Want Space and Clarity in Your Mixes? Use Low Pass Filters

 

Tutorials online about High Passing are about as common as cat videos these days.

It’s so common, it’s almost not worth talking about! If you want space and clarity, then clean up your tracks with high pass filters.

But setting high pass filters isn’t exactly a perfect science, is it?

How much is too much? And isn’t it always a bit hazy finding the perfect frequency to set your filters?

There is such an easier way to do this whole high-pass filter thing. But you have to look at the other end of the spectrum…

And that’s with Low Passing.

Confused? Let me explain:

Hi Pass Filters: Audio’s Vacuum Cleaner

High-pass filters are like the vacuum cleaners of the audio world. You use high passing to clean up your tracks.

More often than not, your track will have some low level noise. You can’t really hear it, but it’s down there:

This noise might be too quiet to notice. But it’s actually robbing your mixes of headroom and clarity!

Aside from kick drums or bass guitars, most of your tracks don’t need sound that far down the spectrum. That sound often comes from ambient noise. For example:

• Air conditioning
• Musician moving or bumping into things
• Neighbor mowing their lawn

Think about the dust in your home. It doesn’t seem too bad, right? Sure, there’s some light dust, but nothing too bad.

Now try vacuuming up all the dust in your house. Go ahead, vacuum the whole place – I’ll wait.

The bag is starting to look kind of full, isn’t it?

That low level noise is like the dust in your house. On one track it doesn’t seem so bad. But across 50 tracks? Now your mix is starting to look dirty.

And that “dirt” is insidiously stealing the clarity and space in your mixes.

The Flaws of Hi-Passing

So if you want space and clarity, you’ve got to high pass.

But the procedure for high passing has always been a bit touchy.

The rule has always been:

• Drag your high pass filter up until you hear your track start sounding thin, and then
• Back the filter off a little bit until your track doesn’t sound thin anymore

That seems to make sense, doesn’t it?

You want to remove everything below a certain frequency. But you don’t want to chop out any important fundamental frequencies of your tracks.

Here’s the problem with setting your high-pass filters like this:

The noise you’re trying to cut out is very low. So low, it’s hard to actually hear it.

Even if your system has something like a subwoofer it can be tough to hear that stuff.

I mean, isn’t the eternal struggle always getting your kick or bass to cut through your mix?

So it stands to reason that it’s gonna be hard to dial back something you can’t actually hear.

And if you think about it a little more:

That’s why low pass filters are your best friend for high passing.

Low Passing Your Way to Success

The mids and highs have always been easier to hear than the low end. While the low end tends to be more “felt” than heard.

If only you could remove the mids and highs, the low end would be a lot easier to hear!

Well, well, well. Low pass filter can do just that – remove the mids and highs.

And what’s left once the mids and highs are gone?

All lows baby.

So the procedure for high passing should really be flipped completely around:

1. Drag your low pass filter until you hear only the ugly, unneeded noise
2. When you settle on a frequency, write it down.
3. Now bypass your low pass filter, and
4. Set your high pass filter to that frequency.

Voila! You’re now able to surgically cut out the dust and dirt from your mixes.

You didn’t have to guess and fumble around for it. You were able to find exactly where it lives.

Beyond the Noise

This low pass tactic isn’t just for low level stuff either. In fact, it can help you really fine-tune the low end of your tracks.

Sometimes guitars, keyboards, and other instruments can have flub that isn’t needed.

Guitar amps can have low end resonances that sound like someone talking through a pillow instead of meaty guitar tones.

Keys can have plunks, mechanical noises, and other unnecessary sounds floating around.

When you low pass, you can have a much clearer picture of what’s going on way down there.

So if the low end of the guitar is just muffled resonances – go ahead! Cut that stuff right out. Even if it creeps into the actually tone of the instrument. You didn’t need that junk anyways.

Conclusion

High pass filters are critical for cleaning up your mixes for maximum space and clarity. The more plugins you throw at your mixes, the more the benefit of high passing will reveal itself.

But trying to High Pass critically is always like trying to find anything in the dark.

Yeah, you can guesstimate what you think you’re hearing. But why not be sure?

By Low Passing, you remove the distracting mids and highs, and can get some real work done.