PHILIPS AH587
¥ 139,000 (1 unit, around 1980?)
Commentary
An active speaker system using the MFB method.
In the MFB method, the piezoelectric element (PXE) mounted on the top of the cone paper of the woofer detects the acceleration of the cone paper and converts it into voltage. The voltage and input signal are compared with each other using a comparator. This makes it possible to make the reproduced sound wave identical to the original waveform and to cancel the distortion component forcibly.
It is a 2-way multi-amplifier configuration. The input signal is divided into mid - and low-frequency ranges by an electronic crossover network, and each is driven by a dedicated amplifier.
A 20 cm cone type woofer is mounted in the low range, and a combidome type squaker is mounted in the middle range.
A dome-shaped tweeter is installed in the high range.
Model Rating
| Method | Built-in Amplifier / 3-Way / 3-Speaker / MFB Method / Bookshelf Type |
| Units Used | For low band : 20 cm cone type For Middle Area : Combi Dome Type For High Frequency : Dome Type |
| Frequency characteristic | 27 Hz to 20 kHz |
| Output sound pressure level | 109dB |
| Crossover frequency | 650 Hz, 3.5 kHz |
| Amplifier output | Low Band : 50W Medium Range : 20W For high frequency : 5W |
| Amplifier harmonic distortion | 0.1% or Less (40W) |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 100W |
| External dimensions | Width 300x Height 487x Depth 237 mm |
| Weight | 13.9kg |