Low pass filter

Hi.

I'm about to build a low pass filter, just because I think the change they make to the sound is really quite cool. There's no good reason why I can't run one from +-4.5v is there?

Also, A Low Pass Filter removes all the frequencies above a certain point yeah? So the result is a sound wave containing just the frequencies below this point, yeah?

Cheers,

Tim

grrr_arrghh said:

Hi.

I'm about to build a low pass filter, just because I think the change they make to the sound is really quite cool. There's no good reason why I can't run one from +-4.5v is there?

Also, A Low Pass Filter removes all the frequencies above a certain point yeah? So the result is a sound wave containing just the frequencies below this point, yeah?

Click to expand...

It doesn't 'remove' them, it attenuates them, at a rate determined by the slope of the filter - this measured in dB/octave - where the higher the value the faster it rolls off the high frequencies. However, the higher the slope the more it affects the sound around the turnover point, in particular giving large phase shifts.

You can happily run one off +/-4.5V, as long as you keep the signal levels through it reasonably low.

Nigel Goodwin said:

It doesn't 'remove' them, it attenuates them, at a rate determined by the slope of the filter - this measured in dB/octave - where the higher the value the faster it rolls off the high frequencies. However, the higher the slope the more it affects the sound around the turnover point, in particular giving large phase shifts.

Click to expand...

hmm, that makes sense, and explains a few things!! As I said, its for nothing better than making a cool effect, so i'm not to bothered about the slope.

Nigel Goodwin said:

You can happily run one off +/-4.5V, as long as you keep the signal levels through it reasonably low.

Click to expand...

ok, well they'll only be line level signals.

Thankyou

Tim