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Band "Q"

HI. Could someone tell me how many Octaves Q=1 Q=2 And Q=3 has?For example, when the Q setting set to these # 1,2, and 3 how many octave they boost or cut?

Edouard Philippe — Jan 17, 2019

Hi,

Q=1/2/3 don't give a "round" number of octaves.

1 Octaves bandwidth will be Q=1.414
2 Octaves bandwidth will be Q=0.667
3 Octaves bandwidth will be Q=0.404

And the numbers go on and on, of course.

Here are some explanations, formulas and even a Q Factor calculator:

www.sengpielaudio.com/calculator-cutoffFrequencies.htm

Hope this helps.

Cheers

Yroth — Jan 18, 2019

Note though that the Q value in Pro-Qx is scaled up by a factor of SQRT(2) compared to other eq's and, as far as I can tell, it's not based on the 3dB points but on half the max./min. boost/cut, so for say a 12dB boost, Q determines the 6dB points. You can see this by changing the bell slope, those are the points that remain fixed.

I just did a quick test in Q3 and can confirm:

1 octave: Q = 2
2 octaves: Q = 0.943
3 octaves: Q = 0.571

Which is SQRT(2) times the values given above by Yroth.

Cheers,

Cabirio — Jan 20, 2019

Thanks a lot Guys

Edouard Philippe — Jan 20, 2019

Thanks for the info, Cabirio.

Never noticed that Pro-Q was using this method, the values are indeed as you wrote.

Yroth — Jan 20, 2019

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