Roughly 9 years ago, I supported a product on Indiegogo called, Aumeo. It was a device that gave you a hearing test and then tailored the sound of your music based on your unique hearing profile. I really liked the results and wished that someone would bake this technology into phones, negating the need for a separate device.
Spex was born out of this wish.
Spex will give you a hearing test and then build a parametric stereo EQ based on the results. If the EQ is not exactly how you like it, you can fine-tune it with intuitive controls. First, you can slide the intensity slider to find your sweet spot. If youre still not satisfied, you can manually adjust the 12-band stereo EQ.
The base version gives you unfettered access to create as many EQ profiles as you want. If you upgrade to Pro, you can also access a volume slider that will give you greater control over volume than is provided by the volume keys. Pro also gives you the ability to tweak the player interface and duplicate EQs.
If you want to skip the hearing test, you can jump right in and tap the Fine-Tune button on the default flat EQ to make use of the 12-band stereo EQ.
Please note that the EQ can only be applied to non-encrypted tracks in your music library. This means EQ cannot be applied to subscription music tracks. If Apple provides a way to EQ encrypted tracks, I will update Spex.