What reversal does to a sound
Most sounds have a sharp attack and a gradual decay — a note struck, then fading. Reversed, that becomes a swell rising into an abrupt stop, which is why a reversed cymbal is a staple of film and record production for building tension.
Reversal is exactly lossless in principle: the same samples in the opposite order. Any quality change comes from re-encoding to a lossy format afterwards, not from the reversal.
Backmasking
Records played backwards were the subject of a genuine moral panic in the 1980s. Some artists did deliberately hide reversed messages; most of the famous examples are pareidolia — the brain finding words in noise, especially once told what to listen for.
Reversing a track here and hearing nothing is the usual and expected result.
Frequently asked questions
Does reversing lose quality?
No — it is the same samples in the opposite order. Any loss comes from re-encoding to a lossy format afterwards.
Why do reversed sounds swell?
Because most sounds attack sharply and decay slowly. Reversed, that becomes a rise into a sudden stop.
Can I hear hidden messages?
Occasionally, where an artist put one there deliberately. Most famous examples are the brain finding words in noise once primed to expect them.
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