Welcome to Day 24 of 31 Days to Better Recordings.
This just might be the most important mixing tip I can give you.
It’s something I talk about in-depth in Understanding EQ, but I couldn’t possibly go through 31 Days to Better Recordings without dedicating one day to the High-Pass Filter.
A high-pass filter (HPF) is also known as a low-cut filter. It’s a very simple tool that simply removes all frequency below a certain frequency. For example, setting a high-pass filter to 100 Hz essentially removes all frequencies below 100 Hz.
<Nerd-Moment>A HPF is actually a sloping curve. When you set the HPF to 100 Hz, then the volume of the signal at 100 Hz is at roughly -3dB. The volume at 50 Hz is roughly – 9dB, etc. etc. It usually doesn’t technically remove EVERYTHING below 100 Hz. </Nerd-Moment>
So, why is a HPF so useful?
I will answer your question with a question. What is the biggest problem with your mixes? Are they too muddy? Too boomy? Too bass-heavy?
A HPF can be a huge tool to help solve those problems. Everything you record has low-frequency information. Acoustic guitar, for example, produces a lot of information in the 50-100 Hz range. These low frequencies don’t really help things; they simply muddy up your mix…but you may not even realize it.
My best advice for your mix?
Use a HPF on EVERYTHING but kick drum and bass.
In most mixes, the kick drum and the bass guitar are the only two instruments that are even supposed to occupy the low end. By removing the low frequencies from the other drum tracks, guitars, vocals, keys, etc., you’re creating a space for these low frequency instruments to live and thrive.
Where should you place the HPF on each track? That’s up to you, but I usually start around 100-150 Hz.
Trust me on this. It’s not a magic pill, and it won’t instantly make you millions of dollars, but it WILL make your job as a mix engineer much easier.
Day 24 Challenge
This one’s obvious. Your challenge today is to use a HPF on every track but kick and bass in your next mix, then report back here and let us know what you thought.
If you’ve already “seen the light,” share with the rest of us how much of an improvement this technique makes on your mixes.
And finally, if you’re wanting in-depth training on HPF and EQ, check out Understanding EQ.