This is a very subjective question. Notification volume has been determined and set in accordance with regulatory standards, BUT what level of sound will wake one person, may not wake another. In addition, the Owlet Baby Monitor can not override volume settings you set on your mobile device.
Although the volume on your phone is controlled completely by you, it can be confusing when it comes to notifications built into apps.
1. Ringer volume is NOT Notification volume (or app volume).
If you are not currently playing any media or in an app that actively makes sound, when you adjust the volume buttons on the side of your phone, you'll notice it adjusts ringer volume. This does not affect the volume of the Owlet notifications.
2. If you adjust the volume in ANY app that makes sound, this adjusts the volume in the Owlet App for Norifications.
If you are in an app that actively makes sound, or while playing music or any media that uses the phone's external speakers, adjusting the volume buttons up or down DOES adjust the volume level for the Owlet notifications.
Owlet App - Test Buzzer // iTunes in background // iTunes in foreground
3. Using headphones
Any time headphones are plugged into your phone, the volume buttons will adjust ONLY sound for the headphones (unless the phone is actively ringing - then it affects ringer volume).
How To Set The Owlet App Volume (which adjusts the volume for all apps):
1. Adjust the volume through the Owlet App:
Enter The Owlet App, go to settings, and select Alarm
Select Test Buzzer and click Test Buzzer - adjust your volume while the song is playing. This will keep the same volume level until you change your regular volume level through this or ANY app that has sound (including iTunes).
2. OR, enter ANY app which actively makes noise and set your volume level.
**ADJUSTING VOLUME IN ONE APP AFFECTS SOUND LEVELS FOR ALL APPS THAT MAKE NOISE - IF YOU TURN THE VOLUME DOWN ON ANOTHER APP, YOU ARE POTENTIALLY TURNING THE VOLUME DOWN ON THE OWLET BABY MONITOR APP AS WELL.