Can someone guide me as to what Single driver ??

Hammer Dynamics Super-12 kit ($650, 97dB/8ohm)

It uses a 12" fullrange single-driver for 40Hz-10k+Hz, then a coaxially mounted supertweeter is used for 10k+Hz and above. 1st order crossover to minimize phase shift and distortion. It is is mounted in simple 70L ported cabinet and produces some of the punchiest, most powerful, bass I've come across in the FR speakers I've heard. The midrange is fantastic and highs just a good.

The Fullrange Driver Forum has a whole section dedicated to simple, cheap, Super-12 mods to raise the performance to an even better level.

I've owned them for 4+ years and listened to a lot of other FR systems in that time. Some were better overall, some were equal in one way or another, many were worse.

A couple of years ago I made the jump to a $12k+ FR speaker system(Fostex double-horns + dual subwoofers) after a few years of auditioning, but I still own the Super-12's. They are that good, especially when taking cost into consideration.

I consider them to be a near-perfect first excursion into high(ish)-efficiency FR speakers. They are affordable, perform extremely well, ably demonstrate all the best and unique qualities of single drivers, and provide extremely good bass response. The last point cannot be overlooked because that is single largest caveat to FR speakers - bass.

I have easily driven them with everything from flea-powered 3-18wpc SET's, 10-40wpc PP tube amps, and solid state 20-255wpc amps.

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.

As you mentioned here, i'm also using a very sensitive horn tweeter. It is quite a bit hotter in output than the paralleled Beta's, but as mentioned, i'm crossing it quite high and there are always EQ's available.

Yeah, we're padding the FT-17H down a little to better match with the Super-12's output. But, it is a much better match padded than the original Audax was with it's lower output. More seamless integration and extension. Surprising, because I am very sensitive to high frequencies and had always preferred soft doem tweeters.