Designs with coaxial drivers;

Use of use of two identical/similar drivers;

Adding sub-woofers.

Heck, I even cringe at including drivers that use of whizzer cones.

IMO there aren't many actual single driver speakers because of a lack of true full range drivers (most are mid/tweeters even if they're 8 inches across).

In many places folks delude themselves into believing that response somewhat flat to down around 50 Hz makes for a full range speaker.

I applaud everyone here for striving for realistic bass. OTOH if we really held to the single driver premise there would be little to discuss here. To get back on track, lets list all known single driver speakers with full/realistic bass (with a somewhat loose definition of "full bass").

But by all means let the premise serve the music, in other words if push comes to shove full range music should not be sacrificed to serve the ideal.

Listen to some of Bob Brines speakers he's used Lowthers and Fostex, and I thought they were some of the best sounding full range drivers with TRUE Bass for a full range driver, being used in bass reflex and transmission lines. His link is on this board.

I've also heard Fostex FE series in some Tuned quarter wave pipes that sounded pretty damn good.

• Brines Acoustics

(I'm the guy who asked Bob to create the FTA-2000, but didn't want to preach on my own stuff.)

I've been a MLTL fan since the 70's and more recently a convert to single driver designs. The mighty Fostex F200A makes it possible. Reportedly other driver exist that might match it, but at much higher prices.

At the risk of sidetracking here, I don't believe in doppler effect in extended range drivers. The complex waveform is not made up of separate bass, midrange, and treble signals, but one integrated one, therefore different frequencies are not piggybacked on each other as some would propose. In fact if that were the case, we'd need an infinite number of drivers so that each could reproduce their own unique frequency.

I do agree with Bob regarding the limitations of extended range drivers, but prefer the volume levels and simplier musical forms they do best so it's of little matter to me.

The only example of FE series Fostex drivers that I liked was a FE206E in 0.75 cu. ft. bass reflex cabinet. Wouldn't meet my "full bass" definition, but didn't sound thin like so many others have and mated well with a sub.

Full-rangers CAN do bass. My bench mark is 40 Hz. If a full-ranger can get down to 40 Hz, then I'll use it in a single-driver speaker. Drivers I know that will go there are the FE167E, FE206E and FE207E. The F200A is the best of the bunch at the bottom. DX2 and DX3 go there. AN6 and AN8 go there. Last March, I took a pair of DX2 MLTL's to a Texas Bottlehead meet. They physically shook the floor on some organ petal notes.

Yes, full-range single driver speakers will do bass. The trade-off? Dynamic range. TANSTAAFL.

Bob

With the 24 db / oct xover I use, 90-3500 hz crossover seems to be the magic number, at least for the trusonics. With 12 db xovers, I agree, the driver should be bale to go upto 6000 Hz with no issues.
I think each driver is a little different, which is one of the reasons there is so much value added by builders like you & Wayne, who pretty much take the trial & error out of it for most folks trying a driver for the first time.
-akhilesh

Efficiency can also be an advantage as background noise stays farther into the background. Unfortunately smaller drivers are less efficient.

Marketing hype has convinced us for the "need" to reach 20 - 20,000 Hz at outrageous spl's. This serves to make building good speakers much harder and distracts from the heart of most musical forms.

As Bob stated above, most drivers that are called "full range" aren't really and would be better served if used as extended midrange. But that whole discussion belongs in a different forum.

As an old fart, 30 - 10,000 Hz and 90 dB continous with 100 dB peaks is plenty for me.

Bob