An aux send is a fundamental feature on mixing consoles and audio interfaces that allows a specific amount of a channel’s signal to be routed to an external destination. This destination is often an effects processor, a recording device, or a separate monitor system, and the send control functions as a dedicated volume fader for that path. Unlike the main mix output, which carries the final stereo image for the audience, an aux send creates a parallel copy of the audio to serve auxiliary purposes without altering the primary signal chain.
The Core Functionality of Aux Sends
At its heart, an aux send is a pre-fader or post-fader output that taps into the signal chain at a specific point. When set to pre-fader, the send level remains independent of the channel’s main fader, which is ideal for maintaining consistent monitor mixes as a performer adjusts their playing volume. Conversely, a post-fader send moves in relation to the fader, making it perfect for applications like group processing or sends to external gear that should duck along with the main mix. The flexibility of this routing is what makes aux sends indispensable in both live and studio environments.
Live Sound Applications
In live sound reinforcement, aux sends are most commonly used to create monitor mixes for musicians on stage. Each performer can have their own blend of vocals and instruments sent to their in-ear monitors or stage wedges, ensuring they hear exactly what they need to perform confidently. Because these sends are often pre-fader, the monitor engineer can maintain a stable mix for the performers even if the main house mix is being adjusted for the audience. This separation of duties allows the front-of-house engineer to focus on the overall sound for the room while the monitor engineer caters to the specific needs of the artists.
Studio Recording and Processing In a recording studio, aux sends are frequently used to route signals to outboard gear such as reverbs, delays, or compressors. By sending a portion of multiple tracks to a single effects return, engineers can create a cohesive sense of space and depth across the entire mix. This technique, often referred to as "parallel processing," allows the dry signal to retain its clarity while the effected tail glues the composition together. Common applications include sending drums to a room reverb, vocals to a plate reverb, or the entire mix to a mastering-grade limiter for translation checks. Signal Flow and Routing
In a recording studio, aux sends are frequently used to route signals to outboard gear such as reverbs, delays, or compressors. By sending a portion of multiple tracks to a single effects return, engineers can create a cohesive sense of space and depth across the entire mix. This technique, often referred to as "parallel processing," allows the dry signal to retain its clarity while the effected tail glues the composition together. Common applications include sending drums to a room reverb, vocals to a plate reverb, or the entire mix to a mastering-grade limiter for translation checks.
Understanding the signal flow of an aux send is crucial for effective usage. The send knob on a channel strip determines how much of that channel’s signal is diverted to the aux bus. This bus can then be patched to physical hardware via outputs or kept within the digital realm to feed software plugins. It is important to consider gain staging at this stage; sending too hot can cause clipping in external processors, while sending too low can result in a lack of effect. Properly managing the level ensures the effect integrates seamlessly with the dry signal.
