In addition to your amplifier’s standard EQ controls, a contour knob, like the one found on many Carvin Audio bass amplifier heads, can further help you find a bass tone that sits perfectly in your band’s mix. While the function and engineering of each given contour knob may vary, the general purpose is to provide an extra tool for tone shaping the midrange frequencies and providing a classic “scooped mids” sound.
Scooped Mids: the Basics
Scooping out the mids is exactly what it sounds like- removing midrange content from your signal at specific frequencies. This practice tends to get a bad reputation for being detrimental to your bass tone, and it is understandable- with the cymbals and guitars occupying the high end, and the kick drum competing with it to hold down the low end, a bass guitar’s midrange is what makes it cut through the mix.
So why would you want to scoop the mids? Many players enjoy dialing in this sound because it accentuates the low end thump and high end attack of the bass and removes some of the clutter and nasally sound of the midrange. This tends to be a great option for slap styles, heavier rock, and players who want their tone to sit a particular way in the mix. Surprisingly a subtle mid scoop plays very well in mellower rock music. It defines the low mid and low note groves without providing extra note noise that mix with the cleaner guitar tones.
Enter the Contour Knob
With a contour control, it is possible to change the nature of your mids without completely removing them. This opens the doors to many new tone sculpting possibilities. On the Carvin Audio BX1600, the contour knob allows gradual scooping of the mids to tame the clutter in the midrange. When set to the leftmost position, the mids are unchanged. Turn the knob to the right and you will incrementally scoop your mids out at about the 250Hz range- this is the range where a lot of the body and low midrange heft of your bass sound is. Too much sound in this range can be detrimental and really muddy up a mix, but the contour knob really lets you find the sweet spot. At full clockwise the midrange content at 300Hz is reduced by 9dB.
If you’re a fan of the scooped mids sound, it can be very useful to find equipment that lets you implement it into your sound gradually via a knob rather than all at once (some amps have a simple on/off switch for a mid scoop function). Don’t be afraid to experiment with the contour control next time you’re playing with the band- it’s another important and often overlooked tool to help bassists in finding the right tone.