Sonifex RM-4C8-E1X

RM-4C8-E1X Reference Monitor, 4 LED Meters, 8 Channel Inputs &
Dual Source Selectors With Dolby Decoder Card, XLR Input/Output
Reference Monitor LogoThis version of the Reference Monitor is the RM-4C8 with the RM-E1X expansion card already fitted. So, it has all of the features of the RM-4C8 as standard together with Dolby Decoding.

The RM-E1X adds to the unit a 110ohm balanced AES/EBU input and output on XLR connectors with the output acting as a loop-through of the input. The XLR input can decode a Dolby E or Dolby Digital audio stream allowing you to monitor visually 8 or 5.1 audio channels respectively and to monitor audibly any 2 of those channels.

By pressing the left hand source select control, you can select the Dolby input. If a Dolby E or Dolby Digital input is detected, the Channels (CHANS) button flashes to indicate that decoding is possible. Pressing the CHANS button displays the Dolby Digital 5.1 or Dolby E 8 channel signal, using the 4 bar-graph meters.

Each meter is split into 2 sections allowing you to view L, R, C, LFE, Ls, Rs for Dolby Digital and an additional Lt, Rt for Dolby E.

Full Dolby Metadata is available using the SCi remote control software. For a more detailed description of Dolby Decoding operation please refer to the Reference Monitor handbook.
SCi logoThis product has settings that can be adjusted using the Sonifex SCi (Serial Control Interface) software. To download a copy of the SCi software, please contact us at: [email protected]


Audio Inputs8 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

Dolby Decoding Audio Input

AES/EBU Input110Ω transformer coupled balanced Input
Sample Rates:32 - 48 kHz
Audio Formats:Linear PCM Dolby E (16, 20 and 24 bit) Dolby Digital (16 and 32 bit)

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
Crosstalk 1kHz input: 10kHz input:Analogue I/O, ref 0dBu <-90dB <-85dB

Dolby Follow Audio Output

AES/EBU Output110Ω transformer coupled balanced output

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

Centre Frequency:200Hz to 18kHz
Bandwidth:0.25 to 2 octaves
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 2. BBC PPM 3. EBU PPM 4. Nordic PPM 5. AES/EBU digital PPM 6. DIN 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 socket (balanced, may be unbalanced)
Audio Outputs:2 x XLR 3-pin male plug (balanced, may be unbalanced)
Dolby Decoding Audio Input:1 x XLR 3 pin female socket
Dolby Follow Audio Output:1 x XLR 3 pin male plug
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


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