Your $40 used amplifier probably won't support Dolby Atmos and other movie formats so it's not really functionally equivalent to modern models.
The speakers in question are real used Pioneers that are a lot more than 3 way, not a scam at all.
I have seen numerous receivers go by at the reuse center, I shoulda bought a Yamaha I saw that was a little ugly but quality. My son has a NTSC-based retro gaming rig with a CRT, I wanted to find him a matching (pre HDMI) home theatre but he was in a hurry so I found him a nice NAD 2 channel receiver from the 1980s.
Now I really do crave a modern home theatre with an insane number of channels, say 11.1 and I don’t expect to find that at reuse, but I have so many other things that support my art projects to get like a PCVR headset, a monitor as close to Rec 2020 as I can afford, a light field camera, etc.
Can’t say I am too excited about Atmos, the “bounce off the ceiling” trick won’t work in my main A/V room, object-based surround doesn’t make a lot of sense for music because it is not about the “flying horns” but about feeding ambience into the other channels, that really does “put you into the world’s greatest concert halls” and I have many 5.1 DTS music CDs of everything from Kraftwerk to Super Furry Animals to Yes and traditional Chinese music to prove it. Similarly most movies still have great DTS sound tracks.
I hear a bit too often about burned out HDMI boards on Denon receivers. Hope my X3000 will last a few more years.
My take is that the more expensive your hardware is the faster HDMI ports burn out. I've had some cheap TVs gifted to me (one reason I haven't upgraded) that had 2 HDMI ports and never had trouble w/ the ports (1) had excellent value engineering and built in speakers better than many soundbars and eventually had the backlight, (2) is a Samsung that just sucks.
I think a high end Sony TV has 8 HDMI ports though you can have 7 ports burn out and still watch TV. My guess is that ports can have various levels of isolation to noxious electrical influences, USB ports are notoriously strong but I think many HDMI ports are under-engineered.
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The other trouble w/ Atmos is it makes no sense at all with smart speakers, headphones, etc. I have screwed around with HRTF tech and for me it works poorly. My Hololens 1 can localize sounds in the space around me very clearly but the fact that it creates matching visual cues must help. I've tried headphone surround in gaming and find it is an absolute joke: I can learn that "the sound must be above me because it sounds like I have a head cold" but it is not realistic at in most cases.
I just can't believe an Atmos mix rendered to headphones is going to approach the quality of a good stereo mix.
