A mixing board was a piece of evidence in Apollo Justice's investigation into the murder of Romein LeTouse. During the course of said investigation, it was used to play back two songs from a Gavinners concert at the time of the murder: "Guilty Love" and "The Guitar's Serenade".
Deciphering a concert[]
- Main article: Turnabout Serenade

Audio mixer interface.
The mixing board was first used by Apollo Justice at the request of an upset Klavier Gavin in order to find out which band member of the Gavinners had missed their cue during the song "Guilty Love". Justice did so, and determined that Daryan Crescend, who was playing second guitar, was the culprit.
During Machi Tobaye's trial for Romein LeTouse's murder, the mixing board was used to locate the sound of a gunshot picked up on Lamiroir's headset during "The Guitar's Serenade". This proved that LeTouse's murder had occurred during the concert's second set, contrary to what was previously assumed.
The mixing board was used one final time during the trial as Justice attempted to establish Tobaye as Crescend's smuggling accomplice, by proving that he was able to follow Crescend's command to press an igniter remote trigger during his piano performance. Using the recording of "The Guitar's Serenade", Justice was able to establish that it was highly likely that Tobaye was playing a particular section one-handed, thereby allowing to use his other hand to trigger the igniter.
Game mechanics[]
The mixer has five channels, each of which records a different performer. Each channel's volume can be adjusted by dragging the respective slider. Like the videotape, there are buttons on the touchscreen for playing, pausing, rewinding and fast-forwarding. Each song is divided into four sections and Justice must set the video to the correct section and select the channel that contains the sound of interest.