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PA horn scoop bins [message #33502] Sun, 01 July 2001 03:56 Go to next message
Andy G is currently offline  Andy G
Messages: 68
Registered: May 2009
Viscount
What driver parameters are required for this type of box, I actually was thinking of trying it with Eminence Gamma 12's, are they suitable?
Vas=80.7L Qts=.89, Fs=55

(Will adjust dimensions for 12" box, I just had the 15" box diagram handy)

Re: PA horn scoop bins (why am I getting involved in this one) [message #33505 is a reply to message #33502] Mon, 02 July 2001 13:31 Go to previous messageGo to next message
Rog is currently offline  Rog
Messages: 5
Registered: May 2009
Esquire
Dear Andy,

That looks like one of my scoop designs. I designed a lot of scoops a long time ago, but am not a believer nowadays. The interaction from the front of the driver and the horn mouth worries me especially with short ones. If you must have scoops then make them as big as you can and with at least an 18" driver, 21" and 24" drivers are better still. This way all the output below the crossover point (and it should be a low one of around 80 Hz) will come from the horn, and not the front of the driver, minimising any phase shifts. So, get the girly Gamma 12's and put them in a front loaded horn for low mid use and get some real bass drivers.

If you really must have scoop bins, and I will only go along with you on this one if your entire record collection is dub and dance hall reggae, because that's all they sound good with, then drivers with the same parameters for other horns should be used, (high EBP's) i.e. a high Fs and a low Qes.

The Eminence Gamma 12 has a very low EBP of 76, oh dear.

Did I mention that Precision Devices has a 12" driver with an EBP of 282, oh well I just did. Should interest all you horn nutters out there.

Scoops away!!! And in with the 6th order bandpass for PA low end.

Best wishes,

Rog Mogale Ebn Hons

That's what I like to see!! [message #33507 is a reply to message #33505] Mon, 02 July 2001 18:03 Go to previous messageGo to next message
Andy G is currently offline  Andy G
Messages: 68
Registered: May 2009
Viscount
Someone who doesn't pull punches !! Cool. Ok so the scoop idea hits the rubbish bin. Why did a buy these 4 Gamma 12's in the first place? yep i got them cheap! but they have proven nothing but trouble coming up with something to do with them.

Oh well, back to the drawing board !!!!

Oh and THANKS Rog.

Re: PA horn scoop bins (why am I getting involved in this one) [message #33508 is a reply to message #33505] Mon, 02 July 2001 18:32 Go to previous message
pickle is currently offline  pickle
Messages: 24
Registered: May 2009
Chancellor
Does your feeling about scoops extend to the old JBL scoops/double scoops? Were they any different/better? Or are you saying that you are not a believer in any scoop design? Just curious. I don't really know much about them, but never knew they might be an inherently bad approach. To build my knowledge about such things, I simply take the opinion of one who seems to have considerable experience of a subject which I won't have, assign weight to their argument, and form my opinion. Therefore, scoop=bad.
MBB

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