Just had a look at a local music shop and noticed a $300 price difference between the Orange PPC212 and the exact same model but with the back being exposed (open back).

What is the difference in tone and does it justify a $300 difference?

Gibson Les Paul Traditional Satin
Fender 72' Thinline Telecaster
Fender Am Telecaster
Bad Cat HotCat 30R

Korg Pitchblack
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TC Flashback X4
Strymon Timeline
JHS Double Barrel
the closed back will give you more bass and a more 'in your face tone' because all the air is pumped out of the front. The open back will give you less bass.
Don't really know why it should be 300usd more expensive.
Quote by Martindecorum
go the open back, and make ytour own backing piece

well, to do it right is not simple as that, but it def beats an extra $300.
Yeah making your own back piece could actually be a bad idea.
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Korg DTR-1000
more bass (as previously stated) with the back.

if you mic it up an open back should have mics in front and in the back