Our Client wanted to hide a Bartolini 3 band EQ in the back of his bass. Â We have done at least 6 basses like this for him. Â Since all of the settings remain preset the only active control on the face of the guitar is the master volume. Â While not for everyone, this setup is a bombproof way to hit the stage and not change your tone while putting on a show. Â Not shown, is the cover plate on the electronics cavity that has small labeled holes through which you can adjust the trim pots with out pulling it all apart.