There have been a few users who have had issues with low speaker volume on the Galaxy S7. A couple were down to bugs in Android that allowed Bluetooth to alter the volume and it remained low and another where the GPS did the same thing. There are a few ways to resolve low speaker volume issues on the Galaxy S7, here are a couple of them.
The first thing to check is that you have the latest Android and Samsung updates. Next, try a pair of known working headphones to compare volume levels with the speakers. If there is no marked difference, the speaker itself is working fine and it’s a setting causing trouble. If there is a difference in volume it could be a hardware issue.
Bluetooth audio issues
Some users said that when they were using Bluetooth, notifications would be loud on their handset but sound volume was quiet. There is, or was, a bug in Android that reset sound levels within the S7. To resolve:
1. Unpair your Bluetooth devices from the Galaxy S7.
2. Switch off Bluetooth and clear the Bluetooth cache.
3. Reboot the phone.
4. Restart Bluetooth and re-pair with your devices.
If you use GPS navigation with audio prompts, it too can affect volume levels. To resolve:
1. Navigate to Sound Quality and check equalizer levels.
2. Maximize all settings within the equalizer and retest.
3. Normalize equalizer settings and retest.
Some users have found changing the equalizer settings fixed the low speaker volume. A few also found that returning them back to normal kept the speaker volume at normal.