line level high pass filter

[rbrockman]

I am looking for some suggestions regarding a line level high pass filter for main speakers. I don't mind building a circuit as long as it is a good or better than something I can buy reasonably.

I would like to be able to filter out <~60hz signals from reaching the mains. If possible I'd like to be able to adjust this freq. I believe a 2nd order filter is what I'm looking for.

I am using a digital source -> DAC -> Amp -> Main Speakers

1) Should this be passive or active?
2) If there is consensus on #1, is there a recommendation for a high quality filter?

Thanks for any feedback.

 

[SY]

At frequencies that low, I think that active is the way to go. You can do it pretty simply (Sallen-Key filter made from opamps) or you can get a bit more sophisticated (for example, the Acheron crossover shown on my website). Either approach will well outperform a large, clunky inductor and equally large, clunky capacitors.

 

[raudio1969]

How much attenuation is needed at 60Hz? Here is a circuit which will give -12.4dB at 60Hz. It was generated by Microchip's FilterLab software.

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en010007

 

[planet10]

The high pass of a PLLXO coule be used. 2nd order gets kind of droppy and if your amp has a low input impedance could be a no go... (i'd suggest 50k or higher input impedance, and if that low make R2' infinite and the cable short).

http://t-linespeakers.org/tech/filters/passiveHLxo.html

If the input impedance is an issue and you still want to approach it this way, you can sandwich the PLLXO between 2 buffers. I have a dual 9V battery powered one for one of my speakers, but it could be done with jfet beffers (like in Nelson's B1 or cathode followers (don't forget the CCS)

SY's XO is also very interesting -- i'm no big fan of SK... I'm happy he did the groundwork for this so the rest of us don't have to. Thanx SY.

dave

 

[donmeadows]

Line Level Sub Output
I have some self powered subwoffers i would like to use on my two channel basement setup.
I'm am very confused how to use the line ouput of one of the 2 chan amps, and send it to the self powred woffer.
I've seen quite a few Subwoffer line level pre-amp boards.
I bought one from Amazon "KNACRO DC 10V-24V Low-pass Filter NE5532 Bass Tone Subwoofer Pre-Amplifier Preamp Board ', all I get is distortion from the Self-Powered subwoffer. Can somone tell me which one to get, or how to accomplish this?
Thanks, Don

 

[DonVK]

Line Level Sub Output
I'm am very confused how to use the line ouput of one of the 2 chan amps, and send it to the self powred woffer.
I've seen quite a few Subwoffer line level pre-amp boards.
I bought one from Amazon "KNACRO DC 10V-24V Low-pass Filter NE5532 Bass Tone Subwoofer Pre-Amplifier Preamp Board ', all I get is distortion from the Self-Powered subwoffer. Can somone tell me which one to get, or how to accomplish this?
Thanks, Don

A diagram of how you connected things would help. Does your amp have both "line in" and "line out" connections? Otherwise a simple 2 channel amp would just have a "line in" and "speaker out". The subwoofer low pass filter RL-in would connect to the same "line in" of your 2 channel amp.