The 651 is a marine approved speaker the 650 is not I think, but I could be wrong. I'm sure someone will let me know. I put 4 of the db651s in my boat yesterday they sound and look great. so much better than the factory one. Cheers.
Both are marine approved. I believe the 651 is just the newer model. Both have the same specs as far as I'm aware. I think the 651 comes with an adapter ring for 6 3/4 cutouts.
anyone have these rings and not using them? I could use 2 pair of them. How thick are they? If they are the spacers that are like 1 cm think, then that is too thick, I am looking for something flat like a plate. Thanks