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EE 445S Real-Time Digital Signal Processing Lab Spring 2012. Lab 7 Guitar Special Effects Chao Jia. Outline. Comb filters Allpass filters Notch filters Special effects with filters Other effects. Comb filters. FIR comb filter (single echo). Number of stopbands is R/2. Comb filters.
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EE 445S Real-Time Digital Signal Processing LabSpring 2012 Lab 7Guitar Special Effects Chao Jia
Outline • Comb filters • Allpass filters • Notch filters • Special effects with filters • Other effects
Comb filters • FIR comb filter (single echo) Number of stopbands is R/2
Comb filters • IIR comb filter (multiple echoes)
Some special effects • Echo • FIR or IIR comb filters • Delay > 100ms • Flanging • FIR comb filter with (periodically) varying delay • Delay between 1ms and 10ms
Some special effects • Chorus • Several independent comb filters
Some special effects • Reverb • Mimic a enclosed space (lots of echoes)
Other effects • Special effects can also be generated by altering the amplitude of the signal. • Tremolo • Repetitive up/down variation in the volume • Fuzz • Intentionally introduced distortion like clipping