Installation guide
Chapter 2: HDX Hardware Overview 9
HD I/O Audio Interface
HD I/O features exceptionally high quality
24-bit analog-to-digital (A/D) and digital-to-an-
alog (D/A) converters, and supports sample
rates of up to 192 kHz.
HD I/O comes in three standard configurations:
• 8 x 8 x 8 (8 analog in, 8 analog out, and 8
digital in and out)
• 16 x 16 analog in and out
• 16 x 16 digital in and out
You can also add or remove HD I/O Analog Ex-
pansion cards (ADC and DAC) and HD I/O Dig-
ital Expansion cards for custom configurations.
HD I/O Features
HD I/O provides up to 16 discrete channels of
Pro Tools input and output, with 4-segment
LED meters for input and output.
Analog I/O
• Up to sixteen channels of 24-bit D/A and A/D
converters for superior analog input and
output at sample rates of 44.1 kHz, 48 kHz,
88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz
with Analog In and Analog Out HD I/O cards
• Soft Clip and Curv limiting circuits to protect
against clipping on analog input
Digital I/O
• Up to sixteen channels of 24-bit digital I/O,
using AES/EBU, TDIF DB-25, or Optical at
sample rates of 44.1 kHz, 48 kHz, 88.2 kHz,
96 kHz, 176.4 kHz, and 192 kHz with a Digital
HD I/O card
• Real-time sample rate conversion on digital
inputs with a Digital I/O card (up to sixteen
channels of AES/EBU, Optical, or TDIF)
• Support for S/MUX Optical for sample rates of
88.2 kHz and higher
• Support for 2 channels of S/PDIF Optical (en-
closed) with sample rates of up to 96 kHz
• 2 channels of AES/EBU I/O (enclosed) with
support for sample rates up to 192 kHz
• 2 channels of 24-bit-capable S/PDIF I/O (en-
closed) with support for sample rates up to
192 kHz
Synchronization
• Loop Sync input and output for connecting ad-
ditional HD interfaces and peripherals
• External Clock input and output for synchro-
nizing HD I/O with external Word Clock
devices
Expandability
• Optional addition of I/O cards to expand ana-
log or digital I/O
• Simultaneous use of multiple Avid HD audio
interfaces to further expand system input and
output (for more information see the
Expanded Systems Guide)
For more information, see the HD I/O
Guide.