Audio Processor Meridian HD621 HDMI


Tech Specs


  • Power Input: IEC connector
  • Connector: DB9M Sub RS232 serial
  • Meridian Comms: BNC and DIN
  • HDMI: 6x input + HDMI output
  • RJ45 Out: 8-ch MMHR digital audio
  • Phono Out: 8-ch coax audio (4x)


  • Power LED: Yes
  • HDMI: 6x LEDs (selected input)

Form Factor

  • 1U 19in rack mounting
  • Free-standing


  • universal PS: 100–250V AC
  • Max power consumption: 40WWeight: 4.5kg (10lbs)
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Meridian HD621 HDMI Audio Processor is a pitch-perfect problem solver. HDMI connectors are common on HD equipment carrying audio-visual signals but digital video signals can prove detrimental to sound quality – the HD621 solves this by extracting the audio signal from the HDMI input and routing it through Meridian’s high-tech audio processing.

Meridian HD621 – Perfect Harmony

The result is a significant boost in your system’s sound quality. Not only that, the HD621 also ensures that sound is always in perfect synchronisation with the picture – no more watching the actor’s lips move and hearing the sound follow a moment after. With space for up to six HDMI-equipped devices, the Meridian HD621 design matches the Meridian line and is available in free-standing and rack-mount versions. Problem solved.

Triple FIFO Buffering

Each sample of a digital recording must remain evenly spaced in time. Unfortunately, timing can vary, especially when reading discs. This is “jitter”, degrading music’s sense of space and diminishing realism. Meridian’s multiple “First In, First Out” buffering system minimises jitter, ensuring perfect timing and improved clarity. You enjoy a clearer feeling of the instruments and their interrelationship.

Meridian Resolution

MHR was the first approved encryption method for transferring high definition digital audio between components. Previously, it had to be in the analogue domain, reducing quality. MHR allows secure movement of high-resolution digital audio within a Meridian system, without compromise, improving quality by reducing cyclic repetition.

Apodizing Filter

Filters are critical in digital audio. Commonly they introduce distortion and harshness because of pre-ringing”. Early digital recordings suffer from harshness too due to primitive filters. After painstaking research Meridian developed a special filter that avoids pre-ringing so it can be steeper cleaning up the effects of early filters. The result: a better cleaner sound from recordings old and new.