Changing key and tempo

Thanks to fantastic hardware and software tools available in the 21st century, tasks that twenty years ago could only be performed by highly-specialized technicians in sophisticated studios now can be done at home, with the help of a personal computer and some software programs.

If you have a computer (PC or Macintosh) connected to the internet, we would like to point out that it is possible for all the Global Choro Music audios to:

a) change the key of the song without modifying the tempo;

b) change the tempo of the songs without modifying the key; and

c) simultaneously change tempo and key

You can easily perform all these tasks without necessarily being a sound engineer. Check why you could be interested in changing the tempo of the songs:

- if you wanted to study a given song in a slower tempo and then develop to the proper tempo as you got comfortable with it;

- if you needed or decided to take on the challenge of playing a given song faster; or

- if you disagreed with the tempo proposed in this work, and wished to play it according to your desire.

You could also be interested in changing the key of the songs if:

- you wished to practice a given composition by playing it in different keys, with or without the corresponding score (in this case transposing the song mentally or “on the fly”), and wanted to have a Choro ensemble always available to accompany you, no matter what key the song is played in;

- you felt more comfortable playing in a key different than the one used in this work; or

- you were playing a different instrument than the ones already mentioned in this work, and that would need a specific transposition.

How is that possible?

To transpose the audio files, the recording containing the Choro Ensemble base music should be transposed. There are several types of software that can do that, but we recommend the open source software that allows free download called "Audacity®". You can download Audacity® from:

http://audacity.sourceforge.net/

It’s worth noticing that Audacity® has support for the Portuguese language.

To make the transposition you have to download the .wav file corresponding to the track you want to change, and then define how many semitones you want to transpose up or down, and finally save the file in the format you wish (.mp3, .wav, etc.).

Changing the tempo is also easy: download the .wav file corresponding to the track you chose and then inform how much percent you want to increase or decrease in relation to the tempo of the original recording. 

The quality of the recording remains almost unchanged for modifications considered within a reasonable limit: 3 to 4 semitones above or below the original key and changes in tempo between less than 20% and 20%.

You will test several combinations of key and tempos until you find your ideal point.  Then, all you have to do is burn your final version onto a CD... imagine the joy of playing your favorite choro, and more – in the key and tempo you defined yourself!

Examples of use

As an illustration, we used the Audacity software for the track containing ‘Brejeiro’ of the “Ernesto Nazareth 2” songbook, and generated the mp3 play-along track you will find below. We also made available the transposed score for your reference. The track was originally recorded in A major.

The original tempo used in the recording was at 87 bpm. We also generated the same track at 100 bpm.