The sonic emitter - Gabriel's bark is an Energy Weapons pistol with bonus damage against robots and power armor wearers, as well as a unique "critical strike knockback" effect, knocking enemies down on critical strikes. This sonic emitter is named after Dr. Borous'cyberdogGabriel, and the holodisk containing the upgrade is found in one of Gabriel's digging spots in the X-8 research center. This sonic emitter modulation has a burgundy oscilloscope.
As with all sonic emitter modulations, it is necessary to install the Blind Diode Jefferson's personality chip before this remodulation can be applied to the sonic emitter.
Bugs
PCPlayStation 3Xbox 360 The knockback effect is a ripped and modified version of the script that bighorners use in their melee attack. The repurposing of the script broke it in its entirety for the bighorners, though it does work for the sonic emitter.
Lonesome Road includes a new bighorner script to fix this.
PlayStation 3 Sometimes, after entering the testing area and killing Gabe, leaving while the Think Tanks are still talking, then returning to the testing area and acquiring the Gabriel's Bark holotape, even though the holotape was picked it up, it is missing from inventory.
Xbox 360 In some playthroughs, Audio Sample - Gabriel's Bark will not spawn in any of the digging spots and there is no way to get the holotape to re-spawn through a previous reload or otherwise.