Sound Fading In and Out
If your sound is fading in and out this can be the L1® System protecting itself from a problem with the bass module (B1/B2) connections.
Please check your bass module cable.
B1/B2 Cable - Connections
From Kyle-at-Bose 
We've seen some past B1 cable quality problems which, because of input from folks like you, we've since resolved.
I'm fairly confident that the connector and wires in the cable assembly are OK. The problems we were having were related to the actual connection of the wire leads to the Speakon connector. Problems would be obvious in one case- the bass module cuts out. The second case would not be so obvious- the EQ to the B1 and L1 would be wrong and would make the system perform and sound poor.
So, if you have a moment and a screwdriver, we can fix these cables together.
Remove the rear shell of the connector by unscrewing it. (See the pic below, not the exact connector but similar). We use a 4-wire connection so what you need to do is re-attach, possibly restripping first (need to use a wire stripper), the wire to the connector terminals. There are four terminals +1, -1, +2, -2. Each wire needs to be appropriately connected to the same terminal on each end of the cable. Luckily, no soldering is needed. These Speakon connectors have screw terminals. All you need to do is unscrew the terminal using a screwdriver, reinsert the bare wire, and then tighten the terminal.
B1/B2 Conductors Broken
From Harry (dancingdogmuse)
The initial symptoms were clicking followed by silence. It turned out to be a problem with broken wires inside the blue jacket of the B1 cable.
I have also experienced this when
- I inadvertently connected to Power Stands together through a stack of B1s.
- I had more than two B1s connected to a single Power Stand without A1
ST 11:36, 17 June 2010 (EDT)
Other things to try...
- If you are not using the R1 Remote try connecting it.
- If you are using the R1 Remote try disconnecting it
- Troubleshooting Sound Drop Outs
youtube video of sound fading in and out - this was caused by a faulty B1 cable.