How do i go about changing what herts bass hits in song???
Sorry but I can make no sense of your question. What are you trying to do?
You can’t easily change the bass frequencies because you’ll make the bass out of tune with the rest of the song.
You can change the intensity of existing bass frequencies with the Equalizer effect. The bass frequencies are on the left. I recommend the Graphic EQ mode for experimenting unless you know exactly what frequencies you want to boost/cut with the equalizer.
If you boost the bass, it’s a good idea to check the volume-peaks before exporting. Run the Amplify effect and if it defaults to a negative dB level, run the effect to bring the peaks down to 0dB. Most audio formats are limited to 0dB. If the peaks go over 0dB and you export, the file will be clipped (distorted flat-topped waves).
Audacity doesn’t come with this effect, but there is something called a subharmonic synthesizer that generates bass frequencies one octave down. Since the new frequencies are one octave down, they are in-tune with the existing music. You generally need a big subwoofer and a big amp to reproduce these super-low bass frequencies. Otherwise, you just drive your amp and speaker into distortion without adding anything you can hear.
I do have a big subwoofer and amp that is why I’m trying to figure out how to change the frequency of the bass levels for demo/competition purposes
You’ll probably have to spend $$ on something like this LoAir Subharmonic Generator Plugin - Waves Audio. I am not sure if that will work fully in Audacity, if not try it in another audio host.
You can also obtain hardware subharmonic synthesizers and plug them into the audio chain. Use your favourite search engine.
You may be able to “roll your own” subharmonic synthesizer…
1. Save the original file (of course).
2. Low-pass filter at (maybe 100Hz or lower) to remove everything except the bass.
3. Run the Change Pitch effect and set the Percent Change to -50%. This will shift the pitch down by one octave (it will cut all of the frequencies in half).
4. Mix the new low-bass track with the original.
5. Normalize (the Amplify effect) to bring the peaks down to 0dB before exporting (to a new file name, of course).
If you want to go even deeper, you can repeat this again.
Audacity has a compressor effect, and there are lots of compressor plug-ins available. A multi-band compressor (which Audacity does not have) would allow you to boost & compress the bass without affecting the rest of the frequency-range.
Audacity’s limiter is a hard-limiter (clipper) so you might want to look for something with less distortion.
If you want to make test-tones at known frequencies you can use Generate → Tone.. It would be good to know what frequencies your subwoofer can handle. i.e. If the sub craps-out at 20Hz, it would be a good idea to high-pass filter to remove everything below 20Hz and make better use of your “watts”.