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Questions tagged [decibel]

Anything related to the usage of the decibel (dB). The decibel is a logarithmic unit of measurement commonly used in electronics and communication engineering.

Anything related to the usage of the decibel (dB). The decibel is a logarithmic unit of measurement commonly used in electronics and communication engineering.

This dimensionless unit is used to express in a compact way ratios that can vary over a broad range of values.

See Wikipedia page on decibels.

118 questions
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How to get a volume measurement of iPhone recording in dB, with a limit of at least 120dB

I am trying to make a simple volume meter for the iPhone. I want the volume to be displayed in dB. When using this turorial, I am only getting measurements up to 78 dB. I've read that that is because the dBFS spectrum for 16 bit audio recordings is…
Cyber
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iPhone - AVAudioPlayer - convert decibel level into percent

I like to update an existing iPhone application which is using AudioQueue for playing audio files. The levels (peakPowerForChannel, averagePowerForChannel) were linear form 0.0f to 1.0f. Now I like to use the simpler class AVAudioPlayer which works…
crashtesttommy
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Confusion with meters in AVAudioRecorder

Simply put, I'm trying to lip-sync something based on the decibel reading from the mic input stream of an iPhone, and the values I'm getting aren't quite what I'm after. I'm using AVAudioRecorder's peakPowerForChannel and averagePowerForChannel.…
whut
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From Amplitude or FFT to dB

I've a Python code which performs FFT on a wav file and plot the amplitude vs time / amplitude vs freq graphs. I want to calculate dB from these graphs (they are long arrays). I do not want to calculate exact dBA, I just want to see a linear…
Selim Turkoglu
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getMaxAmplitude() always returns 0

I'm trying to get the Sound Level Pressure expressed in decibel but I always get 0. (The output of the TextView is -Infinity but because log(0) = -infinity. public class SLP extends Activity{ TextView sound; @Override protected void…
Pier
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How to detect ambient sound level on the iPhone?

I need to create an audio loudness (decibel) detector. To clarify, I am not trying to find the volume at which the iPhone is playing, but instead the volume of its surrounding in decibels. How can I do this?
user762034
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How to scale audio signal from PCM value to a dB SPL value?

I've got a set with MEMS microphones that measure audio signals at specific frequencies. The MEMS microphones have a PDM output which is then converted into PCM (this is necessary to allow for a microcontroller to do certain processing on the…
dg1271
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dB calculator? VBA function writing

So I've got quite the specific task. I want to create a function that will add decibel units together. Currently, you have to input something like =10*LOG10(10^(A1/10)+10^(A2/10)) and make this even longer if you have like 15 parts you want to add…
T. Heng
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html5 volume slider go to 200%

I'm looking for a way to increase the volume past 100%. I have some videos where the volume in html5 maxed to 100% is kinda low. Is there anything to make the max volume 200% or define the decibel level that 100% is?
Steve
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Android How To Find Decibels

I'm trying to get the decibels from the microphone and have looked everywhere how to correctly do it but they don't seem to work. I get the amplitude like this public class SoundMeter { static final private double EMA_FILTER = 0.6; private…
Jared
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Capture dB levels from a WAV file

Python 2.7.3 (default, Sep 26 2013, 16:35:25) [GCC 4.7.2] on linux2 Linux Mint 14 Using Python, I am reading a wav and putting the data to a text file. The entire script is below. It is my first Python Script. The values for the micsec can be…
todwith1d
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How to obtain accurate decibel level with Cocoa?

We are creating an application which records the surrounding sound and take necessary action if the sound crosses specified Decibel. In order to achieve the application objective we are using following method from AudioQueueObject.h - (void)…
yogendra singh
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Get decibel values whilst recording sound?

Is there a way of getting the decibel value of sound whilst it's being recorded? I'm using MediaRecorder to record the sound at the moment I can't use any applications on the Marketplace as I can't be sure the user will have it installed on their…
litterbugkid
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Android decibel meter

I want to create an app that would be able to use the phone's microphone in order to get the outside noise volume in db. What is the easiest way to do it?
JustCurious
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MATLAB: Adjusting the dynamic range of a plot of logarithmic values

I have been unable to find anything close to this with Google, so I'm afraid that my question itself may be flawed... None the less, here goes: I wish to display a matrix of values (Z) at various fixed dynamic ranges. In this case, fixed at 0dB,…
Dylan
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