Hi…
I am new to audacity.
I have downloaded an audio with a *.mp3 extension.
In Spectrogram view, this audio shows a range between 0khz to around 12khz.
I wonder if someone could give me a tutorial to convert the range from 0khz to 8khz without using the High-Pass and Low-Pass Filter in the effect menu ?
Wish you a wonderful day and thank you for allowing me to post a question.
convert the range from 0khz to 8khz without using the High-Pass and Low-Pass Filter
Why are we doing this? What’s the job?
Koz
Hi Koz,
I am sorry to bother you, it’s nothing important, just for my hobby.
I am trying to make an audible song for my bird 
.
Some pet birds can hear up to 10kHz …
the melody is below 6kHz so they should be able to hear that,
they may benefit from a treble boost though.
Why the restriction of not using the High and Low Pass filters? The question seems to be arbitrarily limiting. You can do this job with Effect > Filter Curve, but that’s just a fancy way of creating a custom low pass filter. It is low pass. Let tones lower than a set pitch go through.
You are going to experience a different problem, too. Never do production in MP3. Every time you edit an MP3 file, the sound quality gets worse and you can’t stop it. It doesn’t limit the pitch of the sounds, but it scrambles where and how they appear. After a while, you’ll get honky, talking into a milk jug, cell phone sound. You can’t fix that later. Once you get that, the sound is trash.
So if you have a target sound in mind, you may keep missing it “for some reason.”
Get the original sound in WAV 16-bit at either 44100 (audio CD quality) or 48000 (video quality), and work from there.
Koz
Maybe you want the Change Pitch effect?
You can enter 12000 to 8000Hz (for a -33% pitch shift). That pitch-shifts everything down by 33% so the harmonic relationships remain intact and if it’s music it remains “in tune with itself”. (i.e. Entering 120Hz to 80Hz gives exactly the same results.)
Thank you guys, you solved my problem.