Antex Electronics StudioCard AV Pro, StudioCard 2000, & SC-22 - Manual (Page 92)

Mo n i t o r i n g / F e e d t h r o u g h C h a p t e r 4
Antex Electronics Corporation Antex StudioCard 4-15
Monitoring /
Feedthrough
“Monitoring” is a term used to describe listening to the signal
that is being recorded. It is also referred to as “Feedthrough”
audio, as the input signal is fed to an output line. Feedthrough
audio is often used to set the levels on input signals to optimize
their amplitude and signal to noise ratio. Two types of
feedthrough are possible, analog and digital. This section will
explain the differences, implementation on the StudioCard, and
how to enable and use it effectively.
Analog Feedthrough routes the analog signal at the input
channel directly to the output channel. In this manner, the
signal bypasses the Analog to Digital (A/D) and Digital to
Analog (D/A) converters and their associated filter and gain
stages. This is very convenient at times, but does not
monitor the actual signal being recorded. For example, if
the signal amplitude is brought in too large (hot), the A/D
may be in digital clipping (and sound awful) while the
analog Feedthrough sounds fine.
The second method is digital Feedthrough, the type
supported by the Antex StudioCard. This method routes
the digitized analog input signal at the output of the A/D
directly to the D/A. The output of the D/A is filtered,
amplified, and routed to one of the analog outputs. This
approach is exactly analogous to a two head audio tape
machine that allows the play head to play data immediately
after the record head places the data on the tape.
The advantage of digital feedthrough is that the monitored
signal is based on the digital data being recorded to the
computer’s hard disk. What you hear is truly what you get. By
default, digital feedthrough is enabled on the StudioCard,
enabling you to hear audio during recording. Record device
one is mapped to playback device one and so on. Enabling
and disabling digital feedthrough is accomplished by following
the Simultaneous Record-Play (SRP) Mode instructions in
Chapter 3, Using the Antex Mixer.