You can reset you SAM loudspeakers or subwoofers to the factory settings by using GLM. 
Go to Group Preset > Store to Loudspeakers and click on Factory Reset on the upper right corner, then confirm the reset. ALL speakers and subwoofers in the group are reset.

If you have a newer SAM model with a power button (and not a power switch), you can also do a reset without GLM. Switch on the speaker and then press and hold the power button for approx. 10 seconds. You will then hear a short signal tone. To complete the reset, switch off the speaker and turn it on again.