The oldest military band is Mehter (Ottoman Military Band) and you can enjoy to listen and watch them on your travel to Turkey. Some municipalities and non-governmental organizations have their own Mehter teams. However, we can argue that the most professional is the Mehter team within the Turkish Army.
As regards the origin of the Ottoman Military Band, or more commonly the name Mehter (or Mehteran), it is also believed to be ancient from the Ottomans. The team features both blown and percussion instruments. It was closed in 1826 and reopened in 1908. Although modern army in Turkey and its troops have their own bands, Mehter also remains in existence.
L’arlésienne Suite by Georges Bizet and Turkish March by Mozart are just two of the works inspired by Mehter. You can be witness in this experience on certain days and hours at the Military Museum in Şişli district of Istanbul. The museum is in Harbiye. Also Ankara Metropolitan Municipality has its own Mehter team. That team makes its concerts in different dates and locations. For example, there’ll be a concert in the Castle, today.