Comb filter visualizer
See the notches created when a signal is mixed with a delayed copy of itself.
ms
1 ms ≈ 34 cm of extra path length.
dB
0 dB = same level as the direct signal; enter 0 or a negative value.
First notch
500Hz
Notch spacing
1000Hz
Peak boost
4.65dB
Notch depth
-10.7dB
Notches fall at odd multiples of 1/(2·delay); peaks at multiples of 1/delay.
How it works
Adding a delayed copy of a signal produces regularly spaced notches in the frequency response. The shorter the delay, the wider apart the notches. Equal levels cause infinitely deep notches; weaker copies cause shallower ones.
Typical causes are two microphones picking up the same source, microphones near reflective surfaces, or speakers that are not time-aligned.
Formulas
- |H(f)| = | 1 + g · e^(−j2πfτ) |
- first notch = 1 / (2τ)
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