The dbx 166xl is a dual-channel compressor, limiter, and noise gate used in live sound, broadcast, and recording studios. Known for its rugged reliability and classic “dbx sound,” it features OverEasy/hard knee compression, program-adaptive gating, and a PeakStop limiter to cleanly manage audio dynamics. 

• Dual-Channel/Stereo Operation: Can process two independent mono signals or be linked for perfect stereo tracking.
• Expander/Gate: Smooth, program-dependent timing algorithms that are excellent for cleaning up background noise or drum bleed.
• Compressor Section: Offers full controls for Threshold, Ratio, Attack, and Release, plus an "Auto" mode that dynamically adjusts attack and release algorithms to the source material.
• PeakStop Limiter: Sets a definitive ceiling to protect your gear and prevent digital clipping or harsh analog peaks.
• Side Chain & Contour: Includes a side-chain insert for frequency-dependent processing (like de-essing) and a Contour switch that prevents heavy bass frequencies from falsely triggering the compressor. 

Common Applications

• Live Sound & Bass Rigs: Ideal for patching into mixing consoles or tightening up live bass guitars.
• Drums: Highly regarded for gating tom mics to reduce bleed and heavily compressing (squashing) drum rooms or overheads.
• Vocals: Effective for taming uneven volume levels before they hit a digital audio workstation (DAW) or mixing board. 

Technical Specifications

• Inputs/Outputs: Balanced XLR and 1/4" TRS
• Operating Levels: Switchable between \(+4\text{ dBu}\) and \(-10\text{ dBV}\)
• Rack Size: 1U