Questions tagged [sound]

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72 views

Does a .wav file created from a .mp3 file have better quality than the .mp3 file itself?

A .wav file created from a .mp3 file has the same frequency domain plot as the mp3 file itself https://stackoverflow.com/questions/58706674/difference-between-frequency-domain-in-mp3-and-wav. However,...
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39 views

Conversion from counts to dB

I have a sound signal, recorded by a hydrophone, which units are counts. I would like to convert the counts into dB re uPa (Decibels relative to microPascals), is that possible?
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38 views

How to convert from .wav (hydrophone data) to pressure (SPL)?

I am new here, since I started recently with signal processing. I am trying to analyze a .wav file recorded by a hydrophone, however, I need to convert it to SPL. I have a calibration file which ...
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22 views

How to understand the sound parameters so that it can be reproduced in Matlab

I am reading a paper called "Mouse Auditory Brainstem Response Testing". In order to make the experiment myself I would like to create the stimulus sound using matlab. When describing the sound (in ...
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0answers
16 views

Alone MFCC can identify difference between sound?

I am doing a project to identify different drum beats. There are lots of features like MFCC, Chroma Values, Spectral Bandwidth, Spectral Centroid, Zero Crossing Rate, etc. But most of the projects are ...
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2answers
50 views

How to detect real time sound onsets?

I'm a Software Engineer Undergraduate. I'm trying to detect drum strokes(beats) in real-time in python. I used amplitude threshold-based onset detect (beat detect) algorithm but it takes other noises ...
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22 views

How to Synchronize multiple real time audio streams before mixing them?

I have been working on a VoIP solution in which I have to mix multiple audio streams coming from various sources. I have been facing muffled sound after the mixing of streams. I have implemented ASW ...
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1answer
51 views

with given Sampling rate, what max frequency human voice can be captured?

I'm new to signal processing and sampling rate, I was asked interview question related to this. This is the exact question asked: With 8Khz of sampling rate, whats the max frequency that human ...
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3answers
74 views

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 ...
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1answer
25 views

Mix N sinusoidal waveforms without clipping but at a costant amplitude with no clipping and maximum amplitude

I need to mix "n" sinusoidal waveforms which can be all active or some or all can be silent. The math seemed simple (working with float32 samples) because I just added all waveforms and then divide ...
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0answers
17 views

Identifying “elements” and sounds in music

Note: I have little experience with audio analysis, and no experience with signal processing, so bear with me as I try to ask a question using terms that I'm not too familiar with. As a DJ, the aim ...
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1answer
47 views

Audio Processing Glossary

I'm new to audio processing and I hope here be a good place to ask about the definition of terms in this context. My question is what is difference between sound, audio, voice, speech and tone, from ...
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1answer
184 views

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 ...
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2answers
113 views

Faster way to find the quantization level of a sample

Given a sequence of real numbers that represent a sound signal i.e [1.8, 2.2, 2.2, 1.9, -1.5, -0.7], we must quantize this sequence by dividing the range [-4, 4] to 32 equal parts. If we had to do ...
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0answers
24 views

Problem with calculating PLP coefficients

I am trying to make a programme that will calculate PLP coefficients. The process is described in this paper. However, I am unsure about some of the procedures. Namely, in the IA should I use ...
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2answers
44 views

MATLAB - How do I get the Filter Function to get the output Energy Spectrum?

The image was from a question I posted on reddit, so ignore the title. I'm trying to write a program that plots these graphs I know that the first plot is just a plot of the source-signal so the "...
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1answer
107 views

Formant Analysis Frequency - What makes a peak value?

from spectrograms, how can you tell which peak is really a formant. Like why is the pink arrow the first formant. And in the spectrogram below, which has fewer samples, what makes a value the peak ...
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2answers
421 views

Audio processing. Is it possible to directly access the decoded audio data going into the analog input of a computer

When a computer transcodes an audio file from one file format to another, does the computer first decode it into the raw digital stream (exactly what is fed into the DAC for the audio output) , or ...
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1answer
25 views

extend parts in an existing audio file to make it sound longer without stretching the file

I'm looking for a way to extend certain parts of an exiting audio file to make these parts sound like the where played longer. And I dont want to change play speed or stretch the file. Lets say u have ...
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1answer
159 views

How to set STFT-parameters to visualize woodpecker / Sawtooth Signal? ​

I always wanted to work with FFTs and Spectrograms to characterise sounds and their frequencies using python. Lately I recorded a woodpecker at his work. Woodpecker Wav File To know where to look ...
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0answers
27 views

Resources for learning Sound Processing [closed]

Does anyone know of any resources that explain simply, these are the data objects and variable definitions involved when doing sound processing? I took a class on image processing where we learned ...
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2answers
87 views

Need help cleaning noise

I have been recording sound sample from mouse vocalisations and noticed that a background noise appeared in the recording room. the noise is clearly visible in the spectrograms of the recordings as ...
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0answers
26 views

need help cleaning a sound sample from a constant (stationary) background noise

I have been recording sound sample from mouse vocalisations and noticed that a background noise appeared in the recording room. the noise is clearly visible in the spectrograms of the recordings as ...
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1answer
119 views

How to use the iircomb filter in matlab

I have a sound file that needs filtering which looks like this: Hence I think that I have noise spaced equally at 832Hz. i tried to use the iircomb filter taken from mathworks website and i managed ...
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1answer
90 views

Distortion in sound after multiplying frequency spectrum by constant

I make a simple sound equalizer that operates in frequency domain and lets user to adjust frequencies in sound by using 4 sliders. The first one responsible for 0 - 5kHz, the fourth one for 15-20kHz. ...
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1answer
75 views

How do I know what is causing the noise in my signal

I have a noisy audio file, available here (It is safe to download if you wish to) https://ufile.io/pstrt Now, I inspect it in matlab: And then i plot it on normalised frequency: Now I need to ...
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3answers
612 views

What is the (approximate) function for amplitude of a plucked string over time? Does it differ between string types?

