What's the struggle with mixing bass?

• Published: 2021-10-03 21:16
• Updated: 2023-03-27 18:58

Short answer: our ears are most sensitive for frequencies between 2-5kz. They're optimized for picking up voices. And, with a little help from our brain, we're able to maintain our ability to pick apart voices from other sounds in a wide range of different environments. From intimate one-on-one conversations in your living room to figuring out who's the next to get a drink at Berghain.

Okay great - but what does that has to do with mixing bass? The challenge lies within this:

{{< figure src="fletcher-munson-curve.png" title="Did you get the gist of this curves' implications already?">}}

Hello Fletcher Munson curve

I'm sure you ran into above curve already. And maybe you've got half of its gist: that, in order to perceive frequencies outside the 2-5khz range as equally loud as those within, they need to be amplified by up to quite radical amounts.

However, the curve also reveals a psychoaccoustic trick to protect our ears across different scenarios:

Our brain compresses or expands the sensitivity of certain frequency ranges according to the summed signal and/or perceived overall loudness of the environment we're in. Wait - what?

The higher the sound pressure level, the less sensitive your ear becomes to frequencies in the 2-5khz range. If the brain didn't compensate, the likelihood of damaging one's ears would be much higher. On the other hand: at high sound pressure levels, low frequencies must not be boosted as much to be perceived equally loud.

Louder Distorted sounds better. Doesn't it?

Because of how loudness affects the sensitivity of our ears, certain mix issues even themselves out as we increase the volume. They just vanish. Bass is finally cutting through, the mix appears more even than it is. Overall, the level of immersion increases. It's literally more rewarding: define instant gratification. It comes at a price, and you know it very well:

Once you step out of the loud zone, you face the reality of what you just produced sounds like. In my experience, what happened in the loud-zone also stays in the loud-zone. Dopamine's usually part of that.

Moreso, your ability to pick up on details decreases as the level increases. It's as if you're sitting on a high-speed train and try to see an individual leaf of grass. It doesn't work. Your perception of sound is distorted in itself.

In my experience, the #1 issue people have with mixing kick and bass is that they're constantly switching between modes of perception (high and low levels) without being aware of it. Thing is: can't blame you. It's the very psychoacoustic phenomena discovered by Fletcher and Munson that makes us pump up the volume to hear more bass in order to fix it in the first place.