Questions tagged [audio]

Audio, or in terms of signal processing, an audio signal is an analog or digital representation of sound, typically as an electrical voltage.

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1answer
427 views

Change duration/tempo of a .Wav file without introducing pops or pitch shift?

I am attempting to develop a similar function as Audacity's Effects>Change Tempo effect. Or more specifically: I am in need of a way to create a function in my ...
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0answers
29 views

How to correctly pass filter states from one processing block to the next

I'm processing a 4 channel audio signal and due to memory requirements need to process the signal in an arbritrary number of blocks. To ensure consistent filtering between blocks I've been told I need ...
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0answers
23 views

How to deal with different audio formats for audio classification?

I am working on an audio classification problem statement to classify between two audio classes. I have collected samples from jotform, they are providing audio widget to collect .wav audio but it ...
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1answer
29 views

What is the actual format of this audio file?

I am collecting some data from jotform .wav widget. All the audio files are in .wav format. But when I tried to open the file using python ...
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2answers
42 views

Conceptually confused by LPC for speech: Do we synthesize by the inverse filter (FIR)?

I've been following the process of using LPC to analyse the speech and then synthesize the speech by swapping out coefficients over time. I'm purely concerned with pitched vowels at this point. ...
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1answer
37 views

Phase difference calculation between two wave files

I am doing comparison between two wave files, How to calculate phase difference between those files? Second wave is generated by making some changes in the first one .I have tried calculating phase ...
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1answer
47 views

finding onset of an impulse signal, basics?

New to signal processing, but making good progress, I think. I have a series of (many) impulses I generated, which will be used as impulse responses to model our church's acoustics, in this time of ...
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1answer
64 views

how to lower frequency of a soubd file in matlab?

I am new to programming and sound processing, I have been using matlab to process sound files, a few of which are ultrasonic. my sampling rate is 250kHz. I Would like to be able to play the sounds at ...
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0answers
14 views

How to convert audio buffer stream (of type '_io.BytesIO') to audio data? [migrated]

I'm trying to access the audio of a YouTube video to perform some operation on it. The goal is to capture the audio data and perform the desired operation rather than downloading audio file and then ...
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1answer
99 views

Distort voice to hide talker identity as much as possible

I need to develop an app which makes speech recognition. Because I need to be able to constantly improve the recognition capability, I would like to train the engine with real recordings and match the ...
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1answer
18 views

Is there two version of ulaw and alaw encoding in audio compression?

I am new to encoding in audios and i have searched for ulaw and alaw and found there is conversion from audio to this encoding CCITT alaw/ulaw and as i have known alaw/ulaw belongs to ITUT group not ...
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3answers
10k views

Tips for improving pitch detection

I'm working on a simple web app that allows the user to tune his/her guitar. I'm a real beginner in signal processing, so please don't judge me too harshly if my question is inappropriate. So, I ...
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6answers
859 views

What does one need to know in order to build a software synthesizer?

For someone who has some experience in software development, loves his synths and knows the [very] basics of digital audio representation, what are the first steps he should follow in order to program ...
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1answer
29 views

Match an Equalizer Curve

I’ve passed a sine sweep wave file into an equalizer plugin I have, now I want to model it in matlab so that I can ‘copy’ the equalizer setting sound. I’ve both in.wav and out.wav audio files and ...
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1answer
49 views

Popping sound after using bandpass filter

I'm trying to create guitar Wah Wah effect (basically band pass filter with dynamic frequency range). I'm using Steinberg SDK for it. I refactored this code to work in real time and it looks like this:...
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1answer
59 views

Is it possible for Matlab to read and decode an mp3 file?

I have run the following Matlab code and I got a signal as shown in the Figure below. ...
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0answers
28 views

Spectrogram parameters piano sound

I have to do 'inverse engineering' with piano sound and find sequence of frequencies in it. I have to use spectrogram() and adjust parameters but my problem is that I don't know how. I set window ...
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1answer
89 views

How to compute key of a song?

I'm looking for a precise way to compute the key of a song. BPM would be cool too. Analog is ok. I tried to approach it from the DFT angle, but got stuck and can't really put a finger on what's the ...
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3answers
349 views

How is it possible plotting frequency vs. time in audio?

Something which makes me confused is how it is possible to create plotting of frequency vs. time domain. Isn't time domain is opposite of frequency domain and the only way is to plot amplitude vs. ...
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1answer
35 views

Digital Audio Mixing Fundamental. What will be the data rate of mixed audio?

I have voice data at 128 kbps coming from three different sources. I'm looking for mixing all three voices together and sending it back to speakers. What methodologies are there for mixing digital ...
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3answers
682 views

What is the proper way to implement a real time spectrogram?

I am trying to implement a real time spectrogram and I am not sure that I am implementing it the right way. First I decided to use Matlab, I was taking a short recording of lets say 0.1 seconds and ...
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2answers
2k views

What is Causing a Cyclic 1kHz Noise Signal in Audio Recording?

I dug my old Behringer UCA202 out of my shed and plugged it into a computer. I did some tests and it appears to be working fine... apart from some noise signals on the line input channels. I'm not ...
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3answers
164 views

Is it possible to “equalise” a signal by deconvolving the impulse response of the room in which it is to be played?

I am using a test sweep with a flat power spectrum and linear group delay (Optimized Aoshima's Time Stretched Pulse) to measure a room's frequency response. Having obtained the impulse response of the ...
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1answer
30 views

How to calculate pitch fundamental frequency f( 0) ) in time domain?

I am new in DSP, trying to calculate fundamental frequency ( f(0) ) for each segmented frame of the audio file. The methods of F0 estimation can be divided into ...
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1answer
49 views

How to decide filter order in Linear Prediction Coefficients ( LPC ) while calculating formant frequency features?

