Is your amp really the problem?
This could be a touchy subject to some, but I feel it really should be addressed at some point. So why not now?
When you buy a product you would think that the same amount of thought and care would go into every aspect. Often, this is not the case. You'll see this big hyped up whatevermajig with all it's crisp monochrome and smooth lines, only to start using it and it does at least 1 of 3 things: works as actually hyped up and lasts, or it works, but not as good as you were lead to believe, or the thing ends up as a broken junk pile in short order. It's these last 2 that are the main focus today. And to do so, I want to relate a little find from about 3 years ago.
I had been in the local Dollar Tree (Everything's a Dollar) and I saw this box in the electronics aisle with a powered "ball" shaped speaker. I thought "Yeah, right. Either it doesn't work or it works so poorly that it isn't even worth the cardboard in which it's packaged. So I put it back. A couple months later, JohnAudioTech did a review of those Dollar Tree/Store speakers. As expected they sounded worse than a cheap knockoff transistor radio. BUT, he took it apart, tossed the tiny 10¢ speaker, hooked the board up to a real speaker and gave it a test. Wow, just Wow. It may only be 3W, but boy was it a surprise.
This is the board:
Runs great on USB power, and I have a pair wired up for use on the bench. If you want the chip #, watch the video in the link above.
Back to the point of the story - this thing, outwardly, looked really cheap. Most of it was, but the board is a really good value. So much so that I bought enough to try an experiment - 8 individually amped drivers in a small line array. It's on my list to do, but I bought all the electronics at Dollar Tree: USB wall warts, USB cables, Audio cables, and of course the speakers (see first picture.) If it all works out right, it'll be a low cost audio journey.
In this case it was definitely the crappy enclosure and driver that were the really bad parts, not the amp. So before you go blaming one thing over the other, dig in and investigate. You might just be surprised at what you thought you knew, but really didn't.
There are obviously limits to what this amp can do, but within the parameters it does seem you get more of an impact based on input/output quality than the amps themselves. I've shared my cheap chip amp experiences as well. They may not get as loud as something higher powered, but they can be impressive from a value standpoint. I'd be interested to hear how your project turns out.
Disclaimer: I've been in the forum long enough to know a couple things, but have yet to actually do a speaker build myself =)