November 2, 2010

Sound Meter (ver 1.5) manual

Welcome to Android Boy's Lab.
Sound Level Meter is  in the 4th set of the Smart Tools collection.

This app uses your phone microphone to measure sound pressure in decibels(dbA) and shows a reference. it can be called as a SPL(sound pressure level) meter.

* Introduction video

 20dB : Rustling leaves, Ticking watch
 30dB : Quiet whisper at 3 ft, Library
 40dB : Quiet residential area, Park
 50dB : Quiet office, Quiet street
 60dB : Normal conversation at 3 ft
 70dB : Busy traffic, phone ringtone
 80dB : Busy street, alarm clock
 90dB : Factory machinery at 3 ft
100dB : Subway train, Heavy snoring(2ft)
110dB : Rock music, Screaming child
120dB : Threshold of pain, Thunderclap
130dB : Jet engine at 100 ft
180dB : Space shuttle lift-off

3 red lines mean max., mean, min. values. To reset them, long-click on the center wheel.

The most phone microphones were aligned to human voice (300-3400Hz, 40-60dB). So this sound meter's performances is LIMITED by the phone-makers.

(See sound pressure at the calibrate menu. It'll stop at 32767. 32767=2^15-1, 16bit OS.)
The phone-makers must have thought that their microphones were enough for the voice calling. In order to modify this issue, google has to change the microphone from 16 bits to 32 bits.

For this reason, the louder noise cannot be recognized. Galaxy S3(max.81-84db), Galaxy S2(max.98db), HTC Desire HD(max.85db), Galaxy Note(max.81/91db)...

An experienced user suggested this idea below.
Add 30dB at the calibrate menu, and close your microphone hole on the phone with your finger. Then you can measure the louder sound level. :)

* Unsupported devices
Some manufacturers did not support standard platforms(SDK), my sound meter app does not work on 40-50 android devices. Most are the old phones running OS2.3 and less.
 - Samsung : GT-I9001
 - Motorola : XT320, XT321
 - Xperia : X8, E15i, E15a, E10i, E10a, U20i, U20a
 - LG : LG-C800, LS696, VM696, LG-VM696, Ally, US740, LG-SU370, LG-LU3700, LG-KU3700, LG-P500, LG-P500h, L-04C, Vortex, LG-E720, LG-E720b, LS670, LG-P509, LG-LU3100, LG-MS690, VM670, LGL45C, LGL55C, LG-P505, GT540, LG KH5200, LG-KH5200, GW620, LG-C660, LG-C660h, LG-P350, LG-P350f, LG-P350g
 - Pantech : IM-A730S, ADR8995, IM-A690S, IM-A690L, IM-A740S, IM-A750K, SKY IM-A630K, PantechP8000
 - ZTE : Skate Aqua, N860, ZTE V880E, 003Z, Blade, ZTE Blade, ZTE-BLADE, BASE Lutea 2, Blade S, ZTE Crescent, Orange San Francisco, XCD35, XCD 28, ZTE-RACER, MTC 916
 - N-04C, N-06C, NEC-102, N-01D, IS11CA, C771, ALCATEL_one_touch_990, MOVE, ALCATEL_one_touch_908, MEDION LIFE P4310, ISW11K, URBANO PROGRESSO, SK-S100, Android.

* How to calibrate it
I had calibrated 150+ major android devices. If the measured value is between 35-45db, it has no need to calibrate. If not, you can add/reduce the value at the calibrate menu.

For more accuracy, you have to compare the value with a REAL sound meter. By the way, do you have a REAL one? :)

Just use this app as an auxiliary tool.

* Pro version added features
  1) Vibrometer Pro version is included
  2) Statistic menu
  3) Screen capture
  4) Level notification
  5) Line-chart duration
  6) More models are calibrated
  7) No ads
  Get it on Google Play

* What's new?
- v1.5 : Action Bar added.
- v1.4.2 : Init setting option added
- v1.4.1 : Tablet PC support.
- v1.4.0 : Linechart added.
- v1.3 : New icon, 10 languages suppry.
- v1.2 : App2SD.
- v1.1 : mean value line added.
- v1.0 : release. (07 Nov. 2010)

If there is any idea to improve it, feel free to contact me.