He is correct. There is an issue with timing of a 20kHz signal using 44.1kHz sample rate. The ADC will cause a 90-degree phase shift. There will be another phase shift caused by the anti-aliasing filter. Is this important in audio? Probability not for 20kHz, but given the logarithmic nature of the frequency response any phase-shift at 2kHz may have an effect on the audio quality.
As was pointed out, phase-shift of a single channel (rather than between two or more stereo channels) is inaudible to the human ear and therefore irrelevant, especially in a frequency band that contains little musical information to begin with (the 10kHz-20kHz octave) and in which most people over 40 can only hear the first few notes, if at all anyway.
The LP format is much beloved by many (for some odd reason; I invested in a high-end rig to find out if there was anything to these claims and more importantly to transfer albums that STILL don't exist on CD or digital in general) and while its response does go beyond 20kHz, it begins to roll off by 12kHz and contains mostly unusable surface NOISE above 20kHz (yet people go to great lengths to "preserve" that surface noise of a needle dragging through vinyl plastic. Personally, I use iZotope RX to REMOVE most of the surface noise and all the clicks and pops, leaving a recording that is quieter than the original on CD in many cases and without hurting the sound; now THAT is advanced use of DSP, not some snake oil in a bottle).
There is no "magic" to the LP. It's an irrationality based on poorly mastered CDs (yes sometimes the LP
does sound better, but that "better" can be recorded and put back on a CD and sound identical to the LP so it's clearly the mastering/mix and not the format itself) an the love of being "involved" in the playback process (yes, it's great fun aligning and setting up an LP player, especially for someone like me that does mechanical alignments of industrial automation equipment as part of my real world job). The problem is despite the admitted "fun factor" of the LP for mechanically/electrically inclined folks like myself, ultimately, once everything is on an even playing field, the CD wins EVERY SINGLE TIME HANDS DOWN. The rest is pure nonsense and some fairytale beliefs by willingly ignorant (in my book that means STUPID) people.
Still, given mastering problems galore in the industry, it's not hard to find superior sounding vinyl for many albums (you can only compress an LP so much, so the worst sounding CDs tend to sound at least a "little" better on LP. Sometimes it's night and day as the mastering engineer "sneaks" one past the record label who doesn't pay attention to the LP format anymore. Sadly, most engineers KNOW BETTER but are
forced to put out CRAP because their bosses DEMAND it (it must be LOUD!) and this comes from psychoacoustical studies that show that "louder = better" to most people that only listen casually, particularly on the radio. Look at the audio reviews of Pink Floyd's
A Momentary Lapse of Reason. Most think it sounds "awful" (sound quality wise, not content which is a different issue) compared to earlier analog only albums like Dark Side of the Moon and Wish You Were Here. It's a fully (save the drums) digitally recorded and mastered album. In fact, it has much more dynamic range than ANY Pink Floyd album ever made (including the one after it which is compressed to sound louder). All you have to do to "fix" it is turn the volume up in a quiet environment and it's excellent sounding (the LP version is more compressed but has less detail; I've A/B compared them volume matched). Actually, the CD also isn't "normalized" either (i.e. rip it, put it in something like Audacity and normalize the levels so that the loudest sound is near the maximum and you'll find it a lot louder without having to compress a thing; I'd call that a production mistake).
But as soon as people hear a quieter sounding average volume compared to the song before it on the radio or whatever, their immediate impression isn't just "I need to turn up the volume" but rather "that song's sound sucks compared to the louder one" and that's an issue with human psychoacoustics where louder = better at a "glance" and more detail is revealed as you turn up the volume that is below the room's ambient noise masking level so one is given the impression that yes louder = more detailed (as in compression reveals ALL the details; the problem is they're all at the same relative volume level now and that sounds bizarre and yet that is what studios WANT).
Going to an "HD" format that offers MORE dynamic range makes no sense when it's 100% counter to the studios desire to GET RID OF DYNAMIC RANGE.
The only argument for 44.1kHz sample rate is file size. This was important in the 1980s; it is not now.
The fact remains that the "problems" of 44.1kHz audio were solved a long time ago with oversampling an similar technologies (Sony 1-bit, waveshaping, etc.). There is no need to reinvent the wheel. Getting studios to remaster their albums for actual high sound quality would do 1000x more good at this point for getting truly better sounding music out there.
I'd be FAR more concerned at this stage that new media players like FireTV and AppleTV 2-4 do NOT output 44.1kHz PERIOD. They all upsample to 48kHz! That kills things like DTS Music CDs (that are encoded at 44.1kHz and the signal is destroyed if it's not maintained lossless and output at exactly 44.1kHz or you get a pitch increase ala FireTV running KODI). Is it really too much to ask that Google and Apple offer us an output rate that matches 99.999% of the digital music catalog out there? No, they just assume we won't notice the up-sampling and do it anyway to save a few pennies. (The original Apple TV DID output 44.1kHz when asked to and was bit-perfect as DTS music CDs even encoded as Apple Lossless would play without it even knowing it). And yet people claimed that Apple Lossless wasn't "really" lossless and yet the DTS test proved it as if even a single random bit were lost it would have scrambled the encoded signal.
Also DSP is not perfect. There are 2 unnecessary places where DSP occurs in the record playback process. It would be better just to have the 192kHz sample at all stages of the process.
Better for whom? People that don't want to use oversampling? The same effects are still occurring, just out of your hearing range. You're asking people to buy new equipment, new music catalogs and waste more banwidth just to satisfy your need to say it wasn't oversampled and the audible content is 100% identical to the human ear. That sounds like a waste of time, resources and money to me.