Select an ambient space in your recording environment to use for your chamber. This could be a tiled bathroom, an empty garage, an elevator shaft, or a concrete basement. Your space should be isolated from your main listening environment, and produce an echo when you clap your hands in the room.
Prepare your space for reverberation. Reverb thrives in empty spaces with smooth, reflective surfaces, so clear out any furniture, carpeting and other materials that can deaden your space.
Position the speaker in a corner of the room. Face the speaker towards the corner to reflect its output off of the intersecting walls.
Place a microphone on a microphone stand in the opposite corner of the room as the speaker. As with the speaker, ensure the microphone is facing toward the corner of the room.
Run the speaker wire and microphone cable from your studio's control room to the empty room. The male end of the microphone cable should reside in the empty room, with the female end in the control room.
Hook up the amplifier to an output of your audio interface. If you are using a mixing console, connect your amplifier to an auxiliary output on the console. This will allow you to send signal to the speaker using your interface or mixer.
Connect the speaker and amplifier using the speaker wire. Plug the mic cable into the microphone and the mic input of the mixer or audio interface.
Send audio to the chamber using an auxiliary fader in your recording software or an echo send on your mixer connected to the audio amplifier. The signal plays back in the chamber.
Capture the ambience in the chamber with the microphone. Open a new channel on your recording software or mixer to play back this signal along with the original audio.
Adjust the volume of the echo using the auxiliary fader or echo send, and the microphone gain on your interface or mixer.