analog and digital filters used in audio contexts tufts university – me 93 october 22, 2015
TRANSCRIPT
Analog and Digital Filters used in Audio ContextsTufts University – ME 93October 22, 2015
Outline• Where do we use filters?• History of filters• How do filters do what they do?• What types of filters do we use?• What are the advantages and
disadvantages of each?
Where do we use filters?• ADC/DAC• Equalizers• Filter based effects
History of Filters
History of Filters
History of Filters• Fixed Frequencies• 1971 = Parametric EQ• Movable frequencies• Adjustable bandwidth
Types of Simple Filters• High/Low Pass• Shelving Filters• Band pass/band reject
DigitalIIR• Infinite Impulse Response filter• Non-linear• Delay elements are added to create
phase shift• Often emulated using convolution
DigitalFIR• Finite Impulse Response filter• Can achieve linear phase response but
adds ‘ringing’
What’s this sound like?
Next Steps• Will Pirkle:
Designing Audio Effects Plug-ins in C++• Musicdsp.org
Kvraudio.com DSP & Plug-in development forum• CCRMA• Web Audio School