I'm a clarinetist at heart. I've played the clarinet since the fifth grade, and I'd be lying if I say I didn't truly enjoy playing clarinet. As a matter of fact, I enjoy it so much where I'd personally say that one of the most meaningful acts in Judaism for me is klezmer clarinet, which, ironically enough is not religious in origin. That being said, I cannot help but wonder why denying such a joy on Shabbos could possibly enhance anything. The prohibition, I have been told, can be divided into three reasons:
1: Concern out of repairing the instrument if it breaks, as it violates the concept of doing work on Shabbos (Beitzah 36b).
2: Producing sound is prohibited (Eruvin 104a).
3: The Talmud states that we are mourning for the destruction of the Second Temple (Gittin 7a), and as such, music is not allowed to be played in a state of mourning.
Given what we have, I find this traditionalist prohibition to be poorly based for a few reasons.
Repairing an instrument: Back in the days of yore, instruments were highly simplistic creations. Modern instruments don't merit such a description. For argument's sake, let's take the example of the clarinet, which was invented early eighteenth century. Has anybody seen how complex a clarinet is?! There are so many keys, pads, and screws where if something, G-d forbid, would happen to my clarinet, I wouldn't have the foggiest idea of how to repair it; I'd have to take it to a repairman. This leads me to the question of "how can I be tempted to do something I am quite literally unable to do?" Since most clarinetists such as myself do not know how to repair our instruments, due to the complexity, the law becomes moot. I'm just glad that Tosafot agrees with me on this one (Beitza 30a)! As for smaller "repairs," such as a broken reed, there already is a precedent set for the permissibility of replacing a broken string (Tosefta Eruvin 8:19). Not even the tuning of an instrument is mentioned in Jewish law, thereby making it permissible.
Tehillim 92 and 150: Psalm 92 is known as the Psalm for the Sabbath. The following caught my eye:
לְהַגִּיד בַּבֹּקֶר חַסְדֶּךָ; וֶאֱמוּנָתְךָ, בַּלֵּילוֹת.עֲלֵי-עָשׂוֹר, וַעֲלֵי-נָבֶל; עֲלֵי הִגָּיוֹן בְּכִנּוֹר.
"To declare Thy lovingkindness in the morning, and Thy faithfulness in the night seasons, with an instrument of ten strings, and with the psaltery; with a solemn sound upon the harp." -Psalm 92:3:4
"Declaring Thy lovingkindness with a lute and harp." I read this verse every Shabbos, and I ask myself, "If David HaMelech brought in Shabbos with musical instruments, why can't I?" This verse means one of two things: either he was a blatant violator of Shabbos and should have been stoned to death, or the more likely answer is that playing a musical instrument doesn't violate any melacha of Shabbos. If you need any more convincing of musical instruments being used for praising HaShem, read Psalm 150.
Now, I'm sure my Orthodox friends would retort by saying this analysis is all well and good, but this was before the destruction of the Temple, and this brings me to my next point...
Reverence for Beit Mikdash: Prior to the falling of the Second Temple, musical instruments were an integral part of temple services. (This also means that prohibiting it on the basis of "imitating the Gentile" is also refuted) Afterwards, the Jewish people [supposedly] went in a state of mourning by putting up this prohibition (Gittin 7a), which is codified and expanded upon by Rambam (Hilchot Ta’aniyot 5:14) and Shulchan Aruch (Orach Chayim 560:3). There are two basic flaws within this prohibition. The first is that it applies to every day of the week, not just Shabbos. It doesn't matter if it's Sunday, Wednesday, or Friday evening, you cannot play. Second, and more importantly, this applies to ALL music! Just to re-iterate, it doesn't matter if it's vocal or instrumental, ALL music production is prohibited. (NOTE: the prohibition of vocal music has been ignored from the get-go). This implication is profound, particularly for Chassids who sing niggunim at the Shabbos dinner table. Either they're incosistent for not allowing instrumental music on Shabbos or they're hypocritical for singing their songs of joy. You can't have it both ways, even though you'd like to! It's safe to say that this prohibition is not widely followed, if at all. If you make a concession with vocal music, you have to make it with instrumental music as well.
Producing noise: This Talmudic prohibition (Eruvin 104a) is beyond ridiculous, mostly because nobody practices it. Jews sing and bang the table on Shabbos. Our voices, by definition, produce noise. If we weren't able to produce noise, Shabbos wouldn't be much of a joyous occassion, now would it? Even if you go with the Rishonim that believe that producing noise is limited to music, like Rambam does (Hilchot Shabbat 23:4), then you still have to deal with the aforementioned inconsistencies.
Bringing Joy to the Sabbath: Numbers 10:10 states that "[O]n your joyous occasions, your fixed festivals and your new moon days, you shall sound the trumpets over your burnt offerings and your sacrifices of well being.” The Sabbath, by definition, is a fixed festival, not to mention a joyous occassion. I would like to point out that the supposed prohibition of musical instruments is in junction with the prohibition of clapping and dancing on Shabbos (Beitzah 36b), something which Chassids are infamous for doing. If the purpose of clapping and dancing are to bring joy to Shabbos, then, in the name of consistency, the same should be done for musical instruments. It's also worth pointing out that HaMeiri already noted the fact that Nachmanides' students played instruments during Shabbat (Meiri, Sefer Magen Avot 10). Hearing Shalom Aleichem on the violin or Eishes Chayil on the clarinet would not only preserve the spirit of the holiday (particularly since there's no real basis for the prohibition), but also enhance its celebration.