Beveridge 2SW loudspeaker system

This is an electrostatic column speaker, 6' tall and costing $6000/pair. An integral, fan-cooled amplifier is located in the base (footnote 1). The 2SW is said to cover almost the entire frequency range and is based on a patent, number 3,668,335, issued to manufacturer/designer Harold Beveridge on June 6, 1972. Internal acoustic lenses in front of the electrostatic panels widen the speaker's dispersion: In the Beveridge literature, it says "This 6-foot high device consolidated the entire frequency range into a vertical line source, and uniformly disperses it over a horizontal pattern, 180 degrees wide. The beaming characteristics of the high frequencies are ingeniously translated into the same dispersive pattern as the low frequencies, creating a perfectly balanced cylindrical sound wave front." (footnote 2).

Initially, we were unable to get these to sound much better than dreadful in our main listening room. Despite a respectable (although rather sodden) low end, they persisted in being pinched and thin, almost to the point of stridency.

Finally, Harold Beveridge (footnote 3) paid us a visit, located the speakers in the only place in the room where we had not tried them (facing one another, approximately halfway down the length of the room), and eliminated most but not all of the problem. To us, they are still an odd combination of lower-midrange heaviness and presence-range forwardness, with excellent inner detail but a markedly rolled-off extreme top and, still, a rather heavy and loose low end. We are still experimenting with room placement, but are far from being able to obtain the level of musical naturalness and accuracy that two other publications claimed to have found from them. We are, in short, far from achieving $6000 worth of fidelity from these, and have been getting (consistently) more accurate reproduction of musical timbres from several systems on the premises costing roughly 1/15 what these cost. (FYI, they are the Rogers/BBC LS3/5a, the mid-and-upper-range sections of the M-Z Mod 3, and the lowly Fulton FMI 100.)

Initial Conclusion
We find it .difficult to believe that a system this costly should not provide something close to state-of-the art performance, so rather than climb out on a limb and bomb these, now, on the basis of our own observations to date, we are going to reserve final judgement on them until we have had a chance to hear a pair in a different listening environment. We can say one thing with certainty at this point, though: They can sound pretty dreadful. It remains to be seen how good they can be made to sound.

Follow-Up from May 1979 (Vol.4 No.4)
A couple of issues back, we expressed our surprise to find how bad a speaker system as expensive as the Beveridge 2SW (now $7000/pair) could sound. The pair we heard were shockingly colored through the middle range, had virtually no real high end, and suffered from inordinately heavy, flaccid bass performance.

We have since heard an updated version of that system, and our reactions are as follows:

  • Superb high end, with razor-sharp detail but a subtle deficiency in extreme top which was judged to be more of an asset than a liability.
  • Very slightly on the bright side, but with a perceptible dip in the range around 1kHz, which tended to back things off a bit and to heavy-up the sounds of many instruments.
  • Much-improved low end, deep (to below 35Hz) and tautly under control, but lacking the authoritative bite and impact of a large bass horn or transmission-line system.
  • Stereo imaging less well-defined than from some systems we have heard, but possibly due to the close (8') proximity of a rear reflective wall.
  • Overall: Extraordinary cleanness and detail throughout the entire audio range with the capability of producing very high listening levels (circa 110dB) without strain.

Overall Conclusion
This is now one of the top two speaker systems. (The Hill Plasmatronics is the other.) Neither is perfect, and one's assets are complemented by the other's liabilities. Our personal preference, in terms of sound, is the Plasmatronics speakers, but that is a rather quixotic and arbitrary preference, for neither one is clearly superior in every respect. And it would be nice not to have to bother with Helium tanks.

Beveridge has promised to "look into" the matter of the mid-range dip. Correcting that could swing the balance the other way.

Footnote 1: Roger Modjeski re-designed the Model 2's pre- and power tube amplifiers.

Footnote 2: I once asked the English electrostatic pioneer Peter Walker which speaker he would have liked to have designed. He answered "the Beveridge 2SW."—John Atkinson

Footnote 3: Harold Beveridge died in 1997, and his sons Rick and Bruce Beveridge continue to produce and repair Beveridge loudspeaker systems in 2015.—John Atkinson

Harold Beveridge Inc.

Sal1950's picture

I would be very curious as to how many, if any, of these high tech, high voltage power supply speakers still exist in good operating condition. As I remember from years ago there were reliability issues with both the Beveridge Stats and the Plasmatronics in use when they were new. Both the electronics and drivers were problem-some.
On the other hand I'm sure you can find plenty of vintage LS3/5a's still singing beautifully everywhere.

cgh's picture

I grew up listening to the big cylindrical Beveridge speakers (I think they were the 2a's). My friend's father owned them and I practically lived at their house. This was in the mid eighties through early 90's. My recollection was John Dahlquist modified some aspect of the speaker, but they played music all day and all night. From listening to the New Afternoon Show on WNYU, or the original WLIRR, to late night vinyl sessions. What went after maybe 2 decades were the stators. There was a woofer that fired from the top. The paper wore with age too. Great speaker for the time. Great memories.

The other speakers in the house were the Dahlquist phased array DQ-10. These were the speakers that planted the seed for me.

Russell Dawkins's picture

It is worth noting that Roger Modjeski (mentioned as the young amplifier designer)is still in business and active:

Ronald Koh - SG's picture

Hoping this will make some good sense.

1. The only great and all rounder sounding one is the Quad63 by Peter Walker. As its high & mid frequencies radiates out in concentric circles to give a coherent musical sound image and stage within its design parameter limits to enjoy. However, the caveat is its high charging 2,000(2k) volts that is problematic in high humidity climates like here in Singapore. Of course their latest double stack models are better. But if one wants deep low rhythmic bass below their lower limits, a really good compatible sub-woofer is a real necessity for real world pitching, rolling, grunting, groaning, even sighing, good slamming etc bass for bowed & plugged double bass and cello, all types of bass drums etc.

2. And with 180 degrees dispersion, the caveat is also the 2 crossover points between high & mid and mid & low in any given room to manage its eigentones vibrations & reflections within it audio band. Very complex. And with 2 bass boxes, physical integration is a tough nut to crack acoustically. Like with Infinity's IRS and Genesis' high-end dipole ribbon speakers with separate servo driven woofer columns just as high as their ribbon panels. Wrongly positioned and they can sound over-bright and unbearably unmusical. Even with Infinity's single speaker with servo bass and 4-way dipole ribbons on top via passive crossover networks, it already tough getting them to really sing musically.

3. Thus before buying a pair of loudspeakers, especially of costly hi-end variety, one must get a well experienced person to assess what type of speaker to avoid in one's listening room. By factoring in furnitures etc in addition to its shape, size and speaker placement limitation. As well as WAF too! I've been fortunate to be able to do what I need without WAF problems!