willw99 Posted April 10, 2019 Share Posted April 10, 2019 Just occurred to me, but HP/LP filters have settings such as 6 db/octave, 12 db/octave etc. The octaves change logarithmically (right) as you move up the frequency band yet the slopes of the filters remain constant. I'm wondering what the standard is for the hard filter settings. I imagine it is 20 db as the slopes on the filters are gradual and then it is just reversed for the LPF's? Quote Link to comment Share on other sites More sharing options...
enossified Posted April 10, 2019 Share Posted April 10, 2019 Not sure what you are asking but filters are always in increments of 6: 6, 12, 18, 24, 30, 36, etc. So 20dB is not possible. Each pole of a filter adds another 6 dB of rejection. Quote Link to comment Share on other sites More sharing options...
Ploki Posted April 15, 2019 Share Posted April 15, 2019 OOOH i understand this question now. Yes, one octave down is half the frequency. If a filter is 12dB/8ve and at 400Hz, it means it will be -12dB at 200Hz. If it's at 4000Hz, it will be -12dB at 2000Hz. If you check in the display, you will see that the visual distance between 200 and 400 is the same as visual difference between 2000 and 4000. Because the display of the frequency in the EQ is logarithmic, the slope is visually identical. If you would represent the EQ display in a linear fashion, the filter would change shape drastically as you would sweep it up or down. Some EQs can change the display scale of the frequency, and it's pretty obvious there if you change the scale to "less" logarithmic or for example, the not-as-often-as-log-but-still-often used Mel scale https://en.wikipedia.org/wiki/Mel_scale Quote Link to comment Share on other sites More sharing options...
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