January 19, 2011

Sound Meter Pro (ver 2.4) manual

Hello. I'm android boy, the chief developer of Smart Tools suite.

Sound Meter Pro is the 4th set of the Smart Tools suite. It includes 2 tools (sound meter, vibrometer).

* Introduction video

① Sound Level Meter
This tool uses your phone microphone to measure sound pressure in db(A), and shows a reference. It can be called as a SPL(sound pressure level) meter.

 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.

: toggle buttons for pause/play, text/chart

 : title list for tool switching, capture, statistic, menu

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 sound 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 great idea.
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. :)

* Menu and Setttings

* Statistic menu
 You can see the statistic chart of the current measurement. You can save/load this chart in your device.

There is an [Export] button. You can export the current measurement as a CSV file into your SD card. You may move it to your PC and open it with MS-Excel.
You can save 12 hours data, and the format is "Time[hh:mm:ss],dB".

* 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.

* 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. I hope that yours is not one of them. :)
 - 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.

② Vibration Meter
This tool uses your phone 3-axis acceleration sensor to measure phone's vibration, movement or the earthquake, and shows a reference.

The measured value is Modified Mercalli Intensity scale(MMI), and just for reference. It had no unit.

I : Instrumental. Felt by animals.
II : Weak. Felt indoors by a few people.
III : Slight. Felt indoors by several people.
IV : Moderate. Hanging objects swing.
V : Rather Strong. Some dishes broken.
VI : Strong. Heavy furniture moved.
VII : Very Strong. Difficult to stand.
VIII : Destructive. Fall of walls.
IX : Violent. Noticeable cracks in ground.
X : Intense. Almost destroyed.
XI : Extreme. Rails bent greatly.
XII : Cataclysmic. Total destruction.

To reset Max, long-click on the chart-board.

* How to calibrate it

The measured value is inaccurate due to the various performance and sensitivity of your sensor.

To calibrate it, after shaking your phone fully, adjust the sensitivity at the [calibrate menu] so that the maximum value is about 10-11. And remove the meaningless value at the [Cut baseline] option

- Cut baseline : Because the sensor is sensitive and poor, it could have unnecessary values measured by no movement. Cut off them.

* Alarm level

You can select the alarm level(the threshold) and beep sound at the settings.

Q. It says "Unable to open mic."
A. The other app occupied your microphone. Just restart your phone.

Q. Where is the Screenshot and CSV file saven?
A. /sdcard/smart-tools/, /storage/sdcard0/smart-tools/, /mnt/sdcard/smart-tools/.

Q. I could hear nothing. But it shows 30-40dB.
A. The microphone can catch very low-frequency noise. 0 dB means vaccum (no air).

Q. Are this measurents A weighted?
A. Maybe Yes, it had been calibrated by a real SPL meter with db(A). Because the measured value is not perfect, db(A) makes no sense.

Q. How to disable tick sound switching from chart to text?
A. Turn on upside-down mode at the settings. Otherwise make your media sound mute with volume buttons.

* What's new
 - v2.4.0 : ActionBar added.
 - v2.3.3 : Minor fix. Nexus 10 support.
 - v2.3.2 : Screen capture added.
 - v2.3.1 : Nexus 7 support.
 - v2.3.0 : Export to CSV file.
 - v2.2.7 : Landscape mode for Tablet PC.
 - v2.2.6 : More models calibrated.
 - v2.2.5 : 4 hours line-chart duration.
 - v2.2.3 : Play and pause buttons.
 - v2.2.1 : Tablet PC support.
 - v2.2.0 : Statistic menu and save log.
 - v2.1.2 : Sound level notification.  
 - v2.1.0 : New icon.
 - v2.0.3 : Line-chart added.
 - v2.0.0 : released. (Jan. 2011)

If there is any idea to improve it, feel free to contact me. androidboy1@gmail.com