M-Audio 2626 manual About Software Returns, Why use the DSP Mixer?, ProFire, User Guide

ProFire 2626

Software Returns – This block represents the audio outputs of your audio application. Software returns can be routed to the DSP Mixer and the Router (both described below).

DSP Mixer – This is the 18 input, 16 output DSP mixer contained within the ProFire 2626 interface. The block features a dashed line because the DSP mixer can be completely bypassed by the user if desired.

As shown in the illustration above, the mixer’s 18 input channels accept signals from any of the hardware inputs or software returns. See the “Mixer” section of the “Control Panel Application” chapter to learn how to configure and use the DSP mixer.

In cases where the computer is unable to run with sufficiently small buffer size settings (i.e., the software monitoring latency is too high), the DSP Mixer can be used instead to achieve near-zero latency monitoring of your input signals.

Router – The Router is a device that lets you select the source of each hardware output on ProFire 2626. These sources include any pair of hardware inputs, the main output of the DSP mixer or any of its seven auxiliary sends, and any available software return pair.

The router is an extremely useful tool since it allows you to reconfigure how audio streams flow out of the interface without having to physically re-patch the cables connected to the back of the interface.

Hardware Outputs – These are the physical outputs of ProFire 2626 including the eight 1/4” analog jacks, two ADAT ports, and the S/PDIF connector. The Router (see above) lets you select the source of each hardware output pair.

User Guide 11

About Software Returns:

The term “Return” has its roots in analog recording, where input sources (Microphones, Instruments, etc.) are connected to large format mixing consoles, routed to multi-track reel-to-reel tape machines for recording and then returned to the mixing desk. This allows the recording engineer to hear the recorded signal from tape while the recording is still in process. This way, problems with the recording (e.g. tape imperfections, or distorting signals) can be detected in real-time.

While recording systems have evolved greatly over the years and DAW applications have become more popular for recording and playback, the concept of returning signals from your recording device has not changed. In the case of the ProFire 2626, the output of your audio software (the recording device) is returned to the ProFire 2626 Router section – hence the term “software returns.” Signals returning from your software to ProFire 2626 can then be sent to the DSP mixer and/or any hardware output of your choosing.

Why use the DSP Mixer?

Most audio applications include mixing and monitoring functionality and you may be wondering why you would want to use the ProFire 2626 DSP Mixer for monitoring instead of the DAW application. The main reason for using the DSP Mixer is that software-based audio applications suffer from a phenomenon known as “latency.” Latency is the amount of time it takes your audio signals to pass through the computer (and its DAW software) and become available at the hardware outputs. This delay is usually quite small and is measured in milliseconds, but it may be large enough to distract a performer who wishes to record while monitoring through software.

The amount of latency varies depending on many factors including your computer’s performance and buffer size settings. Powerful computers with fast processors may allow you to run your sessions with very small buffer size settings, providing virtually imperceptible latency. In this case, you can use your application’s software monitoring features and bypass the ProFire 2626 DSP Mixer.