Single driver speakers without the pitfalls?

In researching SET amps, I have learned a lot more about the sort of high efficiency speakers that they are typically paired with, including single driver models like Omega, Blumenstein, Teresonic, etc.
The advantages of these designs are well acknowledged: coherence, imaging, high-efficiency and so forth.
At the same time, there seem to be equally well acknowledged drawbacks to these designs: Limited bass response, rolled off highs, and a harshness or "shout" in the upper midrange.
Some designers, like Tekton and Zu, seem to take the approach of getting the best of all worlds by joining a wide range driver to a tweeter of some sort. (To some extent, my Reference 3AM De Capo monitors take this approach.)
What I'm curious to learn is whether you think there are any single driver, full range systems that transcend the above limitations.
Eager to hear your thoughts.
I spend 5 days a week in my office with a pair of Merrill Zigmahornets. There is nothing harsh about them nor any spikes in frequencies.
You won't believe the bass you can get out of a 4" quarter wave transmission line speaker. These hold their own into the 60-80hz range. There are definitely limits to any full range speaker-nothing is perfect.
The closest I have seen to building these yourself is perhaps Role Audio or something by Ted Jordan or 47 Labs which use Jordan drivers.
I've heard Focals and Lowthers and really prefer my Merrills at the expense of a little bass. I have also tried mine with a sub and they still lose something in the mix. Lack of low bass isn't a pitfall if you don't notice it. I also tried adding supertweeters and was not thrilled.
When there is synergy, you won't believe how good it is. This 10 watt tube system is a smooth and inviting as you will ever hear.
For about three years I listened to these and loved their sound.
Acoustic Technologies
They were at their best with vocals, strings, small Jazz combos.
Hi Rebbi,
My experience fully agrees with Elvick's.
I am using Beauhorn Virtuoso speakers, rated at 106db, with single 8" Lowther DX4 drivers.
A well known reviewer, who's name escapes me, had listened to the few different cabinet designers utilizing this driver and felt that the BV's found the best advantage of that driver.
Even my 45 amps and 300B amps (Wavelength) effortless provide more than enough volume in my small room.
I like the simple purity concept of crossover-less single drivers.
As I realize that nothing is perfect, I am fully content.
Is that Merrill DCA 4 driver even made anymore?
I don't think that the driver you seek actually exists. The closest thing I've heard was a lowish output SET powered speaker using the Jordan 4" driver in a home-built enclosure. It was augmented by a powered subwoofer crossed over somewhere south of 100hz. In some respects, this set-up gets pretty close to your goals - especially since the sub and main speaker were wired in parallel from the pre-amp (the sub was out of the signal path). The only x-over in the system was the high cut on the subwoofer and the Jordans ran full range.

It wasn't the best sounding system I've ever heard, but it was an excellent sounding system of its type.
I had some Decware HDT which had great bass (passive radiators)and no horn negatives. Now I have some Decware MG944 which also have good bass and no honk (2 woofers and ribbon tweeter with no crossover).
With just a few watts only on a very small scale ie headphones. With more
power the fuller range Walsh drivers aka dale harder. Otherwise two ways
with the simple crossover designs. For full range bass off just a few watts
in most any room large drivers in bigger boxes needed. Horn loading
helps. That's how most speakers for pro use are designed, large and horn
loaded for maximum efficiency.

You can't change physics. Pressurizing a room at low frequencies requires
some muscle however one gets it. Headphones can deliver needed spl at
all frequencies with fewest watts due to proximity to eardrums.
Tannoy Westminster should be able to do it ALL, but technically that's 2 drivers (and crossover) in a coaxial configuration. Otherwise, I will never believe that any single driver (besides headphones/earspeakers) can do it all -- as mentioned above, physics cannot be cheated, especially when high quality reproduction across full bandwidth is the goal.
well, there was Yamamura...or look at the is possible but you will always have to pay for it...
How about he Eclipse TD712z ? anybody heard these.
I think what you describe is the idea behing dual concentric designs like the tannoys.
I'd agree large dual concentric drivers in a large box like the big Tannoys (have never heard) is probably the optimal approach for use with low wattage amps, especially for more near field listening scenarios. Dual concentric has less unique advantage listening from a distance where drivers can blend more naturally due to more distant listening perspective.

