An audio phaser gives recordings a sweeping character by moving cancellation notches through their spectrum. This processor combines four all-pass filter stages with the original sound in your browser. Upload a clip, set the sweep rate and range, then render and download the phased WAV.

How does Audio Phaser work?

An all-pass filter changes phase differently at different frequencies. Four first-order stages run in series, and their output mixes equally with the dry source. Frequencies where the signals oppose each other cancel, forming notches. A low-frequency oscillator moves the filter break frequency exponentially over the chosen octave span.

The sweep starts at Minimum Frequency, rises to that value multiplied by 2 to the power of Sweep Depth, and returns. Frequencies are capped below Nyquist for stability. This implementation has a fixed 50/50 mix and no feedback control.

Key Features

Four cascaded first-order all-pass stages
Sweep rate adjustable from 0.05 to 5 Hz
Minimum filter frequency between 100 and 1000 Hz
Sweep span selectable from 0 to 5 octaves
Equal dry and filtered mix produces cancellation notches

Common Use Cases

When and why you might need this tool

Animate a sustained keyboard part
Use a slow sweep to add motion to a pad whose notes otherwise remain steady.
Color a rhythm guitar recording
Try a moderate rate to introduce the hollow shifting tone associated with phase effects.
Create a moving noise texture
Apply the sweep to broadband sound so the changing spectral notches become prominent.
Compare static phase coloration
Set depth to zero to hold the break frequency while hearing the dry/filter cancellation.

How to Use This Tool

Step-by-step guide to get the best results

Upload the clip

Load a recording with sustained or broadband material so the sweep is audible.

Set movement speed

Adjust Sweep Rate. The default 0.5 Hz completes a cycle every two seconds.

Place the sweep range

Choose Minimum Frequency and Sweep Depth. Greater octave depth covers a wider frequency span.

Render and listen

Click Apply Phaser, compare the source and processed previews, and save the WAV.

Pro Tips

1
Use a clip long enough to hear a complete cycle; at 0.05 Hz one cycle lasts 20 seconds.
2
Try a smaller depth when a broad sweep makes an instrument disappear too strongly.
3
A phaser needs frequency content near its moving notches; sparse sources can make the effect subtle.
4
Keep the original if you plan further processing, since the cancellation cannot be undone by changing playback volume.

Frequently Asked Questions

How is a phaser different from a flanger?

An audio phaser uses phase-shifting all-pass filters mixed with the dry signal. A flanger mixes a short delayed copy with the source and produces a different, regularly spaced pattern of notches.

What does phaser depth mean in octaves?

Each octave doubles the highest break frequency relative to the minimum. A 300 Hz minimum and 3-octave depth sweep up to 2400 Hz, subject to the sample-rate limit.

Why can I barely hear the phaser on my clip?

A very short clip may cover only a small part of a slow sweep. The input also needs energy near the affected frequencies. Try a longer sustained recording or a faster rate.

Can I change the dry/wet mix or feedback on this phaser?

The mix is fixed at equal dry and filtered levels to produce deep notches. There is no feedback setting. Rate, minimum frequency, and sweep depth are adjustable.