What Are Amazon’s “Re-EQ’d” Songs?

A reader wrote me asking if I knew anything about Amazon’s “Re-EQ’d” music. I had never heard of this, but a search shows a number of songs are listed as Re-EQ’d on Amazon. Here’s one album: The Best of the Pointer Sisters has 16 tracks, 12 of which are labelled Re-EQ’d.

EQ is the abbreviation for equalizer, an audio tool that lets you adjust frequencies. Technically, any amplifier has an equalizer: you can adjust bass and treble, albeit in broad swaths. A real equalizer has more frequency bands: ten, twenty, or even more. In a studio, it is probably possible to apply equalization to very narrow frequency bands.

Equalization is simply changing volume in one of those bands. As you know on your amplifier, if you increase the bass, the low frequencies get louder. Many audio players have equalizers. iTunes, for example, has a ten-band equalizer, and you can use presets or make your own adjustments.

So what exactly is Amazon doing? Someone asked the question on the Steve Hoffman Music Forum, and none of the answers were conclusive. The speculation is that someone considered that the music didn’t sound right and made some adjustments. It could just be a poor man’s remastering, in the sense that original tapes aren’t used, but that the CD is tweaked a bit to sound better.

Does anyone know exactly what this entails, and why Amazon and some streaming services mention this?