Low-sensitivity speakers — What's special about them?

Mr. Augspurger still designing horn monitors today!

http://proaudiodistribution.com/augspurger-monitors/

http://www.lansingheritage.org/images/jbl/reference/technical/efficiency/page01.jpg

@lonemountain --

This efficiency issue is one "spec" out of many that a designer must balance. All these performance parameters are evidence of the enormous number of trade offs in creating a complete driver/box/electronics design. So designers make their own choice ("I want a horn, that’s what I like") and balance everything to favor their choice ( it will have limited dispersion, HF narrowing, but that’s okay I’ll try and minimize it, etc). This is the way speaker design is, balancing hundreds of issues that represent hundreds of choices and all of them have resulting tradeoffs. You may want a low distortion driver but its too expensive, or the OEM manufacturer can’t build it till next year and you’ll be out of business by then. Or, the horn you want to use wont fit the box you already bought or built, or you don’t care about efficiency as amps are cheap so you want the widest bandwidth possible, ..on and on.

Here's a different perspective: don't mind the reasoning behind and outcome from a manufacturer who's business model is sought kept afloat, but simply choose with an open mind - without blindly converging with consensus - what you as a user/buyer prefer. I'm aware manufacturers usually cater to the majority of buyers, hence why smaller and inefficient speakers became popular in the first place, but small(er) size and inefficiency is something that dictates a whole darn lot design-wise, just like the ripples created from a high efficiency design has implications that go far beyond efficiency alone. It's two quite different segments of speakers in many regards, as you know, and it's why efficiency isn't just efficiency - or "one spec," as you so put it. And the thing about not caring about efficiency isn't something that can be freely compensated for by simply adding power; wattage is wattage, and "innovation" in heat dissipation is only so prevalent that it's a major issue still, and likely always will be. 

There is a practical science at play here, with product development controlled by economics, engineering principles, sales, marketing and a whole bunch of other factors we’ll never know about at the factory that drive those choices. In the end, the company "sells what they have" as ALL speakers are a sum of trade offs. Many of the issues debated are really arguments over someone’s clever marketing points and we as consumers take these marketing issues as gospel, as facts. Since everything is choices, it may be these performance features are important only in THIS type of design. To another design, they don’t matter. Like wide dispersion is not desirable when you are trying to throw sound over a long distance (think football stadium). But to home audio, and wide dispersion means I get to sit on both ends of the couch and hear it properly, that matters a whole lot to me.

Just to narrow this down to dispersion, I mainly think of (and hear) the dispersion characteristics of many horns as something that limits the influence of the acoustics at play, and not (necessarily) a head-in-a-vice outcome or what's otherwise sonically unwanted in a home environment. My actively configured main EV speakers are intended to fill up to large cinema auditoriums with loud movie sound, but they work wonders in a moderately sized living room, at any SPL, and that at a listening distance of 11-12 feet. I WAS afraid their large midrange/HF horn wouldn't gel with the twin 15" woofers below it, but as a 2-way design (in addition to subs) that's not a problem. Go figure. I'm not trying to convince anyone that this is the only viable way to enjoy music (and movies) in your home, but that contrary to what many believe here it's actually an extremely capable option, not least actively configured, and one not overly expensive at that. Dynamics, ease, scale, resolution, presence, coherency - audiophile speakers struggle here by comparison. 

The company I work with makes perhaps the best cone and dome drivers on the planet but their speaker cabinets are plain rectangular boxes. Some say the box is everything but in this design 2 of the 3 drivers have their own chamber and the box is not involved in the driver at all. The baffle is more or less "a holder" for position and improves output as there is acoustic gain by sealing drivers to a surface. Some say the box looks old fashioned- so to balance that we use some exotic woods and make them look like beautiful furniture. The best you can do is find a way to make some happy and others will just not see it/hear it the way you do.

