How To Cut And Keep The Low End Frequencies

Mastering Tips

If you’ve ever tried your hand at mixing then you probably already know that the low frequencies are a nightmare! They’re the first thing to build up into mud, the first thing to distort when going louder, but getting rid of them takes away all the impact and meat of a song. It can get quite frustrating trying to balance it out.

So what do we do? We go online looking for tips and tricks on controlling it. I’ll list a few of the most common solutions, which should be familiar to most of you. If not, try them out, they might get you half-way there:

1. Put a high-pass (low-cut) filter on all the tracks, including the bass and kick.

This is a fantastic idea! It really is. It instantly removes any excess low end of any given track. It even helps on a bass guitar and kick drum. Is it enough though? Well if you want a thinner mix more suited for a portable music player or phone then yes. Of course if you put a mix full of these cuts on a bigger system, it will sound like the band is in a tin can.

High-pass filter on a vocal track.
High-pass filter on a vocal track.

2. Put a high-pass filter, but give it a little boost at the cut-off frequency.

This is a good extension on the previous suggestion because it gives it some extra edge in the low instruments (bass, kick, piano). Essentially it boosts that lowest “good” frequency before the empty “boominess” comes in. If you try this trick on a vocal though, or even a guitar, you will find that it won’t give back much power. Instead you’ll get a thicker “tinny” sound that’s still lacking.

High-pass + boost on a mix bus - works great!
High-pass + boost on a mix bus – works great!

3. Give the low instruments their own space.

This usually means setting a high-pass at around 80Hz for the kick and giving the bass a band-cut at around 100Hz (or vice-versa). This works. It really does. What happens if we have distorted guitars as well? Guitars with a lot of low power. What happens if there’s a piano in there too? All of that needs to be cut somehow to give space, not sound thin and not build-up.

Mastering Tips
Band-cut on bass at 200Hz to give space for the snare.

So, now the question: Okay, smart guy. How do I cut the lows and still keep the power?
Well, curious guy, first you need to try the three above tips. All of them together. Essentially, you have to cut the unnecessary low-end on each track – and don’t be afraid to get slightly carried away! The best way to do this is it to cut all the lows (let’s say up to 1000Hz), then slowly pull back until you feel all the structure of the sound has returned.

In case you’re nerdy for ballpark numbers:

  • bass should rarely be cut above 40Hz
  • kicks depends on the sound (it can range from 20Hz-80Hz cuts)
  • snare also depends on the drum in question (it can range from 80Hz-150Hz)
  • guitars are usually from 100Hz-200Hz
  • vocals often go above 150Hz and all the way to 250Hz
  • piano, strings, brass, choir and anything that has a rich and wide spectrum needs to be experimented with as it’s very situational

Now that you’ve gotten rid of the excess frequencies, we are going to give them back. Wait, wait, not yet! First add compression, reverb, delay, saturation and any other processing you feel the track needs. Add whatever is needed, just don’t try to bring back the low end – yet!

Once you have the sound you want then you can give it that boost. Any DAW should have an EQ at the end of the channel strip, before the sends and the fader. So, use that.

Here’s the trick: Give the lacking tracks a small low-shelf boost (no more than 2db) starting from around their dominating frequency.

Want an example? Here’s a female vocal track.

female vocal mastering

I set a high-pass filter at around 220Hz at the very beginning. Slapped on some compression, added other things I will not go into now. Then I went to the channel strip EQ and found that there’s a lot of power at around 180Hz. So I set my low-shelf there and gave it a 2db boost – voila!

That’s it! How, you ask? Well, this combines the three suggestions in a slightly different way. First we cut the excess frequencies so that all the processing that happens doesn’t affect them as much as it otherwise would – because they’re just “not there”. The truth is that they still are there except they’re very quiet compared to the rest of the sound and thus hardly audible and only lightly affected by processing. That part of the signal is less compressed, less saturated, but it still is. Then we give it a slight boost, but only enough to feel that it’s there, somewhere. We give each instrument that boost starting at their dominating frequency, thus giving each their own space.

Try it out to hear that it does give back a lot power with very little build-up. It’s especially effective on vocals and guitars!

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