ReaEQ’s high-pass band is switched off by default. Are your low cuts actually working?

For weeks, every low cut in my projects did nothing. The 250 Hz cut on the lead, the 120 Hz cut on the guitars, the cut under the pad, the 25 Hz safety cut on the master, even the filter sweep that opens up the pre-chorus: all of it was set, and none of it was on.

I found out while building the intermezzo of my second single. Something in the low end didn’t behave the way the settings said it should, so I stopped guessing and measured. The filters weren’t filtering.

What’s going on

When ReaEQ loads in its default state on my setup, it comes with five bands: a low shelf, two bell bands, a high shelf and a high-pass at 100 Hz. The first four are on. The fifth, the high-pass, is switched off.

That’s easy to miss. The high-pass has a frequency like every other band, and changing that frequency looks like it does something. It doesn’t. As long as the band is disabled, the number is just a number.

It slipped through for me because my projects are set up automatically, so nobody ever opened the plugin window to look.

The ten-second check

You don’t need to read any settings for this. Use your ears:

• Play the track with the EQ on it.
• Drag the high-pass frequency slowly up to 500 Hz or higher.
• The low end should thin out until the sound gets small and tinny. If nothing changes, the band is off.

Switch the band on in the plugin, run the same check again, and then set the frequency where you actually want it. This works for any EQ, not just ReaEQ. If you’ve saved your own default preset for ReaEQ, yours may behave differently, so it’s worth a look either way.

Why I kept the sound anyway

Here’s the part I didn’t expect. Every sound I had picked until then, I had picked by ear, with the filter off. The lead, the guitars, the pad: I chose them the way they actually sounded, not the way the settings described them.

So I didn’t “fix” them. For the parts that were already chosen, I left the low cut off on purpose, so they sound exactly like the version I approved. From that point on, every new low cut gets switched on for real, and the master gets its 25 Hz cut.

That’s the real lesson for me: my ears decide, but the settings get measured. A value in a plugin is a claim. What you hear in the bounce is the fact.

Quick checklist

• Don’t trust a high-pass frequency until you’ve heard the band work.
• Sweep it up high once: if the low end doesn’t disappear, it’s off.
• Check a bounce, not the plugin: compare the low end with the filter on and off.
• If something was chosen by ear with the filter off, decide by ear again before you change it.

reaper.TrackFX_SetNamedConfigParm(track, fx, 'BANDENABLED4', '1')