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Meridian HDMI Audio Processor-HD621

Model #: HD621
Meridian Audio
At a Glance

Meridian HDMI Audio Processor with triple fifo buffering and apodising filter

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Get to know this product.

The HD621 is a pitch-perfect problem solver. HDMI connectors are a common sight on high-definition equipment, helpfully carrying audio and video signals. But digital video signals can prove detrimental to sound quality – so the HD621 cleverly solves this problem by extracting the audio signal from the HDMI input and routing it through the high-tech audio processing of a Meridian system. 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 synchronization 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 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 Apodising 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.
Meridian High Resolution (MHR)
  • 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.
  • Internal universal power supply,

  • 100–250Vac

  • Power input (IEC connector)

  • DB9M Sub RS232 serial connector

  • BNC and DIN Meridian Comms

  • Six HDMI input sockets

  • HDMI output

  • 8-channel MMHR digital audio out (RJ45)

  • 8-channel coax digital audio out (4 x phono)

Front-Panel Indicators
  • Power LED

  • 6 x HDMI Input LEDs (selected input lights)

Useful Documents


HDMI Inputs:6
Coaxial Digital Audio Outputs:4


Sold As:Each



Misc. Specs

Product Weight2.5
WarningProposition 65 Warning for California Residents