FabFilter User Forum

What are the Fabfilter equivalent Q (bandwidth settings)

Hello,
I know FabFilter doesn't use conventional bandwidth settings.

For example:

“A value of one in Pro Q3, is equivalent to 0.72, in most other Filter or EQ plugins, so if you’re not using ‘Q3’, remember to stay below about 0.7 to get this kind of behaviour.” Dan Worrall

...And he states in FabFilter Pro-Q - Advanced EQ'ing techniques: 6:15 if you adjust the bandwidth to 1.4 you get 1 octave.

7:08: "A Q of around Four equates roughly to a third of an octave"

and:

" A Q of eight is roughly one whole tone"

What is the reasoning behind this?

If you look at: www.sengpielaudio.com/calculator-bandwidth.htm

You can see different figures in the "Bandwidth in Octaves" tabulated information.

So...

What is the ***CONVERSION PROCESS***, i.e. the maths behind the FabFilter settings?

And... Please tell me the FabFilter equivalents figures for below

2 Octaves = 0.67 = (please put FabFilter Equivalent after = sign)
1 1/3 Octaves = 1.0444
2 1/3) Octaves = 0.56
3 1/3 Octaves = 0.35
1 Octave = 1.4142 2

1/2 Octave = 2.871
1/3 Octave = 4.3189
1/4 Octave = 5.7635
1/12 Octave = 17.3

3 Octaves = 0.4040
4 octaves = 0.2667
5 Octaves = 0.182
6 Octaves = 0.127
7 Octaves = 0.089

1/1/2 Octaves = 0.92
3 Octaves = 0.4040

I REALLY Don't know why FabFilter have never put out a conversion table for Octaves- or if they did it is VERy hard to find it!

Please help me/us

It would be extremely beneficial for EVERYONE.

thanks

F

F_W

Hi,

We have indeed mapped the default Butterworth Q of 0.7071 = sqrt(0.5) to a Q value of 1 in Pro-Q 3. The reason behind this is because if feels more logical to have a default value of 1 instead of a default value of 0.7071. We're not the only plug-in that has done this, lots of other eq plug-ins have applied this as well.

There is quite an easy formula to calculate this:

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

Ralph (FabFilter)

So...

Bw in Octaves / √(0.5) = 1.4142 ÷ √(0.5 ) = 1.99998081991 = 1 Octave

FabFilter equivalent for 1 Octave - according to your equation.

1 Octave is: 1.99998081991 = 2 (FabFilter Q = 2)

And Two Octaves = 0.948 (FabFilter equivalent Q)

Is this the correct way to apply the equation?

Thanks

F

F_W

And is the scale/range of parameters linear or logarithmic?

F_W

Can you please give me / us an answer Ralph

The Q Factor
Conversion chart or table
'bandwidth in octaves' N to quality factor Q
www.sengpielaudio.com/calculator-bandwidth.htm

2 Octaves = 0.67 = (please put FabFilter Equivalent after = sign)
1 1/3 Octaves = 1.0444 = ?
2 1/3) Octaves = 0.56 = ?
3 1/3 Octaves = 0.35 = ?
1 Octave = 1.4142 = ?

1/2 Octave = 2.871 = ?
1/3 Octave = 4.3189 = ?
1/4 Octave = 5.7635 = ?
1/12 Octave = 17.3 = ?

3 Octaves = 0.4040 = ?
4 octaves = 0.2667 = ?
5 Octaves = 0.182 = ?
6 Octaves = 0.127 = ?
7 Octaves = 0.089 = ?

1/1/2 Octaves = 0.92 = ?

What is the FabFilter Equivalent???
What are the answers?
We would like the answers!
It shouldn't take you that long - maybe a couple of minutes.

Tell us for God's sake!

Thank you

F


F_W

Hi F_W,

That's indeed the correct way to calculate the Q factors. You can just divide the Q factors you mentioned above by sqrt(0.5) and you will get the Pro-Q 3 Q factor. I'm sure you can do the math yourself. It shouldn't take you that long - maybe a couple of minutes :-)

Ralph (FabFilter)

Finally :)

Thank you so much!

For example:
If a centre cut was placed @ 1k and it resulted in affecting the outermost frequencies of 891Hz and 1123Hz.

This yields a result of 4.31 (Q = 4.31) - this is approximately a 1/3 of an Octave.

Would I then have to convert the FabFilter Q with the "given formula" to get the reading for a quarter of an Octave in FabFilter terms?

So... Using the Formula: Q of 4.31 = 6.09 in FabFilter Pro Q3?

i.e.: A third of an Octave = 6.09 in Pro Q3?

I look forward to hearing from you shortly.

F

F_W

** Would I then have to convert the *Bandwidth* (Q) with the "given formula" to get the reading for a quarter of an Octave in FabFilter terms?

Made a slight 'typo' there.

regards

F

F_W

** Would I then have to convert the *Bandwidth* (Q) with the "given formula" to get the reading for a 1/3 of an Octave in FabFilter terms?

Made another slight 'typo' there.

regards

F

F_W

The saying:
"Talk about double Dutch" comes to mind - for this whole scenario!

The phrase “double Dutch” is a common idiom used in English to describe something that is difficult to understand or confusing.

:)

hahahahahaha

F_W

I take it that:

Pro R and Pro R2;
Simplon;
Micro;
Timeless 3;
Volcano 3;
Pro C2;
(Did I miss anything?)

Have the same factors attributed to its Q values - and conversion is necessary to obtain the conventional bandwidth in Octaves?

F

F_W

***Bump***************************************************

And is the scale/range of parameters linear or logarithmic?

***Bump***************************************************

For example:
If a centre cut was placed @ 1k and it resulted in affecting the outermost frequencies of 891Hz and 1123Hz.

This yields a result of 4.31 (Q = 4.31) - this is approximately a 1/3 of an Octave.

Would I then have to convert the *Bandwidth* (Q) with the "given formula" to get the reading for a 1/3 of an Octave in FabFilter terms?

So... Using the Formula: Q of 4.31 = 6.09 in FabFilter Pro Q3?

i.e.: A third of an Octave = 6.09 in Pro Q3?

***Bump***************************************************

I take it that:

Pro R and Pro R2;
Simplon;
Micro;
Timeless 3;
Volcano 3;
Pro C2;
(Did I miss anything?)

Have the same factors attributed to its Q values - and conversion is necessary to obtain the conventional bandwidth in Octaves?

I would like to know the answers to these three queries as well.

LJ

LJ
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