Polarity
The direction of a signal's phase, which matters when two sources are combined and can cancel each other if they disagree.
If two pickups or two microphones are wired with opposite polarity, the frequencies they share will subtract rather than add, leaving a thin, hollow sound with little bottom end. Polarity is often confused with phase, which strictly describes a time relationship, but the practical symptom is the same: cancellation. A polarity switch on a preamp or microphone is a diagnostic tool as much as a corrective one. On three-pickup guitars, one pickup is deliberately reversed to give a hum-cancelling combination.
Example: an acoustic guitar with two pickups blended and one inverted will lose its low end entirely until the polarity is corrected.
See also
Related
- PageOut of phase
- PageParallel wiring
- PageAcoustic guitar
- PageActive pickup
- PageAlnico
- PageBlade pickup
- PageAaron Dessner
- PageAce Frehley