Impetus: I'm currently working on my first synthesizer, after many years of playing with them. I've just added an ADSR envelope to modify the gain, but for some reason it sounds wrong to me. I've ...
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1answer
43 views

Is there an intensity estimation algorithm working solely in time domain

Given a second of sampled sound pressure signal, speed of sound and medium density, can the average sound intensity be estimated without performing DFT, that is in linear time by simply traversing all ...
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1answer
43 views

How to differentiate an empty aerosol from a full one using only sound measurements?

The challenge I have is to detect an empty spray container using sound measurements only, since I can't place any sensor directly into the container because of the mechanism that tightens it. My main ...
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1answer
34 views

make a voice sound signal play faster

Suppose $x(t)$ is a signal containing a voice. How can one derive a signal playing the same voice faster. I tried $x(t+\lfloor{100t\rfloor}/100)$ to double the speed; But it adds a buzz sound. Is ...
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1answer
41 views

How does a sound card translate amplitude values to sound when playing WAV/PCM/FLAC files?

I'm reading the documentation for WAV files (and importing them in C++)It seems like 44100 amplitude (this can change, and is specified by the WAV header) values get sent to the sound card every ...
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1answer
232 views

How to measure acoustic pressure level under water with a hydrophone?

this is my first post here and I am also new in signal processing. Let's say I have a hydrophone with amplifier which is connected to a sound card plugged in to a computer. I gather the sounds to a ...
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2answers
172 views

How to convert a sound signal function to wave file? [closed]

I am new to understanding sound signals. A sound signal, as far as I know, is a real function of time $x:[0,\infty)\to \Bbb R$. For example, $x(t)=\sin(t)$ is a sinusoidal signal. What is $x(t)$. For ...
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1answer
334 views

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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2answers
181 views

Is spectral centroid enough to measure brightness?

i'm new in this group and i'm studying a sound signal. I have used FFT for extrapolate frequencies and see the harmonics of this sound. I have to compare this sound with another similar sound and find ...
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1answer
98 views

Detecting whether reverb is present

I have two different audio short samples of an instrument playing. If one of the samples has a reverb effect applied, how easy is it to detect which sample has reverb? Is this possible?
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3answers
161 views

No-lag causal bandpass filter kernel formula

Can anyone point me towards a formula for a good (for any values of "good") no-lag causal bandpass filter? I am doing sound processing and I need to identify starting points of certain sounds (target ...
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1answer
140 views

Measuring Amplitude of sound wave FFT

Please, pardon my ignorance. This may be a simple question, but I am still unable to explain what is happening. I am using a turtlebot to listen to sound emitted from a stationary sound source. My ...
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1answer
189 views

Uncertainty Relation between time and frequency

Typically, humans can hear sound waves in the frequency range 20 Hz to 20 kHz. If one wants to make digital record of sound such that no audible information is lost, what is the longest time interval ...
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2answers
191 views

Pitch perception - Why does our ear not directly detect the missing fundamental frequency?

My motivation for this question is related to biological phenomenon of our inner ear, so I initially posted in the biology community, but I suspect the answer has a DSP explanation, so I figured this ...
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2answers
1k views

How can I calculate Reverberation Time (RT60) from the Room Impulse Response using Python?

I have the following Room Impulse Response(RIR) in wave format here. I wanted to calculate Reverberation Time (RT60) of it by plotting its Energy Decay Curve using this Python code. The RIR is ...
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1answer
71 views

is there a way to apply a median filter diagonally?

For example, some studies show how to smooth a spectrogram with a 2D median filter vertically and horizontally (along time or frequency). My question is how would I apply 2D median filter along the ...
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1answer
388 views

How does it go about implementing pitch shifting without affecting the duration or speed on matlab? [closed]

I am creating a project that will record a sound sample from the world, for example, a bird's chirping. And then through pitch scaling, I could create different notes. I first tried to change the ...
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1answer
334 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 ...
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0answers
26 views

When we play several audio streams what is responsible for mixing them?

When we play several audio streams what is responsible for mixing them in single audio playing via speakers? Clearly it should be either OS combining the sounds or hardware getting multiple data ...
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1answer
32 views

How to model airborne sound channel

I'm making a soft demodulation/decoding to communicate a microphone and a speaker in short range. I have to calculate the LLR using my constellation and the airborne sound channel probability density ...
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1answer
3k views

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) ...
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1answer
66 views

How exactly does sound get encoded by a cochlear implant processor?

I've been wanting to know more about how sound is processed by a cochlear implant processor, how they are programmed, and how they stimulate the magnets and electrodes inside. How do you take pure ...
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0answers
459 views

PortAudio: sound fade in/out by scaling sample data

I've done already some fade in or fade out effect in portaudio, but that is not working properly. My callback function: ...
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2answers
120 views

recognize unwanted sounds, noises, and deleting them algorithm

I have a function that I need to use denoise algorithm on. What I thought is to divide it to smaller parts and then use Fourier Transform on each one of the parts, but I am not sure what to do next. ...