What I love about ATC speakers (my assumption of what you're referring to above) is their consistent, some may even say conservative approach to making speakers, them being made for the pro market - which is not excluding the domestic ditto, and the lack of marketing BS. Rock solid drive units that stand the test of time; honest, coherent and rather authentic/natural sound, and active configuration (as a main trait of theirs). I couldn't care less about the look of the cabinets; they do what they're supposed to do - no more, no less. 

... There IS more than one way to do it and many good sounding speakers out there. Each has its own application set that it excels at and other applications that it doesn’t do well with. We have not arrived at a universal solution.

Agreed, but speaking of diversity high efficiency is very often disregarded by audiophiles and the associated industry. The latter, figures. The former I'd say mostly buys into the sentiment of the latter, simply because it's gotten the norm, and not least because it's convenient one way and the other. There ARE many accepted ways in the range of low efficiency speakers, but for this to really be diverse high efficiency is definitely to be more readily accepted in audiophilia - or so I find. 

Does your comment Sounds_Real_ Audio mean you think a passive crossover is different in a horn vs a direct radiator?

Different challenges, I'd say; complex passive cross-overs not least suck the life out of already relatively stale-sounding low eff. speakers, whereas passive XO's often do horns a disservice by having them work outside of their safer bandwidth range. Once again: active configuration to the rescue. 

 I'm aware manufacturers usually cater to the majority of buyers,

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Popular vote always wins, But may not necessarily be the vote for the higher fidelity speaker.

If you read through Agon's speaker posts, rarely if ever db sensitivity comes up.

I just recently made the db sesnitivity discovery  late 2020.
After makinga  trial experiement with one of these ~~odd/unusual/off the beaten path** strange 
Wide band/full range.
I1st initial recation,, wow, these things may have some potential for the midrange I;'m looking for my classical music.
Order a  bunch more others, til I finally 1 year later hit on the one I liked,, 

High sensitivity was like a  revelation. 
I recall folks back in the 2004 era, suggesting wide bands/full range/point source, require a  SET amp. 
Or lets say ideally.
Which may be partly true.
This  suggestion prevented me from seeking further into these designs.

Perhaps some of Voxativ and AER's super high sensitivity speakers almost demand SET's. 94-100db

The 2 WBers I know are well design , have 92db sensitivity and  so most PP amps will work out fine.
At say 96db sensitivity WBer,,  there is  a  issue attempting to power with either of my PP amps.

I prefer low sensitivity speakers. Mine are listed at 91, which may seem high, in my room they are not bright at all. 
The listed 91 must be different in the chamber, as the crossover/tweeter the highs are rolled off at 600 hk/kHz, whatever!
  They seem very warm to me, which is what I love. Never any ear splitting/searing/molar grinding treble at all!

  Will try to make my speakers last forever!!

gave my BIC venturi dv84 to my cousin, as the treble, while super perfect and accurate, just hit a nerve , and made me feel anxious, and get up to dial down the volume. 
   The Altec Lansing M-508’s were great, but didn’t have the beef on the bass dept.

anyway, I now look for low sensitivity speakers, or ones that are labeled as “warm”

I prefer low sensitivity speakers. Mine are listed at 91,

@arcticdeth  91dB isn't low sensitivity. Its more of a medium sensitivity.

To put this in perspective, the low eighties is near-criminal inefficiency (its very hard to find an amp that sounds like music and has the sort of power needed unless you are nearfield). This would make them nearly impossible in a larger room.

About 89dB is the bottom of what might be considered 'medium sensitivity. 94-96dB is about the top of that range.

97dB might be considered the very bottom of what is considered 'high sensitivity'.

 

They seem very warm to me, which is what I love. Never any ear splitting/searing/molar grinding treble at all!

The quality of 'ear splitting/searing has nothing to do with efficiency and everything to do with distortion caused by either the amp or breakups in the speaker. So this can happen even if the speaker is only 85dB (and often does). People often blame the speaker because that is what is making the sound, but often the electronics carry a lot of the blame.