Noise Floor

The noise floor is the baseline of unwanted sound present in a recording even when nothing is intentionally happening, made up of microphone hiss, electrical hum, air conditioning, and room tone. It matters because it sets the practical limit on how quiet usable audio can get: anything softer than the noise floor is lost in it. An editor measures it during silent passages and works to keep it low, since aggressive volume boosts and compression lift the floor right along with the signal, making hiss audible. Clean recording, good gain staging, and noise reduction all aim to keep the floor well below the dialogue. When noise reduction is needed, the editor samples the floor as a profile so the tool knows exactly what to subtract without chewing up the voice.