This from my prior review...
Helix performs nearly perfectly as a DAW recording interface. I have noticed a couple of small issues using Mac OS Yosemite and Logic Pro X 10.2. First, Helix outputs via USB to the DAW a signal requiring approximately 6-9 Db of gain over the displayed +/- 0 db of the Multi output section. This, in order to get good recording level and to match the playback of the preexisting tracks already recorded and normalized. There’s no noticeable noise created by Helix with the additional gain however. So, it is just an inconvenience. The second issue I’ve run into is random re-amping of preexisting tracks. Twice I’ve had a single playback track inadvertently begin to run through the preset currently being used for whatever reason without any user change of parameter. First time was on a prerecorded bass audio track. Second instance was on a softsynth/drum machine track. I should note this issue is only on the playback as the track being overdubbed/recorded does not bleed together with the rouge reamped sound. A Helix reboot fixes this issue.