Hi,
1. What is the exact make and model of the Logitech speaker?
2. Does the volume of the speaker increase or decrease with the change of program that you use?
Method 1:
You may try adjusting the level of volume from the playback option
a. Click on Start
b. Go to Control Panel
c. Select hardware and Sound
d. Select Adjust system volume under Sound option and check if the levels are set properly if not adjust accordingly.
e. Also, click on Change system sound under Sound option
f. On the Playback tab check for the default Speakers and set the levels clicking on the speaker selected for the computer.
Method 2:
I would also suggest you to disable audio enhancements and check. I would suggest you to go through the steps under To disable Audio Enhancements from the link mentioned below.
How do I stop my music from skipping or breaking up when I play it?
You may also contact the manufacturer from the link given below.
http://www.logitech.com/index.cfm/support_downloads/&cl=us,en
You may also refer to the link given below.
http://forums.logitech.com/t5/USB-Speakers/S150-USB-speakers-still-too-loud/td-p/410105
Hope this information is helpful.