It seems that I cannot turn up the input volume on the L1 Pro base past 9:00, or three lighted bars.
If I go beyond that I get considerable white noise that increases as the volume increases. This occurs whether I have anything connected or not. It is slightly less noisy if the Music EQ setting is used. Our normal use case is connecting a mixer for a band. Is three bars the maximum input volume?
Professional PA systems inherently have a higher noise floor than other speakers and home electronics. As the largest portable PA system, the Pro32 will have the highest noise floor. This may be most apparent when standing closer to the system, but will likely be much less noticeable once the system is set up for use at a live venue.
Make sure the output from your mixer is at a loud, healthy volume without clipping when going into the L1 system, to ensure your signal to noise ratio is the best it can be. This article may also prove useful for more information on gain staging.