Solid State Logic X-EQ - Manual (Page 19)

Proportional 1
Proportional equalisers are recognised as being more ‘musical’ than
Constant Q. The bells are wider below +6dB and narrower above
+6dB (or –6dB for cut).
Proportional 2
Like Proportional 1 but with larger changes below and
above +6dB peak (or –6dB for cut).
P –3dB
Proportional 3
Like Proportional 1 but with extra widened bells between 0 and
+3dB (or –3dB for cut).
P – 3dB
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