[Mikeinsacramento]

The Kappa 9 had 2 - 12" woofers.

Here's a nice shot of the Kappa 9:


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

I only see one 12" woofer.  Suppose we can get a closer pic just to make sure?

[Russell Dawkins]

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...


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.

The thing is...these warrant the term 'reference'! Andrew Jones designed these with studio use in mind—and they were literally meant to be reference grade. The concentric mid/tweeter, for example employed Beryllium for both the cone and the dome.

Now we have to wait to see what he does at Elac. A high end series is coming after the low enders he just designed to catch our attention.

[milford3]

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...


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.

A great article about the term "reference" speakers by Alan Lofft.

http://www.axiomaudio.com/reference

[JLM]

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.

In the world common to Audio Circle (moderate in most audiophile standards) this is true, but in the larger audio world "ultimate" speakers often involve huge complicated cabinets, use exotic materials, and intensive manufacturing efforts to maintain high efficiency.

Good speakers have full frequency response and deep bass gets into those trade-offs (thus the use of powered subwoofers).  Good speakers have low distortion, but high efficiency drivers have lighter weight diaphragms that flex (distort) more.  Good speakers offer high (life-like) output levels that can require additional drivers, heavier diaphragms, and/or extended travel range that all cost efficiency.  Complicated crossovers lower efficiency but allow for full frequency response, high output, while maintaining other sonic attributes. 

[Big Red Machine]

When you say Reference I think of the large Focals and Wilsons that are like 93 db efficient at $100k+. So I think of ref speakers as being efficient, not inefficient.

[FullRangeMan]

I think reference as the AER MD3B or Feastrex Alnico.

[DaveC113]

I think reference as the AER MD3B or Feastrex Alnico.

In an way... I actually have a set of MD3 coming my way, the speaker I'm putting together might feature them.

But my previous comments on single drivers still apply... less so to the AER as it's FR is abnormally flat but all the other things. A friend has Lamhorns with AERs and it definitely has less compromise vs any other single driver I've ever heard.

BRM, it's relative... the MD3 I'm getting are 106 dB.

[FullRangeMan]

In an way... I actually have a set of MD3 coming my way, the speaker I'm putting together might feature them.

But my previous comments on single drivers still apply... less so to the AER as it's FR is abnormally flat but all the other things. A friend has Lamhorns with AERs and it definitely has less compromise vs any other single driver I've ever heard.

BRM, it's relative... the MD3 I'm getting are 106 dB.

Congratulations on this very nice purchase.
Let me know your impressions on the time.

[Russell Dawkins]

A great article about the term "reference" speakers by Alan Lofft.
http://www.axiomaudio.com/reference

Actually, there is some indication that Alan Loft is actually out of touch with the recording world in this article.
The Yamaha NS10 phenomenon was in no way confined to the 80s. It is still seen in most of the bigger studios, and not just because it has become a familiar standard. None of the brands he mentions as commonly seen in European/British recording studios are in fact commonly seen or spoken of except for Tannoy, and those in a very limited way. More common now are ATC, PMC, Neumann/K+H, PSI, Geithain, Quested and, in Britain, Harbeth. Dynaudio is fairly common and, for a while, B&W 801s were seen—but almost never Spendor, Rogers and KEF which were named.
Recently, Amphion has surged in popularity as a mixing and even mastering tool.

I understand why they were not mentioned, but PSB really does deserve a mention in my opinion as a potentially reference grade speaker, dollar for dollar. Paul S Barton has been making speakers since the early 70s, all of which have been notable for their tonal veracity.

Reference speakers generally need to  be able to play quite loud with low distortion even if they are not used that way - many good engineers mix and master at surprisingly low spl levels. This can be accomplished either with high power handling (and low thermal compression) or high-ish sensitivity. The need to play loud and clear is to do with the requirement for dynamic freedom, so that judgements can be made with regard to dynamic effects, like compression and limiting. Very sensitive (say, 95 dB/W and above) and simultaneously accurate speakers are very rare these days.

The speaker needs to have low self noise, that is, a brief impulse should result in an output which quickly and cleanly returns to zero. This enables subtle sounds, such as the tail end of reverbs and the recording room or hall to be heard.

Finally, a reference grade speaker needs to possess very flat amplitude response, ideally slightly downward tilting, both on axis and across a reasonably wide arc horizontally and, ideally again, vertically, along with good phase accuracy.

This is performance to which most consumer grade speakers in the world aspire but miss in various ways and to varying degrees. The point is, though, that a reference, by performing in an accurate way in all these areas will provide a window into the mean of all of the world's lesser speakers and a recording mixed and mastered on a reference grade speaker will sound as intended on more consumer grade speakers than if the reference speaker had some characteristic anomaly of its own.

This eliminates most of the Wilsons which really do not measure well.

[Vapor Audio]

When you say Reference I think of the large Focals and Wilsons that are like 93 db efficient at $100k+. So I think of ref speakers as being efficient, not inefficient.

