coup-de-foudre / tesla_coil_fm_driver

Raspberry-pi driver for a musical tesla coil
https://www.coupdefoud.re/
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Frequency equalization #9

Open mbmccoy opened 7 years ago

mbmccoy commented 7 years ago

We should test the following equalization methods with the coil:

  1. Low-pass filter
  2. High-pass filter

From Mike Murphy:

[...] A question that's worth discussing is whether we want to devise our own specific preemphasis curve for the coils? Where do we want to handle EQ to give the desired "tone" to the output sound -- in your modulator software? In the computer that's handling the multi-channel playback? In an external mixer or processor? In the mixes as the audio tracks are produced?

My first guesses would have been in the playback computer or an external processor, but customized preemphasis is an interesting idea.

My reply:

I'm very interested in designing filters to improve the sound quality.

I suspect that a low-pass filter will result in higher sound quality. Low frequencies don't produce audible sound, but may cause significant distortion due to high energy. On the other hand, it's possible that flickering or other effects caused by low frequencies make for better art.

A high-pass filter may also improve aesthetics. I suspect that arc "wispiness" is increases with higher-frequencies, so we may get a stronger arc at the expense at fidelity in higher frequencies.