Professional Monitor

IMF Professional Monitor

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This new model is a derivative of the widely acclaimed Reference Standard Professional Monitor on which it is based. It fulfils the need of the dedicated audiophile for a loudspeaker of comparable quality with low colouration and superb phase coherence.

Our rigid styrene and fibreglass coned bass drive unit is loaded by a fully tapered and filtered transmission line, producing an extension of bass performance to well below audibility, where frequencies are felt as well as heard. The mid-range driver is mounted above the tweeters enabling it's separately constructed line to be placed in a position of improved rigidity; isolating it from bass line feed-through. Our new tweeter and supertweeter are damped with ferro-fluid, considerably increasing power handling and avoiding distortion. They are devoid of face mounting flanges thereby allowing them to be placed close together. An "in-line" configuration, together with tightly clustered drive units, results in superb imagery.

The dividing network has basically the same circuit as that of the Reference Standard Professional Monitor Mark VII and the same philosophy is applied. Low-loss multistranded heavy copper cable is used for all internal wiring.

The Professional Monitor is fitted with a three position perspective control. In the central normal '0' position the mean hemispherical response is nominally flat. The '-' position tailors the mid-band energy to provide a response which psycho-acoustically increases the effective distance of the listener from the transmitted performance. Similarly in the '+' position the mid and high frequencies are brought forward to provide an integrated response at a closer listening position. This enhances some popular music presentations, especially under conditions of high ambient noise.

The heavily constructed and damped enclosures are finished in the finest American Walnut, and supplied with stands. We have replaced the standard cloth-covered wooden grille frame with a specially designed acoustically transparent, self-coloured brown foam, thereby minimising edge defraction effects.

With its wide dynamic range and minimal colouration, the resulting accuracy of this transducer allows the listener to hear the true performance of the original programme material in a manner otherwise unattained.



950 x 400 x 460 mm (37 3/8" x 15 3/4" x 181/8") wide

Overall height on stand 1060 mm (413/4")

Drive Units

300 x 210 mm (11 3/4" x 81/4") Bass unit - styrene/fibreglass cone

130 mm (5") Mid-range engineered polymer cone

45 mm (1,"/4") Tweeter high gauss: ferro-fluid damped

20 mm 3/4") H.F. Tweeter chemical dome: ferro-fluid damped

Crossover Frequencies

350 Hz, 3 kHz and 13 kHz

Frequency Response

19 Hz to 40 kHz


Pink noise at 1 metre - 82 dB at 1 watt


Perspective control

Matching Impedance

8 ohms nominal

Recommended Amplifier Power

Not less than 40 watts per channel RMS

Net Weight

79 Kgs (173.8 Ibs.) (pair with stands)

Gross Weight

100 Kgs (220 Ibs.) (pair with stands)


Heavily braced and deadened high-density epoxy saturated particle board. Internally veneered and finished externally with the finest American Walnut veneer

Subject to alteration without notice

IMF ELECTRONICS, INC. 5226 State Street

Saginaw, Michigan 48603 Tel (517) 790-2121 Telex 227461

IMF ELECTRONICS LTD Westbourne Street High Wycombe

Buckinghamshire England HP1 1 2PZ Tel (0494) 35576 Telex 83545