You can make your voice higher by using Audacity’s Graphic EQ and Change Pitch tools. You’ll be boosting higher frequencies with EQ and raising the pitch of your voice with a pitch changer. Still, for the best results, it’s best to record your voice higher using natural techniques.

Make your voice higher with EQ

Here’s how to boost higher frequencies using EQ in Audacity:

1. Select your whole audio recording
2. Go to Effect->Graphic EQ
3. Remove everything below 60Hz
4. Cut 60Hz-250Hz by -4dB
5. Boost 3kHz and above by 4dB

It’s not only just boosting higher frequencies but you’re also going to cut lower frequencies to enhance the higher-end. Also, don’t boost/cut by more than 5dB unless it’s frequencies that don’t belong to human voice such as below 60Hz.

You can play around with the settings in Graphic EQ and there’re some useful presets made by Audacity, you can try them out. Still using EQ the change of the voice should be quite subtle compared to what we’re going to do with the Change Pitch effect.

Make your voice higher with pitch changer

To make your voice higher with the Change Pitch effect in Audacity you’ll be following these steps:

1. Select your whole audio recording
2. Go to Effect->Change Pitch
3. Add up to 4 semitones to your voice (2 is optimal for me)

Using the Change Pitch effect your voice will change the voice drastically, I recommend sticking with more subtle changes if you wish to maintain a somewhat realistic human voice, otherwise you might sound ridiculous. If you don’t mind an absurdly high-pitched voice and that’s what you aim for, then going above 4 semitones might suit you.

These tips alone will help to make your voice significantly higher but if you want to get the best results I recommend recording your voice naturally higher by applying vocal techniques and then further tuning it with audio effects.

To make a demonic voice you’ll need to lower the pitch and add a lot of reverb. You can make a demonic voice in Premiere Pro by using Pitch Shifter and Studio Reverb effects.

Here’s how to apply Pitch Shifter audio effect:

1. Go to Effects->Audio Effects->Time and Pitch->Pitch Shifter
2. Drag the Pitch Shifter effect onto your audio clip
3. Click edit in the Effect Controls menu
4. Reduce pitch by 12 semi-tones
5. Again drag the effect onto your clip
6. Again click edit in the Effect Controls menu
7. Reduce pitch by another 4 semi-tones

Premiere Pro only allows to reduce pitch by 12 semi-tones, that’s why we’re applying the Pitch Shifter effect twice and reducing the pitch by another 4 semi-tones.

Changing pitch will make the voice sound inhumanly low and completely unnatural which is what we’re striving for when creating a demonic voice. You can play around by lowering the pitch less or even more, the perfect amount depends on your preference and the natural pitch of the recording.

After applying Pitch Shifter effect twice you’ll want to add some reverb using a Studio Reverb effect:

1. Go to Effects->Audio Effects->Reverb->Studio Reverb
2. Drag Studio Reverb effect onto your clip
3. Click edit in the Effect Controls menu
4. Set Room Size to 90, Decay to 5500ms, Early Reflections to 100%, High Frequency Cut to 20000Hz, Low Frequency Cut to 20Hz, Damping to 0%, Diffusion to 0%, Dry Output Level to 80%, Wet Output Level to 100%.

Using reverb we are adding even more inhuman voice qualities. You can play around with the effect and change Room Size, Decay and Dry/Wet settings. I would only strongly recommend keeping Low Frequency Cut at 20Hz as we reduced the pitch to very low frequencies and cutting lower frequencies would cancel Pitch Shifter effect.

Here’s original audio without any effects applied:

Audio after applying effects in Premiere Pro to make it sound demonic:

It would also help if you attempted to make your voice deeper and grittier during recording, then you wouldn’t need to rely on using effects as much and could maintain better audio quality. For tips on how to get a deeper voice read this article.