Well what deck do you have, maybe someone else has the same one and happens to know when it clips. I would always assume yours will clip just earlier since you don't know for sure. I've used a few kenwood decks and none of them have ever clipped, but I don't know model numbers so that isn't helpful. My o-scope shows what I consider clipping just barely before the clip indicator on my Arc Audio amp. But I would say if you find clipping then just back it off a bit, slightly more than a hair (you like the exactness there?). If you don't have a way to find clipping of the signal from your deck then you need to invest a little bit more and get a DD-1. They say you can use the 3/4 rule but depending on the deck (boss in particular is the one place I have seen it) it might clip prior to 3/4 volume. Everything is just better with a DD-1. I say DD-1 because it is cheaper than an oscilloscope and it comes with a CD that has the tracks you need to do all this. Its worth the investment if you are planning on doing much with systems, and if you have a sundown amp you obviously are looking for loud and great sound so it would benefit you for your next system as well. We all know you will upgrade or get a new ride and need another, whatever the case may be get the DD-1 and you will be good.