KEF is big on dual concentric speakers, but not for low power tube amps in particular.

I mentioned nearfield listening. There are many more options there for low power amps due to proximity to speakers.

Driver assemblies that approximate a point source (like single or dual concentric) will have an advantage from a coherency perspective for nearfield listening scenarios in particular, but other designs that approximate a point source as well to various degrees may work quite well, depending on exact listening perspective.

Small studio monitors are commonly used in pro apps for more nearfield listening scenarios. Of course headphones play a huge role there also for good reason.

Whenever the low end is offloaded to a good sub or two, teh options for mains always becomes greater, almost unlimited.

Practically, if it were me, I would lean towards a two driver approach off loading the bass to a better qualified design as needed. In the case of a low power SET amp, that would mean separate powered subs in most rooms.

Offloading bass to a sub when needed is pretty much the only solution. You can add the subs yourself, the most practical and flexible solution I think, or buy a large speaker that has what is needed built in already.

I have a pair of STAX earphones that are quite wonderful sounding, especially with good amplification. If there is a SET amp in my future, it might be for those and it might even lead me to upgrade to a bigger better pair of STAX.

For speakers, small planars (Magnepan) or eletrostats (ML or similar) plus separate well integrated subs is something I would consider building around a SET amp. These speakers can be surprisingly tube amp friendly, but not particularly efficient, so powered subs would be the ticket. THis is the approach MArtyKL uses with his MMGs, OHMs, and others I believe, though not sure if he has ever tried this with a SET amp per se.
There will always be tradeoffs. With a well executed single-driver speaker you might not notice the downsides, but they would become obvious if you compared to a good multidriver speaker driven by a powerful amplifier. My two setups: Musical Affairs (single driver) and TAD (multi).
Rebbi, your are correct that my DCA 4 driver is no longer made. I believe these were a single run only. If I were to pick another driver to install it would be the Jordan.

If you are thinking DIY speakers at this point as well (not a bad idea for flexibility) mount the single full range driver of choice in a cabinet, tweak the cabinet as needed, add a sub or two as needed, and you are done with a very nice DIY system (save source).

I see Dale Harder sells German Physiks DDD like Walsh drivers for DIY now. You can go full circle!! :^)

PRobably not real efficient, but assuming its not a hard load to drive (charts I have seen indicate OHM Walsh drivers at least are not, at least not until you get down into the bass regions that a sub can cover)and cross over the right sub at high enough frequency and you might really have something.

OR just stay with conventional directional full range drivers depending on preference. Either way might work.
I'm not really thinking of building my own speakers at this point, but I'm trying to learn more about the "full range" drivers that so many people seem to like to pair with SET amps. I'm also curious about Tekton, since their models are very competitively priced and very efficient (as in 94 db and up).
I see. Makes sense.

Keep in mind that the trend will be for smaller "efficient" speakers to have limited bass response (that's how a lot of the efficiency happens, power requirements go up exponentially as frequency decreases).

If it becomes a problem, and it may not depending on expectations, then that's where adding subs and blending them in well solves the problem effectively, if done right (not always easy to do but usually doable in the end).

The key to good coherency is often to not have crossovers in the midrange frequencies where most music (and voice) occurs. Bass region crossover points as is the case with subwoofers is not problematic in that way, but getting levels right in the bass (reasonable flat one would expect) more so. Electronic crossovers and room correction software is probably the most fail safe way. Again, I believe that is what MartyKL does and often recommends (smart guy!).

