Full Range Driver external high pass filter build

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kmoser

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Full Range Driver external high pass filter build
« on: 10 Sep 2022, 02:23 pm »
I'm looking for suggestions for how to add an external high pass filter capacitor to a full range single driver speaker which have tube connectors installed.
I'm calculating the capacitor at 16 microfarads for a 100 hz cutoff.  I believe this will relieve the driver of unnecessary low frequencies as I have a subwoofer handling the below 100 hz frequencies.

planet10

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Re: Full Range Driver external high pass filter build
« Reply #1 on: 10 Sep 2022, 06:49 pm »
A passive filter at those frequencies is very problematic given hw close you ar eto driver resonance. The impedance is all over the place.

dave

Danny Richie

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Re: Full Range Driver external high pass filter build
« Reply #2 on: 10 Sep 2022, 07:26 pm »
It really shouldn't be calculated. It is best to measure them to see what it does to the response.

Also, pretty much every full range or wide band driver already needs a corrective filter to control nonlinearities. So it is best to design a high pass filter that works well with the main correction filter.

planet10

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Re: Full Range Driver external high pass filter build
« Reply #3 on: 10 Sep 2022, 07:31 pm »
I have never added a ciorrection circuit to any of the literally 100s of FR builds we have done. Because we found them unnecessary.

Some drivers might benefit, but adding a passive circuit can often mean more is subtracted than gained.

dave

Hobbsmeerkat

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Re: Full Range Driver external high pass filter build
« Reply #4 on: 10 Sep 2022, 07:35 pm »
I'm looking for suggestions for how to add an external high pass filter capacitor to a full range single driver speaker which have tube connectors installed.
I'm calculating the capacitor at 16 microfarads for a 100 hz cutoff.  I believe this will relieve the driver of unnecessary low frequencies as I have a subwoofer handling the below 100 hz frequencies.


If you have separate amp and preamps, it will be much easier to put a cap between them than after the amplifier, and much easier to calculate.
The values will be much, much smaller, allowing you to use much higher quality caps and still not break the bank, without having to resort to cheap electrolytic caps.

planet10

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Re: Full Range Driver external high pass filter build
« Reply #5 on: 10 Sep 2022, 07:50 pm »

If you have separate amp and preamps, it will be much easier to put a cap between them than after the amplifier, and much easier to calculate.

You want the hipass filter from this: https://www.t-linespeakers.org/tech/filters/passiveHLxo.html

Same section has a passive line level BSC filter as well.

dave