Practice mutes, also known as Whispa, whisper, or hotel mutes, are similar to straight mutes in appearance, but have a solid ring of cork that prevents air from escaping from the bell like a Harmon mute. There are sound baffles inside the mute, and tiny holes in the sides of the mute that allow air to escape silently. These mutes are extremely quiet and are rarely used in performance. They are usually used for privacy and to avoid disturbing bystanders during practice sessions.

The trumpet playing community has embraced a method for making an inexpensive practice mute out of a conical plastic “Renuzit” brand gel air freshener container filled with tissue or fabric. The mute is held in the bell with weatherstripping. The self-assembly allows each player to custom-fit the mute to the bell of their trumpet, or alter the sound quality and muffling effect.