FWIW, my little Triangle Titus monitors sounded top notch in my decent size family room/kitchen area prior to the sub I used with them finally dying. That with mere 70s/80s vintage 15-20 watt (SS) receivers. I've always had teh Triangles targeted for trying a mimimal power tube amp someday, but would not put them back in that room without a sub or two again. I'd bet your DeCapos would likely do at least as good or probably much better even on a SET amp with subs. Without the subs on a SET, it might be a closer contest.
Tekton 4.5s, good to about 50hrz, not bright, not shouty, great coherent stage, lovely mids, I really like them. Quality all around for about $300 new. I now use the 4.5s in 12x14 bedroom. Break-in time to sound their absolute best about 200 hrs (Fostex driver).
Interesting! I hadn't heard of the 4.5's. Seems that they are working on a 4.5 v.2; no details on the Tekton site, though.
Just for the fun of it, I called Tekton yesterday and spoke to Eric Alexander. Very nice guy. I gave him my system and room details (including the SET amp) and he said I was kind of on the borderline but he'd suggest the Lore or Lore 2.0. They are both 98 db efficient... yowza!
i think Eric prefers the big solid state amps for his speakers, but I've heard of plenty of people driving them with flea watt tube amps. I have driven the Lore S with the Dennis Had Inspire amp - 8 watts? though I prefered the power of my 30 watt push pull, the regular Lores are more efficient. I say go for it. Won't need a sub.
I like the Tekton value proposition and they are on my list of speakers to hear someday. Have not had the opportunity to-date.

I did hear a pair of larger Zu's once at the Capital audiofest. THey sounded nice on smaller scale jazz and classical recordings but I was not impressed overall. However the Zu guy conceded to me that the 6 watt or so set they were running off was likely underpowered for certain kinds of music, so the book is still open there for me. Source material was all vinyl.
"There will always be tradeoffs."

That is a fact.

Practically, I think the best approach is to minimize the # of drivers. Two drivers done well is enough in most cases. THree can work well also but keep the crossover points out to the frequency extremes as much as possible. The tradeoff is multiple drivers have to be integrated optimally for teh best results. With today's digital processing tools and techniques, its very doable. With just the technology of 50 years ago alone, a lot harder.
I am not rushing out to sell my De Capo's anytime soon. Of course, I want to hear what they sound like with my new amplifier. However, the Lore is a very interesting proposition. Looks like an almost unbelievable value and the reviews are universally very positive. Plus, it would be almost a full range speaker. So, my mind is open but I want to see how the new amp sounds in my current rig.
By the way, there is also a 2.0 version of the Lore but using a different tweeter. The website doesn't really make clear what the differences between the two, and Eric only said that they use different tweeters but they both sound great.
There are MANY tradeoffs associated with single driver speakers, so that whether the offsetting positive attributes make them desirable is largely a matter of taste and how a system is used. The most common deal stoppers for most listeners is the limited bass response, peaky upper midrange, and limited volume level. I have heard some very nice fullrange systems, but, on balance, I have not heard one that I would prefer over a high efficiency multi-driver system. I have not yet heard the Voxativ system which I have been told is one of the best at overcoming most of the problems with fullrange systems.

What I have been very impressed with are systems that use one driver to cover a substantial part of the frequency spectrum. One of the best systems I heard had a Western Electric fieldcoil 555 driver that was run fullrange (not rolled off by a crossover) into a Western Electric 15A horn, with a tweeter filling in the very top of the range and two 18" woofers in a horn-based cabinet. The BIG downside to this system was the size of the speakers--it is like standing two Smart cars on their rear bumper in one's living room.

Another system that makes very good use of a wide-range driver is the Surreal Sound system. I recently heard their active crossover two-way system that utilizes a fieldcoil Lowther driver for the midrange and tweeter. Six woofers provide bass from a separate dedicated amp. This 99 db/w efficient system sounded absolutely fantastic and exhibited very little problems in the way of peaky or rough frequency response. I had previously heard a different system from Surreal Sound that used the fullrange Tangband speaker as the midrange/tweeter. This system sounded very good too, just not as good as the one with the fieldcoil driver.

