English producer and four‑time Grammy Award‑winning mixer Robert Orton, aka The Hitmixer, has worked with million‑selling artists including Lady Gaga, Enrique Iglesias, Backstreet Boys, Sting, Lana Del Rey and Robin Thicke. Asked to pick a sonic highlight from his hugely successful catalogue, he chooses the bass in Charli XCX’s ‘Boom Clap’.
“One of the most important elements of ‘Boom Clap’ is the sub‑bass sound that comes in on the chorus, and the trick was getting everything to fit around it, because it’s huge. It’s absent in the verses, but lands on one of the choruses with the word ‘boom’ when it first comes in.
Robert Orton: When you hit the chorus, this all‑consuming bass sound takes over. I had to figure out how to make that sound as big as possible without taking over everything.
“The verses have got this much smaller‑sounding bass part, but when you hit the chorus, this all‑consuming bass sound takes over. I had to figure out how to make that sound as big as possible without taking over everything, to allow for all the other things that are obviously really important for the chorus to work.
“The song has this sort of odd, stilted rhythm made up of all these different elements that come together to form the groove — there’s an acoustic guitar which is more rhythmic than melodic, the snare, and then this slightly weird hi‑hat. These sounds all bounce off each other to form something that’s really quite hypnotic and interesting to listen to.
“So, you get this big boom from the sub, which has to dissipate to make space for these other elements that come in, and compression was the key to achieving that. The bass is keyed off these sounds to ensure they have space over the top. It’s actually quite a complicated processing chain going on, and is really quite different to what I would normally do. Mixing is all about balance, but in this particular case, it needed this type of finesse to get the rhythm to work properly.”
Bass Management
“The bass sound itself has very little processing on it because it was such a cool sound. It was all about getting everything else to work with it. When you’ve got a great sound to begin with, you don’t really need to do much to it. The kick in the verse and the kick in the chorus are the same sound, but they’re treated differently. When that big sub comes in the chorus, I used a transient designer to add attack to the kick so that it pokes through at the beginning of the bass sound, but then gets out of the way. And because that makes the kick sound a bit smaller, there’s also some saturation that comes in on the kick there as well. That also changes the shape of the kick so that it fits better with the sub sound. The saturation was from the stock [Avid] Lo‑Fi plug‑in, but it’s added in parallel so it kind of blends and locks it all together with that sub‑bass.
“Interestingly, when this song first came to me, the sub‑bass element was there but wasn’t as prominent, and for me it was a standout element. The song’s called ‘Boom Clap’, so it’s got to have this huge boom that comes in on the choruses and that has to come from that bass. When I started mixing, I pushed that part right up in the balance and then finessed other parts around it.”
Word Building
“It’s also important to say that the vocals are obviously such an important part of the song as well. Charli XCX sang an amazing vocal and her voice is front and centre. The way the vocals are treated also accentuates the boom and, as that sub‑bass comes in, there’s a separate stack on the words ‘boom clap’. Those are treated differently and it’s an important element of the mix that that phrase is much drier than the rest of the chorus. All these things come together so that, effectively, there’s all this emphasis on those words. By taking the reverb and the delay off them, it not only makes them more in your face but also creates more space for the boom of the sub‑bass.”