op amp eq points

[Archival Audio]

Seeking advice from any clever electronics-people (I am but a humble audio-person).

Attached is a portion of the schematic of my favourite audio mixing desk, a Soundcraft 200SR. It has fixed EQ points, 60 Hz, 250 Hz, 5 kHz and 12 kHz, which appear as (respectively) LF, Lo Mid, Hi Mid and HF on the schematic.

Can ayone tell me component values to change Lo Mid and Hi Mid to (approx) 150 Hz and 750 Hz. These are very salient freq points for snare drums (boost 150, cut 750), and I'd love to have a dedicated, competent, 'snare channel'.

Thanking you in anticipation...

Archival Audio

 

[Analog]

Seeking advice from any clever electronics-people (I am but a humble audio-person).

Attached is a portion of the schematic of my favourite audio mixing desk, a Soundcraft 200SR. It has fixed EQ points, 60 Hz, 250 Hz, 5 kHz and 12 kHz, which appear as (respectively) LF, Lo Mid, Hi Mid and HF on the schematic.

Can ayone tell me component values to change Lo Mid and Hi Mid to (approx) 150 Hz and 750 Hz. These are very salient freq points for snare drums (boost 150, cut 750), and I'd love to have a dedicated, competent, 'snare channel'.

Thanking you in anticipation...

Archival Audio

It is difficult to read your schematic, since it is a chop of something bigger. But it looks like two back to back Baxandall Filter blocks. What I don't understand from your question is the EQ points. The pots on the Baxandall filters allow you to shift the bandpass filter center to give you more 'treble' or 'bass' - as this is what it is intended to do. Are you saying you want to shift the center frequency of the BPF? You may want to google 'Baxandall Filter' to get some of the available data on this type of filter. I think it to be a very good filter for that application.