The disappearance of the traditional amplifier

What, you don't consider Sumo wrestling to be a sport?

I wasn't alive back then, but I think that field-coil speakers in the first part of the 20th century were actually significantly cheaper than permanent-magnet types of similar performance . . . they were NOT a "high end" design. This was an era when the labor and expertise for winding coils was cheap and plentiful -- even budget radios were chock full of inductors, chokes, and RF transformers that were typically wound in-house. On the other hand, high-permeability magnetic materials were VERY expensive or even unavailable - the infrastructure for securing the raw materials (especially cobalt) and making high-quality alnico alloys . . . this is all very high-capital-investment stuff.

The early Lansing alnico designs specified a flux in the magnetic gap of something like 13,000 gauss . . . I'm skeptical that any field-coil design of that era could even produce half of that. And as I understand it the move to ferrites in the 1970s was a reaction to geo-political events - the main deposits of cobalt in the world fell under the control of regimes sympathetic to the Soviets, and the price of alnico alloys shot through the roof in a very short time.

I am also quite skeptical of the claims for the superiority of ferrites vs. neo vs. alnico vs. field-coil arrangements . . . but all of these methods of making the magnetic flux allow very different approaches to the design of the motor structure itself, and this does have a huge, fundamental impact on the driver characteristics. The first generation of JBL professional drivers that used ferrites were very carefully designed to have the same magnetic characteristics as their alnico predecessors, and I've mixed and matched them in sound-reinforcement systems and couldn't tell a bit of difference (except for the odd alnico driver that's lost some of its flux).

But I will agree that the Alnico magnetic structures are so much more elegant in an engineering sense . . . with no stray field, and much easier on one's back when moving them around. And I can see some similar appeal to a modern field-coil speaker.

It is always nice to see a good discussion on pros and cons. There is definitely
more than one way to skin a cat. I tend to agree with Kirkus about the older
generation Genelecs but I happen to like their active newer 8050 and 8020 small
monitors. In fact, I'd be happy with a great many many speaker designs both
active and passive, horn or panel etc. - so it is not like it is ever as clear as
"night and day". In many cases, it is all a matter of combining as
many small incremental improvements as possible - soffit mounting is one,
room acoustic treatments is another, and going active speakers is just one more
increment (similar to tri-amping) etc. etc.

For example, if you prefer Tube power amplifiers then the incremental benefit of
active speakers may be outweighed by the loss of that tube sound...

Most of the active systems I have heard/used have been for the pro market. So the likely hood of using a Tube amp in them is zero. Amp technology has come along way since the bad old days so I think the idea that because it is active means it has less than great amps is probably old now.

All the characteristics can be worked around to make the design work in most situations. You just have know what you are chasing.

The Genelec monitors I have used in studios over the years have always been "nice" sounding, but I have always found them hopeless to mix on. They sound great and musical with that flabby mid bass which gets in the way when you really need to know what is happening in the mix. I feel the same way with the Mackie monitors too (last generation Mackies). They sound great and musical, but take the mix somewhere else and it sounds flat. I do like the ATCs as they seem to have less of the color of the Genelec but still musical and detailed.

I have yet to find a great powered monitor for the studio although I do like the Adam active monitors. Being an Apogee and planar fan, I guess the Adam ribbon tweeter had the detail I crave to an extent.

I have never heard a modern Field Coil speaker, but I see Focal are making one which I am told is good although expensive. I believe the idea is to bring the design to the lower range soon.

I recently bought Avantgarde Trios for my Hifi. A 110db/watt hornloaded speaker with active sub bass after years of various planar speakers. Many of the traits I thought were the domain of the Planar/electrostatic were easily achieved by the Trio, but with the dynamic swing no planar I know is capable of. I am sure if I used Avantgardes own amp design for the passive part of the trio, essentially making it all "active" you would never be able to say active speakers are not or cannot be SOTA.

I kindly disagree with some of the comments concerning Genelec waveguides. In non-anechoic conditions we always listen both direct and reverberant field, most often the reverberant field is dominating. The reverberant field balance depends on speaker system's power response, i.e. total radiated power in all directions, not only on axis. Systems without any directivity control exhibit uneven power response having dips around crossover frequency(-ies) due to the simple fact, that lower frequency driver is more directive at its high end cutoff, than next smaller driver at its low end. The waveguide limits the directivity of the higher frequency driver (MF or HF) to the same as that of the lower frequency driver, and makes the total directivity uniform. This happens with the Genelec waveguides and for example with the JBL Bi-radial horn used in 4430/35. The frequency range depends on the size of the waveguide. The other important consequence is reduction of diffraction from the cabinet edges, and this is obvious in stereo imaging. A trivial mono signal reveals the truth easily.
If the power response is not uniform, the perceived balance depends heavily on the room and listening distance, and these simple facts are source of endless discussions.

As for field coil drivers, they still suffer from the very basic source of nonlinearity, iron. Regardless of that, field coil drivers would be easiest to use with active speakers, as power supply is inherently available. The drawback is naturally heat dissipation.

IMO active speakers can definitely be better performers than passive - there are many inherent technical reasons for that - but in addition to skills in electroacoustic design it requires a second skill set for proper amplifier design.