Audio Art Magazine

Audio Art Magazine Taiwan

Audio Art Magazine

Audio Art Magazine Taiwan

Lenco Heaven

Lenco Heaven 2015, lencoheaven

Lenco Heaven 2015 meeting – the barn

Avis wrote an article about „Men who listen“ – about me – Audio16

Jean Hiraga

Jean Hiraga demonstrates his version of an open baffle speaker

Peter Reiners – not knowing where to secure this lovely woman – PTP Audio

Flee market

About treasures with Jean

The experiment: Decca on PTP turntable and WVL field-coil units „solo“ equalized: Fun

An audio meeting about people, fun and music :-)

A5000 and enclosures

For medium listening distances and richly decorated rooms the direct radiating A5000 unit with a variable flux density up to about 19,500 Gauss is extremely enjoyable. Built in a horn enclosure like Acousta or Acousta De Luxe, at some places called Model 115, the drive unit is housed optimally. The enclosure employs a folded horn, or exponential labyrinth, which operates from the rear of the drive unit. This structure produces the necessary diaphragm loading (almost no movement even at higher listening levels) resulting in a smooth and extended bass response with negligible distortion. Built right and suited for contemporary living, the speaker provides a realism in sound that must be heard to be believed.

Kilimanjaro-Series A5000

Kilimanjaro-Series A5000 with PM6A-DK cone assembly

DK cone assembly

DK cone assembly, available from me

A5000 cut and dimensions

A5000 cut and dimensions

Acousta 115 plan

Folded horn

construction details and plans

Construction details and plans

Lowther pm6mki, PM6A, PM6C, PM2A, PM2C

Lowther PM6MkI from 1969

Lowther Acousta

Lowther Audiovector

Mit den Modellen Audiovector, TP1 und Hegeman wenden einige Hersteller rund um das englische Breitband-Hornchassis das Prinzip des Voigt Corner Horns an und treiben einen beispiellosen Aufwand.

Permanentmagnet PM4 mit Kobalteisen als Polkern, magn. Fluss ≈ 24000 Gauss

Permanentmagnet PM4 mit Kobalteisen als Polkern, magn. Fluss ≈ 24000 Gauss

Bei der Serie Audiovector kommt ein PM4a zum Einsatz, die Membranvorderseite strahlt indirekt nach oben über ein akustisch hervorragendes Gips-Mittelhochtonhorn ab, die Rückseite arbeitet auf ein symmetrisch gefaltetes Holz-Bassmitteltonhorn. Auch bei beachtlichen Schalldrücken bleibt die Membranauslenkung unter ±1 mm. Dieses Beispiel verdeutlicht den eigentlichen Vorteil der Lowther Chassis in korrekt eingebauten Zustand. Intermodulation und Doppler Effekte sind nahezu nicht vorhanden.

Audiovector PM4 mit Gips Streubirne im lackierten Gips-Horn

PM4 mit Gips Streubirne im lackierten Gips-Horn

Teils runder Hornverlauf, Einbauschacht für den PM4

Schön zu erkennen: Teils runder Hornverlauf, Einbauschacht für den PM4

Nach dem Einbau des Chassis wird eine Art Schublade in den Schacht geschoben. Diese stellt den Horn Anfang dar. Was aber wenige wissen und nur so ist eine Audiovector wirklich in Betrieb zu nehmen: Vor dem anschrauben der Rückblende (dicht!) müssen Brettchen individueller Stärke auf die Schublade gelegt werden um das Vorkammervolumen abzustimmen. So wird der Treiber exakt auf das Horn getunt und nur so bekommt man akustisch das, was viele suchen! Grundton!


Audiovector plaster horns

Als Fronttreiber geht nichts über unseren Feldspulen AL2 oder A5000

Als Fronttreiber geht nichts über unseren Feldspulen AL2 oder A5000

In der späten Serie findet man einen zusätzlichen Fronttreiber, oft den PM2 Mk1. Dieser ist in der Lautstärke regulierbar und man kann, abhängig von der Raumakustik, den Direkt / Indirekt Schallanteil bestimmen. Ebenso wie der Haupttreiber PM4a wird der PM2 ohne Frequenzweiche betrieben.

Der Vorteil eines zusätzlichen, in der Lautstärke variablen Fronttreibers liegt in der Möglichkeit des Zuhörers, seine Hörentfernung zum Orchester selber zu bestimmen. Bei kräftigem Einsatz des Direktstrahlers rückt man nahe an das Klanggeschehen, je leiser der Fronttreiber eingestellt wird, umso weiter scheint der Zuhörer räumlich entfernt. Auf diese Weise entscheidet der Zuhörer selbst welchen Platz er im Konzertsaal einnimmt.

Audiovector EX

Explosionszeichnung der Audiovector

Audiovector mit Kilimanjaro-Series A5000 Fronttreiber und Lowther PM4a


Einzigartige Fertigung des modernen Feldspulenlautsprechers A5000
Glocke und T-Yoke aus Reineisen, nur eine einzige 140 mm Passung! Die Elemente werden aus dem vollen Material gearbeitet – wo gibt’s so etwas noch? Aber der Aufwand endet nicht bei Kilimanjaro-Series Treibern, das Gesamtergebnis ist die Summe aller kleinen Details…

Kilimanjaro-Series A5000

Kilimanjaro-Series A5000

Die Lebendigkeit und Frische dieser Hochwirkungsgradbreitbandlautsprecher ermöglichen intensives und ermüdungsfreies Langzeithören.


INTRODUCTION Horns have been in use in one form or another for the distribution of speech and music for many centuries: for instance, Alexander the Great had enormous horns to summon his vast armies, whilst today horns are invariably used in Public Address systems to marshal! crowds of many thousands. 

