Short answer: Yes.
However, OBST does not need to be loud to be effective. What matters is that the sound is audible in each ear (to ensure delivery of our proprietary modulation), not the volume level itself.
Here's the best way to set it up
- Go into a quiet room
- Slowly turn the volume down to the lowest level where you can just hear the rain sound in each ear (it doesn't need to be loud — just faintly audible)
- Check each ear individually to make sure the sound is present in both
- Once that baseline is set, it's completely fine if you later move into a noisier environment (TV on, general background noise etc) where the rain sound may no longer be noticeable. As long as it was set to be audible in a quiet setting, the system is doing what it needs to do.