🚀 go-pugleaf

jeffreygough@lineone.net wrote
on topic "Graphic Equaliser Project":

> Hello all.
>
> I have recently been toying with the idea of creating a graphic equaliser
> program. I would like it to play wav files (and if possible mp3s), and have
> slider controls to alter the volume of each frequency band. I would aim to
> make an equaliser with around 5 to 10 frequency bands.
>
> So does anyone have any handy resources that i may find useful (eg: volume
> components, ways to isolate different frequencies, URLs, help files)?
> Anything vaguely related is welcome, since i have a couple of other audio
> projects on the go, and i would like to add some extras to them.
>
> One guideline is that i would rather avoid integrating with other programs
> that do this (such as winamp etc)
>
> Thanks in advance :-)
>
> Jeff.
>
> PS: does anyone know if this is even possible with delphi?!

a nice idea.
Delphi won't be the problem.
The user interface will be the most simple part of it.
There are special "digital signal processors" (as you will
them find in modems) that could do the job (but nothing else).

What you have to do is perform a frequency analysis, multiply
the results with the values of the graphic equalizer, and
calculate a frequency synthesis.

It sounds simple, but it is a lot of mathematics, and I doubt
you get it done with a 2 GHz Pentium in real time.

Otherwise you could do it by digital filtering but you have
to calculate the coefficients for the filter.
I can send you a very simple example for a high pass if you
are interested.

People did it some 50 years ago with a network of analogue
components as resistances and capacitors which work with
light speed (nearly).

What you might do is control the resistances of such a network
by your computer. You just need some additional I/O ports.

Klaus