the gain of the virus ti snow using it as a soundcard is too low. is there a way to change it?

Taken from the Setup Guide...

My Virus sounds less loud than other virtual
instruments. What do I need to do?

Using the USB outputs, you will recognize that other virtual instruments have more
output level than the Virus TI. This is because the Virus reserves enough headroom
to play dozens of voices at the same time. Fortunately this needn’t be a
disadvantage as long as you make sure that you use the headroom of your digital
mixer. Todays digital mixers and sequencer have more headroom than any of us
will need. Here’s an idea for you:

Before you start working on your next project, put every channel fader to -20dB.
Next, put the master fader right up so you can still hear things loudly enough. Once
you instantiate Virus Control, put this fader to e.g. -12dB instead of -20dB to make it
equally loud. Here, you need to experiment a little - the Virus obviously gets louder
the more voices you play, and also all virtual instruments have a different loudness
to each other.
After working on the song for a while, you will notice that your mix gets louder when
you add more instruments. Reduce the level of the master fader once it gets close
to red.
You will be surprised how powerful, clear and dynamic your mix will sound and how
well the Virus fits in.
✓ If you cannot achieve a suitable level by pushing the master fader right up when
you start working, use a gainer plug-in to push it further.