History: Which of the following is NOT a common capability of a sampler?

Which of the following is NOT a common capability of a sampler?

• Slowing down playback
  Slowing down playback is a basic sampling technique.
• Reverse
  Reverse is an iconic sampling technique.
• Looping
  Looping is one of the most heavily used sampling techniques.
• Convolving
  Convolving is a complex technique, not a typical feature of a sampler.