>> But the audio quality is a noticeable upgrade from my iPhone 8 Is this still true with latest iPhone? I would expect that iPhone hardware is not a limiting factor for audio quality (assuming a wired adaptor for HiFi headphones)
> I’m not an audiophile, and I’m sure said people would blanch if they read about the files I play. But the audio quality is a noticeable upgrade from my iPhone 8. It sounds so much clearer, especially in the midrange. Its EQ settings also add extra sparkle and pop, for want of better words! It’s the biggest uplift in sound I’ve experienced since I bought AKG monitors for home.
According to gsmarena measurements, the output of the iPhone 8 is extremely accurate across the entire spectrum[1]. Sampling a few gsmarena reviews, this is also true for a typical modern Samsung or Xiaomi phone, or even an ancient iPhone 4s.
I believe accurate audio quality is indeed a solved problem, and what the author's describe as an upgrade in quality is just more pleasantly tuned (though distorted) EQ settings (c.f. the "warm" sound of vinyl vs accurate redbook CD-audio).
[1] https://www.gsmarena.com/apple_iphone_8-review-1664p7.php#