hifi literally just stands for high fidelity which would be defined as a system that can reproduce sound in a way that is as close as possible to the original work. now alot of factors play into this including alot of things that are very expensive to fix which is generally why the amount some one has spent on their equipment is usually SOME indicator of how well it will sound. generally i define a system as hifi if it meets these requirements a flat in room response from 25hz to 18khz a noise floor of at least 85 db a total signal chain snr of 85 db other things such as impulse response in the room and distortion from the speakers are less important but can make the system sound cleaner my current system is about 2700$ and i would consider it hifi and even though i consider it to be way more than hifi i still think it could be improved. but the hardest things in audio to fix (bass, amplifier power, room acoustics) are incredibly expensive to achieve reference levels of especially accurate bass like damn dude i feel any less than twin svs sb 1000 subs isn’t even close to reference level bass then you need dirac or rew and bam youve already spent close 1500$ after tax.
dunno what to say about the pressure as there is no way that some plastic pc speakers have enough low bass to pressurize the air to do that. as far as the beaming thats just shitty directivity and id say that for the first time ever you lowered your head enough that the speakers were on axis with your ears causing them to not sound like shit in the high frequencies. hope this helps if you want to know more look up speaker directivity and radiation.