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 solution?

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.

  • dA

    its hard to even work when that muds slowing you down, everyone please use hpf, you then can move on to your next frustration

    • “you then can move on to your next frustration” … ha ha. So true. 🙂

  • cozy

    I actually learned this after I mixed our first EP.  I had eq’d everything and got the mix sounding nice in my studio.  Got a nice final mix, sent it to mastering, got it back from mastering and there was this “cloud” over the entire project.  What happened was the guy who mastered it boosted the lows and I didn’t cut lows from the snares, vocals, sample and synths.  This resulted in quite a muddy mix.  People said that they didn’t notice it, but I sure did.  On the full album I didn’t make that mistake and the mix came back sounding so much better.  HPF are a necessity in a mix.  Thanks for the article.  Moving on to day 25 now…

  • RJ

    Great post! The only problem I have with taking the low end out of everything except the kick and bass is that I tend to use a lot of synths that use a good amount of low end and in the end, actually help give the kick & bass (more so bass) more power and smooth out all of the areas where a low end instrument is not present.

    This is probably a more prominent issue when mixing dance/electronic music than it is with other genres.

  • Arjun Ramesh

    I am very excited to try this out. I just got done with a frustrating mix session yesterday. I have yet to go back and have a listen again, as I don’t know if ear fatigue played a part in it. So, hopefully, I can use this trick and see how the track turns out.

  • Matt

    Great post!! Yes, this is one of the first things I learned to do when I 1st started recording/mixing. I was always wondering why my mixes sounded muddy and not punchy. I wondered why my mixes overall levels were lower than the pro mixes. The reason was that I let just about everything have a full freq. range. By the time you have a couple guitars, piano, bass and drums, the amount of low freq. energy was HUGE! That’s when I started to use a high pass and immediately my mixes were punchier and I had more headroom to boost the overall level of the song.

  • Preshan

    This is a great tip.

    To save some CPU, I put a HPF on the subgroup tracks e.g. vocals, to clean everything up with less plugins. For this reason, I often split bass and guitars into their own subgroups, so I don’t high-pass al the guitars and the bass along with it. It’s amazing how much it cleans up a mix. Long live the HPF!

  • Ryusei Kawano

    This is probably the first thing I do when I’m mixing a song, put high pass filters on everything except kick and bass. I agree it helps a lot when you’re trying to take the mud out of the mix but you can overdo it just like many things. When I first started mixing I used to cut so much low end off of my guitars that they just ended up sounding really thin.

  • Dean

    Should you also do this if the track is just an acoustic guitar and vocal?

  • Bob Sorace

    I started using this a few months back after reading one of your other posts.
    great tip! I’m still in the process of going through older mixes and applying this, it does make a huge difference!

  • i started doing this after reading your understanding eq article. this really has helped a lot. i used to have to push my kick drum levels through the roof to get them to stand out, but i now realize there was to many other things taking up space. i actually use HPF on the kick and bass too. i do about 40-45 on the kick, and even up to 65-70 on the bass. i usually don’t find anything below that extremely necessary and my mixes still have plenty of oomph to them. i roll basically everything else off at like 150, so the kick and bass have plenty of relative low end to do the job.

  • Paulo Fortes

    WOW! The best so far. Never thought it could make so much difference. Now things look more like they should be

  • Frank Adrian

    This is good practice. Guitar subtones can get really muddy below 80Hz or so and clog things up. I also occasionally use an HPF on kick and bass and will supplement with an sub-octave generator if more low is needed (oddly enough, most people don’t hear subtleties of timbre down below 60Hz or so).

  • There are engineers out there that even use HPF on kick and bass and it really helps. Even a HPF at 40hz can help to provide a little more headroom.

  • Everett Meloy

    I think this is the “Best” tip and it made a world of differance.

  • mark b

    i learned this from you a while back and it makes a HUGE difference. relly clears out the mud. also i have a frind i am collaborating with–he sent me his mixes to do some vocals over and i could tell right away that he did NOT know about the power of the HPF. so there i was able to pass on this awesome advice!

    “HPF–making the mix a better place for kick and bass!”