I cannot hear any signal from my computer speakers
When your ESI audio interface is the default playback device, then
all signals from standard applications such as system sounds, Windows
Media Player, iTunes, etc. will play through the output of your audio
interface and not through the onboard soundcard (the audio output of
your computer or built in speakers of your laptop computer). This means
that you must connect a pair of speakers or headphones to the output of
your ESI audio interface.