Studio Mic Sound for your Acoustic Instrument. The first to use Impulse Response (IR) technology with acoustic instruments, Aura Image processors provide the most realistic acoustic sound available for plugging in on stage or in the studio. Aura Spectrum DI combines Aura with a high-quality preamp featuring 3-band EQ, Compressor, Automatic Feedback Suppression, Chromatic Tuner, Effects Loop, and XLR DI.