Audio Recording

One of the most important audio processing tasks is to change the pitch of the music. This is particularly useful if a certain singer is joining a singing competition but just cannot properly sing the current pitch if it is either too high or too low.

If the pitch is high for the singer, the best suggestion would be to lower down the key signature of the song, this is done by lowering the pitch of the entire music notes. So if the current key signature is G major, the singer might need to transpose it down to F major or E major, depending on her choice.

The same case if a certain singer finds out that the current key is too low for her and wants to increase the pitch of the minus-one music higher.

It is interesting to know that this feature is available in open source audio editor like Audacity. Not only changing the pitch but normalizing the audio wave is also important. This is essential if you are needing to extract the maximum volume out of the music without achieving distortion.

If you are using Adobe audition audio editor, you might be interested to read the tutorial on “How to maximize volume in audio recording?”.

OK supposing you only have Audacity sound editor and you need to transpose the pitch either up or low, you need to follow the steps below (the screenshots of this tutorial are taken from Linux Ubuntu but can also be applied to other operating system such as Windows) :

Step1.) Launch Audacity (Applications – Sound & Video – Audacity).
Step2.) Open your Audio project that you need to change pitch or normalize. (File – Open)
Step3.) Now go to Effect – Change Pitch. The Change pitch tool automatically detects the current Key signature of the music, for example in the screenshot below:

The current pitch of the music is A#/Bb. If you need to change the pitch higher, select the radio button “Up”, and set “To:” C, (if you like to transpose from A#/Bb to C).

If you need to transpose the pitch down to G. Then set it as:

Pitch from: A#/Bb
Select “Down” in the radio button.
To: G

Step4.) Do not do anything to the rest of the controls just perform the above suggestions. You can even hear a sample preview by clicking the preview button. Finally if all are set, click OK.

Now to normalize the audio wave after transposing the pitch (this is purely optional). Go to Effect – Amplify. The Audacity “Amplify” tool will automatically detect how many decibels it needs to amplify to reach the full volume. For example,

The tool detects that in order to reach maximum possible volume without distortion, it needs to amplify the audio wave by 4.8 decibels. If you are happy with the suggestions, just click OK and its done. Sometimes if your wave is already normalized before, the tool will give a 0 dB suggestion, meaning it is already normalized.