By Antony Elwell
Warping audio can often be an area of confusion and there are many ways to do this. Here I will explain what exactly warping is, why we do it and give you a step by step guide on how to get the best results.
The reason for warping (time stretching/compressing) audio is to increase or decrease the tempo (BPM) of the audio file. This is usually so that it can be aligned with the project grid in your software which will allow you to get it in time with other elements of your project.
For example, if I take an a-cappella (vocal) from a song that is 120BPM and I want to use it in the track that I am making but the tempo of my project is 128BPM, I could use warping to increase the speed of the vocal to 128BPM. This way it will sound in time with all the other elements of my project. A very powerful tool for remixing!
As you will discover, there are a lot of options of how to go about this process and some are more suitable than others depending on the type of audio you are working with. For example, the way I might go about warping a short drum loop could be very different to how I warp an EDM vocal or even a band recording from the 60s. There are also several algorithms that Ableton can use to give you the best results.
All of this is covered in depth on the ‘Audio Editing’ module of our music production courses.
Warping music with a straight tempo
Step 1 – Import you music
In this instance I will be working in Live’s arrangement window although this can also be done in the session view. If you are not not in the arrangement view use the TAB shortcut to switch screens. Next you can bring in your chosen song from the browser on the left or drag and drop it from your desktop, iTunes etc.. and place it on an empty audio track.
Next double click on the clip that you just added to open up the sample editor in the bottom half of the screen.
Step 2 – reset the warp markers
Ableton will have had a go at warping this track for you when you imported it. However, to ensure it is warped correctly we will do this manually from the start. Click on the ‘warp’ button to turn warp off (the track will now be at its original speed) and then turn it on again to completely reset the warp markers.
We will now need to locate the first beat of the first bar of the track to start warping it from that point. If you are unfamiliar with counting beats and bars click here for more info. With the track I am using, it is at the very start of the song. Once located, right click and set 1.1.1 here.
Step 3 – align the track to your grid
Now you can align the track to your current grid, just move the transient markers so that they line up with the relevant grid numbers. For example, I have taken the transient marker for the forth beat of my first bar and dragged it to align up with 1.4 on my grid. Now turn on your metronome and listen to make sure the clicks are in time with the beat.
You can now continue to go through the track and adjust these markers until the all fall exactly in to the grid. For the next marker I will look at is the start of the 17th bar, from there I will look at the middle of the song and then check the end. As long as the very first marker is correct, the rest should all line up nicely.
If you feel that the tempo starts to drift at any point, you can double click on a transient marker to fix its position making it a yellow ‘warp marker’. This way everything you have adjusted prior to the warp marker will be fixed in place and won’t be affected by adjustments you make further along in the track.
Step 4 – Saving your work
Once you have everything lined up, you can click the save button in the sample editor to update the analysis file that is located next to the original audio file on your computer. This means that next time you import this track, it will remember all the warp and transient markers so you won’t need to warp it again.
Warping music with a drifting tempo
Some music, as you will find, tends to drift in tempo throughout the song or sample. A good example of this would be a recording of a live band in an instance where a metronome wasn’t used when recording the song, even the best drummer in the world would drift slightly at some point.
This can make it a lot harder to warp a song to a grid.
All of this and much more will be covered in part 2