Sound Level Meter is described as 'You can measure the environmental noise in decibels. Sound Level Meter is the part 4. of Smart Tools series. (noise) Acoustimeter uses your phone mic to measure noise volumn in decibels(dB) and shows a reference. SPL(sound pressure level) noisemeter'. There are six alternatives to Sound Level Meter for Android, iPhone, Android Tablet, iPad and Windows. The best alternative is AudioTools. It's not free, so if you're looking for a free alternative, you could try Digital Level Meter or Decibel X. Other great apps like Sound Level Meter are Audio Tool (Paid), Sound Meter (Free) and Sound Meter by Splend Apps (Free).
Decibel X is one of very few noise meter apps with highly reliable, pre-calibrated measurements and supports dB468, dBA, dBC. It turns your mobile device into a professional sound level meter, precisely measures the sound pressure level (SPL) all around you.