RM-4C8 Reference Monitor - Discontinued

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With 4 x bright high-resolution 26 segment meter displays and separate left and right source selectors, the RM-4C8 is ideal for monitoring audio channels in an SDI group, or groups of de-embedded
AES/EBU channels.

The RM-4C8 offers the same functionality as the RM-2S4 but with an additional source selector so that any of the 4 channels in the selected group, or bank, can be monitored independently on left and right speakers.

Also, 4 meters are provided so that every channel in the selected group, or bank, can be visually monitored and 4 expansion port groups of 4 channels are allowed, so that all audio channels in an SDI signal can be monitored, using the optional RM-HD1 card.

The audio inputs on the RM-4C8 are auto-sensing, for digital AES/EBU using the left input XLR, or both XLRs for analogue inputs. The inputs can be used in any combination of analogue or digital.

With full remote control via GPI, RS232 or USB, a 5 band parametric equaliser, 6 front panel modifier buttons and the ability to take the optional 3G/HD/SD-SDI expansion cards, the RM-4C8 is a flexible and versatile monitoring solution.

The same high level of care has been taken in the design of the RM-4C8 as in the RM-2S4 to ensure that it will be the best sounding 1U rack-mount audio monitor that you listen to.

Technical Specification For RM-4C8


Audio Inputs 8 analogue or AES/ EBU digital channels (autoselecting)
Max level (0dB input gain): +18dBu (analogue)/0dBFS (digital)
CMRR: >60dB typical
Input Impedance: 20kΩ (analogue) 110Ω (digital with termination switchable)
AES/EBU Sample Rate: 32 to 192kHz, converted internally to 48kHz
Input Gain: 0, +6, +12 or +18dB digital gain (switchable)
Selection: 2 x Front panel rotary control with indicator LEDs

Line Level Outputs

Audio Outputs: 1 x stereo analogue or AES/EBU digital (switchable)
Gain re Selected Input: Unity or variable, following volume control (switchable)
Maximum Output Level: +18dBu (analogue)/0dBFS (digital)
Output Impedance: <50Ω (analogue)/110Ω (digital)
AES/EBU Sample Rate: 48kHz
Distortion: <0.02% (1kHz, +8dBu output)
Noise: -84dB RMS, unity gain ref +8dBu output
Frequency Response: 20Hz-20kHz +0/-0.5dB
1kHz input:
10kHz input:
Analogue I/O, ref 0dBu

Audio Modifiers

Modifier Selection: Illuminated front panel pushbuttons
DIM: Reduces speaker audio level by 10dB
CUT L & CUT R: Mutes left/right speaker audio
MONO: Combines left and right audio inputs
PHASE INVERT: Inverts phase of right audio input
M+S: Converts stereo input to Middle (sum) and Side (difference) signals

User-Variable Equalisation

Type: Parametric
Bands: Five
Centre Frequency: 200Hz to 18kHz
Bandwidth: 0.25 to 2 octaves
Boost/Cut: ±12dB
Programming: Via USB/serial control port


Configuration: Three-way with stereo mid/ high-frequency drivers & mono low-frequency driver
Power Output: 2 x 5W (HF) + 20W (LF) with protective limiter
Crossover: 500Hz (3rd order Butterworth)
Distortion (HF Outputs): < 0.05% (1kHz, 3W output)
Distortion (LF Output): < 0.05% (100Hz, 6W output)
Noise: More than 80dB below full output
Volume: Mute to full volume via front panel rotary control
Balance Trim: ±6dB via front panel rotary control
Peak Acoustic Level: 102dB SPL @ 2ft

Level Metering

Number: 4 x 26-segment tri-colour LED bargraphs
Characteristics: Selectable by switch from:
1. Dual BBC PPM + standard VU
4. Nordic PPM
5. AES/EBU digital PPM
7. Standard VU
8. Extended VU
Ballistics: According to selected characteristic
Line-Up Level: According to selected characteristic

Phase Metering

Type: 5-segment, indication at 0, 45, 90, 135 and 180 degrees

Remote Control

USB: Slave device, 19200 baud
Serial: RS232, 19200 baud, 3-wire connection
Alarm Outputs: 1. Audio underlevel/fail (latching)
2. Audio overlevel (latching)
3. Sustained phase error (latching)
4. AES/EBU input unlock (non-latching) Open-collector outputs rated at 30V,
50mA maximum
Output low/conducting in normal condition (no alarm)
Control Inputs: 1. Mute audio
2. Dim audio
3. Alarm reset
Pull-to-ground to activate inputs

Status Indicators

LIMIT: Indicates loudspeaker protection limiter is active.
CLIP: Indicates internal digital clipping due to overlevel.
LOCK: Indicates lock achieved on selected digital input(s).
OPT: For future use.


Audio Inputs: 8 x XLR 3-pin female (balanced, may be unbalanced)
Audio Outputs: 2 x XLR 3-pin male (balanced, may be unbalanced)
Headphones: 1/4” (6.35mm) A-gauge 3-pole stereo jack socket
USB: Type B socket
Serial: D-sub 9-pin female
Remote I/O: D-sub 15-pin male
Mains Input: Filtered 3-pin IEC male, continuously rated 85 - 264VAC, 47 - 63Hz, fused, 60W peak, 30W average
Fuse Rating: Anti-surge fuse 2A 20 x 5mm

Equipment Type

RM-4C8: Reference Monitor, 4 LED meters, 8 channel inputs & dual source selectors

Physical Specification

Dimensions (Raw): 48cm (W) x 30.5cm (D) x 4.4cm (H) (1U)
19” (W) x 12” (D) x 1.73” (H) (1U)
Dimensions (Boxed): 57cm (W) x 52cm (D) x15cm (H)
22.4” (W) x 20.5” (D) x 5.9” (H)
Weight: Nett: 4.5kg Gross: 6kg
Nett: 10lb   Gross: 13.2lb


RM-HD1: 3G/HD/SD-SDI expansion card

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