FFT tutorials/FAQ?

[rockabilly1955]

My daw has a fft eq on it that I usually use for finished songs. It let's me copy an eq curve from any song (commercial CD) and add it to my mixes and then I just tweak the main EQ to taste. Is there any sites or anybody here on the forum that have a good explanation on how to use an fft eq? I would like to know how to use it manually instead of copying other eq curves and why its used instead of or with the other types of eq's. Thanks all.

[LogicDeLuxe]

It basically works like a regular EQ, except there is no phase shifting. Just draw the curve you desire and judge by ear. That's actually all you need to know in order to use it.

That said, if you're interested in the math anyway, here we go: http://en.wikipedia.org/wiki/Fast_Fourier_transform
And more about conventional filters here: http://en.wikipedia.org/wiki/Electronic_filter

[rockabilly1955]

Thanks for the links. I'll check it out. The thing I hate about my fft is that the GUI doesn't list the frequencies across the bottom so I am not too sure what frequencies I would be cutting and or boosting. I'm guessing that most probably go from 20 to 20000?

[LogicDeLuxe]

Sounds like you're using a curve-stealing-tool, rather than a general purpose filter.
Look for a FFT filter. Any serious audio software should have one. It should look like this:
http://img118.imageshack.us/img118/9063/fftvy7.png

[bennychico11]

ignore the FFT.
Taking an EQ and trying to match your song to someone else's is a waste of time. You'll never get it to sound like another recording. There is so much that is involved when recording/mixing that is not taken into account when you're trying to compare your song to another CD.

worry about making it right in the mix. if you're trying to change the way your stereo file sounds, then you need to go back to the mix and fix the individual track. otherwise you're just messing with tools that will mess up your mix.

[rockabilly1955]

So an fft filter really isn't necessary? What are the benefits of it? What's the difference between a HPF/LPF in a parametric eq and an fft filter? I usually use the filters in the parametric eq to cut out any lows below 30 or so.

[masteringhouse]

Originally Posted by rockabilly1955

So an fft filter really isn't necessary? What are the benefits of it? What's the difference between a HPF/LPF in a parametric eq and an fft filter? I usually use the filters in the parametric eq to cut out any lows below 30 or so.

Think of an FFT filter as a graphic EQ with thousands of small bands. It's better used for notching out small bands of freqs over getting rid of an entire range as an HPF would do (kinda like eating soup with a fork over a spoon). While it can be used for the application above, the audio quality will probably be better by just using an HPF. On the other hand if you had a 60Hz hum to get rid of but didn't want to affect the surrounding freqs the FFT would be a better choice.