What is a reasonable low frequency cut-off?

[Logistics]

This pertains to an amplifier I'm building, but the question relates more to headphone listening than DIY amp building. Since the output capacitor will affect my low frequency cut-off, I'm wondering what an actual reasonable frequency to settle on is. I could use the suggested value in the datasheet to give me a theoretical cut-off of 14.1Hz, which would require me to use electrolytics for cost-sake. But I could use a lesser value to give me a theoretical cut-off of 66.31Hz and get away with films. And I have to wonder if that's not already much better than what I'm getting running straight off my SbLive!, anyway!

Now, I'm not going to worry about my phones supposedly responding to 5Hz. I don't think with my SbLive! nor my cheap Magnavox reciever, that I have been hearing any fantastic infrasonic performance. While 66Hz sounds like a reasonable cut-off to me, I want to know what you guys think.

 

[ericj]

It's not really a cutoff, it's a rolloff. The frequency you're referring to is probably the corner frequency - which is the point at which there is 3db of attenuation.

There's a good visual high-pass-filter calculator at this site: http://www.st-andrews.ac.uk/~jcgl/Sc...hpass/hpf.html

If you have the space in the enclosure for it, you can get very large film capacitors. look for motor run (not start) capacitors.

You can also get a whole bunch of smaller film caps and hook them up in parallel.

a corner frequency of 20hz or so probably won't lose you much bass, but generally, if for only the sake of less phase distortion, it's good to push it down as far as you can.

 

[Duggeh]

Fine educational establishment that university.

 

[Logistics]

20Hz eh? Well, since I'm used to running my 24-Ohm cans straight off my SbLive!, which it's really not meant to do, I'm assuming my roll-off point was very high compared to 20Hz. What do you think?

 

[MD1032]

I'd say go as low as possible. Many of the pipe organ recordings I have feature 32' stops - 16 hz at low C, of course. Having a contra bombarde cut out of the music would ruin my listening experience!

Also, atlantic city has a 64 footer (8 hz) that makes a fun recording.