What frequencies do different instruments produce?

Is it possible to relate frequencies to instruments? For instance, will the voice will be more present with a boost at 3 kHz? What about other instruments?

Yes you can find charts that show the frequency ranges of various instruments.

There is a problem however...

The chart will show the frequency range of the double bass as 40 Hz to 200 Hz; the piccolo from 630 Hz to 5 kHz, approximately.

However this does not tell the whole story.

These are the fundamental pitches of the notes that can be played on these instruments. The chart takes no account of the harmonics of the instruments.

All musical sounds possess harmonics. If you play a single note on any string or wind instrument, a fundamental frequency will be produced, which is the note you hear. But also there will be frequencies that are whole-number multiples of the fundamental frequency. These are the harmonics.

And the harmonics of any acoustic instrument range right up to the limit of human hearing and beyond. Even for a double bass.

In sound engineering however, you will find that certain bands of frequencies can be used to enhance different instruments. Experiment with the frequency control of your EQ and you will find that certain settings can make the trumpet more 'trumpety', the violins more 'violiney' etc.

And indeed the human voice can often be brought out with an EQ boost around 3 kHz, even though this is way beyond the range of fundamental pitches that anyone could sing.

So, take frequency charts with a degree of caution. Experimentation, listening and good judgment will always bring you better results.