PHILIPS RH541
¥ 68,000 (1 unit, around 1979)
Commentary
Active speaker system of Studio Monitor Series.
The Studio Monitor Series uses the Motional Feedback (MFB) method to achieve undistorted bass playback.
The RH541 uses an electronic crossover filter to divide the signal from the built-in amplifier into high - and low-frequency ranges. The high-frequency range drives the tweeter, while the low-frequency range uses an MFB loop composed of a woofer and a comparator (waveform comparator) to enable distortion-free playback.
In the MFB, 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 to a voltage. This voltage and the input signal are compared with a comparator, making it possible to make the reproduced sound wave exactly the same as the original waveform and to control the distortion component forcibly.
The low range has an 18 cm cone woofer, and the high range has a 2.5 cm dome tweeter.
It is equipped with an input sensitivity selection switch that supports both preamplifier output and power amplifier output.
Equipped with automatic power on / off mechanism.
This function turns on automatically with an input of 1.5 mv or more, turns off automatically with no signal for 2 minutes or more, and the operation status is indicated by the indicator lamp.
The enclosure is made of wood with a black ash finish.
Equipped with a power switch.
Since parallel connection is possible for each channel, power up for multiple use is possible.
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Model Rating
| Method | Built-in Amplifier / 2-Way / 2-Speaker / Bookshelf Type |
| Speaker Unit | |
| Units Used | For Low Band : 18 cm Cone Type (AD7066/MFB4) For High Range : 2.5 cm Dome Type (AD0161/T8) |
| Frequency characteristic | 35 Hz to 20 kHz |
| Crossover frequency | 1.4kHz |
| Enclosure volume | 8 liters (acoustic part 4.5 liters) |
| Input sensitivity | 1 : 1V/10k Ω 2 : 7.5V/100 Ω 3 : 19V/100 Ω |
| Electronic ON/OFF switch | ON (for 1 second or more at 1.5 mv or more input) Off (2 minutes or more without signal) |
| Amplifier Unit | |
| Output | Continuous Sine Wave 30W |
| Harmonic distortion factor | 1% or Less (30W) 0.1% or Less (20W) |
| Output bandwidth | 14 Hz to 50 kHz |
| <Others> | |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 65W max. |
| External dimensions | Width 230x Height 295x Depth 175 mm |
| Weight | 6.5kg |