[JLM]

My opinions after 40 years in audio:

As stated above, there is no perfect speaker, choose the lesser "evil(s)".

Some speaker cabinets resonate more acoustical energy than the drivers (and some designers do this on purpose).  I prefer to listen to the drivers.

Vertical arrays try to (unnaturally) stretch images from floor to ceiling.  (Talk about coloration.)

Dipole/bipole designs radiate both +/- sound waves into the room.  (That's not natural either.)

Most horns excessively compress (to gain more efficiency) the air such that the wave form is distorted. 

Most horns are very poorly braced for the higher pressures involved.

Wave guides are not horns and shouldn't do this (note that wide frequency range drivers have wave guides built into them).

Due to the size and stiffness needed horns either can't do deep bass or do it very badly.  This worked great back when amps were tubes with low damping factors and lower wattage ratings.

I've found most high efficiency speakers to be colored (but larger drivers are naturally more efficient).  OTOH adding crossovers and filters reduce efficiency/dynamics.

Trying to match the sound between big drivers and small, cones to domes or ribbons, and drivers located in different places in space around the crossover frequency(ies) are all recipes for coloration.

Driver magnets make a difference too, I prefer AlNiCo.

Better drivers make for better speakers, the fewer the better.  A well braced cabinet is better than a poorly braced one and much better than no cabinet at all.

[Duke]

Flux modulation is a nonlinear interaction between the static magnetic field and the AC field generated by the voice coil current. Flux modulation increases both with increasing flux density and increasing AC current, causing high frequency harmonic and intermodulation distortion.

My understanding is that flux modulation vs flux density follows a curve which rises and then decreases as magnetic gap saturation is approached.   Note also that as flux density goes up, less AC current is needed to reach a given SPL (up until gap saturation).   

[Aom-Uom]

Duke,
you are right, OK, I try again on flux modulation: the nonlinear interaction between flux density and magnetic field strength of the voice coil creates a varying (with the voice coil current) permeability and inductance, representing high impedance properties.
However, in my view, the main point is that the voice coil should be allowed to perform as a pure voltage source, supplied from a high impedance current source, just like any voltage source, in order to provide immunity against some for linearity devastating effects. I see this as an incomparable possibility to in real terms improve linearity in audio. Unfortunately, speaker drivers and speaker systems are optimized for low source impedance.

[Aom-Uom]

JLM,
good points.

[Duke]

However, in my view, the main point is that the voice coil should be allowed to perform as a pure voltage source, supplied from a high impedance current source, just like any voltage source, in order to provide immunity against some for linearity devastating effects. I see this as an incomparable possibility to in real terms improve linearity in audio. Unfortunately, speaker drivers and speaker systems are optimized for low source impedance.

You probably know more about the advantages of using a high output impedance current source amplifier than I do.  I'm aware that there's a window of opportunity to extend the bass a bit deeper than normal, and also thermal compression is somewhat offset because the wattage delivered increases (instead of decreases) as the voice coil's resistance rises due to heating.  But if you'd like to fill me in on other advantages, and/or point me towards a source of information, I'd appreciate it.

For some time now I have been building speakers that work well with fairly high output impedance amplifiers; I'm not sure the term "optimized" would be precise in my case because I also shoot for compatibility with low output impedance amps.  To get more specific, my speakers will work with many SET and OTL amps, but I'm not sure they would work well with First Watt amps. 

[OzarkTom]

One more to add to that list, ALL crossovers color the sound.

[Wind Chaser]

One more to add to that list, ALL crossovers color the sound.

Have you heard all crossovers?

[Wind Chaser]

    Anyway, I'm surprised that Magnepan is mentioned here as low-coloration speaker. Guess what? I used run Maggie 1.5 in my system until built myself TQWT based single driver with 6.5" Fostex driver. And all I can say is that Maggies are now store behind them acting like a tuning sound panels.

Best comment of the day!

And when placed together they can serve as a privacy partition.

