It appears the standby mode on the T20 speakers is meant to be there and is not a fault. There is no mention of it in the manual or the spec on there site. From Creative
"Hi Customer,
Good Day!
We have received your question about the Gigabits 20 Series II turning off after 10 minutes.
With regards to that, it's normal that it will automatically turn off after some time when there is no music being played, then it will automatically turn on once it detects a music.
If the above is not your case, kindly provide us more information on the issue.
If you still require assistance, please reply to this email and include any previous correspondence to ensure a quick response.
Regards,
Ryan
Creative Worldwide Customer Response"