Why are single drivers disliked to such an extent by most in this forum?

[FrankW]

I am aware that these have a few issues, from IMD, to limited SPL capability, and beaming at higher frequencies, but are they so poor at these aspects that single driver sets are basically a pointless design to consider?

Not if you like all those aspects, including zero (real, not imaginary) deep bass, as some do

 

[somebodyelse]

For the last point you made, it's usually because there's a lack of any real BMR that is designed to go that low right? Or is it an inherent limitation of a BMR's design?

If it's not inherent it's tricky enough to solve that nobody has brought one to market yet. From the measurements I've seen, the ones that are large enough to have half-way acceptable bass get messy at the high end, and the ones that do reasonably at the high end can't go much deeper than mid range. I assume it's more difficult to manage the breakup modes with the larger diaphragms.

 

[egellings]

i think this place quite likes the KEF LSX, Meta whatever the hell variants. It can be done, just not as well as KEF apparently... and at what cost.

Doesn't the KEF have two drivers, tweeter and woofer, coaxially mounted in the same frame?

 

[fpitas]

Doesn't the KEF have two drivers, tweeter and woofer, coaxially mounted in the same frame?

Yes. And their flagship speaker has a woofer to go with it.

 

[Mart68]

I think there was some confusion between point source speakers and single driver speakers since they are a point source speaker too.

 

[DonH56]

Well, there are full range electrostatic speakers like the Quads using a single driver ...

Note most of these (as well as planar dynamics) split the panel mechanically and/or electrically to reduce beaming and improve HF performance.

There have been speakers using multiples of smaller speakers to provide full range performance, including various line sources by Bose (professional), McIntosh and Carver, and of course the Bose 901 series (not a line source). Coaxial drivers are a special case not really a single driver but rather co-located drivers IMO. I am not aware of a single-driver full-range system that has excellent performance but have only heard a few over the years, none recently, and do not follow the market.

FWIWFM - Don

 

[Steven Holt]

Yes. And their flagship speaker has a woofer to go with it.

That's true, and thanks for pointing this out. I think the trouble we are having here is defining 'single driver'. Hell, I'm confused. It could be anything from a coax to the Bose 901. I hope the OP, or someone, can make this well - defined.

 

[fpitas]

That's true, and thanks for pointing this out. I think the trouble we are having here is defining 'single driver'. Hell, I'm confused. It could be anything from a coax to the Bose 901. I hope the OP, or someone, can make this well - defined.

I take it to mean no crossovers. But I guess it could be construed differently.

 

[Steven Holt]

I take it to mean no crossovers. But I guess it could be construed differently.

Thanks, you've laid down a good starting point. Just thinking about it, do u know if the 901's had a crossover, or were they just wired in series?

 

[DVDdoug]

Speaker design involves many compromises & choices. After many years, the traditional 2 or 3-way designs still dominate the market for home & pro use. (A separate subwoofer is "new" but it's not THAT much different... It allows multiple smaller 2 or 3-way surround speakers.)

"Small things make high frequencies and big things make low frequencies." A kitten can't roar like a lion...

An array of many small speakers should "work" if you have enough total surface area for the bass. And a vertical array should be OK as long as you don't need vertical dispersion. I've seen pictures of speakers made that way but I've never heard one. You'd have to somehow "handle" the higher resonant frequency of the smaller drivers. It's probably costlier than a traditional design and probably no better performance (if not worse). If it was a good design (good compromise) you'd see more of them.

 

[fpitas]

Thanks, you've laid down a good starting point. Just thinking about it, do u know if the 901's had a crossover, or were they just wired in series?

To my knowledge, no crossover.

 

[DonH56]

Series-parallel for the 901 (and 800). No crossover. External active EQ box.

 

[Steven Holt]

Series-parallel for the 901 (and 800). No crossover. External active EQ box.

Thank you for this, just excellent. let's take this one more step : do u think that a single driver speaker, with an equalizer (inboard or outboard) could possibly be high - fidelity? Or is this simply not practical?

 

[SSS]

I am aware that these have a few issues, from IMD, to limited SPL capability, and beaming at higher frequencies, but are they so poor at these aspects that single driver sets are basically a pointless design to consider? Or is there something else about them that makes them such an unattractive option measurement wise?

You said it, there are inherent issues. Further there is also the doppler effect which modulates the highs when cone extension due to bass. This is also measureble and hearable. Whatever was tried, it was a compromise. Physics and acoustics make the rules which cannot be changed. Even dynamic speakers in earphones have problems to give a good sound for 20-20k. There are some mechanical tricks to make it.

