On rare occasion, the sounds of silence aren't loud enough to drown out the neighbors

And the sight of those neighbors might not be something to swoon over either.

This is why humanity invented entertainment systems. And curtains.

I had already installed a monitor and Blu-ray player, but it was a real hassle to also include music sources, or to easily switch between the various sources.
Worse, the only speakers were in the monitor, and they sound awful. But still, better than the neighbors.

So I entertained myself by making an entertainment system, so we could be entertained when we couldn't hear the sounds of silence.
I hope you are as easily entertained by my rambling as I am.

The Blu-ray and monitor are both designed to run on 110V, through the MS2012's inverter or shore power transfer switch. I don't want to run the inverter when we don't actually have a 110V device, because it's parasitic current draw is relatively high.
But we would want to play music at any time, probably for hours on end.

So I needed to find an amplifier that could switch between the video HDMI source, and some source of MP3, or on-line music source when in range of cell towers. This amplifier also needed to be controllable by remote (signal source, volume, etc.), powered by Annie's house 12V system, and have a low power sleep mode...so it could be wakened via the remote.
It also needed to be cheap.

I could not find a car entertainment system that could do all that...especially support Blu-ray.

We suffered in abject misery for months.😭

But finally, my google-fu kicked in and I found a likely suspect prospect.
It is a Pyle PFA 540BT. Cost under $90. Supports HDMI in and out, 5.1 surround, and Bluetooth. With IR remote. (Plus FM and aux inputs, which we won't use.)
It is nominally a 110V unit, but it's actually powered with 12VDC as supplied by a wall wart.

The question is if it could handle the expected range of battery voltage we'd see in Annie without letting out its magic smoke.

I figured it was cheap enough to risk a bench smoke test. Brought it into my lab and checked it out.

You may notice that I follow the philosophy of Einstein's apocryphal quote: “If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?”

It works fine, all the way up to 15.5V, at which point it exceeds the max voltage rating of our fridge, and besides, I chickened out. 

Sleep current is about 12 mA, which should be fine for our 400AH batteries (Although if Annie never got those batteries recharged, they'd be down to 50% in about 70 days. Think we can live with that.) 

The Bluetooth easily connected to an older unused phone, which I'll use as an MP3 & WiFi player. I'm using 2 leftover Logitech speakers (shown)...from a fairly decent 5.1 computer sound setup, that we're only using as 2.1.

So, now we've got music, we've got amplification, we've got good speakers for a small space. I also verified that it played nice with our HDMI setup. We're ready to install.

It's going in the space between our nifty new driver side overhead, and our closet.
Here, I'm mounting one of the speakers.

Building the shelf for the amp

And mounting it in Annie

Wired everything up, and made sure it all worked.

Built a back panel with a 12V and a dual USB set of sockets.

The USB socket is where the MP3 phone will always be plugged in.

Neatened everything up, and done...almost.

Last step was to program a universal remote that had codes for the 3 electronics.