Questions tagged [sound]
The sound tag has no usage guidance.
274
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22
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5
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What are the audio equivalents of images like "Lena", "Mandrill", and "Cameraman"?
I don't know what to call these images, but they're very often used in the image processing world as standard examples to show the output of a particular operation. Here's a link to the page ...
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4
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How to compute dBFS?
I asked myself how to compute dBFS (dB full scale) from a value of sample between 1 and -1?
and in general?
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13
votes
2
answers
1k
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Sound synthesis effects for natural sounds
I´m currently working on an accordion synthesizer and I would like to make it sound as natural as possible.
I really like how the following wave sounds:
https://dl.dropbox.com/u/20437903/onda%...
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12
votes
3
answers
5k
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Transmit data through sound between 2 computers (very close distance)
I'm writing an example on transmitting data through sound betwwen 2 computers. Some requirements:
The distance is very close , i.e the 2 computers are basically adjacent to each other
Very little ...
- 269
11
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2
answers
2k
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Does the Nyquist frequency of the cochlear nerve impose the fundamental limit on human hearing?
The bandwidth of human hearing by empirical data is $20 \; Hz$ to $20 \; kHz$. A cochlear implant stimulates the auditory or acoustic or Cochlear nerve directly so that the hearing can be improved in ...
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11
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2
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What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?
Human hearing range is commonly known to be 20 Hz to 20 KHz
But what about speaking range? We know that speech Sounds are generated through our vocal cords. So What is the maximum value of frequency ...
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10
votes
3
answers
2k
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How does Siri recognize me saying "Hey Siri"?
I am trying to understand how my iPhone can continually listening for me saying Hey Siri, Alexa, ...
- 201
9
votes
5
answers
3k
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Why Do I Get This Crackling Noise on Zeroing out the High Frequencies?
I recently started playing with the Fourier transform (after spending a few weeks learning about the mathematics behind it). I decided to try hacking together a low-pass filter on the following sound ...
- 195
9
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2
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6k
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PC-to-PC data communication over Sound FSK / PSK / DSSS
For fun and work I've to implement a java based application that can Encode text or data to sound and transmit using PC's speaker and on the receiving side is a microphone with decoder software.
I ...
- 191
8
votes
4
answers
5k
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How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?
I have a 22 kHz mono audio recording, which is mainly speech, a reading. I would like to upsample somehow to 44 kHz, to improve the audible quality. I have read about there are AI methods for ...
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8
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3
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How is a human whistle a pure sine wave?
According to Wikipedia human whistling is a pure sine wave.
If that is true and if a human is whistling and produces a rhythm like any song, is he still producing a pure sine wave?
For example, if I ...
- 2,145
8
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1
answer
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Does our brain constantly ifft to hear?
From my understanding our ears have hairs/cilia in the cochlea that resonate at frequencies within our hearing range. To me this means we are hearing in the frequency domain as opposed to the time ...
- 201
8
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1
answer
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Why should one use windowing functions for FFT?
So I just revised my pitch calculation algorithm using a harmonic product spectrum algorithm. I was just curious about why this explanation of Harmonic Product Spectrum states that you need to ...
- 291
8
votes
2
answers
8k
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Loudness of PCM stream
I'm receiving PCM samples through stream which is one channel, 8000 samples per second. I figured out way of finding out loudness by calculating 'force' of signal by adding abs value of every next ...
- 211
6
votes
2
answers
4k
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Why isn't silence just zeroes in an audio file, and how can I make it?
I'm completely new to the world of audio and signals. I noticed that when I opened Audacity and generated one second of silence (details below) and converted the raw WAVE file to a list of integers, ...
- 159
6
votes
3
answers
4k
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How to de-noise raw sound data
What techniques/algorithms can I use to remove noise from a raw recording of sound (voice)?
The purpose is to get a smoother graph (removing the "jaggedness"). What I have tried was to average-out ...
- 163
6
votes
3
answers
7k
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Audio time stretching, without pitch shifting
This might be a Sound Design question, or a StackOverflow question since I am attempting to do this with Java.
I would like to play back a sound at the same pitch, but stretched out in time.
My ...
