Mine don't care about my speakers. They jump on them occasionally as one is by the window and the other between one of the trees and the staircase but they have never shown any interest in scratching or moving them, with or without the music on.
TV/cable-wise I have quite a mess behind and around my TV rack: the TV, DVD, amplifier, CD player, the mutimedia HDD, Playstation with its pads... all of it connected to the current and to each other as appropriate and most of it connected the Internet (mostly by cable) so there's a lot of cables. Oh, I forgot the guitar amp and the speaker next to it. Again, they're not interested in any of those, they sometimes try to climb the TV but no harm has come to it so far, they're repeatedly on top of the guitar amp but that by its nature is very heavy and bomb-proof. They don't care about the cables at all.
The PC (desktop) with its speakers and monitor (and all the cables in between) is ok as well, they do jump on top of the PC tower as its by the window and quite high but they're not interested in scratching any of these.
They have 3 trees and a couple of scratching pads around the place and also a big cardboard box on he floor which they love, although less than before. They occasionally go for the blankets on the chairs but that's what they're for. I also have a few mats like this:
http://www.ikea.com/es/es/catalog/products/80186688/.
I've had them before as they're ridiculously cheap and quite useful if your feet are wet or dirty (coming back from the porch, for example) and the casts like to scratch them as they're quite rough on the surface and don't easily move around.
Good luck if you have curtains, though.
One funny aspect of bengal proofing my place is that I managed to successfully hide a lot of small items I now can't find myself
.