So, I don’t really want to buy and expensive interface or microphone because what I have works well except for recording higher and lower vocals. Is there anything that I can manipulate so that the pitches and frequencies don’t cause ringing or screechiness?
what I have works well
If you have a live microphone in the room, you should be on headphones. Are you?
I’m just using the internal mic which works well for my purposes excepting notes that are several pitches higher than normal speaking frequencies.
If you mean certain frequencies are recorded louder (not “higher”) than they are pecieved by your ear,
then that is correctable with Audacity’s equalizer … http://manual.audacityteam.org/man/Equalization
If you have ringing you may be accidentally creating a feedback loop somewhere, feeding some of the output sound back into the input.
Check Audacity is only recording your internal microphone, not “what-U-hear”, aka “wave out” as well.
Acoustic feedback via speakers / headphones (which Kozikowski alluded to above) is another possible source of ringing and squealing.