If you are looking for loud clean sound to the rider. The 3-Some is the set up. With the SYN-6 powering it.
The Double Up system is loud and clean for the rider as well but the 3-Some will provide more output.
Most that go with the Double Up are wanting a system that can provide a ton of punch in and around the boat. For surfing and party coves. Still loud at 80 feet but not as loud as the 3-Some set up.