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Sonifex RM-4C8-E1B - Reference Monitor RM-4C8 with RM-E1B Dolby Decoder Card

£3,660.00 £3,050.00 (ex. vat)

Sonifex RM-4C8-E1B

  • Sonifex RM-4C8-E1B
  • Sonifex RM-4C8-E1B
  • Sonifex RM-4C8-E1B Rear

Sonifex RM-4C8-E1B - Reference Monitor RM-4C8 with RM-E1B Dolby Decoder Card

The Sonifex RM-4C8-E1B is a version of the RM-4C8 Reference Monitor with the RM-E1B expansion card already fitted. So, it has all of the features of the RM-4C8 as standard together with Dolby Decoding.

The RM-E1B adds to the unit a 75ohm unbalanced AES/EBU input and output on BNC connectors with the output acting as a loop-through of the input. The BNC 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.

Sonifex RM-4C8-E1B Specifications


  • 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

Dolby Decoding Audio Input

  • AES/EBU Input: 75Ω transformer coupled unbalanced 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: Analogue I/O, ref 0dBu 
    • 1kHz input: <-90dB
    • 10kHz input: <-85dB

Dolby Follow Audio Output

  • AES/EBU Output: 75Ω transformer coupled unbalanced 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

  • 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 
    • 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 (balanced, may be unbalanced)
  • Audio Outputs: 2 x XLR 3-pin male (balanced, may be unbalanced)
  • AES/EBU Input: 1 x BNC
  • AES/EBU Output: 1 x BNC
  • 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
Manufacturer Sonifex
Model Sonifex RM-4C8-E1B
Sonifex RM-4C8-E1B
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+44 (0) 151 707 4545
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