RL 904

RL 904
RL 904 Detail
The RL 904 is an all purpose main loudspeaker for middle size or smaller audio-, video- and film production studios. Its coaxial arranged transducers ensure a sound impression with a high degree of homogeneity to a point source. The power concentration is designed for middle distance monitoring situation, at which a great differentiation in depth and a high fidelity of sound is guaranteed. Non-linear distortion remains small even at high sound pressure levels. The bass reflex system obtains a low-frequency cut-off at 40 Hz and provides a high degree of sound accuracy. We designed the whole system to achieve an optimum group delay.

The two-way MOSFET-amplifier with active crossover is situated at the back of the cabinet and is easily accessible for maintenance. An intermittent LED indicates sound pressure levels within the overload margin of 3 dB and warns of clipping. Beyond this limit the output level gets damped by 20 dB to protect the speaker’s components. To compensate their placement the speaker features two controllers to continuously adjust the low-frequency response.

There are various stands available as optional extras, which fit in the integrated appliance.
active two-way monitor for use in small and middle audio-, video production studios, in mobile broadcast vans, and for multi-channel and near-field purposes
Maximum SPL
106 dB / r = 1 m (3.3 ft)
40 Hz ... 20 kHz ± 3 dB
Acoustic output level / PE = - 14 dBu

> 83 dB / r = 1 m (3.3 ft)
Directivity index
from 100 Hz ... 10 kHz

increasing from 1 to 8 dB
Inherent noise sound level
≤ 7 dB (A) / r = 1 m (3.3 ft)
Total harmonic distortion
measured at 96 dB / r = 1 m (3.3 ft)
from 100 Hz ... 10 kHz

≤ - 40 dB
Nominal Input level
+ 6 dBu adjustable
Input impedance
≥ 10 kOhm RC balanced
Electronic Crossover frequencies
2.5 kHz
Nominal output power MOSFET-amplifier

150 Watt / 4 Ohm
100 Watt / 4 Ohm
Input Connector
Loudspeaker systems

160 mm (6.5") cone
25 mm (1") dome
Operation and Clipping indicator
LED on front side
Power requirements
Europe 230 Volt (± 10 %), AC, 50 Hz
USA & Canada 115 Volt, AC, 60 Hz
Power consumption
max. 160 Watt at full load
Mains Connection
IEC power connector
Dimensions (H x W x D)
398 x 254 x 345 mm (15.7 x 10 x 13.6 in)
16 kg (35.2 lbs)
Temperature requirements
for use
for storage

+ 15°C ... + 35°C (59°F ... 95°F)
- 25°C ... + 45°C (-13°F ... 113°F)
45 ... 75 %
Design of the Cabinet
MDF-wood in ash black veneered, optional different veneers or colors
with holding device; optional without holding device
RL 904 Free field frequency response
RL 904 Total harmonic distortions
RL 904 Gabelständer
Floor bracket stand
Loudspeaker rotable mounted
Deliverable heights (Top edge loudspeaker): 1184 mm (46.6 in), 1414 mm (55.7 in), 1544 mm (60.8 in) and 1684 mm (66.3 in)
Base panel (W x D): 520 mm x 450 mm (20.5 in x 17.7 in) oder 380 mm x 430 mm (15.0 in x 16.9 in)
Base panel and stabilisation panel veneered
Racks black powder-coated
RL 904 Standfuss
Integrated cable duct in the pedestal
Height (Top edge loudspeaker): approx. 1109 mm (43.7 in)
Base panel (W x D): 275 mm x 365 mm (10.8 in x 14.4 in)
Pedestal veneered
RL 904 Wandhalterung
Wall bracket
35° tilting und 35° rotable
Wall bracket black powder-coated
RL 904 Deckenhalterung
Ceiling bracket
Loudspeaker rotable mounted
Standard height between adapter plate and bracket: 300 mm
other length available
Ceiling bracket black powder-coated
Brochure and Documentation
Installation instructions for floor bracket stand
Technical drawings
Technical drawing to the loudspeaker
Technical drawing to the floor bracket stand with details of the standard heights
Technical drawing to the pedestal