The crossovers of the different generations did start very simple with a 6 db filter for the 1000 hz cut frequency at the beginning. Tannoy used huge paper capacitors and waxed impregnated copper coils for the Monitor Black. With higher production numbers of the Monitor Silvers they got a specially made paper capacitor with three units in one can supplied. With Monitor Reds Tannoy started to use electrolytics for the crossovers (cost cutting).
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The Silver and Red 12'' versions did drive the cone in full range mode, just the tweeter got cut to be protected for the low frequencies. All the crossover designs kept efficiency in the foremost stage. With Monitor Gold and the new lower impedances of 8 ohms the crossovers needed to be redesigned completely. Tannoy used the chance to change to more complex filters with the possiibility to cut or damp the HF-horn in four steps each for all three sizes. This new luxury brought the opportunity for room compensation of the cabinets. Thanks to the believe in quality Tannoy made these attenuators with switched auto transformers, the by far superior way to do so (expensive). And they supplied compensating filters to improve measured linearity over the entire spectrum. All supplied "improvements" were accepted as further degradation of efficiency as tolerable side effect.
Over the years the speakers have been treated with numerous improvements, mostly in order to improve power handling capabilities for high output transistor devices. The company tried to follow the tremendous increase of power output in amplifier design, right to a point were it found a simple physical limitation. Seen from today the treatments did not always improve the general performance soundwise, in particular if you do use them with low powered tube amps. It is more like permanent stepping backward. At the end the lightweight cone with the 30 watts voice coil of the early designs, added up to the double weight with the HPD range. These differences together with more complex crossovers lead to clearly listenable degradations, foremost in terms of lost dynamics and a decrease of fine details. If you ever have compared a Monitor Silver to a Monitor HPD you might know what I am talking about.
In this logic a lot of products did not benefit from the advantage of its "market advance"; i.e. means have fallen down their staircase of development. This is fairly common observation and a poor truth at the end of modernism and industrialized mass production with almost any of its products.
When Guy R. Fountain, the founder of the Tannoy company died in 1977, the company was sold. This chapter ended the "West Norwood"-history and the company was moved to Scotland by its new owners in order to cut production costs. From 1978 the "Dual Concentric"-speaker got completely redesigned with ferrite magnets for both frequency parts. New materials got applied, as well a new hf-driver design was developed to cut production costs. Only within the Prestige-Series some of the old magnets ("alcomax 3" named) get installed in countable amounts to enclosures at tremendous price ranges. The other dual concentric designs got a horn amplified dome tweeter design ("tulip wave guide" marketing speech) with hefty coils wound, able to play 300 watts of power, as a tribute to modern demands of audio fidelity.
Изменено: - 19-08-2015 14:33:49