I am new in signal processing and trying to calculate formant frequency features for different .wav files. For calcuating formant frequency, I need three parameters values : Linear Prediction ...
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5answers
9k views

Equal power crossfade

I am working on an audio system where I need to implement an equal power crossfade between two signals over a specified number of samples. Initially I implemented a linear fade but this creates a dip ...
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1answer
34 views

Hydrophone sensitivity rating

If I use a hydrophone with the sensitivity given as: "-200 dB re 1V/μPa". Question: How should I interpret this? Is it the voltage given at -200 dB SPL or?? All the Best!
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0answers
12 views

Masking threshold in psychoacoustics

I am reading the paper Adversarial Attacks Against Automatic Speech Recognition Systems via Psychoacoustic Hiding here. In Section III-F, they explained how they keep perturbation below the masking ...
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1answer
23 views

script to check zero crossings to check if microphones phases are aligned

I have 'n' microphones placed in square fashion and I want to make sure that all the channels must be aligned in time exactly the same if the signal is equidistant from all the 'n' microphones i.e. in ...
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2answers
2k views

Compare two wave files

I have two .wav audio(stereo) files to be compared. The files may vary in frequency or amplitude or phase shift. How to compute the difference between the wave files in Scilab? The expected output is ...
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1answer
284 views

generate a repeated square pulse train in python

Generate a pulse train with -2dBFS pulses of 20 sample duration every 8 seconds. I have referred here to generate a pulse train but not able to repeat it. How can I repeat this audio signal every 8 ...
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0answers
26 views

How can I detect the presence of echo in an audio?

The presence of echo during a phone call can be extremely irritating. Echo consists typically of the speakers sound being picked up by the microphone with a certain delay (10-200ms). One of the causes ...
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2answers
291 views

can MFCC coefficients alone be used to do voice detection?

Aim of my project is to differentiate between cases of silence, single active speaker and multiple ( simultaneous ) active speakers using as basic ( but effective ) logic as possible. Is it possible ...
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1answer
15 views

What does librosa.load return?

I'm new to signal processing and I'm working with librosa library quite a bit. I would like to know what is the information that is returned by librosa.load function when I read a audio(.wav) file ...
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3answers
326 views

audio for VOIP - filter and resample or viceversa?

I am a noob to signal processing, but I need to create some audio files for IVR for Asterisk VOIP. So my lady friend with a nice voice records her message on a Windows machine and sends me a 44KHz, ...
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1answer
751 views

$1/n$ octave complex smoothing

An excellent answer to this post explains how to do $1/n$ octave energy smoothing and mentions complex smoothing can be done as well, but it's tricky business because of phase wrapping. How is phase ...
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2answers
25 views

Sudden loudness changes producing unwanted noises?

What's that effect called? Is that one of the reasons for having attack and release parameters when implementing synths? And is there a generic method to avoid such sound artifacts? Example: I have ...
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0answers
16 views

Can someone help me this db transform applied on melspectogram?

I have read some audio processing codes written in Python : ...
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1answer
330 views

What are F0 counters in Speech signals? What is represented by F0?

I can't find any dedicated definition for Frequency F0 counters. Can anyone tell me what does F0 exactly mean, I am confused about that.
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0answers
32 views

Hide audio inside other audio using FFT

How can i hide audio inside other using FFT, I need to know how to begin and what to do ? the first image is for the first audio and the second which i want to hide
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2answers
99 views

Realtime sample rate conversion

Is it possible to have a realtime sample rate conversion in a way that a peer A with an audio stream at 44.1 KHz sends it signal over the network to another peer that is on an audio stream at a 48 KHz ...
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2answers
137 views

How to graph magnitude plots for basic 4-pole filters?

I have developed magnitude plots for basic one-pole and two-pole filters derived from various Physics PDF's and tutorials I have found online and calculated from: https://www.desmos.com/calculator/...
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0answers
8 views

Spectrogram vs MelSpectrogram

I am a university student in computer science and during a project, I run into the Mel Spectrogram. Doing some research, I found that the MelSpectogram is essentially a spectrogram where the distance ...
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2answers
197 views

How can I insert message bits into the frequency spectrum of an audio signal using Matlab?

I have been trying to use the DSSS spread spectrum technique for audio steganography in MATLAB. I multiplied the PN sequence with the message bits. Now I want to insert this spread message into a ...
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1answer
16 views

Ambient noise levels in desert and recording studio

Are there mathematical models which suggest which of the two - desert or recording studio - is likely to be quieter? I would think a recording studio would be quieter than a desert. Is there a ...
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2answers
1k views

STFT overlap add method - What am i doing wrong?

i am trying to implement a short time fourier transform of an audio signal to do some filtering (subtract another stft signal using spectral subtraction). I am using a hamming window function with 50% ...
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1answer
2k views

Audio steganography using phase encoding technique

I referred the below papers to understand the working of Phase Encoding,but the explanation is not proper.Just a few steps have been given in brief. ijcsi.org www.ijarcce.com Can someone please ...
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3answers
121 views

Modeling the human perception of noise

Add together some sinusoids with irrational or "nearly" irrational frequency ratios, and you get something pseudoperiodic. If there aren't too many, you can hear that it has only pitched components, ...
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1answer
29 views

How can I filter a noise with pattern type in audio?

I have a set of audio files rescued from a source of phonograph record like a gramophone. Very old family stuff records from my elders back in year 1946. A relative has digitalized these with a ...
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1answer
2k views

Bandpass filter for audio wav file

How do I apply a bandpass filter on an audio file which is in wav format? And write back the filtered data in a new wav file for further analysis.

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