 21", 22" + 24"....

[escholl]

[quote name='alexclaber' post='314389' date='Oct 25 2008, 10:22 AM']I was actually referring to the Whappo Grande made by AccuGroove which uses the Beyma 21" woofer. It does indeed exist but their -3dB @ 22Hz and -6dB @ 19Hz frequency response claims are more than an octave different from reality!

Alex[/quote]

i'm guessing by the octave difference part you mean they're -3dB at 44-ish Hz while they're at their max SPL, or something like that? I don't remember what those graphs were called that you had, something about frequency response at max SPL -- is this what you mean here?


on another note, i would add something constructive to the topic debate but i think that everything that needs to be said has been, and then some....

[alexclaber]

[quote name='escholl' post='314487' date='Oct 25 2008, 01:19 PM']i'm guessing by the octave difference part you mean they're -3dB at 44-ish Hz while they're at their max SPL, or something like that? I don't remember what those graphs were called that you had, something about frequency response at max SPL -- is this what you mean here? [/quote]

No, they're actually about -3dB @ 44Hz with 1W, that's their true frequency response. The Beyma 21" is a good driver (though quite expensive) but it is crippled in that relatively tiny cabinet - it needs to be in a box the size of a fullsize 2x18" PA sub to really do what it's meant to do, i.e. something of about twice the volume of an Ampeg 8x10" and far far larger than the AccuGroove enclosure. It's like putting a 1000bhp engine in a super-aerodynamic car to break the diesel engine speed record but only setting the gearing so in top gear it hits the redline at 100mph, not 300mph!

Alex

[skankdelvar]

I am genuinely filled with admiration for all of this; yet I'm sure I've seen it somewhere before. After all, it is about sound, our 'Holy Grail':

Soldier: Where'd you get the coconuts?
King Arthur: We found them.
Soldier: Found them? In Mercia? The coconut's tropical!
King Arthur: What do you mean?
Soldier: Well, this is a temperate zone
King Arthur: The swallow may fly south with the sun or the house martin or the plover may seek warmer climes in winter, yet these are not strangers to our land?
Soldier: Are you suggesting coconuts migrate?
King Arthur: Not at all. They could be carried.
Soldier: What? A swallow carrying a coconut?
King Arthur: It could grip it by the husk!
Soldier: It's not a question of where he grips it! It's a simple question of weight ratios! A five ounce bird could not carry a one pound coconut.
King Arthur: Well, it doesn't matter. Will you go and tell your master that Arthur from the Court of Camelot is here?
Soldier: Listen. In order to maintain air-speed velocity, a swallow needs to beat its wings forty-three times every second, right?

Etc...ad inf.

Edited October 25, 2008 by skankdelvar

[escholl]

[quote name='alexclaber' post='314587' date='Oct 25 2008, 03:50 PM']No, they're actually about -3dB @ 44Hz with 1W, that's their true frequency response. The Beyma 21" is a good driver (though quite expensive) but it is crippled in that relatively tiny cabinet - it needs to be in a box the size of a fullsize 2x18" PA sub to really do what it's meant to do, i.e. something of about twice the volume of an Ampeg 8x10" and far far larger than the AccuGroove enclosure. It's like putting a 1000bhp engine in a super-aerodynamic car to break the diesel engine speed record but only setting the gearing so in top gear it hits the redline at 100mph, not 300mph!

Alex[/quote]

haha really? how can they claim 21 Hz then, that's absurd....surely it's some sort of false advertising? tbh, i've always thought the box was a bit small for that driver, but given that i only know a little of speaker design i'd put it down to some sort of clever engineering

[Bill Fitzmaurice]

[quote name='escholl' post='314929' date='Oct 26 2008, 06:16 AM']surely it's some sort of false advertising?[/quote]False advertising of this cab's capabilities wouldn't be a first for AG. All of their claimed cabinet responses are way over the top, while their 'AccuSwitch' that claimed the ability to switch between 4 and 8 ohm impedance was proven to be snake-oil. Unfortunately for every person who says that AG's claims are at the least dubious, if not patently false, two more will say 'we don't care, it's the tone that counts'. It would be unfair, however, to single out AG for making claims that don't hold water; the practice is common throughout the industry.