Filters
Transcript of Filters
![Page 2: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/2.jpg)
To filter
• To filter is to select certain elements with desired properties from a larger set.
• A filter will modify the amplitude of the partials according to their frequency
![Page 3: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/3.jpg)
Lowpass (HP)
• Attenuates frequencies above cut-off frequency fc
• Sometimes lowpass filters are called highcut.
![Page 4: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/4.jpg)
Highpass (HP)
• Attenuates frequencies below cut-off frequency fc
• Sometimes highpass filters are called lowcut.
![Page 5: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/5.jpg)
Bandpass (BP)
• Select frequencies between a lower cut-off frequency fcl and a higher cut-off frequency fch
• Frequencies below fcl and higher than fch are attenuated
![Page 6: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/6.jpg)
Bandreject (BR)
• attenuate frequencies between a lower cut-off frequency fcl and a higher cut-off frequency fch
• Frequencies below fcl and higher than fch are passed
![Page 7: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/7.jpg)
Resonance
• Amplifies the frequencies around the cutoff frequency
![Page 8: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/8.jpg)
Stepness
• First-order: 6 dB roll-off pr. octave• Second-order: 12 roll-off pr. octave
![Page 9: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/9.jpg)
Equalizer
• a series of shelving and peak filters, which are controlled independently
![Page 10: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/10.jpg)
Practice your listening skills
• Harmans How to Listen• Free application for Windows and OS X. • Download from
http://harmanhowtolisten.blogspot.no/
![Page 11: Filters](https://reader036.fdocuments.net/reader036/viewer/2022071722/55b99686bb61ebdd778b461d/html5/thumbnails/11.jpg)
References
• Filter design, http://en.wikipedia.org/wiki/Filter_design
• Low-pass filter, http://en.wikipedia.org/wiki/Low-pass_filter
• Zölzer, Udo (2011): DAFX Digital Audio Effects. Second Edition.