Audio Fundamentals
In audio engineering, phasing refers to the misalignment of two or more versions of the same signal in time, causing partial cancellation or reinforcement of frequencies. Unlike the intentional phasing effect, this form of phase misalignment is an unwanted condition that degrades sound quality and stereo imaging.
Phasing as a technical issue occurs when identical or related signals are combined but their waveforms are not perfectly synchronised. Because sound waves are periodic, even a small time difference between signals can cause certain frequencies to add together while others cancel out. This results in a comb-filtering pattern where the frequency response alternates between peaks and dips, giving the sound a hollow or thin character.
Common causes of phase problems include miswired cables (with one channel reversed in polarity), incorrectly placed microphones capturing the same source at different distances, or latency mismatches between analogue and digital signal paths. In stereo or multi-mic recordings, phase discrepancies can weaken bass response, blur localisation, and make the mix sound unfocused.
Phase alignment is especially important when combining signals that represent the same source, such as multiple microphones on a drum kit or a direct and miked bass track. Engineers use time alignment tools, polarity inversion switches, or sample-accurate delay adjustments to correct phase errors and restore clarity.
Unlike polarity reversal, which simply flips the waveform vertically, phase misalignment involves timing differences that vary with frequency and cannot be fully corrected by polarity alone. Proper microphone technique, consistent signal routing, and accurate digital delay compensation are the most effective ways to avoid phasing problems in recording and mixing.
