Procedure For Making Your Own Atmos Elevation Speaker:
Select a smallish bookshelf speaker that can easily fit on top of your front and/or rear surround speakers (choose something with similar output and frequency response capabilities above 200Hz as your other surround channels if possible).
Place the speaker (with the front baffle firing up towards the ceiling) on top of your front and/or rear speakers at 20 degrees using a door stop or foam wedge.
Connect the top firing speaker to the Atmos channel of your AV Receiver.
Set your AV Receiver HPF bass management for the Atmos channels between 150-200Hz.
Level match and time align.
Caution: Don't place an Atmos logo on the speaker to avoid a potential patent infringement lawsuit
Atlantic Technology, Definitive Technology, KEF, Onkyo, Pioneer USA, Teufel, and Triad Speakers