Hey,
Studying in the city for 4 years already and I always hit the streets every time I am able to, but I don't live in BCN! This is why I do not have much knowledge of events around aside of what is on the streets. Specially evening... Rarely stay around after 8PM because it gets late to be home. Feel free to PM me if you need something around. If you have time (in that week) you may take day trips to somewhere else.
I'm from the Tarragona province and don't frequent the northern part (Maresme-Costa Brava) that much. Of this side, Tarragona itself is worth for the Roman legacy (the week of 15th they hold free entries to most locations). Sitges, for the Mediterranean town (one of the points that sent emigrants to Cuba - Bacardi was from here) which is interesting if you like to be in a passeig maritim on a bar near the beach. Montserrat, the temple in the particular mountain. I could go on and on.
You could very well tour Tarragona and Sitges the same day.
Perhaps you have sensed that of being a lot of time in BCN, I've become saturated of it and searched for other nice locations.
The specific music you ask for, I'm afraid I do not know much at the moment. Googled for Cant de la sibil and Santa Maria del Mar (Old quarter, Born) held up a concert last April. Mostly interpreted during Christmas.
Flamenco is rather common and I'd guess tourist oriented too. AFAIK Japanese specially loved it and around Liceu there is often someone handing leaflets for a Flamenco performance. No experience in attending any though.
Now, to the city itself:
Old quarter / barri Gòtic is the usual 1st stop. Plaça Catalunya and Rambles of course, hard to miss. Quite interesting but tourist land nowadays. Eastern side has the Cathedral, Plaça St Jaume (Gov't and Town hall). Western side has el Raval, which is much more interesting because it's more authentic and not as sanitized (ie. nice looking)... but you have to be careful on some parts.
El Born (part of the old quarter). The market holds up archaeological remains and the district itself is gentrifying. Santa Maria del Mar church. The streets around are very interesting and there are parts with laberynthic alleyways. Well reknown for food. My uni is on the other side of Parc de la ciutadella (it has a huge fountain with a golden horse carriage statue on the top) so I frequented the area a lot.
Barceloneta holds up a lot of the essence from former times and not as sanitized. Heard there were problems with apartments and drunken tourists around.
Eixample. Well known for its squared structure, you can find interesting architecture and it is the quintessential cosmopolitan Barcelona. Pg de Gràcia, Casa Batlló, la Pedrera, Sagrada Familia are in this district. Interestingly, August is holiday and it's rather quiet once you get a couple streets out of the bustling touristy parts.
Sants-Montjuich. Worth taking the funicular from Paral·lel or just walk up the stairs from Pl. Espanya; the views up in the mountain and the Olympic legacy. In Carmel (different district) there are the Bunkers, never been there but it is a popular but obscure spot for the views.
Gràcia has park Güell amongst the main attractions, nowadays charging entrance fees. Worth the visit and quite full of people. However, the district itself (Vila de Gràcia) is quite a contrast compared to nearby Eixample!
Well, that was off and top of my head. If you need any tips I'll gladly help. I'm rather specialized in moving around on public transportation and hopefully helped a lot of tourists asking for directions.
, I will read it again in peace later when I am home, and most probably send you a PM.
