The "true" definition as "sound quality" would best be described as: an accurate reproduction of the source material in every respect. If one's goal were "true" sound quality, then their goal for their system would be to reproduce all aspects of the source material as accurately as possible. What most people actually mean when they say "sound quality" is not accurate reproduction of the source material but rather their subjective personal preference for what constitutes good sound. They want a system that sounds good to them, even if it isn't completely accurate to the original source (the easiest example would be those who enjoy exaggerated subbass). That doesn't make their goal wrong.....certainly the goal of any system should be, first and foremost, to achieve maximum enjoyment for the primary listener. But they do use the wrong word to describe what it is they are looking to achieve with their system. They are mistating their goals. Sound quality, and what someone perceives as good sound based on their personal subjective preference, are not synonymous and interchangeable ideas....but unfortunately that's how they're used. Not necessarily. There are certainly valid reasons to use a ported enclosure in a system designed primarily for accurate reproduction of the source material.....another large misconception is that ported enclosures are only for those who don't care about "sound quality". But it would depend on your reasons for wanting to use a ported enclosure. Although, rather an go into more details about why, I think you'd be better off to not to assign a label to your system and just go for what you like regardless of what term might be used to describe that. Too many factors at play to say one way or the other. It will more than likely sound different, subjectively whether it's a good or bad difference is going to depend on the listener and the overall goals for the system.