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Speakers w/Full-range Drivers

mdalton

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New member here, though long-time beneficiary of the forum, particularly DAC reviews (I have a Topping E70 and Okto DAC8 in two of my systems).

Anyway, with regard to speakers, over the last few years I’ve increasingly been drawn to the sound of crossover-less (or minimalist) designs by companies like Fern & Roby, Rethm, Voxativ, Songer, etc. I know there are many on this site who believe that such a design is fundamentally flawed, or limiting, such that it is unlikely to ever compete with a well-designed two- or three-way speaker.

The most obvious challenge to a design using a full-range driver is at the frequency extremes. But some of these companies using full-range drivers have come up with interesting approaches for addressing this challenge. Rethm, for example, essentially uses a powered subwoofer - 4 drivers in an “isobaric configuration” to fill in the low-end - but of course most of these companies do not provide detailed specifications on their speakers’ performance.

So finally to my point: At Capital AudioFest this year I heard a pair of the Audience 1+1 speakers and found them remarkable. They use two full range drivers and two passive radiators in each small box. But here’s the kicker - unlike some of the other examples I’ve heard, Audience publishes info that includes some detail regarding their frequency response. I’d be very interested in others’ views on this, as it appears as if they have accomplished a remarkably flat and extended frequency response with these little speakers:

Audience white paper

I appreciate everybody’s patience with such a long, first post!
 
Welcome. There are a lot of benefits to a single full range driver like aesthetics but things like dispersion are much harder to control. Something with an even on axis measurement may not sound even in room. This can be a feature or a bug depending on your particular room.

With DSP, there may be a lot that can be done with a single full range driver.
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But the sweep doesn’t tell you about max SPL (which is a compromise with single range drivers). Many good headphones are single full range drivers, but they don’t need to reach high SPLs due to the distance nor do they have major dispersion issues (though the spatial effects do involve dispersion).

I sent @amirm my Meyer Sound MM-4XP which is a full range 4” active speaker to measure. That is one of the fanciest full range single driver speakers I know. It’s about 120 Hz to 18 kHz at high SPL. If you didn’t need high SPL, it potentially could go lower in bass extension.
 
Interesting. So here’s a possibly ignorant question: Since I assume SPL is achieved thru the range of frequencies, I also assume it’s a weighted measure. If I’m right, do low frequencies represent a significant percentage of said measure? And if the answer to that is “yes”, does that mean that if a single-driver speaker is supplemented by some form of low-end support (a la Rethm or Audience), does that not in some way address the SPL limitation?
 
Interesting. So here’s a possibly ignorant question: Since I assume SPL is achieved thru the range of frequencies, I also assume it’s a weighted measure. If I’m right, do low frequencies represent a significant percentage of said measure? And if the answer to that is “yes”, does that mean that if a single-driver speaker is supplemented by some form of low-end support (a la Rethm or Audience), does that not in some way address the SPL limitation?
Reducing bass frequencies will allow some extra SPL depending on thermal or other distortion limits.

Mark Audio drivers seem to be reasonable too with full range drivers. Lightweight, curved cones with small voice coils and dust cap acting as semi-tweeter. I think Peerless did this with their little 2". Has been a thing since the 70's though, using metal cap for additional high frequencies
 
Reducing bass frequencies will allow some extra SPL depending on thermal or other distortion limits.

Mark Audio drivers seem to be reasonable too with full range drivers. Lightweight, curved cones with small voice coils and dust cap acting as semi-tweeter. I think Peerless did this with their little 2". Has been a thing since the 70's though, using metal cap for additional high frequencies
While it was, arguably, the best-ever cone tweeter (which actually isn't as oxymoronic as it might sound! ;)), I am not sure that the Peerless AlNiCo cone tweeter is the sine qua non of the dome dust cap tweeter era.

The "cone-dome hybrid" :rolleyes: tweeter was Henry Kloss's stock in trade, though, all the way from KLH to Advent to Cambridge Soundworks. Indeed, AR did some nice little two-ways with Kloss-y tweeters, too, although I am not sure if Kloss actually finagled any "cone-domes" into AR loudspeakers during his relatively brief tenure there.

AR4x -- ask me no questions re the white "adaptor plate" behind the correct AR tweeter -- and I'll tell you no lies. ;)


KLH 24
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KLH 5 (which, like the KLH Six, kinda sorta tried to hide the cone tweeter behind a screen ;))
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Advent (utility Advent, photo from Holt Hill Audio in Andover, MA)

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Teledyne-era AR18 (mid-1970s) -- at the time and IMO the best sounding inexpensive loudspeaker available ($65 each ca. 1977).


Early (US made) Cambridge SoundWorks Model Six, sporting a freshly refoamed woofer. :)


Radio Shack used an eerily similar looking tweeter to that CSW Six's in several cheap but not too bad two-ways in the same timeframe (early 1990s). :rolleyes:
 
Integrating different drivers, e.g. a woofer and tweeter, to create a seamless presentation is definitely a non-trivial exercise. Full-range drivers avoid this problem and can, for certain source material and at modest volumes, sound quite good. But the laws of physics work against the full-range driver. A small driver would require unrealistic excursions to reach decent volume levels at low bass frequencies. And even if you could design a small driver that had inches of excursion, the Doppler (inter-modulation) distortion it would introduce in the higher frequencies would be problematic. Using a ported enclosure helps, but does not solve the problem. (Passive radiators are a form of ported enclosure.) Making the driver bigger to address the bass causes compromises in the treble. 'Round and 'round we go. As mentioned, a driver whose effective radiating area decreases with frequency would address this, but building one that works well across many octaves has yet to be done. And probably stating the obvious, but adding a subwoofer to a full-range speaker creates a 2-way system, which kind of runs counter to the design premise. It's just that the crossover effects are less audible in the lower frequencies.
 
These Stan White speakers used a metal cap on a large paper cone. Almost like a mini coaxial cross waveguide tweeter

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I've seen Sansui with a similar thing too.
They were quite nice sounding at least for my low listening levels
 
Since I assume SPL is achieved thru the range of frequencies, I also assume it’s a weighted measure.
SPL is Sound Pressure Level and refers to the absolute volume in a given space. It is often weighted, SPLa is a common measure used, which weights some frequencies more than others. Typically in speaker measurements SPL is not weighted.

However, the demands on a system to produce (say) 90dB SPL vary a great deal from low to high frequency. Generally speaking, it's exponentially harder to hit a given SPL as frequency drops below 100hz or so.
If I’m right, do low frequencies represent a significant percentage of said measure?
Generally overall SPL capability is limited by low frequency output.
does that not in some way address the SPL limitation?
It can. If you are asking a small driver to do 80hz and then you pass the job along to a larger one (e.g. with a sub) it doesn't increase the SPL the first driver can hit, but the overall SPL the system can hit will tend to increase. If nothing else you have 2x the output at the crossover frequency.

As for the Audience white paper - I have to say it's better than I expected. It does beam in the upper octaves but it could be worse.

Beaming is an unavoidable consequence of a transducer that is significantly larger than the wavelength of sound it's producing. The sound coming from one edge of the transducer cancels out the sound coming from the other edge, leaving only the sound in the middle to propagate away from the speaker.

Since the Audience speaker only has a 3" cone, it explains why the beaming isn't too bad. They get a good amount of bass out of the speaker given the size of the driver.

For $4K I wouldn't say they're a value play, but unless you want to DIY something and go on a serious hunt for high performance, small full range drivers, I couldn't suggest similar alternatives.
 
does that mean that if a single-driver speaker is supplemented by some form of low-end support (a la Rethm or Audience), does that not in some way address the SPL limitation?

That’s your two-way speaker now when you supplement it. The other I forgot to mention about single driver speakers is that it is easier to design stuff like the Fujitsu/Eclipse enclosures.

For $4K I wouldn't say they're a value play, but unless you want to DIY something and go on a serious hunt for high performance, small full range drivers, I couldn't suggest similar alternatives.
Oh wow. I hadn’t realized they were $4K. Lots of better options out there.


A small driver would require unrealistic excursions to reach decent volume levels at low bass frequencies.
+1

@mdalton,
The other way around that would be to use a bunch of small full range drivers. You have the benefits of minimizing the crossover problems.

Full range drivers hit a lot of the audiophile buzzwords about simplicity, but it’s a lot less exotic sounding when you say that Bose uses full range drivers as their default strategy.

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I've mentioned it elsewhere/elsewhen ;) here @ ASR, but one of the most weirdly imaginative :eek: fullrange extended-range :) drivers was the late 1940s Altec 603B.

Aluminum dustcap plus the front of an Altec 604 Duplex's treble horn stuck in front of it! :cool::eek::facepalm: It's not a bad sounding driver, but hardly life-changing. There are other 15 inch (!?!) extended range drivers that sound at least as good.


 
There is something to be said for a full range driver, but only if they don’t beam too much and you don’t expect much bass.

The Audience model looks quite nice I think, but you would definitely want a sub or two and a high-pass in them.


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The frequency response shown in the white paper doesn’t tell us much apart from the general trend is flat. But because it is 1/3 octave smoothed and shown with a 100dB vertical scale it’s undoubtedly hiding its true nature.

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The CSD plot is again 1/3 octave smoothed, but only shows 25dB in the vertical axis so they could be hiding resonances.

Still, it looks good and off axis looks ok even this graph is also overly smoothed . Wonder what the THD is like?

I work with Italian Pro brand, K-array and their line arrays all use multiples of full range drivers ranging from 1/2” up to 4”. Used with their matching DSP amps they have a pretty linear response. Also very high SPL and the sound is incredibly clean and dynamic. They cross to their matching subs at 150-120Hz depending on the model. The main reason for this approach is to closely approximate an ideal line source and to do minimise phase shift.
 
New member here, though long-time beneficiary of the forum, particularly DAC reviews (I have a Topping E70 and Okto DAC8 in two of my systems).

