Symphonic black metal is a style of black metal that uses symphonic and orchestral elements. This may include the usage of melodic instruments found in the sections of a symphony orchestra (string instruments, brass instruments, woodwinds and keys). Vocals can be "clean" or operatic in style, song structures are more defined or are inspired by symphonies. However, much of the characteristics of "traditional" black metal are retained, such as shrieked vocals, fast tempos and high-pitched electric guitars often played with tremolo picking. The sound is not always literally symphonic; that simply refers to the thick-sounding instrumentation and arpeggios, dramatic soundscapes. Nor is its connection to black metal always readily audible; although nearly all of symphonic black metal bands started out playing standard black metal, symphonic black metal often bears little surface resemblance to its immediate forebear. Black metal groups began emphasizing the guitar and adding elements of progressive rock (primarily psychedelic rock and space rock) and gothic metal, with its emphasis on a chilling, eerie texture. The result is a sound usually lush, and much more accessible than standard black metal. The symphonic black metal movement remains somewhat limited, partly because of its epic ambitions and partly because it isn't traditionally metallic, but its fascinating synthesis of influences made it an instantly identifiable alternative .