An aux send is a fundamental feature found on nearly every mixing console and audio interface, acting as a controlled tap from the main signal path. It allows you to route a specific amount of an audio source to an independent auxiliary channel without altering the primary mix destined for the main speakers. This parallel path is essential for creating separate mixes for monitors on stage, processing external effects, or feeding audio into a recording system, all while keeping the front-of-house sound untouched and pristine.
Understanding the Core Functionality
The technical operation of an aux send is relatively straightforward but incredibly powerful. When you adjust the aux level on a channel, you are changing the balance between the direct sound heading to the main outputs and the signal branching off to the aux bus. This is typically a post-fader or pre-fader send, depending on the console design. A post-fader send means the aux level moves with the channel fader, which is ideal for monitor mixes where an artist wants the blend to change naturally as they sing louder or softer. A pre-fader send, on the other hand, keeps the aux level constant regardless of the fader position, which is the standard for effects processing, ensuring the effect level remains steady even during quiet passages.
Applications in Live Sound Reinforcement
In a live performance setting, aux sends are the backbone of the monitor system. Each musician on stage can require a unique blend of vocals, drums, and guitars to perform confidently. Engineers create multiple monitor mixes, sending specific amounts of each instrument to the respective stage monitors. This solves the critical problem of acoustic feedback and allows artists to hear exactly what they need in their headphones or in-ear monitors. Without aux sends, creating these personalized mixes would require a separate mixing board for every single performer, which is impractical and inefficient.
Utilizing Effects Processing
Beyond monitoring, aux sends are the standard method for applying effects like reverb, delay, and chorus to a mix. Rather than inserting an effect directly on a channel, which would permanently color the sound, an aux send routes the signal to an effects processor. The processed "wet" signal is then mixed back with the dry "original" signal on the console. This technique allows you to apply the same effect to multiple sources, such as a drum kit or a group of vocalists, maintaining a cohesive sound. You can adjust the intensity of the effect on each source independently using the aux send knob, creating depth and space without destroying the clarity of the core sound.
Recording and Broadcasting Workflows
For recording engineers, aux sends provide a clean method for capturing alternative mixes. You might send a balanced version of the band to a multitrack recorder for archiving, while the main mix goes to the house speakers. In broadcast applications, aux sends are used to feed separate lines for commentators, streamers, or recording devices. This ensures that the technical production crew receives a consistent and clean audio feed that is distinct from what the audience hears in the venue, allowing for greater control over the final product.
Optimizing Gain Staging and Signal Flow
It is crucial to manage the signal chain when using aux sends to avoid noise and distortion. The aux output on a mixer sends a post-preamp signal, meaning the level is already optimized for processing. When patching an external device, you should feed it into a line-level input on the destination device. Overloading the line input of your effects processor or interface can introduce unwanted distortion. Always check the signal meters on your auxiliary channels to ensure you are providing a strong, clean signal without clipping, which ensures the highest quality processing on the return channel.
