S/Pdif - E-Mu 404 Owner's Manual

E-MU USB Audio Control Panel
7. Digital Input Status
Displays the sample rate of external sync source, if used.
8. S/PDIF Output Format
Selects between S/PDIF or AES/EBU format for the S/PDIF output. This sets
the S/PDIF-AES status bit, but doesn't affect the signal level.
9. Soft Limit
Enables or disables the analog peak limiters on the inputs. Soft limiting
allows you to record a hotter signal without clipping. The soft limiters
gradually engage at -12 dBFS. Signal levels below -12 dBFS are unaffected.
10. Tool Tips
Enables or disables pop-up tool tips about E-MU USB Audio control
functions.
11. Lock Indicator
Indicates that the 0404 USB 2.0 is locked to an external clock source.

S/PDIF

S/PDIF (which stands for Sony/Philips Digital Interface Format) carries two
channels of digital audio at sample rates of up to 96kHz, and also carries an
embedded clock for synchronization. The 0404 USB 2.0 provides two types of
S/PDIF: Coaxial or Optical.
The Coaxial interface has an advantage of using commonly available RCA-type
connectors. However, high-quality cable should be used to avoid data dropouts
and interference from radio frequency radiation. Coaxial S/PDIF uses a trans-
former on the transmitting end to prevent ground loops, but ground loops may
still occur, mainly because of improper S/PDIF implementation on some
equipment.
The Optical interface is immune to radio interference and also prevents ground
loops between different pieces of equipment. On the downside, optical fiber is
generally more expensive than coaxial cable. For best performance use high-quality
glass cables. Plastic fiber lightpipes work well for short distances.
Using External Synchronization to S/PDIF
To synchronize to an "External" S/PDIF sync source, you must use the 0404 USB
Control Panel to set the sample rate to match the external device, then switch to
external sync. In addition, the S/PDIF source must be chosen by pressing the
S/PDIF button to specify Coaxial or Optical input.
Refer to the information on the following page for additional information about
S/PDIF synchronization.
S/PDIF to Analog / Analog to S/PDIF converter
The 0404 USB can be also used as a standalone S/PDIF -> Analog or Analog ->
S/PDIF converter.
Analog Input to S/PDIF: Attach analog device to Dock A/B (Left/Right); enable
direct monitoring (set to S/PDIF). Analog input will be mirrored to S/PDIF out.
S/PDIF to Analog: Attach a S/PDIF source, power cycle the device, and set direct
monitor to "Main".
0404 USB 2.0 Owner's Manual
TIP . . .
The following functions are
stored in non-volatile
memory if the unit is left
powered on for 5 seconds
after the setting is changed.
• Phantom Power on/off
• Soft Limit on/off
• S/PDIF Output Routing
• Sync Source
NOTE
The S/PDIF digital input is
not available at 176.4 or
192 kHz.
TIP . . .
The 0404 automatically sets
its sample rate and locks to
the source if a S/PDIF
source is present at power-
up.
If you are having a difficult
time setting up S/PDIF sync,
connect the source, then
power cycle the 0404 USB.
It should automatically sync.
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