 

[Tangband]

really I am not much for two way designs either, unless they use a good compression driver. Both sets of speakers I have in daily use are three-way.

IMO two way cone and dome is almost as big a compromise as a single driver unless used with subs and high passed.

Electrostatics also have too many compromises for me although what they do well they do very well.

But there are single driver speakers that are good enough to make an acceptable sound, that's the point I was making. I don't really understand why anyone would want that compromise, and obviously anyone claiming they have some unique benefits is, well....wrong.

Yes , 2 ways are troubled because the crossover is in a sensitive area and the size difference between the bass and the tweeter are to big to be inaudible - This is easier to make good with a dsp 3-way speaker.
But the point is , a good fullrange driver dont have any crossover point in any sensitive area for the brain/ears.
This might be the one of two reasons it might have some qualitys that 2-way speaker lacks. The other advantage with a full range driver is that all the sound are coming from one spot, very audible If listening nearfield.

 

[DonH56]

Thank you for this, just excellent. let's take this one more step : do u think that a single driver speaker, with an equalizer (inboard or outboard) could possibly be high - fidelity? Or is this simply not practical?

I am not a speaker designer, but I do not believe it practical, though different folk have different definitions of "high fidelity". IMO a single driver cannot solve the physical issues of beaming and need for high excursion with extremely rigid cone surface to provide adequate output and sensitivity over the full frequency range. And as @SSS mentioned you have the Doppler, or as I learned it frequency-modulation distortion, that occurs when a single cone is required to reproduce such a wide range of frequencies. You'd need to approach a point source design with very small radiating surface and very long throw (excursion) and the physics are against you. I'll go out on a limb and say it is impractical to get sufficient LF output with low distortion from a very small radiator, and impractical to obtain broad dispersion with low distortion from a large driver suitable for bass. The closest practical single drivers, as mentioned earlier, are large panels that are segmented to improve their dispersion, and even then it is very difficult to obtain high LF SPL with low distortion as it is difficult to provide a linear voltage (ESL) or magnetic (planar-dynamic) field over a long enough range (excursion) and/or large enough panel to produce the required LF output.

Multiway speakers are used for good reason, though getting smooth response across the midrange is a challenge because it spans so many octaves. The choice of drivers and crossover design become very critical to provide a smooth response across the entire "midrange" region of say 300 Hz to 3-8 kHz or so. But they solve more problems than they create, at least most of the time for decent designs. I have to think single-driver speakers would be cheaper and easier to manufacture so if they were a viable solution we'd see more of them.

IME/IMO - Don

 

[Blumlein 88]

The Quad ESL 63 was designed as a quasi-point source. It has concentric rings with a time delay between each ring and frequency contouring so it was only driven full bandwidth over the center and progressively less over the rest of the speaker. This let it function like a simplified point source from a point that acted as it were 9 inches behind the panel. Some variation on this, perhaps more segments, perhaps with DSP for better integration of the segments would have maybe the best chance to create a large full range, or nearly full range single driver. One that has dispersion as needed at each frequency. Obviously it is more complex than a cross-over for three or four way multi-coned speakers.

Maybe one day beam-forming will be well enough worked out so multiple drivers can function like a perfect point or line source speaker. A single rigid cone won't work well, a single cone not rigid is going to be an iffy proposition.

 

[Tangband]

The Sibelius loudspeaker driver is probably designed with Fletcher Munson curve in mind. The same rise in the treble.
This is much like newer B/W speakers.

What is the Fletcher Munson Curve? Using Equal Loudness Curves in Mixing and Mastering

What are the Fletcher Munson curves, or equal-loudness contours, and how do they apply to audio mixing or mastering? This article will cover that all in detail.

www.izotope.com

 

[fpitas]

The Sibelius loudspeaker driver is probably designed with Fletcher Munson curve in mind. The same rise in the treble.

What is the Fletcher Munson Curve? Using Equal Loudness Curves in Mixing and Mastering

What are the Fletcher Munson curves, or equal-loudness contours, and how do they apply to audio mixing or mastering? This article will cover that all in detail.

www.izotope.com

View attachment 287127

I believe you'll find that is simply break-up and beaming effects. In any event, that will sound bad (well, it would to me), unless you listen off-axis where the treble is reasonable.

 

[Tangband]

I believe you'll find that is simply break-up and beaming effects. In any event, that will sound bad (well, it would to me), unless you listen off-axis where the treble is reasonable.

I will soon find out….