Chorus & Flanger as One
Chorus and flanger are both "delayed copy mixed with original, delay modulated by LFO." The only difference is delay time range and feedback. They are one effect with a continuous parameter space.
The Same Circuit, Different Numbers
In Part 102 we built a single delay line and watched it morph from comb filter to flanger to chorus to echo as we swept the delay time. Now we zoom in on the flanger-chorus region and treat it as one continuous effect. A flanger uses very short delays (0.5–5 ms) with moderate feedback and a slow LFO. A chorus uses slightly longer delays (10–25 ms) with no feedback and a faster, gentler LFO. Between them is a no-man's-land with its own unique character.
The "morph" slider below interpolates all parameters simultaneously. At 0% you have a textbook flanger; at 100%, a textbook chorus. Everywhere in between is a valid, interesting effect that does not have a standard name. This is the reality of synthesis: named effects are just points in a continuous space.
Stereo Width
Real chorus and flanger effects often use two delay lines with LFOs offset in phase, panned left and right. This creates stereo width because the left and right channels are slightly different, so the sound fills the stereo field. The width control below offsets the right channel's LFO by 90 degrees from the left, creating a widening effect from mono to full stereo spread.
Try it: play a note and sweep the morph slider from Flanger to Chorus. Listen to how the metallic sweep gradually becomes a warm thickening. Then push the width slider to hear the stereo image expand.