You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Adult_contemporary_music

Context:
Adult contemporary R&B may be played on both soft AC stations and urban AC. It is a form of neo soul R&B that places emphasis on songcraft and sophistication. As the use of drum machines, synthesizers, and sequencers dominates R&B-rooted music, adult contemporary R&B tends to take most of its cues from the more refined strains of 1970s soul, such as smooth soul, Philly soul and quiet storm. Classic songwriting touches and organic-leaning instrumentation, often featuring string arrangements and horn charts, were constants.

Question:
Along with drum machines and synthesizers, what electronic instruments are often found in modern R&B-based music?

sequencers