The first two loudspeakers I ever paid for in my life were Lowther PM2 units. I calculated a rear horn loading and reviewed almost every other similar kind of home construction. Among them of course were the original plans from Lowther UK; but also plans from J. B. Lansing, Jensen, Schmacks, Tannoy, Wireless World, and others. I decided to mount the full range unit on a marble soundboard and succeeded. However the enclosure was modified several times to get matching low frequency response and time behavior. In the end the performance was comparable to that of the large JBL 4333B Studio Monitor; and, in fact, they stood side by side in a recording studio for several weeks, but mine didn’t have the bass overhang and was more detailed and native in its presentation. 

Lowther units accompanied me for years. Over these years I got real treasures as well as garbage. I owned originals-- speaker systems like the early Acousta, the model Audiovector, the Mini-Acousta, the TP1 'D', the Audiovector Auditorium, and built several other systems, like 115, 124, Bicor 200 and 2000, Delphic 500, and horns for use exclusively as mid-high frequency units. The main thing affecting performance, however, turned out to be the cone assemblies. Recently, in developing a drive unit for existing cone assemblies, I made it a point to listen to assemblies from other manufacturers, like AER or Stefan Stamm, who worked for Loth-X years ago. Lowther UK can do a very good job, but they also failed for a long period and delivered awful sounding stuff. Today there is a cone assembly made in the UK which is excellent and based on my experience, very consistent in quality.

Voigt Loudspeaker name plate

Voigt Loudspeaker (high resistive field-coil)

Paul Voigt Mains Energised Drive twin cone (shellac treated)

Paul Voigt Mains Energised Drive twin cone (shellac treated). Look at the centering, isn't it fancy?

Lowther Mini-Acousta PM6Mk1, Acousta 109

The best vintage Lowther „chain“ I listened to in 1992
Turntable "The Source" equipped with a tangential tonearm "Airtangent"
Clearaudio "Insider" moving-coil cartridge
Preamplifier Mark Levinson "ML-7A"
Power amp L'Audiophile "300B Polypropylene"
Lowther "Mini-Acousta" with PM6Mk1

Not only do paper and the glue affect sound quality; the drive unit of course plays a major role. A lot of research and development around the world has gone into the geometry of the cone and twin cone, voice coils, and their electrical dampening; but the magnet assemblies have for the most part remained constant. Of course new lighter magnet materials, far better for commercial applications, have been released.

Lowther Acousta and Acousta De Luxe

Acousta 109

My job was to develop a drive unit that sounded better than permanent magnet devices. In March 2010 I released the AL2. This unit was designed for direct radiating applications and has a maximum flux density of 1.925 Tesla. The motor is comparable in its dimensions to a PM4, so it unfortunately won't fit in a lot of standard enclosures. But if you’ve ever heard what is possible in terms of detail, resolution, timing, and color, you’d accept the burden and partly reconstruct an existing cabinet or build something new. 

prototyp AL2

Prototype AL2
To achieve even higher flux I tested also the theoretical best material (50% CoFe) for very high flux density pole-shoes  (Vacoflux 50), which is extremely expensive and really hard to machine – but pure iron, which also is not a real joy to cut, lathe, and drill, did sound more native, more detailed, and transient speed and purity were retrieved.  

AL2 and AER cone assembly

AL2 with AER (Keller) cone assembly

A5000 drive unit in horn enclosure

Back loaded horn enclosure with perfect cutouts for A5000 drive unit

Christine von Langa - Roedlas 54 - D - 91077 Neunkirchen a. Br. - Phone +49 (0)9192 996926 - E-Mail: listen(at)wolfvonlanga.com -
WOLFVONLANGA produces unique field coil loudspeakers and drive units. As a manufacturer we solely use the highest quality materials.
We deliver worldwide unique loudspeaker technology. All WOLFVONLANGA products are developed and handmade in Germany.
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