RECORDING November 2024 - 36

Studio
By Joe Albano
Audio Repair
O
ver the past year, we have been exploring common
recording and mixing processes, from preamps
to EQs, compressors and effects. In our past few
lessons, we have moved into more specialty processes, such
as time and pitch correction and mastering, and this month
we are moving into audio repair.
Modern audio repair and restoration, by and large,
lives in the digital domain as software tools designed to fix
technical problems and imperfections that might compromise
a recording or otherwise render it useless. Audio repair
software can also sometimes provide creative possibilities
that previously would have been difficult or impossible to
implement on already-recorded audio files.
Restoration Then and Now
In the early days of digital audio, restoration was often applied to
older recordings to compensate for or fix flaws, allowing many classic
recordings to be re-released in a more listenable state. For example,
fixing uneven tonal balances, removing noise and static on old tapes,
and removing clicks and pops on worn-out vinyl recordings. Modern,
often AI-infused audio repair software can target and address these
problems with almost laser-like automatic ease. The software can also
isolate, separate, and rebalance problematic audio and other things.
Bundles of Restorative Joy
While you can find individual
task-specific audio repair plugins,
most audio restoration-type software
comes as software bundles and/
or DAW-like restoration suites from
companies like iZotope (RX), Cedar
(Audio Studio), Steinberg (SpectraLayers),
Sonnox (Restore Bundle), Waves
(Restoration Bundle), Zynaptic
(REPAIR Bundle) and others. I'm
personally the most familiar with
iZotope RX, but many of the
RX processes and workflow
apply to the similar
options mentioned above.
36 RECORDING November 2024
101
Basic Repair
Perhaps the most basic audio repair tasks involve removing common
audio problems like low-frequency hum, hiss, crackles, clicks
and pops and even some environmental noise. These noises are typically
present on top of (or behind) the desired audio (say, music).
They typically can't be completely removed with conventional means
(filters, EQ or gating) without compromising the main audio signal.
Applying static filters/EQ may remove some of the main audio
spectrum, and noise gates can only effectively remove undesirable
sounds when the main signal is not present, relying on the
audio to mask the noise when both are present.
Audio repair modules can address each issue by analyzing the
undesirable noise in isolation (called a noise print) and subtracting
it from the combined music+noise signal, leaving just the cleanedup
music (or voice) signal. While early digital noise reduction processes
required capturing a dedicated " noise print, " some modern
options can do a serviceable job on the fly without one.
Vocal Cleanup
Vocals are arguably one
of the most complex and
temperamental sources to
record with a host of specific
" noise " issues to address-
plosives, sibilance, breaths,
spittle-clicks and such.
While de-essing can often
be done effectively with traditional
dynamics processes to
remove sibilance and plosives
(low-frequency thumps in a
vocal recording), these can
also be eliminated manually via editing, but this can be time-consuming.
In both cases, dedicated repair software (like De-ess and
De-Plosive) can quickly and effectively eliminate each.
Prominent breaths (between phrases) can be distracting in a
voice recording. While these can also be removed or reduced in
level by hand or via a traditional expander/noise gate, repair
processing can often do a better job of detecting and reducing
these without noticeably affecting the voice.
RECORDING November 2024

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