Not efficient, sensitive.  Both big Focals and Wilsons have 2ohm loads, so 90db efficient.  Which IMO kinda defeats the purpose of high sensitivity, because the vast majority of tube amps will sound downright bad into 2ohm loads.  Many solid state amps even have issues into 2ohm loads, becoming non-linear and with distortion ramping up significantly.

[OzarkTom]

So what are the qualifying specs for high vs. low sensitivity, over and under 90db?

[FullRangeMan]

So what are the qualifying specs for high vs. low sensitivity, over and under 90db?

What determines whether a speaker is low or high efficiency is the electrical efficiency or:
no or η0 = the TS par know as no or η0 % = electrical efficiency.

Wiki:
η0 - The reference or "power available" efficiency of the driver, in percent.

The expression ρ/2πc can be replaced by the value 5.445×10−4 m²·s/kg for dry air at 25 °C. For 25 °C air with 50% relative humidity the expression evaluates to 5.365×10−4 m²·s/kg.

The expression 4π2/c3 can be replaced by the value 9.523×10−7 s³/m³ for dry air at 25 °C. For 25 °C air with 50% relative humidity the expression evaluates to 9.438×10−7 s³/m³.

From the efficiency, we may calculate sensitivity, which is the sound pressure level a speaker produces for a given input:

A speaker with an efficiency of 100% (1.0) would output a watt of energy for every watt of input. Considering the driver as a point source in an infinite baffle, at one meter this would be distributed over a hemisphere with area 2π m² for an intensity of (1/(2π))=0.159154 W/m², which gives an SPL of 112.1 dB with regard to the reference pressure of 2e-5 Pascals.

 SPL at 1 meter for an input of 1 watt is then: dB(1 watt) = 112.1 + 10*log(η0)

SPL at 1 meter for an input of 2.83 volts is then: dB(2.83 V) = dB(1 watt) + 10*log(8/Re) = 112.1 + 10*log(η0) + 10*log(8/Re)
The Eminence Alpha 15A is stunning η0=4.11%

[Tyson]

I don't understand why more reference level speakers don't have self-powered bass sections.  Then you main amp only has to power the mids/highs, which is a much easier task.

[Early B.]

I don't understand why more reference level speakers don't have self-powered bass sections.  Then you main amp only has to power the mids/highs, which is a much easier task.

Most self-powered bass sections on speakers use cheap plate amps that don't sound good. I'd love for someone to list a couple of "reference quality" plate amps. Perhaps a better solution would be a bi-ampable reference speaker.  Although I'm not sure the cost/benefit would work in this scenario.

[FullRangeMan]

In this scenario I prefer a two-way loudspeaker w/a woofer w/big VAS to big enclousure, in this case the bass under 60Hz is good.
I missing the Klipsch RF83.

[JerryM]

The solution lies within winning the lottery. 

For $225K, these solve a lot a problems: AC's own Von Schweikert Audio

Reference, indeed.

[TomS]

Most self-powered bass sections on speakers use cheap plate amps that don't sound good. I'd love for someone to list a couple of "reference quality" plate amps. Perhaps a better solution would be a bi-ampable reference speaker.  Although I'm not sure the cost/benefit would work in this scenario.

Vandersteen 5 and 7 come to mind...

[ctviggen]

Most self-powered bass sections on speakers use cheap plate amps that don't sound good. I'd love for someone to list a couple of "reference quality" plate amps. Perhaps a better solution would be a bi-ampable reference speaker.  Although I'm not sure the cost/benefit would work in this scenario.

Don't the Salk Exoticas have amps for the bass part of the speakers?  I couldn't tell what type of amp they used, though.  This page implies it's a plate amp:

http://www.salksound.com/exotica%203%20home.htm

[OzarkTom]

Danny Ritchie's GR Research speakers have great bass with plate amps and are very high efficient.

[DaveC113]

Most self-powered bass sections on speakers use cheap plate amps that don't sound good. I'd love for someone to list a couple of "reference quality" plate amps. Perhaps a better solution would be a bi-ampable reference speaker.  Although I'm not sure the cost/benefit would work in this scenario.

I've been looking into this and the solution seems to be, again, DIY... I'm going to have a custom-programmed hi-rez DSP/electronic crossover mated to a nice digital amp module with a few different curves set to compliment the room and a programmable parametric EQ to tame bass peaks. These components will be built into the speaker cabinet like a plate amp or passive xo would, and would also have a simple 1st order passive xo for the mid/high section.

I think this sort of active bass system has the potential to work much better than a purely passive speaker and offers more design flexibility at the same time. Having different curves and an eq will make the speaker work well in different sized rooms, the only downside is a perfect setup will require professional calibration. But the preprogrammed curves by themselves will get folks much closer than speakers that offer no adjustability at all...

The new VSA VR55 is a good example of a speaker with a well-executed active bass section that's way better than a plate amp, but it isn't cheap either.