Hi James, good sound is matter of personal taste. You may voice a speaker so it sounds perfect to your ears, in your room, but suggesting that people don't fine tune it for their own room and preferences above 150Hz, well...
A few years ago I bought the very highly regarded KEF LS50. According to almost everyone in the industry, these things are supposed to be great. Well I hooked them up to a B60 expecting audio bliss, only to be met with serious disappointment. I found the top end dull, and the mids too forward. Those speakers are still in use today, and are still driven by a B60, but only because I use an equalizer in the tape loop to shape the sound to my liking.
I took measurements with and without EQ in my room. Below chart is using the "moving mic" technique, green trace is with EQ and 10db offset. I do not enjoy listening to this system with out the eq.
You don't need to build DSP functionality into your products, but rather just allow for the integration into your products. Long live the tape loop.