How to Write a 2-in-1 Bass Line - Music Theory from Rationale “One By One” 

Bass lines need to be low, cos that’s the whole point of them, but this restriction can very easily result in boring bass lines. So how can you break out of that limiting range, while still keeping your bass low? The answer comin’ up. But first… tea!

Hello music makers, we are Kate and Ray Harmony, and welcome to Hack Music Theory. This channel helps you make great music that stands out, so you can get discovered!

The music theory hack in today’s video is from the new single “One By One”, by the artist, Rationale. Quick but crazy story for you: When we were swiping through the New Music Friday playlist on Spotify this morning, to decide what song to hack for this video, we swiped and the Rationale single came on, and I was like “Wait! What the…?!”, that’s my old student from London haha, so I’m totally buzzing right now! #ProudTeacher. And you won’t believe it, but the exact same thing happened last week with another one of Ray’s former students. They all seem to keep turning up on the New Music Friday playlist, how amazing is that?! Anyway, it’s time to open your DAW to hack music theory.

A bass line is the foundation upon which all other melodies and chords are built. Therefore, a bass line has the dual purpose of functioning as your song’s musical ground, as well as its lowest melody. However, so many bass lines these days only fulfill the former purpose, resulting in a solid foundation, but with no melodic interest. To achieve both of these roles simultaneously, use the theory hack from “One By One”, where Rationale grounds his bass line into the root note of each chord, before launching it into the melodic air for a few high notes. This creates an awesome 2-in-1 bass line that carries out both its foundation and melodic duties. And please note, for the sake of this lesson, our example is very similar to the original song. Instead of copying the song though, have fun exploring how you can use this theory hack creatively with your own musical personality, so it sounds like you!

Step 1 - Ground
Set up two bars of 4/4, with your grid set to 1/16 notes, and your tempo set to 94 BPM. Next, you need to choose four chords from a minor key. The original song is in E minor, so we’ll stick with that. The chords we chose are: Em, Gmaj, Dmaj, Am. Now, each chord is played over two 1/4 note beats. The first beat will be used to ground into the root note, and the second beat will be used to fly away, but more on that in Step 2. Next, delete the second 1/4 note beat of each chord. Then, over that first 1/4 note beat of each chord, play the root note a couple times, with a rest in between. And be sure to play one root note of each chord on an off-beat 1/16 note, which is called syncopation, and that adds groove!

Step 2 - Air
Right, now that you’ve grounded your bass line, it’s time to launch it into the melodic air. So, over the second 1/4 note beat of each chord, you’re gonna allow your bass line to break free of its low-notes-only restriction, and elevate its range and melodic interest with some high notes. So, choose three ascending/descending notes from your scale, and play them in a higher octave over your first chord. Then do something similar over your third chord. And these are all 1/16 notes. Also, be sure to start on the off-beat, for even more syncopation. Then over your second chord, you’re actually not gonna go higher,cos that’ll be too much of a good thing. So, just add in a couple low notes there. And then finally, over your last chord, use the same three notes that you used over your third chord, but reverse their order.

Right, now that you’ve got one section down, how do you write a new section for it, and then, how do you transition between those two sections? Great questions, and if this is something you need help with, then check out our cutting-edge online apprenticeship course, where you’ll literally learn every step of the music making process, and most importantly, you’ll learn how to finish your songs! You’ll also gain access to our Private Network, which is a safe social media platform exclusively for our apprentices (and we already have over 400 apprentices, from over 40 countries). Our Network is a super supportive place for you to ask theory questions, share your music, get feedback, meet like-minded music makers, and more! So if all that sounds useful to you, then head on over to our Apprenticeship page now.

Kate & Ray Harmony (AKA Revolution Harmony)
Music Teachers & Producers in Vancouver BC, Canada


1: Read our free book (below) & watch our YouTube videos
2: Read our "Part 1" book & "Songwriting & Producing" PDF
3: Learn our Secret Art of Song-Whispering & finish your music!

Learn how to make great music that stands out, so you can get discovered! Taught by award-winning music lecturer Ray Harmony, and his protégé (and wife) Kate Harmony. Ray is the author of critically-acclaimed book series "Hack Music Theory" and has been teaching music theory for 24 years, and along the way he's made music with Serj Tankian (System Of A Down), Tom Morello (Rage Against The Machine), Steven Wilson (Porcupine Tree), Devin Townsend (Strapping Young Lad), Ihsahn (Emperor), Kool Keith (Ultramagnetic MCs), Madchild (Swollen Members) and many more! Kate has the highest grade distinction in Popular Music Theory from the London College of Music, and is the only person on the planet who's been trained by Ray to teach his Hack Music Theory method! While our YouTube lessons teach music theory for producers and DAW users, they are designed to accommodate all music makers (songwriters, guitarists, etc.) and all genres, from Electronic Music to R&B, Pop to Hip-Hop, Reggae to Rock, EDM/Dance to Metal (and yes, we djefinitely Djent!).

Photo of Rationale from the cover of "One by One"
Courtesy of Best Laid Plans Records