[salvasol]

... I have a perfectly quiet house it won't make a difference, right?

... the addition will reduce outgoing noise from the HT as well, but if I'm the only one home it doesn't matter, right?

You reasoning is correct, if you don't feel the need of using GG, clips, DD, etc. don't do it. If you're always home alone and the noise won't bother anybody else, save your $$$.

...the articles I read about soundproofing is to eliminate the transmission of it and nothing is mentioned of improving sound quality within the room ...

I think this is correct, soundproofing will tell you how to eliminate the sound transmission, to help you improve the sound I think you need to read more about "Room treatment with accoustic treatments" :huh:

I'm sure that you can use part of the $$$ you'll save to treat your room.... start with some panels and see if that helps.

 

[salvasol]

Please don't forget to account for ventilation isolation ....

+1 ....and also, be sure you have enough air circulating in the room; or it will be either to hot or to cold (that was my previous experience) :whistling: