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EMS 8-Octave Filter Bank

EMS Data Sheet

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The EMS Range of Ancillary Studio Modules EMS Modules are designed not only for use with Synthi synthesisers but with any complex of voltage controlled equipment, of whatever manufacture. They are supplied in handsome afrormosia cases, but can be removed and mounted in standard 19" racks, occupying only 1.7" (44mm) of vertical space. They contain their own mains power unit with a very wide range of stabilisation to cope with poor mains line conditions, being operable at anything from +10% to more than—23% of nominal line voltage. Connections to and from the modules can be made either from the jack sockets on the front panel or via the multi-way socket at the back.


The EMS Eight-Octave Filter Bank is a group of eight individual resonating filters fixed-tuned one octave apart in the range 62.5Hz—8KHz, arranged in parallel. The unit is inserted into an audio signal line, and since the output of each filter may be separately controlled very subtle variations of colouring can be made. It is simplicity itself to operate, and no voltage control is involved, its purpose being to provide characteristic colourings which are on the whole constant during a particular application. The cut-off is sharp enough to permit sections of the spectrum to be virtually removed, making profound changes in the character of a sound. With all the controls at maximum the signal will emerge unchanged except for a 10dB overall gain. At intermediate settings the response is comblike, levelling out to total rejection of the whole band when all controls are at zero.

A valuable extra facility is the access given by jacks or the facilities socket to each filter separately. The main output contains all the filters in parallel, but in addition the spectral content of the output of each filter is available at the appropriate jack. Thus up to nine simultaneous timbres can be obtained from a single complex signal. An additional use for the filter bank is as a signal improver. Hum or any other unwanted fixed frequency phenomenon can often be removed completely without serious distortion of the signal spectrum.

Apart from its use in electronic music, the eight-octave filter bank is a great asset to any studio; a group of several (at least as many as the number of output lines) can be arranged for instant patching in to any channel needing correction.


Power Supply:
240 or 115VAC 50/60Hz +10% to—23%

Input Level:
6V p-p max.

Max. Overall Gain:
10dB +/- 1.5dB.

Individual Filter Gains:
9dB +/- 3dB max.

Hum and Noise:
—80dB referred to max. gain conditions.

Filter Frequencies:
63, 125, 250, 500, 1,00O, 2,OOO, 4,000, 8,000 Hz.

Filter Tuning:
Centre frequencies all +/10%

Filter Slope:

Channel-to-channel crosstalk:
—60d B.

Electronic Music Studios (London) Limited
277 Putney Bridge Road London SW15 2PT
Telephone 01. 788 3491/2 Telex 92 83 72
New York: Suite 2222 110 East 59 Street NY 10022
Telephone 212 832 3115 Telex 42 40 33
New Address: 1977: C/o Peter Zinovieff, The Priory
Great Milton, Oxford
Telephone 08446-729

Data Sheet (Optically Character Read) from The Terrey Collection Library

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