Today I initially intended to just make a Bluetooth speaker from an old surround speaker I had laying around. I wanted a speaker to take to the beach that sounded better than the little inexpensive guys you get. And I didn't want to buy something expensive that I was constantly worried about down there. Anyway, it dawned on me this morning heading down to the beach, instead of hauling both my guitar and speaker down there, why not just throw the speakers in my guitar? lol
Step 1: First Step - not your main guitar!
Get out your old guitar or get a cheapie out of the paper, you probably don't want to use your Martin:-).
Step 2: Pick some speakers
Find yourself some speakers. I had some old 4" speakers that seem to sound good. As long as they fit and match the ohms in the unit shouldn't be a problem.
Step 3: Amp
I bought this little guy off eBay for thirteen dollars. I am more than impressed with it. It is not only Bluetooth, but plays SD cards and USB flash drives, AND charges your power source through the mini USB in the front! Which allows everything to be tucked away all neatly inside.
Step 4: Power supply
You can get these little units anywhere. I am sure you have seen them. I actually grabbed mine from my old deadbolt keypad lock I had replaced. But an electronics store should carry these for a couple bucks.
Step 5: Cut holes and place unit and speakers
Here I just positioned the speakers where they fit and sound best and the unit where it would be out of the way (because I still plan on playing this guitar). Also, because the guitar is meant for sound it is perfect for this sort of thing, so placement of the speakers will make somewhat of a difference.
Step 6: Wire it up
Pretty simple here, just left speaker to the left speaker port on the unit. Right speaker to the right port on the unit and the power supply to the power port. And then re-string your guitar and your good to go! I just need to find the speaker covers now.lol.