Check price options >
Order >
Advantages
F.A.Q.
Warranty
Support
Contact
        AuI ConverteR 48x44 RSS Audiophile Inventory on Facebook Audiophile Inventory on Google+ Audiophile Inventory on LinkedIn Audiophile Inventory on Twitter     [Login/Register]

HDMI for Audio

Share 

In this article we talk about using HDMI, USB, FireWire, USB for connecting audio devices (DAC, sound cards, receivers, TV, etc.). Here we compare HDMI with other digital audio interfaces. The article intended for audiophiles, musicians, music producers and wide circle of readers.

We talk here about:

1) USB 2.0 and higher.

2) HDMI 1.4 and higher.

3) DAC (digital-analog converter device) as sound card without record capability.

Audio applications:  HDMI vs. SPDIF vs. USB vs. Fire Wire

HDMI vs. SPDIF vs. USB vs. Fire Wire
Feature HDMI SPDIF USB Fire Wire
Playback throughput uncompressed PCM capabilities (channels x bit-depth x sample rate) 8 ch x 24 bit x 192 kHz 2 ch x 24 bit x 96 kHz 8 ch x 24 bit x 192 kHz 8 ch x 24 bit x 192 kHz
Back audio data capability (audio record or conditions or etc.) Yes   Yes Yes
Connectors images

HDMI connector female

HDMI connector male

SPDIF RCA

SPDIF RCA female

SPDIF RCA male

SPDIF optical

SPDIF fiber female

SPDIF fiber male

USB connector female

USB connector male

FireWire connector female

FireWire connector male

Reliability of connectors Middle reliability Middle reliability Middle reliability Middle reliability

Reliability of professional connectors achieves by using special connectors with screw elements.

 

HDMI

HDMI has been extended recently.
HDMI 1.3 and higher have 2 advantages:
1) One cable for audio and video
2) Simultaneously HD-video (1080p) and multichannel HD-sound (8ch x 24bit x 192 kHz) is allowed.

 

Some word about jitter.

Jitter is instability of clock of samples passed to input of playback DAC (chip of sound card). Jitter add the noise to output signal of DAC chip.

Jitter of audio data passed through HDMI occurs by reason sync by video. It's right for external synchronization of DAC or sound card by HDMI video clock.

In this case buffering (internal buffer of sound card) don't fix jitter. Samples passes to DAC (chip, not device) from the buffer with clock rate of HDMI, synced by video.

If use builtin to DAC buffer and internal stable clock generator (or external high precision generator). Audio data passed from buffer with clock rate of the generator. In this case jitter will reduced as capable internal generator. In pro applications used external high stable generator (WordClock).

For buffer case we have probability of buffer overflow or empty.
But value of sync rate of HDMI quite equal of sync rate of the internal DAC sync generator. So for a certain length of buffer we protected by emptying or overflowing of buffer.

Why manufacturers of serious audio use HDMI rarely? Reason is significant value of license fee for HDMI.  It isn't profitable for small series as expensive audiophile DAC.

 

SPDIF

SPDIF is consumer version of AES/EBU audio interface.

Jitter value depend by stability of clock generator.

Some audio cards have capability synchronize clock by external SPDIF source of audio signal or by internal clock generator.

 

USB and Fire Wire