- 181
5
votes
3
answers
800
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Signal processing for audio and speech
I have started learning about signals and I am interested in sound signals.
There are some questions that I need to resolve. For example in music, difference of notes like 'sol' and 'la' are about ...
- 277
5
votes
3
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5k
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Best beginners guide to sound/audio
I'm trying to learn audio programming, but am struggling with the basics of audio.
Audio programming is new to me (I'm a C/C++ developer with over 30 years of experience), but I don't have any ...
5
votes
3
answers
12k
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Is there any free software that can recognize and classify sounds?
i am making a smart home automation software and i would like to know if there is any software that can recognize noises such as speech ,playing music,phone ringing etc
The exact software i am looking ...
- 153
5
votes
1
answer
1k
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Maximum cross-correlation coefficient value for time delay estimation
I am using cross-correlation for time delay estimation of two synchronized recordings ($x_1$ and $x_2$) of a fixed sound source from two different locations.
I understand that the delay is associated ...
- 153
5
votes
2
answers
2k
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Double the "speed", double the frequency?
Usually, when some sample is played-back at twice the rate it was recorded, the pitch of the recording sounds an octave higher.
For example: $g(t) = \sin(2 \pi f t)$ and $g(2t) = \sin(2 \pi f 2 t) \...
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5
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3
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863
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Proof-of-concept for active noise cancellation to block consistent low-frequency HVAC noise transmission
Background
We live in a multi-unit building where each unit's HVAC system/closet is located directly across a party-wall from the neighboring unit's bedroom, and adjacent to a shared external curtain ...
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3
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2k
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Are there libraries for extraction of sound wave features?
I am looking help for my project for which I need C++ (or any other language) libraries useful for extraction of sound wave features like frequency, loudness, pitch and orientation. Using these ...
4
votes
2
answers
381
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How are sounds recorded and reproduced (played back)?
Someday I have suddenly got wondered how sounds are recorded and reproduced. I searched a little bit but the information I got was composed of difficult words and contents, so I couldn't understand ...
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4
votes
2
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14k
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Mathematical equation for the sound wave that a piano makes
Is there a mathematical function that can output the sound that a piano makes at different frequencies?
So if the simplest equation for a sound wave (at a given frequency and for a given sample rate) ...
- 205
4
votes
4
answers
434
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How to determine precision needed for sin approximation used for sound synthesis?
I am doing some procedural sound synthesis in Java. I want to have a sine wave as one of the possible basic sounds. When experimenting with that, I have found the default Java ...
- 141
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1
answer
3k
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How to decide the number of cepstral coefficients?
For audio classification we are using cepstral coefficients, but how should I decide the number of coefficients?
- 333
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votes
3
answers
4k
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FFT of a AM modulated signal
I am generating an AM modulated sinusoidal wave. The carrier frequency is set at $1000 \ \rm Hz$; the modulation frequency is set to $40 \ \rm Hz$ and $100 \%$ of the amplitude is modulated.
I ...
- 191
4
votes
1
answer
691
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What does MATLAB display when plotting a sound signal?
When you load the speech file 'mtlb' in MATLAB (which is by the way the voice of a woman saying the word 'MATLAB'), and plot the data, you get the following plot:
My question is this: what does the ...
- 143
4
votes
1
answer
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Polyphase Filter decomposition. It is not working
So, I want to do a polyphase implementation of a filter bank (I had problems with it since the beginning and I already asked for help to the community in the past, indeed: Norm MPEG-1 Layer III (Mp3) ...
- 97
4
votes
1
answer
759
views
Algorithm for identifying beat grid in music with non-constant tempo
Are there any algorithms for automatically fitting a beat grid to a song (tempo matching) when the song has a slowly changing tempo or BPM?
The output would be a vector of onsets.
Here's a picture ...
3
votes
4
answers
1k
views
What are possible reasons a sound may be continually clicking (low amplitude, no sudden changes in amplitude)
I am making a digital sound mixer and get this wav file (200kb, Wetransfer)
I looked through the waveform using Audacity. It uses 20% of its maximum amplitude and I see no sudden changes in the ...
- 133
3
votes
1
answer
871
views
What features describe audio signals? (Besides frequency and amplitude)
I recorded sounds with a microphone and I try to distinguish them in my Java program. The frequency works quite good, but if I look at the fourier transforms it seems like there should be more ...
