This was a well considered request for information, Luiz. I'll give you my 2 cents worth, although you can see from my signature what my bias may be.
I too live in a rural area, so not much auditioning went on before my choice of speakers. I joined this fine forum
after I purchased my JBL's...but am still undecided as to whether I bought prematurely. I have subsequently been to a Megalopolis (Portland, Oregon), visited high-end a/v stores and discovered new-found appreciation for my system. There is much wisdom you will find here regarding speakers, but as you say, it's all in what sounds good...in this case, to gramps.
My father too had hearing difficulties. Old age primarily robs the upper end of the frequencies from us. So the Klipsch are likely to not affect him. That said, I'd recommend the JBL's because they are relatively, uh,
passionless (for lack of a better word) as speakers go. Not to bright, not too dull. They're pretty clear across the audio spectrum. And they are most definitely efficient. Concerning the Northridge line, you may hear some negatives here. I think they are a fine speaker for what they are and how much they cost. But they are definitely built for the Best Buy market. As such, they are not the very best to have come out of JBL.
If you can, I suggest you watch JBL's eBay merchandiser, HarmanAudio. You can sometimes find an older or better line being sold by them...such as the Studio Series. Prices are remarkably affordable.
As for a subwoofer....my strong suggestion is to stay clear of both manufacturers. They are not known for their premier subs. My experience with a JBL S120PII was very poor. Go with an Hsu or SVS. Or for cheaper, many here approve of the Cadence XSub.
Happy hunting. Get it right for your wife's grandfather. After all, you may be in the will.
