Concretely, the gain is applied to the PCM samples directly, so the change is exact and reversible; headroom is checked before writing so a boost clips nothing. You set a gain in decibels or as a percentage and it is applied uniformly across the whole file.
Will boosting the volume distort the audio?
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Only if it clips. Headroom is checked before the file is written, so a boost that would push peaks past full scale is flagged rather than silently squared off. If the recording is quiet because it is noisy, boosting raises the noise too.
Does the source format matter?
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It does. AIFF is Apple's uncompressed PCM format — the Mac-side equivalent of WAV, same size, same fidelity. That decides whether a gain change is an exact edit of the samples or has to go through a re-encode.
Anything specific to AIFF to know?
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Yes — AIFF is big-endian PCM where WAV is little-endian; the audio is equivalent, and the choice is really about which ecosystem opens it without complaint. Relevant if you plan to adjust the level more than once.
Should I use volume or normalisation?
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Use volume when you know exactly how much louder or quieter you want it. Use normalisation when you want a set of files to end up at the same perceived loudness — that is a measurement problem, not a fixed gain, and applying one when you meant the other is the usual mistake.
Can I adjust a whole batch to the same gain?
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Yes, though be careful what you are asking for: the same gain on files recorded at different levels keeps them at different levels. If you want them to match, normalise instead.