I have heard a number of fullrange systems that use the Tangband driver. These systems sounded pretty good, particularly given the price of this driver. I bet a system designed around this driver as a midrange driver would be quite price competitive.
Reb, I would definitely not ditch the Decapos until you get the chance to get things ticking in your new "dedicated" room. I predict the Decapo/SET combo might really shine in there eventually, but you know, "famous last words".....
As much as I like the Tekton Lore, M-Lore and 4.5s that I own, I'd take Mapman's advice above. Keep the DeCapo, get them and your system working together, likely will sound terrific. If you do run into any problems with efficiency (doubt it) for price to performance the Tekton should be on your short list.
Yes, totally, absolutely! I have enjoyed the De Capo's so much over the past couple of years and I have no intention of ditching them anytime soon. I hope and suspect that you are right – that the De Capo sounds fantastic with the SET amplification. By the way, spoke to Brian over at Audio Note this morning, and my kit should be shipping out tomorrow (Friday) or Monday at the latest. I can't wait. :-)
By the way, I am going to be blogging about the building of my amp. If anybody out there is interested in following along, I have already started the blog and it is here.

Good luck on your build & blog. Have you considered some of the fancier build techniques that are described all over the internet for Audio Note kits? I know that some builders even go so far as to use the PCB to lay out the parts, but they then hard wire the circuit with wire that follows the board traces.

Another interesting thing that some builders do is to employ wire looms to hold wires together neatly instead of plastic ties. A friend of mine uses this "old school" practice. Note that other builders actually dislike having wires neatly grouped together because of the electromagnetic coupling (inductance) and prefer a "bird's nest" haphazard form of wiring. I don't know what is the "right" approach and would be inclined to follow the manual myself, but, I thought you should know about the lively discussions out there on Audio Note builds. For example, take a look at this discussion of wire looms:
This is super interesting. He even has a blow-by-blow description of building an older version of the Kit 1! Cool.
I never knew about wire looming - very interesting. I know about the rap against neat wire bundling causing inductance, etc. Steve Deckert of Decware told me that he deliberately doesn't bundle his amp wires for that very reason.
As for eliminating the PCB's and hard wiring the whole kit, I think I'm going to pass on that option! Although it may sound nominally better if you get it right, I think I'd forfeit any claim to Brian's tech support time if I do radically circumvented the build instructions. Also, this kit wasn't cheap, and the thought of ruining it is sobering!
I know your blog is in its early stage but I'm enjoying your style already and look forward to more.
This is all good stuff. I'll be soaking it all in so in 10 years or so if/when I retire I can perhaps be more DIY perhaps. They say you become more like a child again as you grow older. I built many electronic kits as a kid, nothing so bold as a high end SET though. Those experiences have served me well.
The Voxativ mentioned above is interesting in that it shows a good point: that audio can get carried away with features and forget about the benefit package.

Having had several good listens, I'm amazed this speaker was given the coverage it has been given. I think it's only real impressive thing is that it sounds as good as it does while using only one driver. I think that impresses folks not because that sound is so good on an absolute basis, but rather that it's as good as it is while only having the one driver.

If that speaker were covered in fabric so nobody could tell it was a single driver system, and therefore would not have the "surprise factor" that one driver could really work, it would be derided for being so limited and having such high coloration and distortion. I doubt anyone would be trying to point out some great "directness of sound" or "magic midrange". It's like the bumblebee: it is not amazing that it flies so well as it does not. It's amazing that it flies at all.

Oh...I realize I have forgotten to point out a true strength of many single driver systems: good sensitivity. But there are much better 2 way high sensitivity systems.

I suppose another strength is that they are easy to make, and fun to play with, and appeal to some folks due to the utter simplicity along with the challenge of getting them to sound anything other than awful. But none of that has to do with great sound.