- 133
3
votes
1
answer
665
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Why are zero values added in the FFT of a concatenated noise signal?
After concatenating an 11-second *.WAV (sample rate 44100 Hz) file 27 times (just by gluing them head-to-tail), I obtained a ~300-sec noise signal. I used MATLAB(2015b) and the FFT function on both ...
- 298
3
votes
3
answers
203
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Amplify Sound From Known Direction
I have microphone array which records sound. There is one main sound which direction I know and some noises in the background. Now I want to selectively amplify sound from known direction. This looks ...
- 229
3
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5
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2k
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Pitch Detection: avoiding frequency doubling / halving
I am working on a tuning app. I have so far tried 3 different libraries with a number of different algorithms. However, when I compare to other tuner apps, I seem to be getting frequency doubling on ...
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3
votes
2
answers
428
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Why is the reference pressure for dB SPL 20uPa?
The article here says that
This 20-micropascal reference was selected because it was the quietest
sound pressure level that a group of normal hearing test subjects
could detect.
which makes me think ...
- 521
3
votes
2
answers
878
views
Generating inaudible sound waves using MATLAB
I want to generate inaudible sound waves (above 18kHz) with 48kHz sampling rate using MATLAB.
Generating a sound wave with 18kHz frequency makes it inaudible.
I've inserted the data in the 18kHz ...
- 65
3
votes
2
answers
715
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Sound absorption coefficients for frequencies higher than 8kHz and lower than 80Hz?
I am building a matlab simulation that applies room compensation to a 3D audio rendering system, and I'm searching for the frequency dependent sound absorption coefficients of various materials in ...
- 108
3
votes
4
answers
593
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Why every musical instrument sounds different than any other while listening?
This is soft question.I am not expert in music. We know that English language has 26 letters (which are again grouped into vowels and consonants) , while language of music is same all over the world ...
- 407
3
votes
1
answer
294
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How to add more cowbell?
Remember that Christopher Walken skit on Saturday Night live where he told the band “it needs more cowbell” https://en.wikipedia.org/wiki/More_cowbell ? This site automated it http://www.morecowbell....
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1
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How to make pop-free, crisp two-beep ringtone?
I hope this ultra-noob question is not entirely out of place here.
I'm trying to make a super simple ringtone: 0.5s silence + 1s "pure tone" + 0.5s silence + 1s "pure tone" + 0.5s silence. By "pure ...
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2
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Maximum frequency of any mobile phone speaker
Which is the maximum frequency of a speaker of any common mobile phone? I would like to use sound to repel some animals, so I need playback sampling rate to be above 44100 Hz.
3
votes
2
answers
191
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Two generated tones creates a side tone - how to avoid the side tone
I'm trying to create two tones at different frequencies. So I have one tone at 15000 Hz and one at 15400 Hz using Audacity. The problem i'm running into is there is a third tone created at a much ...
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3
votes
2
answers
880
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Signals cross-correlation
I am trying to measure phase difference between two received waves which are recorded by two separate PC's (microphones). The two PC's starts recording at the same time, then I make a sine wave sound ...
3
votes
1
answer
65
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What effect causes this Pattern?
I've conducted a measurement of underwater noise in a laboratory experiment.
Therefore i am using a sweep signal.
Sometimes -I guess when the signal is much more louder- I get this fascinating ...
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3
votes
1
answer
308
views
Best method to measure phase difference between acoustic recordings of sine wave?
I am using multiple digital MEMS microphones in an array which are 8mm apart. Now I recorded a sine wave of 20kHz for calibration (at angle 0°) and want to measure the phase difference over time ...
- 33
3
votes
1
answer
2k
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Colored noises: Stationary or non-stationary?
I know for sure that white noise is considered as a stationary sound, but is that true for the rest of them? http://en.wikipedia.org/wiki/Colors_of_noise
Also, can we meet some of these sounds in ...
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3
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2
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141
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Acoustic measure of a specific room
I would like to make an acoustic measure of one room, so I can compare it with a acoustic measure of some other room. Then compare these data. So when I take an acoustic measure of the first room ...
