Bias / Level Calibration
Bias and level calibration adjust a tape recorder's recording behaviour to suit the tape being used.
Bias is a high-frequency signal added during recording to help the tape respond correctly to audio. Its setting affects distortion and high-frequency response. Level calibration compensates for the tape's recording sensitivity; it is different from setting the music's recording volume.
Bias / Level Calibration — Cassette Deck
On a cassette deck, fine bias control lets you trim the recording response for a particular tape. Record level calibration adjusts sensitivity, while a built-in test-tone generator supplies signals for checking the adjustment. Automatic calibration measures the tape and makes the supported adjustments itself.
Compare which functions are actually available: automatic tape-type selection is not individual tape calibration, and a test tone alone does not perform the adjustment. Follow the deck's procedure with the tape you intend to record. Fixed settings offer no user calibration, and bias controls do not correct the playback of an existing recording.
Bias / Level Calibration — Reel-to-Reel
On a reel-to-reel recorder, calibration matches recording to the tape formulation and operating setup. User controls may provide fine bias, recording-level or recording-equalization adjustment; equalization shapes frequency response. A test-tone generator helps check the result, while an automatic routine performs the adjustments it supports.
Compare accessible operator controls with fixed calibration, rather than counting internal service adjustments as user features. Follow the machine's instructions for the selected tape and speed. Changing the tape position is not necessarily individual calibration, and this feature does not describe playback-only machines or the mechanical alignment of their heads.