Full Range Drivers

Donjr, try and find some people within driving distance who have single drivers. You really should hear several different types before making the plunge.

Check out The Fullrange Driver Forum, that's where all the fanatics hang out. Drop a post looking for people in your area, I'm sure there are a few. That's also the best place to ask any questions, members there have tried every possible of driver, cabinet, amplifier, etc.

One thing that should be made clear is that "Full Range" is a bit of misnomer for the average listener of moderate income and room size. Very, very, few speakers of any driver design actually cover 20Hz-20kHz(-3dB) accurately. Very few do 30Hz(-3dB) accurately. Those that do are usually very big, very heavy, and very expensive.

Fullrange single drivers have their advantages and limitations. I think the first sonic benefit that most fans, like myself, will tout is their musical "coherence". What does that mean? That the entire musical spectrum seems to emanate from one, seamless, sonic tapestry without any inconsistencies. It's very hard to describe in words, but once you hear it, it is very hard to accept anything else.

Why do they seem more "coherent" to some people than other multi-driver designs? I think most of us, like Macrojack, will cite no, or 1st order, crossovers and no need to transition between differing drivers at the crucial midrange frequencies where the ear is most sensitive to anomalies. Seamless transition between drivers of different size and construction materials is not easily done and fairly rare.

The downsides - like all speakers, bass. There are only three ways to deep, accurate, bass; 1) large driver surface area, 2) long driver excursion, 2) big cabinet. Usually, two of the three are necessary unless lots of power is needed.

And single drivers generally need really large cabinets to go deep with any authority. Even then, they won't move the same amount of air as good multi-driver designs. But, well-executed designs will have very fast and clean bass, which can be supplemented by good subwoofers.

Which brings us back to - is that really a single driver system? No, not in the strictest sense. But, single driver advocates are primarily concerned with a driver covering the most critical section of the frequency range in it's entirety - the full midrange (400Hz-6kHz). Most single driver proponents would even like to push that out to 8kHz-10kHz.

BTW, Tannoys aren't single drivers, they are coaxials with a center-mounted tweeter. But, their 12' or 15" driver does cover the entire critical range anyway. And they are pretty awesome when properly implemented in the right cabinet.

Donjr, almost any true fullrange "single driver" system is going to need a supertweeter and subwoofer(s), making it a 3-way system, in reality.

But, some have done a great job to moving the crossover between highs and lows way beyond the entire midrange frequencies.

A great starter system for a real taste of true fullrange glory is the $650 Hammer Dynamics Super-12 kit. It uses a professional 12" widerange driver to cover everything up to ~8-10kHz where it crosses over to a coaxially-mounted supertweeter.

This speaker does bass in a BIG way, along with all the benefits of other single drivers. A 12" driver has it's own benefits compared to smaller ones. There are a ton of upgrades that can be done to the speaker, like a better tweeter and crossover mods.

The kit is easily built by anyone with a table saw or circular saw and a few other simple tools. It can be made in a few hours from three or four 4'x8' pieces of plywood/mdf, if you are the least bit handy.

There are a few magazine reviews of the Super-12 on their website.

Donjr,

The FullRangeDriver.com(home of the FullRangeDriver Forum) still maintains it's original SingleDriver Website archives. Inside of that is a priceless resource that has in-depth theory, construction, and upgrade/modification information on a lot of the most popular designs a few years back.

But, most importantly, they maintained the Hammer Dynamics Super-12 Tweaks page. It documents the evolution of the Super-12's from the late creator's, John Wyckoff, original kit to better tweeters, crossovers, wiring, cabinet reinforcement, etc. Some really talented and enthusiastic people experimented every which way to squeeze the best performance possible out John's speakers. And their final tweaks take it to a whole 'nother level.

I think John's wife, Colleen, has incorporated a lot of those final tweaks into the kit now, so there may not be much to do anymore. I think the upgraded Fostex FT17h supertweeter now comes as part of the stock kit along with the better Solen hepta-litz wire wound inductors. Send Colleen an email, she is very nice and helpful. Supplying the kit is way to keep her late husband's dream alive. It's been a few years since I last sent her an email, so I can't say for a fact that she's still doing it, but the website is up, so i guess so.

If she isn't, I have an extra kit that I bought for my brother years ago that he never ended up building due to his first kid being born.

I have the Super-12's and still love them even though I have a much, much, more expensive and complex system now. There are things that a large single driver does well that smaller ones cannot match, bass being the most obvious. But, there is also a difference in the sonic presentation.

The Super-12's can rock with the best of them and still do jazz and chamber music extremely well. Vocals are eerily real. The Super's are a true 97dB efficent, so the whole range of flea-powered SET amps are perfect, from 2wpc 45's to "monster" 845's and 211's.

But, they also do extremely well with low-powered and larger push-pull amps. I preferred more power for most complex music, but have used them with 8 wpc 300B SET and 6wpc PX-25 amps with superb results. They also do well with good solid state amps.

The Super-12's are a great way to experiment with all types and designs of amps because of their relatively high efficiency.

Great point, Paul. Of course, there are wideband drivers w/o whizzer cones, too. Like the Fostex FE-E Sigma range in C&C speakers(I own IM-Bens). But, as you say, there is always some limitation to every driver and design.

I'm in the planning phase of my next big system change, it's looking like large Apogee ribbons or line arrays. But, I still really love widerange speakers for jazz and vocals.

If jazz and vocals are your thing, then a widerange driver system is really gonna float your boat. If the Super-12 ends up being the one, shoot me an email and I'll cut you a great deal on the unused kit I have(w/ upgraded tweeters)

Yep, Donjr, I have Fostex FT17H Horn Super Tweeter and the original Audax tweet that came with the kit.

As you've probably already read, the 98.5dB Fostex more closely matches the Super-12's 97db efficiency and only requires minor padding down to integrate well. On top of that, it actually sounds better.

01-27-10: Donjr
Darkmoebius...What does putting that kit together entail?

Darn, I used to have a .pdf copy of the manual on my computer, but I cannot find it. The printed manual is in the kit box in storage.

Essentially, you need only 2(or 3) pieces of 4'x8' mdf wood, wood clamps/straps, table saw, wood glue, and some screws. A router(and roundover but) is best for the port hole and driver cutout, but they can be done with a jigsaw. The speaker plans are designed so that all panels and bracing come off the 2 sheets leaving no real scrap. So, you cut the 4 side panels and two top off each 4'x8' along with 4 1"-2" strips for vertical corner bracing/screw in.

I'm not real good with a table saw, so I spent a lot more time stressing over getting straight cuts than need be. But, it really didn't take that long once I got going. It probably took me an hour or two to trace out and make the cuts, including the port hole and driver cutout. Assembly after that is pretty quick if you've got clamps and/or wood straps to hold the cabinet together while the glue dries.

Some people added extra thin strips of ebony(?) strips diagonally across the largest panels to break up and tame resonances. I added Deflex sound panels in mine behind the 12" driver to absorb and break up reflections from the back of the driver off the back wall. Also some Wispermat on the walls(not completely covered). Both these products absorbed reflections AND deadened the panel resonances. Also, the plumbers putty on the speaker spider. This brought a much higher level of refinement to the sound.

I think I still have 2 extra Deflex pads to go with the kit.