hispls
5,000+ posts
CarAudio.com Veteran
This is what I've been thinking - using a Class D for the sub and a Class AB for everything else. This seems to be the trend for manufacturers, such as Hifonics and Oz Audio, where their mono blocks are Class D and their mids and highs are driven by Class AB.
Several years ago I had a Rockford Fosgate P3001, think it was Class D, that seemed to control a pair of Series 1 12's quite well. I see the advantage as increased efficiency, leading to less heat and current draw, where any sound quality of the Class D would be hidden by the natural flaws with a sub and the fact that they wouldn't be audible in sub 80 Hz ranges. I'm not saying I could hear a difference in the two technologies with mids and highs but it would be nearly impossible to hear a difference in a sub that's in the trunk of a car.
-Eric
The issue with full range class D in it's early stages was the switching frequency on the power supply was rather low so they had some issues in high (tweeter) frequencies. Semiconductors have come a LONG WAY (just think of what a computer was back in those days) and any modern full range class D operates at such a high frequency that any artifacts from the switching frequency would wind up well beyond even what a bat could hear.
The reason the junk drawer companies are still using A/B for full range is that technology is older and cheaper. The better full range class D these days is mostly done by brands that do their own R&D, not those that call up the sweatshop in China and ask them to put a brand name on a generic board. AFAIK JL makes full range class D, Arc, Zed, Alpine, PPI (their SX series is Zed design), Focal (also Zed design with some really unique features) and JBL/Infinity definitely do, and I'm sure there's some others. There's a few brands I wouldn't really mess with that have full range class D as well about which haven't heard any negative, you're on your own doing your homework on those, but I've heard enough of the better brand ones to be convinced that they perform just fine.
In short, just about any full range class D you buy these days will sound indistinguishable from A/B. The only reason to use A/B is if space and efficiency isn't an issue, you want to save a few bucks, or you have your eye on some cool old-school piece that you want to run for the sake of nostalgia. I switched over 5-6 years ago from some very nice A/B amps and haven't looked back.