24 db/oct filter questions

[Mike I]

Mr. Moog makes an interesting point in his VCF patent. He notes that 
only in a 4-pole (identical sections) filter will the resonant peak 
occur at the -3dB "corner" frequency when regeneration is used. At this 
frequency each section exhibits 45 degree phase shift (giving a total of 
180 degrees for all 4 sections). When the sections are not identical the 
resonant peak will occur at a different freq than the corner frequency. 
This is not necesarily bad, but will affect the sound of the filter.