Phaser Rate Calculator
Sync your phaser's LFO to your track's tempo by converting BPM and cycles-per-bar into a precise rate in Hz. Essential for producers and mix engineers who want rhythmically locked modulation effects.
About this calculator
A phaser effect sweeps a series of all-pass filters across the frequency spectrum, creating that swooshing, swirling sound. To make the sweep feel musical, the LFO (Low Frequency Oscillator) driving the phaser must be locked to the song's tempo. The formula is: rate (Hz) = (BPM / 60) × (cycles / 4). Dividing BPM by 60 converts beats per minute into beats per second. Multiplying by cycles-per-bar divided by 4 scales the rate to how many full sweep cycles you want per bar, assuming a 4/4 time signature. For example, one cycle per bar at 120 BPM gives a slow, broad sweep, while four cycles per bar gives a faster, more agitated modulation that pulses on every beat.
How to use
Suppose your track runs at 120 BPM and you want the phaser to complete 2 full cycles per bar. Step 1 – Enter BPM = 120 and Cycles Per Bar = 2. Step 2 – Apply the formula: rate = (120 / 60) × (2 / 4) = 2 × 0.5 = 1 Hz. Step 3 – Set your phaser's LFO rate to 1 Hz. At this setting the phaser completes one full sweep every second, which equals two sweeps per bar at 120 BPM, perfectly locked to the groove.
Frequently asked questions
How do I sync a phaser LFO rate to my DAW's BPM?
Convert your BPM to beats per second by dividing by 60, then multiply by your desired cycles-per-bar divided by 4. This gives you the exact LFO rate in Hz to enter into your phaser plugin. Most hardware and software phasers accept Hz values directly. Some DAW plugins offer a 'sync' mode that does this automatically, but knowing the Hz value lets you set it manually or on hardware units.
What is a good cycles-per-bar value for a subtle phaser effect?
For subtle, slow-moving phase modulation, values between 0.5 and 1 cycle per bar work well — the sweep is long enough to feel gradual rather than obvious. At 1 cycle per bar the effect is noticeable but not distracting, making it popular on rhythm guitars and pads. Values above 2 cycles per bar become more pronounced and rhythmic, suitable for funk or psychedelic sounds. Always listen in context: what sounds subtle soloed can feel more intense in a full mix.
Why does phaser rate matter for music production?
An unsynced phaser LFO creates random-feeling sweeps that can fight the rhythm of a track, making elements sound out of place. Syncing the rate ensures the modulation peaks and troughs land on musically meaningful points like beats or half-bars. This transforms the phaser from a static tonal colour into a dynamic, rhythmic element. Tempo-synced phasers are a classic technique in funk, soul, and electronic music production.