I this previous blog post I wrote about how you could use the Flex & Follow setting in Logic Pro X to change the bpm of audio files while keeping them in key. Welp, after doing some experimenting this is now my go-to method for changing the tempo of acapella vocals so I can lay them over a cool instrumental background of whatever remix I'd like to make.
How To Do It
Disclaimer: I am not recommending you do any of this, and I assume no responsibility for any trouble you get into. Lol. Now with that out of the way, let's walk through how to might slow down Demi Lovato's "Confident" vocals from the original 130bpm to a more moombahtony bpm of around 110 or 115. Seems like a big jump, I know, but let's see if Logic can manage it!
Step 1 - Find a High Quality Acapella
There are actually tons of great quality acapella tracks out there floating around on the internet today (there are plenty of low quality ones too so you may have to sift through them for a while until you find the gems). Youtube and reddit are great places to start. For example, this youtube video is a pretty nice acapella version of the song we wanted. Nice.
Step 2 - Download That Shyit
A lot of times a download link will be available in the description. A faster, easier, and slightly less ethical way could be to use a tool such as saveclipbro.com to help you rip audio files. Always down as a .wav file as that has the highest quality with the smallest file size.
Step 3 - Create A New Logic Project And Set Initial BPM
Alright, now we're ready to boot up logic. Up a fresh project with a single audio track. Now, don't get ahead of yourself and don't add the acapella file yet. First, we need to set the project bpm. You can easily adjust the project bpm by clicking on it in the fake LCD display and dragging your mouse up or down. They key thing here is to bring the project bpm to the same bpm as the original song of the acapella.
Step 4 - Import & Analyze The Acapella
Logic uses the name "Flex Mode", but actually it is much more powerful than just a way to stretch and shrinks sound clips. When you enable Flex mode it will "analyze your file". I don't know exactly what it does when it analyzes the file, but when do you it on a large audio clip Logic locks up, and "analyzing files..." popup appears, and you have to wait for a progress bar to finish so that leads me to believe that some moderately intense computational shit must be going down. Suffice it to say that when you have Flex mode on and you are changing bpm's then it'll sound better. So, first click the main "Show/Hide Flex" button near the top of the window in Logic. Then click the "Enable Flex" button on the audio track containing the audio file to be flexed. Ok, now you also just want to make sure you have "Flex & Follow" turned on. To do that you need to open the "inspector" panel, find "Flex & Follow", and make sure the selected value is "On".
Change The Project BPM And Watch The Magic Happen!
That's right. If you enabled the Flex, Flex & Follow settings on the track then you should be able to just change the project bpm and the acapella audio file will change to match the new bpm. Notice how the speed changes but the pitch stays about the same, making it sound like it's the same voice, just singing the piece faster or slower (as opposed to it being sung by a chipmunk or an evil demon). I was pretty amazed that it could even push up to a 20bpm change higher or lower than the original tempo, and it still actually sounds good! Just in case you don't believe me I've included a few bounced versions at different tempos just so you can see that they do actually sound quite good even after a pretty drastic bpm change!
First Match Up Beat With Acapella. Then Decide On The BPM Of Your Remix
Ok, so now you have a method of changing your vocal acapellas to a different bpm, and this method of bringing the vocals into logic, changing the pitch, and bouncing out a file at a new bpm if fine if you already know exactly what bpm you want the final song to be. Although different genres do have certain bpm numbers more commonly used than others, I would strongly urge you to not decide on a bpm up front because, well, why the fuck you want to do that anyway? It's jumping the gun. It's way too early. It's a completely premature decision because you don't even know what it sounds like yet!
Think about this for a second: instead of changing the bpm of the vocals in a separate project, why not change them right in the project that already has the beat in it? Then once the vocals and instrumentals are in sync (same bpm) you can then change the project tempo, adjusting both the vocals and instrumentals at the same [damn] time! This allows you to listen to the combination of vocals and instrumentals at every bpm, or at least a few in the general area where you were originally thinking. In my opinion this is the quickest, most enjoyable process that often leads to the bpm that sounds best because you can organically settle on the bpm that sounds best to you for the specific style of music you are going for with the combination of beat and vocal in this particular project.
Anyway, the key thing to remember here is to first change the instrumental project's bpm to the bpm of the original song of the acapella. You should be change the template project's bpm the same way. Of course you will probably have more tracks, but the steps are all still the same. Midi will respond to you changing the project bpm automatically so you don't even have to worry about that. Make sure you example "Flex & Follow" for any non-midi audio regions in your project. By initially changing the beat's bpm to that of the acapella song, the beat and acapella will instantly have the same tempo when you then bring the acapella into the project! Now, all you have to do is adjust the project bpm and settle in on one that sounds good for your remix!
Other Non-Bpm Considerations
While figuring out tempo is of one the very first things I do when making a remix, there are other things to consider such as making sure the down beats are hitting at the same time, checking that the musical key of each song is not totally clashing with one another, and just getting a balanced volume level of the vocals and beat together. Then do some region rearranging, throw some plugins on that bitznatch, and make add in a few of your own instruments, and you'll be making hot remixes in no time!
Thanks for reading this blog post! You can hear some of my finished remixes on Soundcloud here, and don't forget to follow me on your favorite social media platforms @JizmoMusic.
The posts on this site are written and maintained by Jim Lynch. About Jim...