User's Manual

User’s Guide ADI-2 DAC v2.2 © RME
31
The Bit column shows the amount of bits found in the SPDIF audio signal. Note that a 24 bit
signal that is shown as 16 bit is indeed 16 bit, but a signal shown as 24 bit might contain only 16
bit real audio plus 8 bits of noise…
But SPDIF can also transport AC-3 and DTS encoded surround sound. This signal sounds like
chopped noise at full volume. Therefore the ADI-2 DAC receiver circuit checks the Non-Audio
flag within the Channel Status. If found the signal is already muted directly in the receiver. An
error message is shown in red colour in the lowest line, saying SPDIF NON-AUDIO, explaining
why there is no sound at the analog outputs despite a valid input signal.
Finally also Emphasis, a special treble boosting equalization method from the early days of
digital audio, is detected and shown as SPDIF WARNING EMPHASIS. See chapter 31.2.
16. Warning Messages
The ADI-2 DAC will show different warning messages and provide guidance in certain cases.
Hi-Power Mode Active (Phones)
When Hi-Power mode is active with the Volume set higher
than -15 dB and a phone is plugged in, this message
reminds the user to check the current volume setting, and to
make sure the used headphone will stand the high output
power without getting destroyed. The audio signal is held at
a low volume until the gain is set to -15 dB or below. The
Volume knob is active on the current phones output and can
be used to turn down the volume. Once -15 dB is reached
the volume is ramped up to the current gain.
Pressing encoder 1 removes the message immediately, with volume ramped up within 2 sec-
onds to the set value.
The message will also vanish when the phone is unplugged again.
This message is not shown when Volume is set to -15 dB or lower, or when the device is
switched on while the phones are already connected.
Overload / Short detected (Phones)
An internal overload can be caused by too high output levels
and too low load impedance. A short circuit in the TRS plug
will also trigger the overload detection. In such a case the
relay will permanently disconnect the phone from the Extreme
Power output stage. If the phones plug is removed and
plugged in again after one second, the unit will activate the
phones output again.
This scheme has been introduced to force the user to check
cabling and connection. For example, a TRS plug not fully
inserted might stay unnoticed but can cause a short circuit.