Mixing drum kits can be fun. Banging on something to produce a rhythm may have been our first musical experience as a species. Modern recording tools finally gave musicians the ability to share that emotion with a much wider audience of fans and other musicians than live shows alone could reach.
Rock ‘n’ roll can be traced back to early blues and folk music that was popularized in the late 1800s and early 1900s. The excitement of listening to W.C. Handy play his Boogie Woogie piano was intoxicating. Right hand playing melody, left hand pounding out bass counterpoint, foot stomping in rhythm with the bass line the whole time. A very plausible precursor to the modern concept of drums and bass.
Kick drums grew in popularity starting in 1909, when the Ludwig brothers secured the patent for a successful kick drum pedal. The bass guitar has been completing the rock rhythm section since the beginning of the genre.
The 1953 Chess Records recording of “Hoochie Coochie Man” by Muddy Waters, featuring Willie Dixon on upright bass and Elgin Evans on a four-piece drum kit, was probably the first rock ‘n’ roll rhythm section in audio recording history.
The rhythmic beat of the kick drum and the upright bass were synced up. The blues beat of the kick drum lay on the same beats as the notes on the bass. The bass and kick drum melded into a single groove, forming a rhythmic backbone supporting the sinuous flowing flesh of melodic instruments and vocals.
I find the kick drum/bass guitar relationship crucial to the level of emotion or excitement a mix can convey. The way I approach that combination is by separating and optimizing different aspects of each instrument.
Controlling The Ratio
To sculpt my kick drum sound, I use two transducers with vastly different techniques and results. I want to be able to control the ratio level between the midrange beater attack and the low frequency thump and decay. Divide and conquer. Inside I have a Shure BETA 91A half-cardioid condenser microphone on a Kelly SHU mount, which does a great job of capturing the impact of the beater head and the decaying resonances of the shell.
In the console, I apply both a high-pass and low-pass filter to tailor the bandwidth of the BETA 91A to fit my mix. The high-pass filter rolls off at 80 Hz and the low-pass filter varies around 4 kHz. In some rooms I raise or lower that frequency for more or less high-frequency detail from the beater impact. If the room is boomy and reverberant, the low-pass can be as high as 6 kHz, but if it’s a sterile room with a short reverb decay time (RT60), it may be as low as 3 kHz.
For the low end of the kick drum, I use a subkick style speaker, the Tang Band W6-1139 (6.5-inch), which has a free-air resonant frequency of 38 Hz. The speaker is mounted on a stand in front of the kick drum, close to the head. In the console, I don’t need any filters since the speaker naturally rolls off very rapidly above 80 Hz.
I do delay the BETA 91A signal to align with the subkick. Neither kick drum signal has inline compression applied, although I use parallel subgroup compression to reduce the overall dynamic range of the kick drum. This makes it much easier to mix with the dynamic range of the bass guitar. I also sometimes apply a gate on the speaker using the BETA 91A as a key input, depending on room acoustics.