When I first heard the Mehter band in Istanbul I immediately bought some ten copies of their CD, which upon return home I started handing to friends. I later found hardly any of them appreciated the gift, it taught me love for this most ancient of all military bands is an acquired taste that is not shared by many. In 2016 I witnessed another performance in the company of one of those friends. Though he thought the music "simple" (he plays Bach, Mozart, Schubert and such) he confessed that the actual performance was far superior to listening to the CD and as such he liked it a lot.
The weather being good the band entered from the garden through a large gate, marches around a couple of times, than members take their positions, perform, and after a photo opportunity for visitors marches off again into the garden.
The Wikipedia of course has more, I quote: "Ottoman military bands are thought to be the oldest variety of military marching bands in the world. Though they are often known by the word mahtar (مهتر; mehter in Ottoman Turkish) in the West, that word, properly speaking, refers only to a single musician in the band. In Ottoman, the band was generally known as mehterân, though those bands used in the retinue of a vizier or prince were generally known as mehterhane (مهترخانه, meaning roughly, "a gathering of mehters", the band as a whole is often termed mehter bölüğü ("mehter company [troop]"), mehter takımı ("mehter platoon"). In the West, the band's music is also often called Janissary music because the janissaries formed the core of the bands." And: "Today, the Armed Forces Mehter Unit (Mehter Bölüğü) is the traditional band of the Turkish Armed Forces and it performs regularly at the Military Museum (Askeri Müze) in Istanbul as well as during certain state ceremonies. There is also the Ministry of Culture Istanbul Historical Music Ensemble." They are the ones you see here.