Hello everyone,
I was trying to design a circuit where I split an audio signal in two channels: one which is a low pass filtered version of the original and the other which is a high pass filtered one. Both LPF and HPF are 2nd order and have same fc.
The idea was to merge the two signals back at the end of the circuit, after the high end signal gets minor level adjustments. Though when I do this, using a simple summing opamp, I happen to have a notch in the frequency response precisely at fc, which I realised it's where the phase of the two signals is +90 and -90 respectively.
I tried inverting one of the signals 180 degrees to make the frequencies at fc in phase, but there's still some weird modulation due to phase happening at fc which also compromises the flatness of the frequency response. And also the signal's low end would be out of phase with the rest of the audio band which I'd rather avoid.
I was wondering if anyone knew how would I be able to restore the filtered low end in the high end signal, archieving a flat response at the end?
Thank you in advance for any help, stay safe!
A
I was trying to design a circuit where I split an audio signal in two channels: one which is a low pass filtered version of the original and the other which is a high pass filtered one. Both LPF and HPF are 2nd order and have same fc.
The idea was to merge the two signals back at the end of the circuit, after the high end signal gets minor level adjustments. Though when I do this, using a simple summing opamp, I happen to have a notch in the frequency response precisely at fc, which I realised it's where the phase of the two signals is +90 and -90 respectively.
I tried inverting one of the signals 180 degrees to make the frequencies at fc in phase, but there's still some weird modulation due to phase happening at fc which also compromises the flatness of the frequency response. And also the signal's low end would be out of phase with the rest of the audio band which I'd rather avoid.
I was wondering if anyone knew how would I be able to restore the filtered low end in the high end signal, archieving a flat response at the end?
Thank you in advance for any help, stay safe!
A