Can someone guide me as to what Single driver ??

Darkmoebius: I would not doubt that the Hammer Dynamics system works reasonably well, as i've used the same basic 12" Eminence driver in several different yet similar PA installations. I've made mention of this Eminence driver a few times when talking about full range drivers here on Agon, but nobody has ever asked for specifics on it.

I've got four of these Eminence drivers in my basement right now. They are in partially finished PA cabs that i'm building for a local band. I'm running two of the Eminence 12's per cabinet full range and bringing in an Eminence horn tweeter at 6 dB's / octave at 11 KHz. The shallow slope allows the tweeter and full range drivers to blend right at the point where the larger full ranges are starting to take a nose dive. It also negates the losses involved with a passive crossover on the full-range drivers, improving sensitivity.

We've run similar cab's as mains in small clubs and electronically crossed them with subs below them when more volume and bottom end is needed. They are versatile enough as designed, but the added wallop of the extra woofer area and electronically crossing the full-ranges really adds quite a bit of punch.

Thanks for the links to the "Super-12 mods", as i'm sure that i'll check that out very soon. Sean
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Sean,

Which Eminence driver are you talking about? Not that I have a project for it right around the corner, but if you like it that much then I want it in my bag of tricks.

Thanks,

Duke

Duke, for an inexpensive driver, the Eminence Beta 12LTA offers pretty wide bandwidth and high sensitivity. Eminence has recently revamped their measuring techniques, so some of the spec's may be different than what is posted on PE's website. Lot of basic mods that can be done to improve performance without a lot of cost. Still want to check out the list of mods for the Hammer Dynamics that Darkmoebius listed above though, as maybe others have caught some things that i haven't.

Other than that, one can build a complex crossover with Zobel's to flatten the rising impedance, but i've never bothered. Running a pair of these nets you 99+ dB's @ 1 watt without ever dipping below 4 ohms anywhere in the band. Easy load, wide bandwidth and high efficiency for not that much money. Sean
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Still want to check out the list of mods for the Hammer Dynamics that Darkmoebius listed above though, as maybe others have caught some things that i haven't

Oh no, tell me it ain't so!

"Maybe" somebody thought of something you didn't?

A little full of ourselves don't you think?

Hi Sean,

Glad to hear you put these great Emminence drivers to good use. They are a true miracle value when properly used.

I should point out that there are some significant construction differences between the commercially available 12LTx driver and (the late)John Wyckoff's custom made Emminence Super-12.

To quote JW from the Super-12 mods page I linked above:

John Wyckoff's description of the Super 12 (compared to the Eminence Beta-12LT)

Cone composition: Beta-12LT is conventional Kraft type. Super 12 is slightly heavier (different mix of fibers).

Voice coil: Super 12 has smaller gauge wire with a Nomex former. (I dropped the Kapton former after the first ten samples.) Beta-12LT uses Kapton former which is not quite as neutral in the mids. Super 12 coil is slightly lighter bringing moving mass to about the same. Super 12 uses one shorted voice coil turn to reduce inductance and improve high frequency response.

Motor: Super 12 has a soft-iron polepiece to improve BL. Beta-12LT has low carbon steel. Super 12 has shorting ring at the base of the polepiece and is capped with an aluminum shorting ring (also called Faraday ring).

Spider and suspension: Super 12 spider is woven Kapton fiber and is slightly softer. The suspension on the Super 12 is doped to be slightly stiffer.

Glue: Super 12 uses a lower-mass, harder formulation, and less of it. Improves high frequency response.

As to how big a sonic difference that all makes, i have no idea. I've never heard the regular Beta 12LT.

Other than that, one can build a complex crossover with Zobel's to flatten the rising impedance, but i've never bothered.

The Super-12's use a very simple series 12uf cap + 7 ohm resister [url=]Zobel network[/url](x-over diagram) on the 12".

One of the big changes was switching from the stock Audax tweeter to the more sensitive horn Fostex FT-17.