Throw rocks as you wish.

Now don't hold back... tell us how you really feel. ;-)
Yeh, I do not think the OP was trying to get the full range sound of single driver unit...he just wanted the best compromise you get with it.....means the most extended system using the SFD. If he wants to have it all, well he has to go for multi driver, multi amplified system using active crossovers....well another topic.
You might take a look at the Classic Audio T-7, it's the closest approach I know of to what you're looking for.

dealer for other stuff
Wow, Duke, those are HUGE!
I have had 3 full range based speaker.

forget about it.

the highs isnt refined enough, and forget high spl, and forget bass extension

never again
Owned several, heard others, IMO single drivers just can't reproduce any instrument, save perhaps a guitar, accurately .
There is a reason why single driver speakers are a niche market, at least for hifi systems. TEchnology has probably improved but again those darn laws of physics just stand in the way. HEnce the proliferation of other designs.

Midrange is where most music happens so nothing wrong with the tradeoffs involved. Limited frequency response makes finding a suitable amp an easier task, not to say that any two will sound exactly alike.

Its all about tradeoffs. Dale Harder's modern Walsh drivers probably have the best chance of pushing the limits but I would still be concerned about power needs, overdriving them, or just being able to stay in good working order over teh long term. All those things that limited their mass appeal in the first place.
Zus with the latest Radian tweeters are quite an accomplished speaker nowadays. Highs are very natural. With active bass on the Definitions, really an ideal compromise.
How about the Manger drivers? They are pretty unique. Have always wanted to hear but not very commonly found in these parts.
Never liked speakers that used the Manger drivers. They did not seem to integrate well with other drivers.
And what about these guys? They advertise here, FWIW.
I have gone part way down the single driver path w a pair of DIY open baffle speakers that I bought from a member here, and I like them very much. They use the Feastrex 5" field coil driver w a whizzer cone, running full range, no x-over. The low bass is provided by 2, 12" subs driven by a 500w plate amp. The mids are to die for and the bass is pretty darn impressive, as well. Of course, I can dial in the bass balance as I please w the attenuators and low pass filter in the sub amps. And you get true stereo subs, to boot.
Its pretty apparent that while single driver speakers do many things very well, that they do **all** things poorly. Put another way, if you want to get the best out of them, consider setting them up with a good subwoofer at the very least.

Getting the bass excursion off of the cone will reduce the distortion of the driver and improve the presentation.

The appeal of having no crossover and the driver do everything you need is like a siren call. -but-
Bottom Line: There are no single driver speakers without the pitfalls.
Well put, thank you!
When in doubt powered subs done well are almost always the great equalizer.
Fostex fe208e sigma can make for a wonderful sound if used in massive BLH but will need a super tweeter. The Fostex f200a has advanced cone and extreme quality build it can produce massive bass FS is 30hz but again needs large cabinets. The SEAS X-1 again very high quality works well in very large monitor. I've used most available FR Lowther AER Festrex etc etc. I found the drivers I mentioned to be quite stellar performers if used properly. Many FR designs use small thin cabinets or filter away the perceived offenses. But if design is proper full ranges or wideband with tweeters exist that can do great service but you're not going to hear what's possible out of small cheap transducers in overly small cabinets. A full range driver loudspeaker needs as much if not more care in construction over conventional after all you're expecting a heck of alot out of 1 transducer.
The original poster's question is akin to asking for a unicycle without the pitfalls of a unicycle; like asking for a unicycle for the balance of a bicycle; a bicycle with the stability of a 4 wheeler.

The physics just does not allow a driver to span a full frequency range without a lot of distortion. When I listen to "the best" single driver speakers I am amazed that folks can live with that distortion on a regular basis just to get some "directness" of sound. The only way I can make sense of that is that the technical challenge of using only one driver and no crossover is as important to them as the sound. In other words, they see the endeavor as a "fun thing" and a challenge as much as a "musical thing".