EQ Filter Quality and Bandwidth

Oddly, a few software parametric EQs use “bandwidth” in octaves instead of the more common “Q” value to describe their selectivity. Here is a quick conversion chart with third octave, half, one octave, and other common settings.

BandwidthQ
0.024
0.025
0.032
0.048
0.05
0.066
0.09
0.1
0.125
0.131
0.167
0.18
0.25
0.257
0.333
0.36
0.479
0.5
0.513
0.666
0.714
0.75
1
1.388
1.5
1.804
2
2.543
3
4
4.165		60
57.7
45
30
28.8
22
16
14.424
11.538
11
8.65
8
5.763
5.6
4.318
4
3
2.871
2.8
2.145
2
1.902
1.414
1
0.92
0.75
0.667
0.5
0.404
0.267
0.25
40th


20th


Tenth
Eighth

Sixth

Quarter

Third


Half

Two Thirds

Three Quarters
Octave

1.5 octave

Two Octaves

Three Octaces
Four Octaves