This was so good to read. I've been reading through so many ff for Shiro lately and this one just really struck me. I was debating on doing a music piece myself but you really brought it home with this. This really emphasizes the true human quality that we start to miss out on while they are up in space. This story made Shiro and these characters feel all the more real and human for me.

Good job! Nice ending too :)

I LOVE this! The concept, your depictions of Shiro's relationships with Keith and Pidge, and the way you describe the music and emotions are all wonderful! I do have some constructive criticism, but overall I really enjoyed this. Once again, I can't believe it all came out of a group of random words, and that you made it all seem organic and realistic!

The first scene doesn't seem entirely necessary. It could be merged with the second, since only a few moments pass between them, whereas the other line breaks indicate the passage of multiple days.

I don't think "Patience yields focus" makes much sense the first time Shiro says it, when thinking about Slav, because it's more often used in situations when someone is getting frustrated with their failures which impairs their ability to focus enough to succeed. But I like how it's hinted that Shiro learned that adage from his grandmother in the context of piano.

You might want to point out (or have the characters point out) that Shiro seems to be responding negatively to almost opposite occurrences involving the piano: he gets upset when they play it too much or at odd hours, but then also gets mad at Slav and Allura for not respecting it. I feel like someone should notice how odd that contrast is, and wonder whether he likes it or hates it.

Lance is totally the kind of person who would brag about his skills and act like he's the best at a skill when in the company of people who don't have it or know much about it. But he doesn't seem very surprised or humbled when he hears how good Shiro is. That seemed odd to me. I like him fist-bumping Keith, but it seems strange because the two of them didn't do much (anything?) to bring this about, so they can't be congratulating each other. I think either Lance should be part of the conversation with Keith's revelation, or he should be more surprised when Shiro reveals his repertoire.

Miscellaneous mechanical details:
~ The first sentence is a bit of a run-on; it could easily be split into two.
~ I don't think "failed" is the right word, because that makes it sound like Keith actually tried.
~ "You have to agree" sounds like it would be better placed before Keith gives in. Pidge's "If I'd known" sounds like it would make more sense after learning the reason for Shiro being out of sorts.
~ Keith says "It never occurred to me," but he was wary about Shiro's reaction from the start.
~ Pidge's line about Shiro saving Matt and Matt being alive seems unnecessary. It doesn't really have much to do with their conversation. I know it's part of the foundation of Pidge's relationship with Shiro, but she doesn't need to mention it to them, and the audience already knows about it.
~ I think "or" was supposed to be "of" in "flurry or determination".
~ How was Shiro set up? It is not stated why he went to that room at that time. Did someone ask or tell him to do so?
~ "had got" should be "had gotten" or "had become"
~ I'm not sure "realized it to be" is a grammatically correct phrase; I've never heard it used before.
~ "handwriting" is one word.
~ You spell Pidge "Pitch" before the note.
~ I'm not sure if "obtained" makes sense when describing the friction and grip. Maybe you could just say "of" instead of "that was normally obtained by"
~ "was sat"
~ I don't understand the sentence "Shiro didn't understand ... when faced with utter failure."
~ "The harshness of reality" sounds cliche.
~ I'm not sure what you mean by "tentative like he did"
~ "Allura felt about ready to cry" seems out of place at the end of a paragraph all about Shiro and his music. It would make sense to say that when describing the others' reactions, or leave it out.
~ You might want to avoid contractions for "he'd thought he'd", because those are contractions of different words, "he had" and "he would"

Finally, I'm wondering why this isn't labeled with characters or with "Complete." Are you going to continue it? Actually, now I'm wondering if it would be good as a three-chapter story, since it has three main sections of about the same length.

I would say that your labor has definitely borne fruit. The fic is a delight and let nobody else tell you otherwise.

THIS IS BEAUTIFUL! ! !
The theme of a piano being used by the Voltron team is an odd and very risky one because another story on this site had tried to write something like this earlier but unfortunately they didn't really keep it feeling like Voltron and so it made me hesitant to read this- BUT: after reading your other Voltron story: A Moment To Reflect I really wanted to try this :D! AND I'M SO GLAD I HAVE BECAUSE YOU HAVE ABSOLUTELY PULLED IT ALL OFF BRILLIANTLY BY KEEPING EVERYONE TRUE TO THEIR CHARACTERS YET CAREFULLY ADDING YOUR OWN TOUCHES (WHICH ALL REALLY STILL WORK) AND MAKING THINGS DEEPER TO THIS THEME BY BRINGING UP HOW SHIRO PLAYED THE PIANO AND THEN LEARNT TO ACCEPT REPLAYING IT MEANT IT TRULY GAVE THIS LOTS OF ABSOLUTELY INSPIRING MOMENTS AND IMPACTING FEELINGS! ALSO THE PACING WAS PERFECT AND USING EVERY PROMPT WORD WAS ALL SPOT ON SO OVERALL YOU DEFINITELY DESERVE TONS AND TONS OF KUDOS AND HEARTS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ :D