[Freo-1]

Over the years, it seems that the majority of the speakers considered as "reference" are of low to moderately low efficiency? 

This is one of the major factors that drive audiophiles to higher power amps.  These high end speakers need more watts to perform at there best. 

So, wanted to start a discussion as to the factors that drive this issue.   It does seem pretty challenging to make a high efficiency speaker that performs as well as many of the better low efficiency models.

[milford3]

Omega's.  Single driver brilliance with high efficiency.

[Freo-1]

Omega's.  Single driver brilliance with high efficiency.

But no real low end to speak of.

[Tomy2Tone]

Ryan from Vapor answered some questions regarding sensitivity here. I thought it was a great read.

http://audioshark.org/vapor-audio-190/ask-ryan-7690.html#.VfRm_7eCOrU

[mca]

Not the case with Daedalus Audio 

[mresseguie]

Certainly, there are exceptions, but I agree with your premise about low sensitivity. My newest speaker acquisition are the Fritz Speakers LS/5-R monitors with 5" Illuminator midwoofers and SS Ring Radiator tweeters. They've got 83.5 dB sensitivity, but I imagine they'll beat the pants off many other speakers in sound quality.

[FullRangeMan]

Over the years, it seems that the majority of the speakers considered as "reference" are of low to moderately low efficiency? 

I also noted it, I think its a business strategy to boost sales, they target the mid of the power range to fit most of the amps on the market.

It does seem pretty challenging to make a high efficiency speaker that performs as well as many of the better low efficiency models.

With hi sound quality yes its, it may show speaker project defects at xover, untreated box resonances, unbalanced freq range etc

On the other way there is so many mid sensitivity speakers over the years it already have a usual formula of parameters how to make a such speaker.

[Folsom]

People expect sheer bass force in expensive speakers. It's hard to get it without designing in such a way you lose sensitivity, without simultaneously using strange enhancers that often people can audibly identify such as transmission lines etc. That said, if you can design a good transmission line or such, to be utterly transparent... well not everyone can.

Vapor said it well, there's a lot of balancing. There's only so much you can squeeze out of a driver.

[DaveC113]

It's because multi way mid efficiency speakers are the norm, they are what's been developed the most since transistors made high power amps cheap.

Like anything, there are examples off all different speaker types that are "reference " caliber.

[Bemopti123]

Infinity Kappa 9, circa 1989, last of the creations from Andy Nuddel, one of the original creators of Infinity....that is medium efficiency like 86 db or something like that, but without it being paired with a high current, high powered amp, would eat amps for lunch.  Low end is astonishing, so is its power requirements. 

I do not think you can generalize a lot about high end speakers being such and such.  Yes the majority might be low efficient BUT, then I can think about very high end speakers that have ultra high sensitivity. 

[Freo-1]

The Kappa 9's were certainly special.  They did need a fair bit of power to work well.

For example, my current speakers are ATC's with the Super Linear driver.  They are among the very best drivers on the market.  The 6 inch driver weighs 20 lbs or so.  The current SCM-19's are rated Class A in Stereophile.  Many of their speakers sport super linear drivers, which have special magnets and coils.  Their efficiency levels are in the mid 80's. 

Planar/ESL's also tend to have low efficiency.  Yet, they are often cited for superior overall performance.  While I realize that there are some superior high efficiency speakers out there, there are not many compared to amount of superior lower/mid level options available. 


I think the physics involved to get high efficiency speakers to perform in a linear fashion and provide proper sound stage dispersion is very challenging. 

[neobop]

The Kappa 9 had 2 - 12" woofers.  In extended mode it had an impedance dip to 0.8 ohm.  Blew up amps like crazy.  In normal mode had a 50 watt/1 ohm resistor in series with the 2 ohm woofer. Other woofer was 4 ohm.  Impedance spec was 4 to 6 ohm.   

In general terms woofer efficiency is traded off for bass response.  Take a look at this 12" pro woofer:
http://www.parts-express.com/eminence-delta-12a-12-driver-8-ohm--290-414

98+ dB sensitivity - Resonant frequency 55Hz.  In a 2.8 cubic foot cabinet F3 is 59Hz. 

Here's a 12" home woofer:
http://www.parts-express.com/dayton-audio-ds315-8-12-designer-series-woofer-speaker--295-434

91 dB/24.2Hz  -  vented 1.9 cu ft - F3 = 37Hz.   Add mass to the cone and bass goes lower.  So does efficiency.  The smaller the driver, the less efficient it is.  If you put a giant magnet on midbass driver you'll usually have a pro midrange, unsuitable for home speakers.

Here's a nice shot of the Kappa 9:


Sorry, that girl got in the way of the giant amp.
neo

[FireGuy]

I think the physics involved to get high efficiency speakers to perform in a linear fashion and provide proper sound stage dispersion is very challenging.

