Phase Shift Calculator
Convert delay, path offset, polarity, and frequency into phase angle, radians, wavelength, and comb-filter spacing for audio alignment.
🎧 Phase Alignment Presets
⚙ Phase Shift Inputs
📊 Wavelength Reference Grid
| Frequency | Wavelength at 343 m/s | Half Wave | 1 Cycle Delay |
|---|---|---|---|
| 40 Hz | 8.58 m / 28.13 ft | 4.29 m / 14.07 ft | 25.00 ms |
| 80 Hz | 4.29 m / 14.07 ft | 2.14 m / 7.03 ft | 12.50 ms |
| 250 Hz | 1.37 m / 4.50 ft | 0.69 m / 2.25 ft | 4.00 ms |
| 1 kHz | 34.3 cm / 13.5 in | 17.2 cm / 6.8 in | 1.00 ms |
| 5 kHz | 6.86 cm / 2.70 in | 3.43 cm / 1.35 in | 0.20 ms |
| Delay | 80 Hz Phase | 250 Hz Phase | 1 kHz Phase | 5 kHz Phase |
|---|---|---|---|---|
| 0.10 ms | 2.9° | 9° | 36° | 180° |
| 0.25 ms | 7.2° | 22.5° | 90° | 90° wrapped |
| 0.50 ms | 14.4° | 45° | 180° | 180° wrapped |
| 1.00 ms | 28.8° | 90° | 0° wrapped | 0° wrapped |
| 5.00 ms | 144° | 90° wrapped | 0° wrapped | 0° wrapped |
| Scenario | Typical Offset | Frequency to Check | Phase Concern |
|---|---|---|---|
| Kick in and kick out microphones | 0.5-1.5 ms | 60-100 Hz | Low-end punch and body |
| Snare top and bottom microphones | 0.2-0.8 ms plus polarity | 180-250 Hz | Body loss near half-cycle |
| Subwoofer and main speaker crossover | 1-6 ms | 70-100 Hz | Crossover summing or dip |
| Bass DI and cabinet microphone | 0.5-3 ms | 80-200 Hz | Fundamental focus |
| Early wall reflection | 3-15 ms | 300 Hz-3 kHz | Comb-filter spacing |
| Spec Comparison | Resolution | Best Use | Calculator Field |
|---|---|---|---|
| Milliseconds | Direct time offset | Plug-in delay and speaker processing | Signal Delay Amount |
| Samples | 1 sample = 0.0208 ms at 48 kHz | DAW nudging and recorded track alignment | Delay Unit plus Sample Rate |
| Inches or centimeters | 1 ms is about 13.5 in / 34.3 cm | Mic spacing and acoustic path differences | Path Offset |
| Polarity inversion | Always adds 180° | Snare bottom, DI/mic checks, speaker wiring | Polarity Inversion |
Phase shift are the phenomenon that occurs when two versions of the same sound arrive at two different microphones at different times. When two versions of the same sound arrive at different times, the sound waves begins to overlap. When sound waves begin to overlap with each other, the sound waves can either stack together to create a larger sound or the sound waves can cancel each other out to create a hole in the sound.
This hole in the sound is often referred to as a null. Phase shift isnt a malfunction of audio equipment; rather, phase shift is a result of the law of physics. Many people understands the concept of phase shift as a binary state in which sound can be either in phase or out of phase with another incoming sound wave.
Phase Shift Between Microphones and How to Fix It
However, the concept of phase is actualy a sliding scale of degrees; total cancellation of sound occur at 180 degrees but sound can also become hollow and muddily at other degrees, such as 90 or 120 degrees. Additionally, phase shift is also dependent upon the frequencies of the sound that is being recorded. Low frequencies has long wavelengths.
As a result, even a small distance between two microphones can lead to a signifficant loss of the fundamental frequency of a bass instrument or kick drum. The relationship between distance and time is important in calculating phase shift. Sound travel at a specific speed.
Furthermore, the temperature of the room can change the speed of sound. Therefore, warm stage environments will create different mathematical calculations of phase shift compared to a cold recording studio. The path offset between the two diaphragm of a microphone can be calculated; this path offset will determine the number of degrees of the cycle of the sound wave that has traveled from the sound source to the second microphone.
By calculating the path offset, engineers can remove the guesswork of whether moving the microphone will fix the issue of muddy resonance from the sound. Some sound engineers will utilize a Digital Audio Workstation to nudge the sound waves of a recording; this is a process of moving sound waves that has already been recorded to align the sound waves. However, adjusting the samples of a recording within the Digital Audio Workstation is essentially a digital solution to a physical problem.
If the engineer know the specific target frequency of the sound that is problematic, the engineer can utilize the total arrival offset of that frequency to calculate the number of samples that the engineer must shift the sound track. By shifting the samples of a track, the engineer can move the null of a comb filter out of the targeted frequency of the sound that is being recorded. When a signal and a delayed version of that same signal are combined, the resulting signal contain a series of peaks and notches that can be viewed on a spectrum analyzer.
These notches in the frequency response will make a vocal sound as if it is being recorded through a pipe. Additionally, the spacing of the notches of the comb filter can be utilized to determine on which frequencies the notches will land. For instance, if a notch land on the primary frequency of a snare drum kit, the engineers will need to change the timing of the microphones that are picking up that signal; it isnt possible to fix a notch created through a comb filter effect with only equalization.
It is important for sound engineers to remember that not all frequencies can be fixed at the same time. If the engineers aligns the two microphones so that they are in phase with each other at 80 Hz, that could lead to problems with the phase of the sound at 800 Hz. This is one of the tradeoff that engineers must make in aligning sound; they must decide which frequency is the most important to that particular instrument.
For example, the primary frequency of a kick drum is low-end frequencies and must be in phase, yet a vocal doubler will require a bit of phase shift between the two vocal tracks. Engineers should of consider phase shift as a measurement of distance and time between two microphones to control where the sound waves lands.
