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