That is a loaded question and on this sight largly based on a false assumption! People on this sight and on most hi-fi and audiophile sights assume that the synthetic and artifical stereo effect is the goal but their is nothing hi-fi or audiophile about it if you actualy like the way music sounds when being produced natural in real life in a smaller venue like a small church or small jazz club not talking about the horroific sound you get at a mega venue or stadium who could like that?!?!?!
So by default hifi and audiphiles actualy hate the world and hate music but they like the artifical and synthetic sound created by mostly box speakers the last 60 years or so with modern stereo recording and studio mastering. The idea of a a 3D sound stage that is almost halographic is not at all like real life and real live musical performance!
So hifi which stands for high fiedelity and the sterophonic revolution is the thing most people think is the goal or the standard but no one every defines that clearly and most act as if that is how sound has always been or is the way it should be percieved.
Prior to stereo when things where mono we still had hifi but boy did it take off once stereo was mastered and the large studios figured it out!
Origanaly the goal of hifi was to make the most realistic sounding musical reproduction at home so you could put on a record of the Bostons Pop's and have it sound in your living room the way it sounded int he concert hall! This is also why I laugh at people that love to hate on early Bose loud speakers since that was the goal of direct reflected sound as well and what the Bose 501 and 601 did masterfuly. The real problem is that most people with no idea of the history of sound and music recording and reproduction have no clue. Stereophic came along and has so overwhelmed the population that anything else is either not even remembered or seems like a relic of the past like black and white TV and TV tubes and crt tubes and vaccum tubes.
Do not get me wrong I love basking in stereophonic sound and all it's glory but I also like monural sound and direct reflecting sound and quality live performances in small venues. I do not think one is better than the other's but they are all different. Most hifi and audiophile types would love it if they could stamp out direct reflected sound and control every single vibrating molecule because to them the thing that sounds the best is actual the most artificala nd synthetic sound imaginable but they will not admit it. Not sure if they do not understand how sound actual works and how music is actual made in real life or if it is some form of cognitive disonance because what they like and think sounds good is not in line with actual reality so they choose on some level to ignore it and not to confront that while it sounds good it is not how real music sounds!
So asking what is "hifi" depends on the generation of the person you ask and how perceptive they are with regards to reality and their own selfperception. Then you have what was the expectation of hifi when they grew up and how it has changed with time and technology!
I like the perception of sound so much I do not want to nail it down too much. That is why I have variety of different speakers not like minded speakers ones based on Direct Reflexting sound and some that are based on the pure pursuit of sterophonic sound at it's best. I am working on building some open baffle speakers again because I do not own anything like that and I am all about experincing music and audio books and movies in as many ways as I can. I did the surround sound thing inthe 1990's and early 2000's and got that out of my system. I want to try synergy sound speakers as well.
Most people today do not want realistic sound and that is fine. They want something that is more real than real and richer and cleaner than real sound can actual be. I do not mind that either I just think people should know what they are actual after and understand that it is not real. We should always understand ourselves, our world, our desires and how we interact with technology. Nothing I have said has been meant to be judgmental either. You can not find what you do not know your looking for! Well sometimes you accidently fall into it but only when you know your self and you understand your perceptions and paridigms(sp) can you fast track to what you trully want if not you end up on this constant safari searching for the perfect speaker, the perfect DAC, the perfect amplifier on an endless journey whent he real problem is you do not even know what sound you are looking for! 10 DACs latter 5 amplifiers latter and 6 sets of speakers latter you either still have not found what your looking for or you old enough than anything you purchase will outlive you!
There is no mid-fi and hi-fi boundry since almost no one can define it with a gold standard we can all agree upon as a starting point. You know why we can not agree on a starting point that is the standard? No one that sells gear wants a gold standard except maybe those on the mass consumer side and even though do not truly want it. Those selling and purchasing hi-end gear dread anything empirical as do those that review or act as marketing devices. Once you nailed down a standard by which all other's could be judged the lower priced mass consumer side would rush to meet or exceed it. Those ont he hi-end side would be revield for the hype train that is 2/3's of their selling power and anytype of prestige associated with performance might melt away leaving just price point for prestige would would kind of reveal what some of us already know about electronics, sound and human perception of sound. The people that own such gear also seldom want to admit they where had or that they have buyers remorse some will but many will not. So no one wants a meaningful standard they want something the opposite of intelligent and empirical like a price point that can be used to dictate what level of gear it is! Now if we have a gold standard and use empirical standards tested with labtratory test gear and coralate those results with the subjective nature of people and prefeences under a controlled set of conditions like a "standard" room than I would be happy to have things brocken down into simpleton catagories where each item and item combination get's put into a "Little Boxes Poem" Ticky Tacky Box. Learned this poem in 8th Grade Poetry Class 1987-1988.
- Little boxes on the hill side, little boxes made of ticky-tacky.
Little boxes, little boxes, little boxes all the same.
There’s a green one and a pink one and a blue one and a yellow one,
And they’re all made out of ticky-tacky, and they all look just the same.
And the people in the houses all go to the university
Where they all get put in boxes, little boxes, all the same.
And there’s doctors and there’s lawyers, and there’s business executives
And they’re all made out of ticky-tacky and they all look just the same.
And they all play on the golf course and drink their martini dry
And they all have pretty children and the children go to school
And the children go to summer camp and then to the university
Where they all get put in boxes and they all come out the same.
And the boys go into business and marry and raise a family
And they all get put in boxes, little boxes all the same.
There’s a green one and a pink one and a blue one and a yellow one
And they’re all made out of ticky-tacky and they all look just the same.-Malvina Reynolds