How to tell if a Mac EQ is actually doing anything

Some EQ apps make everything louder and call it an improvement. Louder reads as better in a quick comparison, so the trick works. Here is how to check whether an equalizer is doing real work, and what else to look for in any Mac audio tool.

The loudness trap

If an app raises the level when you switch it on, it will sound better for a few seconds no matter what the curve does. Compare at the same loudness. Turn the app on and off and match the level by ear or with a meter before you decide anything.

The null test

A flat EQ should be identical to no EQ at all. Not close. Identical. Audio engineers call this a null test: send the same audio down both paths, invert one, and sum them. Silence means the paths match.

By ear, the test is simple:

1. Set every band to flat.
2. Play a track you know well.
3. Toggle the app on and off while it plays.
4. Listen for a level change, a click, or a tone change. At flat, there should be none.

If flat sounds louder or different, the app colors the sound before you have touched a setting. That matters, because it means the improvement you hear is not your curve.

What else to check in any Mac EQ

Earwave is built around the null test. With every band at 0 and Loudness off, its output matches bypass sample for sample: 0 differing samples, on a sine and on a test signal of stacked tones and drum-like thumps. Two honest conditions. Loudness is on by default, because lifting the bass at quiet levels is its job, so switch it off before you test. And the limiter, also on by default, holds peaks to -1 dBFS, so a track that peaks above that will differ where it does; switch the limiter off for a strict null. Slider changes glide in instead of jumping, so they do not click, the audio thread never allocates or frees memory to apply them, and the default output device is never changed.

Try the same test on whatever app you are using. If flat is not silent, you are hearing the app, not your headphones.