PHILIPS RH544

Commentary

A 3-way active speaker system in the Studio Monitor series.

The Studio Monitor Series uses the Motional Feedback (MFB) method to achieve sound without distortion or coloring.
In the MFB method, a 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 a voltage. This voltage is compared with the input signal by a comparator, making it possible to make the reproduced sound wave identical to the original waveform and to cancel the distortion component forcibly.
For RH544, the input signal is fed into an electronic crossover network and divided into mid - and low-frequency ranges. The mid - and low-frequency ranges are driven by a dedicated amplifier and crossover network to drive a tweeter and a squaker. The low-frequency ranges are reproduced by an MFB loop composed of a low-frequency amplifier, woofer and comparator.

It has a 20 cm cone woofer in the low range, a 5 cm dome squaker in the middle range, and a 2.5 cm dome tweeter in the high range.

The input sensitivity can be adjusted continuously for all output signals such as preamp output and power amplifier output.

Equipped with an automatic power ON/OFF mechanism driven by relay.
This mechanism is automatically turned on with an input of 2 mv or more, automatically turned off with no signal for 2 minutes or more, and the operation status can be checked with the indicator lamp.

The enclosure is made of wood with a black ash finish.

Since parallel connection is possible for each channel, power up for multiple use is possible.

Model Rating

Method	Built-in Amplifier / 3-way / 3-speaker / Bookshelf Type
Speaker Unit
Units Used	For Low Band : 20 cm Cone Type (AD8067/MFB4) For Middle Area : 5 cm Dome Type (AD0210/Sq8) For High Range : 2.5 cm Dome Type (AD0160/T8)
Total output	Continuous Sine Wave 60W
Frequency characteristic	30 Hz to 20 kHz
Crossover frequency	Electronics crossover : 500 Hz Passive crossover : 3.5 kHz
Enclosure volume	15 liters (acoustic part 9 liters)
Input sensitivity	1 V ~ 3V/100k Ω 3 V ~ 20V/1k Ω
Electronic ON/OFF switch	ON (2 mv or more input for 1 second or more) Off (2 minutes or more without signal)
MFB Amplifier Unit
Output	Continuous sine wave 40W
Harmonic distortion factor	1% or Less (40W) 0.1% or Less (30W)
Output bandwidth	10 Hz to 3 kHz
Middle-High-Range Amplifier Section
Output	Continuous Sine Wave 20W
Harmonic distortion factor	1% or Less (20W) 0.1% or Less (15W)
Output bandwidth	100 Hz to 5 kHz
<Others>
Power supply voltage	110 VAC / 220 V, 50Hz/60Hz
Power consumption	Up to 150W
External dimensions	Width 290x Height 390x Depth 216 mm