Prior to getting my pair of Omega Super 5's I had ask the question on this forum... that is,  if single driver is so good why are most speaker vendors staying with multi-driver, xover designs?  High efficiency, single-driver is challenging, I agree.  Makes sense to me as it appears easier and incurs lower costs to go with multi-driver.  I'm not saying one design is superior to another.  There are compromises in every speaker architecture.  When purchasing low efficiency speakers and then you have to turn around and spend as much or more on the amp to drive them, that's a huge compromise.  I own both single and multi-driver... and enjoy them both.  But, there's something about the single-point source, high efficiency design that has me hooked. Omega for me is paradise, but I do understand not for everybody.   

[milford3]

FireGuy you have nailed it.  My single driver Omega Hoyts can be driven with no effort at all by my Musical Paradise MP 2 SET amp (at 8 watts ).  Buy the way, no cost for crossover parts with Omegas.   

[DaveC113]

Single driver speakers are a good compromise for many, myself included, but they aren't exactly a reference type speaker. Fun to listen to for sure, but even frequency response, limited SPL levels and bass response are tradeoffs that keep them from being a good reference speaker.

Compression drivers and horns are one way to get high efficiency without so many tradeoffs... if you consider Magico, they are measurement driven and their conventional speakers are reference grade products but their top of the line speaker is a horn system.

The best speakers I've heard do happen to be conventional mid-efficiency speakers, TAD Ref 1s, but they are $90k and are optimally paired with another $250k worth of TAD electronics. Not exactly cheap...

[milford3]

Single driver speakers are a good compromise for many, myself included, but they aren't exactly a reference type speaker. Fun to listen to for sure, but even frequency response, limited SPL levels and bass response are tradeoffs that keep them from being a good reference speaker.

Compression drivers and horns are one way to get high efficiency without so many tradeoffs... if you consider Magico, they are measurement driven and their conventional speakers are reference grade products but their top of the line speaker is a horn system.

The best speakers I've heard do happen to be conventional mid-efficiency speakers, TAD Ref 1s, but they are $90k and are optimally paired with another $250k worth of TAD electronics. Not exactly cheap...


Most of us do not have 90k for speakers.  My high efficient speakers are with two (2) subwoofers.  The listening results are amazing. 

[FireGuy]

The best speakers I've heard do happen to be conventional mid-efficiency speakers, TAD Ref 1s, but they are $90k and are optimally paired with another $250k worth of TAD electronics. Not exactly cheap...
[/quote]

I think the term "reference" is used way too much in the audiophile world... ad nauseam.   Such a relative term.  I would hope speakers at $90K and then add 2.5 X's that...would be best in class.  Certainly hope so.  I wish I was there though.

[DaveC113]

Most of us do not have 90k for speakers.  My high efficient speakers are with two (2) subwoofers.  The listening results are amazing.

I'm sure... I've owned Omega for about 10 years now and still do because improving on what I have is not financially feasible. Most speakers I like better are over $10k. As good as Omegas are they still are not reference-type speakers though, which is what Freo is on about. Personally, I don't feel a ruler-flat FR is all that important in my list of priorities but to be a reference speaker it's gotta be darn close. Omegas are pretty flat for a single driver but not even close to what can be accomplished with a traditional multi-way speaker. They can't play low bass or high SPLs, dynamics are only good at lower volumes, higher and they get compressed fast, there is lots of IMD/Doppler distortion at higher SPLs, the dispersion pattern narrows with rising frequency more than is ideal, etc... I am a single driver enthusiast, for many people they are the best choice, many people would be happier with a single driver system vs what they have now, but you have to be honest about their limitations to avoid possible disappointment.

FG, I agree the term is overused but that does not mean it does not have a meaning anymore. Reference implies a cost-no-object design that performs at the highest level possible and makes the fewest compromises. Single driver speakers are compromised in a few areas I mentioned above, but those compromises may not matter given your personal preferences and listening habits. But others, say folks that value startling dynamics at high SPLs, listening to dinosaur rock, using the speakers in a large space for a techno dance party... these people would never be able to live with a single driver speaker. OTOH, the TADs simply make no compromises in any area of speaker performance.

[WGH]

I'm sure... I've owned Omega for about 10 years now and still do because improving on what I have is not financially feasible. Most speakers I like better are over $10k...
OTOH, the TADs simply make no compromises in any area of speaker performance.

Oh yea, I heard the TADs and I agree they are definitely reference quality, yes FireGuy the term can be overused but in this case it is appropriate.

Dave - keep an eye out for used Nola's. A friend picked up a used pair of Nola KO's at 1/2 price - 90 dB sensitivity at 2.8 volts and an average 8 ohm impedance, they are full range, easy to drive and sound fantastic with an AVA 35 W/channel Ultravalve.

[DaveC113]

I wouldn't trade my Omegas for NOLAs. Heard them a few times at RMAF and they are not my thing...