not have a combo amp who are laying down tracks in the recording studio can plug into a DI unit (any professional recording studio will have one), which is connected to the audio console; the audio engineer can provide the bassist with the sound of their instrument through headphones. See also Bass effects Guitar effects Instrument amplifier Guitar amplifier Guitar speaker Isolation cabinet (guitar) List of bass amplifier and loudspeaker manufacturers Further reading Hopkins, Gregg; and Moore, Bill. Ampeg: The Story Behind the Sound. Hal Leonard, 1999. Fliegler, Ritchie and Eiche, Jon F. Amps!: The Other Half of Rock 'n' Roll. Hal Leonard Corporation, 1993. Zottola, Tino. Vacuum Tube Guitar and Bass Amplifier Theory. Bold Strummer, Limited, 1996. References Bass amplifier types and related. - Bassamplifier.org Amplification Loudspeakers Instrument amplifiers Bass (sound) Blues instruments Rock music instruments Folk music instruments Jazz instruments Contrabass instruments