FabFilter User Forum

Calculation of Q factor in fabfilter plugin's?

It seems that Q values in e.g. Pro Q3 are not directly comparable to Q values in EQ plugins from other companies or daw's. Looking at a Dan Worrall video it seems like the factor is 1/2 SQRT 2 (=0,707) which is suspiciously like the sine peak-to-peak to RMS factor, but can you use this as a conversion factor for all values of Q or is there more going on behind the curtain?

I appreciate the intuitive fabfilter approach, which I understand to be "Q=1 is the max Q value before you get pre-ringing", but how do I translate it to a comparable Q factor in e.g. Logic Pro stock EQ?

SoundStudent

Hi,

We are using the standard Butterworth Q of 0.707. However, since this is a weird number to have as a default, we have mapped this value to a Q of 1 in Pro-Q 3. So when you set the Q to 1 you actually use a Q of 0.707. You can use the formula below to calculate the Q of Pro-Q 3:

Pro-Q 3's Q = Butterworth Q / sqrt(0.5)

Ralph (FabFilter)
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