Phaser or flanger: hear notches versus a comb

A hollow that moves through the note

The first example is an original eight-second additive synthesis exercise, not a recorded guitar or an amplifier demonstration. Its bright attacks and fading harmonics let you follow which parts of a note become hollow. Begin with the Phaser setting as supplied. Listen across several notes: the slow sweep continues while the source changes pitch, so every attack need not have the same colour.

Temporarily set Amount to zero. Move Center from about 900 Hz toward 1.8 kHz and compare the body of the note, then restore Amount to 30%. Center positions the all-pass filter structure; Amount lets the oscillator move it. Rate at 0.5 Hz takes roughly two seconds per cycle. Raising Rate changes how quickly the pattern moves, not the basic number of cancellations.

Notches changes the number of all-pass stages used by this implementation. Try four versus eight with the same Center and Amount. Listen for a denser pattern rather than assuming twice the number means twice the depth. Spread changes the stages' resonance shape. Blend distributes modulation between Center and that resonance parameter; it is not the dry/wet mix. Start with Blend at zero to keep the experiment easy to interpret.

A short delay makes a different pattern

The second source contains original synthetic noise bursts with a quiet noise floor between them. Broadband energy makes the flanger's comb easier to notice than a nearly pure tone would. Use the gaps to hear feedback, but remember that the source is not completely silent there.

Set Amount to zero and compare Time at 1 ms and 3 ms. Mixing a signal with a short delayed copy creates a series of cancellations across frequency. A longer delay brings the teeth of that comb closer together; it does not simply make the sound darker. Restore Amount to 35% and listen for the metallic pattern sweeping through each burst.

Here the Flanger Time value is the top of the delay sweep: modulation moves downward from it. It is not a centre value with an equal excursion on either side. That distinction matters when you try to recreate a static colour with modulation enabled. The separate Doubler mode uses a longer delay and a different, two-sided sweep; treat it as another sound, not merely a slower flanger.

Decide how much of the effect earns its place

Increase Feedback from 25% toward 45% on the bursts. Judge whether the ringing helps connect them or covers their beginnings. If the resonant part becomes louder than the source, reduce Feedback and use Output to make a fair level comparison. FB Invert changes the polarity of both the processed tap and feedback loop, moving the cancellation pattern; it is not a stereo swap.

Dry/Wet at 100% still includes the internal direct-plus-processed combination that makes phasing and flanging possible. It does not mean you hear an isolated all-pass filter or delayed tap. Reducing Dry/Wet introduces more external dry signal, which can make the deepest cancellations less pronounced. Try this before reducing every modulation control at once.

Keep Phase at 0° while learning the tone, then try 90° for different left/right modulation timing. Check that stereo interest survives your mono check. TuttiDAW's feedback paths include Web Audio delay-block constraints, particularly relevant at very short flanger times. Warmth and Safe Bass are not modelled in this graph; neither is a remedy for excessive ringing or weakened bass.