rafafredd
Well-known member
I am working on a mastering passive EQ circuit for my friends studio.
So I am studying and doing some simulations with passive eqs, and all the circuits I tried had this same issue...
I am trying to have a EQ that all bands can be switched to boost or cut, like Manley's Massive Passive, Knif Soma and so many others.
The problem is that all circuits I use, based on Pultec variations, NYDave, RuffRecords, etc, have the same Q issue. It works good on boost, but when switched to cut, Q turns very steep, high Q curves.
So I found some curves of the commercial EQs and none of them has this problem. The Qs of the boost and cut seems exactly the same in these.
Do any of you know what circuit does they use for maintaining the Q on switchable boost/cut EQ? Maybe just a direction?
I came up with a solution by isolating boost and cut, and working with different impedance (and reacende) with an amplifier in between. But it is an expensive solution, and still not a perfect one, as the Qs still don't match perfectly, but are close.
What bothers me is that Manley and others seems to get perfectly mirrored Qs for boost and cut with a much simpler approach.
Thanks a lot for this.
So I am studying and doing some simulations with passive eqs, and all the circuits I tried had this same issue...
I am trying to have a EQ that all bands can be switched to boost or cut, like Manley's Massive Passive, Knif Soma and so many others.
The problem is that all circuits I use, based on Pultec variations, NYDave, RuffRecords, etc, have the same Q issue. It works good on boost, but when switched to cut, Q turns very steep, high Q curves.
So I found some curves of the commercial EQs and none of them has this problem. The Qs of the boost and cut seems exactly the same in these.
Do any of you know what circuit does they use for maintaining the Q on switchable boost/cut EQ? Maybe just a direction?
I came up with a solution by isolating boost and cut, and working with different impedance (and reacende) with an amplifier in between. But it is an expensive solution, and still not a perfect one, as the Qs still don't match perfectly, but are close.
What bothers me is that Manley and others seems to get perfectly mirrored Qs for boost and cut with a much simpler approach.
Thanks a lot for this.