DSP no audio output volume

Shing-Kwei's icon

Hello!
I use Firestudio Presonus as audio interface,DSP output volume isn't available (gray, but input is OK) OS Preference Sound already assigned on Presounus firestudio. how can I fix the problem? thanks

Shing-kwei
MaC. Core Dual OS 10.6.8
Max/MSP 5

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