PHILIPS F9638 MFB (1983) | Motional Feedback

 

The MFB loudspeaker F 9638 from 1983 incorporated Philips' latest scientific findings in active loudspeaker technology. While these are "super-high-tech" loudspeakers they went fairly unnoticed in the world of high fidelity. The main problem these loudspeakers went unnoticed is the fact that Philips brochures presented them as just another Philips product. These however incorporated a series of features that were unknown/revolutionary while the way they were presented created confusion in understanding what they really are. 

Revolutionary, that's what they were. In todays language these features are as follow: 

- Active loudspeaker technology. Built-in amplifier with dedicated 75W bass amplifier and 55W mid-high range amplifier and active crossover network.

- Automatic power on-off when used with a pre-amplifier

- Pre-set audio level adjustment on the front

- Side selector switch to assign which speaker is left and which is right channel

- Increased acoustic reproduction power possible by connecting several MFB speakers in series. 

- Flat diaphragm woofer and midrange

- Isophase ribbon tweeter

- MFB (Motional Feedback System). A built-in accelerometer detects movement of the bass loudspeaker while it's feedback results in less distortion.

- Designed to be used directly with a preamplifier in a multi-speaker configuration

- Designed for Digital Audio. These were introduced when CD was just introduced and the "for Digital Audio" badge (as used by many manufacturers) induced the fact that you absolutely need these loudspeaker for perfect audio from CD. This was of course just an exaggerated term. 

- Frequency range 27-40,000 Hz

- Total amplifier power (DIN): 105 watts nominal, 130 watts music

- Size: 31x63x24cm

And just as a final notice. Let's not forget that these loudspeakers were simply presented as a special kind of Hi-Fi loudspeakers not some kind of Ultra High-End out of this world Exotic creatures.

Looking for more? Head to 1001hifi.com for everything vintage audio.