PoducateMe: Practical Solutions for Podcasting in Education
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understand how the interface’s sample rate and bit depth will affect the quality of your
recording.
Onboard DSP
Onboard digital signal processing (DSP) obviates the need for your computer
software to add effects such as reverb or equalization to your audio during recording
or later, in post-production. With onboard DSP, the effects are added by the interface
as you record. This frees up your system’s processing power to concentrate on other
tasks while greatly cutting down on latency. What’s latency? Read on.
Zero-Latency Monitoring
When recording audio on your computer, latency describes the amount of time it
takes for an audio signal to complete the following steps:
4.
Analog audio travels from the microphone or other instrument to the interface,
where the analog signal is converted to a digital format the computer can
understand.
5.
The digitized signal travels from the interface to the computer, where the signal is
processed and recorded.
6.
The processed signal travels from the computer back to the interface, where the
signal is converted back to analog so you can hear it through your monitoring
system (headphones or speakers).
Because all of this signal manipulation takes time and consumes system resources,
some lag is always introduced into the process. Different sound cards will have
different latencies at different sampling rates—the higher the sampling rate, the lower
the latency.
If you’re recording a podcast and hear a delay between what you‘re saying and when
you’re hearing it, you’re experiencing latency. Because it’s extremely disorienting to
hear your speech or instrument delayed in your headphones as you’re recording,
many interfaces offer “zero latency monitoring,” or “direct monitoring.” This feature
allows you to plug headphones into the interface and hear the sound coming into the
device in real-time before it is shuttled on to the computer for processing and
recording (this is where the majority of latency is added to the signal).
Using direct monitoring, however, will only allow you to hear the audio signal before
any DSP effects are applied by your recording software (if you’ve configured the
software to add such effects). If you’re determined to hear the exact signal being
recorded, effects and all, but are being vexed by latency issues, you might consider
(A) Purchasing an interface with onboard DSP effects (B) Buying an external
hardware unit to add DSP effects or (C) Applying DSP effects during the post-
production process. External hardware effect processors will be discussed a little
later.
