No. It's not necessary with this unit.

The Solo is designed for use with native signal processing and, optionally, external hardware processing.

Generally, hardware DSP effects can exacerbate compatibility issues, and help obfuscate the software mixing interface. In addition, onboard DSP effects cannot usually be used for software digital mixdown, as they operate in real-time.

The Solo provides support for real external hardware effects units (ie: dynamics processors, EQs) to be used as inserts in the signal path before the A/D converters. This usually provides the best route for the use of nonnative processing.

Hardware DSP is also used on some systems to reduce input monitoring latency. The Solo, because of its built-in mixer, already has this ability.