At the time I made the post, you hadn't posted a circuit. A high-pass filter will make overshoot. That's just how it works.
Lol thanks guys.
I guess i didn't think things through all that well. I dd study this last year so i recall the integrator and differentiator bit. Seeing it on a scope and connecting the dots is experience.
Attenuation of harmonics again, just in the opposite way?
Clearly I'm not used to looking at a waveform in quite that way.
Lol I'm still adding the caps i somehow managed to forget.
I guess i didn't think things through all that well. I dd study this last year so i recall the integrator and differentiator bit. Seeing it on a scope and connecting the dots is experience.
Attenuation of harmonics again, just in the opposite way?
Clearly I'm not used to looking at a waveform in quite that way.
Lol I'm still adding the caps i somehow managed to forget.
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I learn something every day. Thanks Mooly. While I know what low pass and hi pass filters sound like, I don't have any scope experience with them. I was a digital designer once, everything was supposed to be square waves with maybe a little ringing after state changes.Well
Lol thanks guys.
I guess i didn't think things through all that well. I dd study this last year so i recall the integrator and differentiator bit. Seeing it on a scope and connecting the dots is experience.
Attenuation of harmonics again, just in the opposite way?
Clearly I'm not used to looking at a waveform in quite that way.
Lol I'm still adding the caps i somehow managed to forget.
Its accentuating the harmonics, making them bigger because they are higher in frequency than the fundamental. So the 2nd is bigger than the fundamental, the third bigger than the second and so on up to the limits of the response of the circuit (opamp is the limiting factor ultimately) Your welcome.
Both of you might find LTspice useful in simulating "basic building blocks" and then you could simulate your complete circuits just as they are drawn to see how they all perform. Its easy to display the actual response of each stage and see instantly the effect of changing values etc. You could simulate it with squarewaves too and see how they look. And you can start with something as simple as one resistor and one cap to get the hang of it.
Thanks again. Ive downloaded filterpro and had a play, but given the way ive calculated filter curves, using boxsim to sim the real acoustic spl, it hasn't proved to be alot of help.
Once i had each stage Q and Fc,i used a calc on Okawa electric website. The initial values it spat out for the LP work fine. The HP gives me some 4dB of loss, small cap sizes and Rs too.
Reworking with larger caps and i get better results. But still not quite correct.
Once i had each stage Q and Fc,i used a calc on Okawa electric website. The initial values it spat out for the LP work fine. The HP gives me some 4dB of loss, small cap sizes and Rs too.
Reworking with larger caps and i get better results. But still not quite correct.
If the fundamental is in the pass band then the squarewave will show a downward tilt on the "top" part and an "upward" on the bottom part. When the fundamental is well below the pass band then you just see small peaky "spikes"
Turns out i had a connection wrong in the highpass since altering things today. Retook the filter response curve,and now IM back to square one.
Both filters look ok. No oscillation ��. The simmed Vs actual responses are thus the same as in the 'filter Q' thread i started in this forum, so I'm wary of reposting the image.
Suffice to say, it looks reasonable. To really know, i think i shall have to remove the additional passive cap from my sims and replace with a buffered RC, merely to make analysis more straightforward.
Both filters look ok. No oscillation ��. The simmed Vs actual responses are thus the same as in the 'filter Q' thread i started in this forum, so I'm wary of reposting the image.
Suffice to say, it looks reasonable. To really know, i think i shall have to remove the additional passive cap from my sims and replace with a buffered RC, merely to make analysis more straightforward.
I didn't explain well Mooly.
Both sections of the filter differ.
The 5th order LP looks very good and close to the sim.
The 4th order HP looks like it has a reduced slope compared to the electrical sim.
I may have to sim again replacing the 5th pole on the HP which is passive external component,with an RC and remodel for a flat acoustic output as before.
I initially thought the HP slope would become steeper with the addition of the DC blocking cap, then realised the plot doesn't take this into account.
As it stands it appears i will have a dip at crossover. I plan to test with music and the drivers later to see if it sounds ok, or how obvious the issue is.
Its no biggie, it just looks like ill have to ditch the DC blocking cap on the loudspeaker and redo the HP.
Still, I'm chuffed with how well the LP functions.
Both sections of the filter differ.
The 5th order LP looks very good and close to the sim.
The 4th order HP looks like it has a reduced slope compared to the electrical sim.
I may have to sim again replacing the 5th pole on the HP which is passive external component,with an RC and remodel for a flat acoustic output as before.
I initially thought the HP slope would become steeper with the addition of the DC blocking cap, then realised the plot doesn't take this into account.
As it stands it appears i will have a dip at crossover. I plan to test with music and the drivers later to see if it sounds ok, or how obvious the issue is.
Its no biggie, it just looks like ill have to ditch the DC blocking cap on the loudspeaker and redo the HP.
Still, I'm chuffed with how well the LP functions.
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