Anyway, with regard to speakers, over the last few years I’ve increasingly been drawn to the sound of crossover-less (or minimalist) designs by companies like Fern & Roby, Rethm, Voxativ, Songer, etc. I know there are many on this site who believe that such a design is fundamentally flawed, or limiting, such that it is unlikely to ever compete with a well-designed two- or three-way speaker.

The most obvious challenge to a design using a full-range driver is at the frequency extremes. But some of these companies using full-range drivers have come up with interesting approaches for addressing this challenge. Rethm, for example, essentially uses a powered subwoofer - 4 drivers in an “isobaric configuration” to fill in the low-end - but of course most of these companies do not provide detailed specifications on their speakers’ performance.

So finally to my point: At Capital AudioFest this year I heard a pair of the Audience 1+1 speakers and found them remarkable. They use two full range drivers and two passive radiators in each small box. But here’s the kicker - unlike some of the other examples I’ve heard, Audience publishes info that includes some detail regarding their frequency response. I’d be very interested in others’ views on this, as it appears as if they have accomplished a remarkably flat and extended frequency response with these little speakers:

Audience white paper

I appreciate everybody’s patience with such a long, first post!
Many wide range divers exhibit pretty low distortion figures in the mids, and a smooth frequency amplitude response in that range too. Others fail miserably in literally all aspects of true-to-input sound generation. Independent that is of cost and technological effort. It‘s a topic for real enthusiasts who sacrifice much and more for the idealistic principle as such.

That‘s why the commercial success is limited to quite basic offerings nobody cares about, or super expensive idols, where a single sold pair may save the whole company for a year—I‘m exaggerating, sure.

The speaker „audience“ shows according to white paper a bass reflex tuning of 80Hz. That doesn‘t fit contemporary demand, to put it diplomatically. No go, in modern language. Nothing on max sound pressure level and so forth ad nauseam, to many answers left in the mist, no insight. If it was groundbraking, and that it better should be as an offspring of an extinct path of tech evelution, much more was to be expected. The silence speaks out loud.
 
I've never heard a one-way that can compare to a 2-way, 3-way etc. Sure if the budget is really low then a one-way is a solution but otherwise they sound so lacking. Am I missing something? Do really good ones exist?
 
I've never heard a one-way that can compare to a 2-way, 3-way etc. Sure if the budget is really low then a one-way is a solution but otherwise they sound so lacking. Am I missing something? Do really good ones exist?
I've heard claims of some single drivers being quite excellent (like the one the Mark is based on, which I can't remember the name of, but a good designer from what I remember). Just if you want extended bass (particularly) they fall short of course, but not so much for upper frequencies....but I'd like to try one for myself other than the single speakers that came with less than hi-fi intended stuff :)
 
I've never heard a one-way that can compare to a 2-way, 3-way etc. Sure if the budget is really low then a one-way is a solution but otherwise they sound so lacking. Am I missing something? Do really good ones exist?

Comes down to personal tastes more than budget. I've owned many 2-way and 3-way speakers from $15k-$30k+ yet I use single driver speakers for half of my listening. I had spent over 30 years in the hobby not giving them any consideration until I heard a nice Voxativ system.
 
I've heard claims of some single drivers being quite excellent (like the one the Mark is based on, which I can't remember the name of, but a good designer from what I remember). Just if you want extended bass (particularly) they fall short of course, but not so much for upper frequencies....but I'd like to try one for myself other than the single speakers that came with less than hi-fi intended stuff :)
So small drivers are the order of the day, lacking bass unless a transmission line design and the top end relies on the low mass of the single driver. Is transmission line a thing with one-way speakers? I made one-way car speakers boxes and a carry along speaker that I used when weed-eating the yard but it sounded like garbage as a one-way.
 
Comes down to personal tastes more than budget. I've owned many 2-way and 3-way speakers from $15k-$30k+ yet I use single driver speakers for half of my listening. I had spent over 30 years in the hobby not giving them any consideration until I heard a nice Voxativ system.
Interesting.
 
So small drivers are the order of the day, lacking bass unless a transmission line design and the top end relies on the low mass of the single driver. Is transmission line a thing with one-way speakers? I made one-way car speakers boxes and a carry along speaker that I used when weed-eating the yard but it sounded like garbage as a one-way.
I'm not particularly a fan of drivers that are undersized to purpose....but maybe I misunderstand your comment. Transmission lines can get more out of drivers, tho. Car stuff I don't even think about much.
.
 
I'm not particularly a fan of drivers that are undersized to purpose....but maybe I misunderstand your comment. Transmission lines can get more out of drivers, tho. Car stuff I don't even think about much.
.
The whole one-way is something I know little about and some people really enjoy them so it's interesting that way.
 
In a case of synchronicity, I have recently re-activated a much-beloved pair of mass loaded folded, tapered quarter-wave tubes (ML TQWT) enclosures using slightly tweaked Radio Shack 50-1354 EDIT 40-1354 (sorry about that!) twincone drivers. :cool: They are quite nice.

The notion of "undersized to purpose" drives is an amusing one -- look at the loudspeakers @amirm has tested over the past few years. ;)
 
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