Those artists saying it can like the pianist in the video, either hear the difference but don't want to say, or don't hear it which is well, just as bad.
Very interestingly, I found an interview explaining more about the session. Limitation is the machine translation, but it makes more sense.
Basically the actual recording engineer emphasizes that he recorded using carefully placed B&K 4009 mics with no modification whatsoever of the digital recording such as a low pass, etc. He does mention that PCM and DSD is least important element of the recording but mic placement and room selection.
From what GPT says, the B&K 4009 is a precision stereo matched version of the B&K 4003, which is a premium version of the B&K 4006 that Stereophile uses to measure speakers. The 4003 uses 130V instead of 48V and as a result handles and extra 10 dB of SPL without clipping and is more accurate in the lower frequencies as well
国産フルコンサートピアノのマスターピースとして高い評価を得ている河合楽器製作所の“シゲルカワイ”。そのフラッグシップに位置づけられるモデルが“SK-EX”です。その音の魅力をアーティストが奏でる空気感・タッチ感まで余すところなく捉えた音源を作り、さらにはアーティストの感情まで余すところなく再現できる機器を開発し、お客様にハード/ソフトの両面で最高の音をお届けしたい−−−その思いからハードの開発と共にハイレゾ音源の録音プロジェクトがスタートしました。カワイとオンキヨーのコラボレーションから生まれた、至高のピアノ・サウンドをぜひお楽しみください。<br><br><Div...
www-e--onkyo-com.translate.goog
——
■Recording without any unnecessary signal processing
-- How was the recording done?
Ono: It is said that there are more than 200 ways to record piano. I have roughly eight different theories depending on the genre and the client. This time, I recorded Chopin in a classical, but not concert hall, salon-sized listening room, and the sound source was "high-resolution 2ch only, no processing", not intended for broadcast or CD release. In most cases, multi-microphone recording is done, and the balance is adjusted later, and the applause from the audience is mixed in to create a "good" final result. Even if the subtle nuances of the actual recording are different from "as is", the purpose of post-production is to create a "good" final result. If you are not going to process it "as is" like this time, there is no hesitation, just two B&K microphones. This was also the method used when we conducted an experiment in distributing DSD live streaming of the Chopin Competition from Warsaw in 2015. I don't think there should be any directing in the recording or tone at the competition. The touch and tone must not change from the actual image.
Similarly, for this recording, I decided on the microphone position and did not apply low cut or any signal processing. Since the concept was "as is," I used a pair of microphones, the B&K 4009, which is also the standard for measurement. The famous 4006 is a 48-volt phantom specification, but the 4008 is 130 volts, and the matching pair is the 4009. It is a microphone that picks up the sound as it is heard on the spot. In fact, I brought another pair to the site to compare them. The latter spreads a sense of air a little farther. If it were an entertainment recording, I would have recommended the former, but I chose the B&K for the "as is" sound. Of course, I did not mix in off-mics later, and the stereo format was also decided, so I set up the microphones in a position where the direct sound of the piano and the reflection and reverberation of the room were just right, checked it with my own ears, and then had Murakami check the test recording immediately. For me, the microphone position was OK when Murakami said, "The sound is pretty close." If there is anything that bothers you, we will work together to adjust the reverberation of the room itself and the piano. Tuners are very important in piano recording. This time, the sound of the SK-EX was already completed when we arrived at the site. It's Murakami's home ground. The other important factor is how well pianist Ayano Maruya concentrates on playing. Rather than trial and error, you need to psychologically bring out the best performance from the performer to make a good recording. If you organize and rank the priorities for capturing the best sound quality, they are ① the pianist's performance, ② the piano itself, ③ the space, ④ the microphone position, ⑤ the microphone, ⑥ the microphone amplifier, ⑦ the recorder, ⑧ the cable, etc., and ⑨ the specifications and media format.
In high-resolution articles, 11.2MHz DSD is often said to be the highest specification, but what is more important than the specifications is the instrument, the space, and the microphone position. That is why a professional balance engineer is essential for important recordings that will be listened to by many people. It's the same logic as not everyone can take photos like a professional photographer just because they have an expensive camera. How can you bring out the best smile in a photo?
—-
GOING back to your recording question…
Knowing that this B&K 4009 is special for piano recording, a Google search took me to this article
And toward the bottom, you have one recording engineer who gives very clear opinions
1) Mic 4-8 ft away from piano
2) Place about midway of the longest string from audience perspective and point the omnidirectional mics in the direction of the hammers, keeping them parallel
3) 18 inches to 5 ft apart. Width of the mic space captures desired width of the image of the final recording
4) Hard pan the left and right.