Kasha-
I sincerely apologize for taking so long to respond. Things have been very hectic lately and I have not had the chance to be at the coffee room. At any rate, let me respond to your point.
The Halacha, from the standpoint of Torah Judaism since the time of the Ge’onim, always has it’s source in the Gemara. No one, not a contemporary posek, nor a rishon, has the power to institute new halachos. Sure, every community can make a takkanos, and a rav can issue a cherem, and a minhag can evolve and become somewhat obligatory, but Halacha per se must always have its source in the gemara.
Of course, the gemara is not so simple. There are various ways to understand many sugyas, and not only must one have good critical thiking and analytical skills, but to say pshat in one line of gemara one needs to know all of the related statements of chazal. This is what the rishonim spent their time with.
The Shulchan Aruch is basically a compendium of the halachos which come out of the gemara, based on the understandings of the rishonim, particularly the Rif, Rambam, and Rosh. It was not intended as a ‘final word’ on any halachos, but rather as a short summary to assist a posek who wishes to ascertain the halacha from the gemara. The mechaber writes this explicitly in his hakdama.
Accordingly, no posek truly has the authority to pasken solely based on his understanding of Shulchan Aruch, without knowledge of the sugya in the gemara, for perhaps his application of the SA is completely incorrect. And certainly no posek has the right to issue a psak which is grounded not in the gemara, nor in the rishonim or the SA, whether l’kula or l’chumra.
I have been taught by my rebbi and by my rav that when approaching a sugya I should learn it with the rishonim, and the Tur/Beis Yosef, and to come up with the halacha from that. If something stated by a later source seems to contradict my conclusion, the I should discuss it with my rabbeim and through pilpul chaverim, and if I still think it is incorrect then ‘ein l’dayan ladun ela ma she’einav ro’os’ – I must follow my own logic.
Not everyone is qualified to learn a sugya and pasken. One who does not have much background in gemara with rishonim should not even be discussing halacha, they should just follow their rav and not get involved in technicalities and reasons, because doing this with their severe lack of knowledge can cause much harm to the halachic system. This is why I consistently tell people on this forum to ask their rav.
When I actually debate a halacha on this forum, my intention is for those who are not simply following their rav. It is for those who wish to ascertain the halacha as though they are poskim themselves, though it is not proper in my opinion. As such, I will not back out of an argument because ‘this rav says this’ or ‘this rav says that’, no matter how great that rav is; even if it is someone I have the utmost respect and honor for. A source for me is a gemara, be it explicit, or implicit through the give-and-take of the meforshim over the ages. Blanket statements, even of gedolim, do not count here.
Everyone should follow the da’as torah of their rav. But that is not what truly determines halacha. It is a safety net for those who do not ascertain the halacha for themselves. We have the right to blindly follow a particular rav, and for the general public this is really the only thing they should be doing. For those who are qualified however, to ascertain it for yourself means to figure it out ultimately from the gemara, without specific regard for da’as torah.
As an afterthought, being qualified isn’t all or nothing. Once a person has reached a certain level of understadning he might be qualified to pasken a sugya that he knows even if he doesn’t quite know all of shas yet. That is something each person should figure out with the guidance of someone who knows them well enough and is qualified to make that judgement about them.
Regarding this particular case, I am aware of the sentiments expressed by many people, even rabbanim, about the inherent impurity existing in non-Jewish music. I do not know of a source for this in the gemara/rishonim, and on the contrary, as I pointed out the Sheilos U’tshuvos throughout the ages permitted the use of non-Jewish music by chazzanim. Therefore I maintain that there is no problem with it (obviously not including where there is nivul peh involved), and anyone wishing to refute this claim will have to do so with more than just the claim of da’as torah.