[Duke]

Dipole/bipole designs radiate both +/- sound waves into the room.  (That's not natural either.)

The backwave of a bipole is in-phase with the front wave.   The backwave of a dipole is out-of-phase with the frontwave, but the ear isn't sensitive to this under normal circumstances.  The ear can of course hear the difference between reinforcement and cancellation in the bass region, but this is primarily because of its effect on tonal balance.

If the goal is to recreate, as closely as possible, the perception of hearing a live performance, then that which contributes to this perception is desirable.  According to Floyd Toole and others, in-room reflections consistently play a significant role in subjective sound quality.  In many cases a well-designed dipole or bipole speaker does a better job of delivering a perceptually beneficial, spectrally-correct, relatively late-arriving reverberant field than more conventional speakers do. 

So from a perceptual standpoint, good bipoles and dipoles have inherent benefits that can contribute to natural sound. 

[OzarkTom]

Have you heard all crossovers?

Have you heard the same speaker without any crossover?

There are many speakers that I like, even with crossovers, but crossovers still color the sound.

[Construct]

I would like someone to name one single speaker on earth that isn't colored, distorted, omitting, additive or otherwise offering a point of view.  I don't care if they cost a million a pair---they still produce altered sound in some fashion.

[Wind Chaser]

I hardly think a multi driver system can be improved or made less colorful by removing the crossover.  I use to be full range single driver kind of guy, but in my experience I have found none of those designs can sound as full, pure and clean as a good two or three way system.

Danny Richie is famous for his crossovers, in everything I've heard made by him, color isn't a word that comes to mind in the soundness of his work.

[Aom-Uom]

Hi,
I continue to think that "coloration" is being used loosely for all kinds of phenomenon. In the first place, crossovers give rise to phase distortion, which is a kind of serious "coloration" by nature.

[cujobob]

Since no one driver can do it all, there's no perfect speaker.  Crossovers are necessary until then.  Lesser of two evils.

[werd]

Who cares if they are colored!!! If you like what they sound like enjoy them.  . Cant tell me you haven't banged a fake blond before and not liked it.........

[planet10]

I would like someone to name one single speaker on earth that isn't colored, distorted, omitting, additive or otherwise offering a point of view.

My view is there is a lot of room for speakers to get better. If we imagine a holey grail i figure that even the very best speakers are maybe 10-20% of the way there.

That leaves lots of room for 2 equally valid loudspeakers to me completely different.

dave

[Berndt]

For some time now I have been building speakers that work well with fairly high output impedance amplifiers; I'm not sure the term "optimized" would be precise in my case because I also shoot for compatibility with low output impedance amps.  To get more specific, my speakers will work with many SET and OTL amps, but I'm not sure they would work well with First Watt amps.

Building an F4 current source to try between my 6v6 pp amp and the Jazz Modules, have heard the Pass Aleph with the Jazz Modules but must say my front end has changed considerably since then so any relevance would be out the window. As a diy amp builder the Jazz Modules offer a very nice load that is very tolerant of amplifiers, amps that would occilate with other designs are happy with dukes speakers.

[planet10]

in my view, the main point is that the voice coil should be allowed to perform as a pure voltage source, supplied from a high impedance current source

I'm (slowly) working on a speaker indended to be used with current source amplification.

Duke: buy this book: http://www.audiocircle.com/index.php?topic=73767.0 a more dynamic discussion here: http://www.diyaudio.com/forums/vendors-bazaar/157787-secret-tube-amplifiers-revealed-much-more.html

dave

[Hebrew Hammer]

IMO, it's not the driver most of the times but more the application   

[OzarkTom]

Since no one driver can do it all, there's no perfect speaker.  Crossovers are necessary until then.  Lesser of two evils.

There are becoming quite a few loudspeakers out now without crossovers. And they sound like it. The female and male vocals now sounds better than ever thanks to these speakers. Imaging also improves  without a crossover.