Garage into listening room?

So I'm thinking of trying to put a stereo into my garage and use it as my main listening room.  It's apx 20x25 with about an18 foot ceiling.  It's not finished.  

If I set up in an equilateral triangle, say 8 to 10 feet, in the middle of the garage, would that eliminate the need for acoustic treatment?  And if I need treatment, I was thinking of putting a carport frame into the garage and using it to support acoustic treatment.

I wish I had thought of trying this out during the weekend versus on my drive into work this morning.  

Would this work?

Thanks.