In the earliest days of the phonograph, horns were used for recording and reproduction purposes and now with the electroacoustic era, horns are once again in evidence, and most schools of thought agree that they are ideal for the reproduction and distribution of speech and music. 

Lowther-Hegeman front

Horns were further called upon by Acoustic Engineers for domestic use, but due to their large dimensions were considered impracticable: full use, however, is made of them in cinemas and auditoriums. 

The Acoustic Engineer has always sought for ways and means to use this principle for speech and music; for example, Voigt and Klipsch have excellent loudspeakers of their kind (descriptions of these speakers are dealt with in other literature), but though these two particular systems, as well as a few others, arc successful, there seems to be a great gap between their reproduction and the original, inasmuch as these may have a "distant" or heavy effect (unbalanced). 

Lowther-Hegeman rear

The Lowther Company used the Voigt Domestic Horns as a standard loudspeaker for a great many years, but realize that with new materials and techniques now known and available, greater realism can be attained. 

In 1947/48 the introduction by Lowther's of the P.M. 1 (19,000 gauss), closely followed and superseded by the now famous P.M. 2 drive unit (19,500 gauss) for horn loading, marked a great step "towards perfection", the electro-magnet drive unit having been eclipsed in its class by the permanent magnet unit with increased efficiency and improved overall performance. 

Lowther Drive Unit PM2 or PM4

Drive Unit Type P.M. 2 or 4

The P.M. Units are robust in construction, employ anisotropic magnet alloy (Ticonal G); diaphragm and cradle are cast aluminum, detachable as one unit; body housing stand affords short circuit protection for the magnet, mounts the moulded two-pin socket for speech connecting plug. The special shape of the magnet (patented) is of considerable importance, enabling such magnetic force to be derived from so small a mass. Another important feature is that the pole faces are run at magnetic saturation, important because the speech coil does not move in a field of unequal density which would otherwise cause distortion. 

The diaphragm is of 6 in. twin cone aluminum speech coil design, having compliances throughout its system, i.e. major cone, inner cone and speech coil, in enable a wider frequency range to be obtained with one assembly. 

THE DRIVE UNIT (P.M. 4) The development, also in 1948, of the prototype Lowther P.M. 4 driver with 23,5OO gauss, and now its release at 24,000 gauss establishes an all world record of performance and at the same time a further step "towards perfection". This increased magnetic efficiency, affording greater damping, together with a change of speech coil construction, gives improved frequency response, transient and decay factor performance combining to form the heart of a hi-fi reproducer of unequalled characteristics. 

THE HORN There yet remains the problem of utilizing the remarkable performance and high efficiency of the Lowther P.M. 4 drive unit to its full advantage. 

In conjunction with Hegeman Laboratories, N.J., U.S.A., a very ingenious compound manifold horn system was designed. 

Lowther-Hegeman top

Based upon orthodox principles, offering horn loading lo the Lowther P.M. 4 drive unit from the highest overtones to the lowest notes, broadcast or recorded, a further remarkable achievement is made, culminating in the reproducer known as the Lowther-Hegeman. 

This reproducer type "W" gives sound distribution over 180 degree and can be positioned where desired. 

Lowther-Hegeman plaster horn

By careful choice in parameters of the horn sections high efficiency has been attained over the audio range, phase differences are at a minimum and for all practical purposes time constants is zero, wide angle distribution without beam effect is a material and a pleasant feature. 

The middle end higher frequencies are covered by dual outlet double rate flare horns, the mouth acoustical impedance of the small horn is the throat acoustical impedance of the second section. 

The bass folded horn is operated by the rear of the diaphragm, special steps being taken in both design and construction to give freedom from resonance over the lower octaves.

Lowther Lowther-Hegeman horn

PERFORMANCE OF THE LOWTHER-HEGEMAN REPRODUCER To describe the differences between any two hi-fi system is, we believe, beyond the scope of man; factors alone involved in attempting to form such an opinion are too numerous in themselves and too complicated to know where to begin; we will therefore confine our remarks to the principle and achievements of the Lowther-Hegeman Reproducer. 

Design features mentioned above seem to have covered the salient and desirable points, but there remains a feature more necessary for "towards perfection" reproduction if an illusion of the original is to be attained. This is to maintain correct relationship between fundamental and harmonics of the original sound. 

Instruments of the orchestra are recognized for their tonal qualities by the various degrees of their harmonics or overtones, similar instruments are distinguished by yet a further minute change of this relationship or percentage variation. 

Employing only one Lowther P.M.4 drive unit this objective is possible. When two or more units are used the complex wave-form is dealt with by more than one section or units having entirely different time constants, quite apart from frequency characteristic deviations, including possibly a cross-over network, the relationship is therefore changed, retarded, emphasized or even advanced at different points, besides being changed yet again at various volume levels. 

Ribbon or pressure type units are commonly used to improve the "hi's"; this is similar to requesting a "sprint cyclist" to assist a penny-farthing cyclist in making his performance more spectacular, they neither start nor finish together! 

The Lowther-Hegeman Reproducer has only one basic time constant and covers the entire audio range, thus giving a remarkably live, forward and natural performance. The efficiency of the overall system being such that even at a few milliwatt input level complete balance is maintained. 

As one critic remarked „it is usual to listen in a darkened room for ethic illusion, but with the Lowther-Hegeman Reproducer in broad daylight the feeling of presence is there all the time." 


SPHERE in Farbe

Wolf von Langa Sphere Gelb (yellow)

Wolf von Langa Sphere Blau (blue)





Christine von Langa - Roedlas 54 - D - 91077 Neunkirchen a. Br. - Phone +49 (0)9192 996926 - E-Mail: listen(at) -
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.
WOLFVONLANGA is a registered trademark.