Audacity Forum

I am new to sound recording and I need to change the frecuency of an audio file. I need to test changing to frecuencies greater than 20,000 hz and below 20 hz, beyond the human audible range.

Is this posible with Audacity software? If so, I will very much appreciate if you tell me how.

With respect,
Jorge Maldonado

One of the complaints of Audacity is that it will manage "sound" that nobody can hear. It will manage sound with zero frequency, battery voltage, and there are actually well-used tools to get rid of that signal.

Higher is more of a problem. I think Audacity will cheerfully go up there, but you will need a sound specification that can follow you up. 44100 sample frequency will not go up reliably further than 17.8 KHz. Barely high audio. Figure a Nyquist number of 2.6. Highest audio frequency multiplied by 2.6 to get the sampling frequency. 36 KHz audio would need sampling of 96000. 36 KHz x 2.6 = 93600.

Most sound cards will not produce electrical signals at those frequencies. So you may not be able to get the performance out of the computer.

Koz

Thank you for your reply Kozikowski.
From your answer I understand that Audacity is able to achieve my goal but the problem lies on the sound card. Is this correct?
Does is mean that I need to find a sound card capable of generating the frequencies I need?

With respect,
Jorge Maldonado

What are you intending to do with these high/low frequencies? Do you need to "play" them? If so, what other equipment do you have? If not, what do you want to do with them?

We are working in a project with subliminal audio messages and one of our tests has to do with changing the frequency of the audio files to values beyond the human perception which is 20hz-20000hz. After getting this result, we plan to play them in an audio component not in a PC.

Respectfully,
Jorge Maldonado

JORGEMAL wrote:we plan to play them in an audio component not in a PC.

Is this "audio component" capable of reproducing frequencies outside of the audio range?
Do you have loudspeakers / headphones / amplifiers ... capable of handling frequencies below 20Hz/above 20kHz ?