Summary of dm70
Page 1
B&w dm70 instruction manual test certificate and guarantee.
Page 2: Dm70
Dm70 b&w d m . Trade mark of b&w electronics.
Page 3: Contents
Contents 1. General description 2. The listening room 3. Installation — unpacking and connection 4. Installation — siting 5. Ancillary equipment 6. Specification page 2 3 5 10 12 13 b&w electronics meadow road • worthing england -bn11 2rx.
Page 4: General Description
General description and introduction the dm70 is a precision monitor loudspeaker for domestic and profes- sional use, built to very high standards. This loudspeaker, employing the combination of dynamic bass drive unit in conjunction w i t h an electrostatic transducer for the mid-range and upper fr...
Page 5: The Listening Room
The listening room m o s t people have relatively little control over their listening room in terms of size or shape, but as the environment in which the loudspeaker is used plays such a big part in the quality of sound we hear, some comments on room characteristics may be helpful before we proceed ...
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The ideal is a solidly built ground floor room w i t h a concrete floor. In rooms where there is a board and joist floor this will play a part in both adding to bass gain and room colouration. The suspended floor acts as a supplementary bass radiator operating at the main resonance of the room. If y...
Page 7: Installation -
Installation - unpacking and connection for safety in transport t h e d m 7 0 improved system is packaged in three cartons, f o r each loudspeaker:— carton 1 main cabinet w i t h fitted power supply unit. Carton 2 t w o metal stands for the pair of loudspeakers. Carton 3 the " 7 0 2 " electrostatic ...
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Fig. 1 rear view of continental power supply, showing label indicating the power supply voltage. The power supply for the standard version is similar but rotated through 90 degrees. The regulation of the power supply is such that, normally, no adjust- ment will be necessary and the unit is set for t...
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. To remove the power supply unit from the cabinet, unscrew the four screws at the side of the rear panel of the unit and w i t h d r a w it, un- plugging the audio output to the bass unit. (if the 701 electrostatic unit has already been fitted to the cabinet, it will be necessary first to remove th...
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It is advisable to keep the series resistance of connecting cables as low as possible by using reasonably heavy gauge cables. Our recom- mendations are.— loudspeakers under 10 metres away from amplifier: use 16/0.2mm. Loudspeakers over 10 metres away from amplifier: use 2 4 / 0 . 2 m m . Phasing. Th...
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J i desired to operate the dm70 at very high sound levels, or where high powered continuous sine wave inputs are applied, the rear absorbent pad should be placed in position. It will be observed that on the rear panel of the power unit there is a neon indicator. This shows that the mains supply is f...
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Although in the case of the dm70 (due to its remarkable dispersion characteristic) positioning is not as critical as w i t h many conventional loudspeaker systems, this system is quite a substantial piece of furniture in its o w n right, and it is worthwhile taking care in siting the loudspeakers in...
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3. Due to the wide and balanced horizontal dispersion of the dm70, their horizontal position will not be critical. We w o u l d normally suggest that in domestic rooms of normal size they be not closer than eight feet (2.5 metres) apart, or separated by more than fifteen feet (4.5 metres) to give an...
Page 14: Ancillary Equipment
Ancillary equipment because of its exceptionally good frequency linearity and relative freedom from colouration and distortion, the dm70 is capable of ex- tremely faithful reproduction, provided that the signal fed to it is of the very highest quality. A monitor loudspeaker — and the dm70 is such a ...
Page 15: Specification
Specification general description b. & w. D m 7 0 is a h y b r i d design employing exclusive model 701 11-element wide dis- persion doublet electrostatic unit (patent n o . 1239658), dw 13/70 high power low distortion moving coil bass u n i t w i t h com- plex crossover and filter u n i t and divid...
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A prime design p o i n t of the 701 is that it is free-standing. This makes it possible easily to remove the unit in the event of damage etc., and service being required, thus avoid- ing the transportation of entire heavy and bulky system. Crossover and filter u n i t the 500 hz. Crossover frequency...
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Standard continental dimensions. Weight: weight w i t h stand: 4 5 . 4 k g . (100 lbs) standard overall height (on stand) 31 i " (808 mm) overall width 3 2 " (815 mm) overall depth 1 5 " (382 mm) continental overall height (on stand) 32 s" (820 mm) overall width 2 6 s " (680 mm) overall depth 1 5 1 ...
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Frequency response. On-axis ± 5 db. 60 hz. To 15khz. On axis response of a production sample d m 7 0 taken in ft & d anechoic chamber. B & k equipment used t h r o u g h o u t , w i t h t y p e 4133 microphone at 1 metre. Crossover and filter unit. Individual acoustic o u t p u t f r o m each drive ...
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Impedance. Nominal impedance 8 ohms. Not greater than 30 ohms or less than 4 ohms 20 hz to 9 k.Hz., the impedance m i n i m u m occurring in a frequency region of very low music energy. Plot of impedance of production sample of dm70. Distortion. Harmonic analysis plotted against frequency content of...
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Transient response. Tone burst oscillograms taken at one-third octave intervals in ou research anechoic chamber. Microphone type b & k 4133. 31.5 hz 40 hz 50 hz 63 hz 80 hz 100 hz 125 hz 160 hz 200 hz 250 hz 315 hz 400 hz 500 hz 630 hz 800 hz 1khz 1.25 khz 1.6 khz 2.0 khz 2.5 khz 3.15 khz 4 khz 5 kh...
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Polar response 100 hz polar response 1 k.Hz. Polar response 10 k.Hz. Polar response r k h ? 19.