If you have a system with no ARC or eARC, you can use a splitter called the HD Fury Arcana to get audio to the SoundSend.
For this setup you would use your Source(Roku, Firstick, AppleTV, PS5, etc.) HDMI cable to the HDMI input of the HD Fury Arcana. You would then connect the eARC HDMI to the SoundSend, and the HDMI out to the TV, projector or other display device.
You even might be able to utilize your display's controller for volume control with CEC, but HD Fury states in their manual:
"ARC/CEC features added during development due to people request are not yet flawless on all display
brands/models and will need many updates to become anywhere close to perfect simply because CEC is
25 years old coming from old SCART age in Europe. There is no standard for it and every manufacturer
implements it as they want it."
We have tested the HD Fury Arcana and have confirmed on a few TVs + Video Sources, that you can indeed control the volume, but that will depend on your display's capabilities and the manufacturer's implementation of CEC.
To do this, you would need to set your mode to Display+eARC on the HD Fury Arcana.
If you have any questions about the operation of the HD Fury Arcana, please refer to the user manual (CEC is located on PG 29-30):