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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20 views

Improve $\rm dB$ level after upsampling audio

I am doing upsampling from $44.1\textrm{ kHz}$ to $48\textrm{ kHz}$ on android device, using $\rm sinc$ interpolation. The output $\rm dB$ level is upto the mark for wave file up to $15\textrm{ ...
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1answer
21 views

How to calculate Long Term Average Spectrum of an audio file?

I'm working with audio files and I have to find their long term average spectrum. Although I had an option available in the software Praat but I don't understand the algorithm of finding the spectrum. ...
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0answers
14 views

Synchronization of two audio tracks via Mel-frequency cepstral coefficients (MFCCs)

I am trying to solve the (common) problem of synchronizing (i.e. measuring the delay between) two audio tracks recorded from different sources during a conference talk (about 1h of audio). One track ...
1
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0answers
7 views

STM32 Discovery dev platforms [closed]

I'm still researching this but though I'd post asking about experiences. Looks like st.com offers a variety of STM32 Discovery dev boards for ARM CPUs to, among other things, play with DSP. But ...
3
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4answers
107 views

How to calculate an azimuth of a sound source in stereo signal

Let say we have a stereo recording of only one source. What is a correct algorithm to calculate its azimuth using inter channel time difference and inter channel level difference?
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1answer
42 views

Bandlimited PWM

Trying to figure out how to synthesize a Bandlimited PWM in my audio code in C. I have already figured out a bandlimited pulse wave but I can't really figure out how to translate that to PWM. I have ...
0
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1answer
36 views

How do I measure frequency of an audio file into an array?

So I know how to plot fft the audio file within Matlab and a window pops up. My question is, what next? I want to know how to go about measuring the frequency(s). I have two similar audio files, of ...
3
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1answer
62 views

How to do continuous signal processing (i.e without windowing)?

I'm working in speech recognition research, and I wonder if there is a way to analyse sound just like how ears do (i.e. without windowing), so for example to take some feature continuously with an ...
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0answers
27 views

How to calibrate two microphones to same frequency range

I am recording stereo with two same microphones but they are physically insulated from eachother and have some additions on sound input side. Not to complicate story, I have a human head simulation ...
5
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1answer
64 views

Bandwidth expansion by computing missing harmonics in music?

In old recordings or highly compressed audio files (lossy), the higher frequencies are lost, and we hear a distinctive muffling effect. (Just like if the song was played through a wall) Is it ...
0
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1answer
37 views

How to overlap and add the frames after applying some modification in time domain

I am trying to apply Dynamic range compression (DRC) in time domain in MATLAB. But I am having problem in overlapping and adding the frames. Here is my work: ...
1
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2answers
69 views

Problem with Generalized Cross Correlation (PHAT filter)

I have to calculate time delay between two signals.I am using the GCC-PHAT method. First, I cut the signals into smaller parts (~0.5s) and then try to calculate the delay. When I display those two ...
0
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2answers
29 views

I want to know if there is a practical way to find out if multipath propagation is significant for audio in a given environment?

I am employing audio signals generated by a mechanical press for Blind Signal Separation. But, prior to algorithm application, I need to clarify if the signal strengths coming in multipath (except ...
0
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1answer
33 views

Specs for creating sample set?

I would like to create a set of audio samples for playback as a midi-controlled instrument. Thus: a sample for every key of the piano range, with multiple volume timbres for each note. I am able to ...
0
votes
1answer
45 views

How many DFT bins must I use to get best precision when analyzing melody scale

I need to analyze some signals containing chords. How big DFT spectrum is needed to identify each possible musical note in such a signal sampled at 44100 Hz? I can see that 8192 bins gives some ...
1
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2answers
35 views

Sampling frequency of audio

Based on what we choose sampling frequency when sampling some song? Do we use Nyquist–Shannon sampling theorem, or maximum sampling frequencies are pre-defined, so it will never come to aliasing ...
0
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1answer
64 views

Audio Broadband Noise Detection

I have to quantify the broadband noise of an audio track. I've seen lots of things around and the only viable option to estimate the broadband noise (without having any information about it) is ...
1
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1answer
51 views

Best DSP algoritms for ultrasonic background noise cancellation

I am looking into detection of pressurized gas leaks by means of the broadband hissing sound (white noise) generated from pressurized leaking gas. The instrument will have a broadband microphone ...
0
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1answer
65 views

Slope of 2nd order low pass vs band pass Butterworth filters

I have noticed that some manufacturers of audio processing products label a 2nd order Butterworth low pass as having a slope of 12dB per octave, but then also label a 2nd order Butterworth band pass ...
1
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1answer
43 views

Looking for low-noise audio data to benchmark some noise-processing techniques

I'm looking for a source of very low-noise audio data for use in benchmarking various methods of random noise correction methods. My intention is to have a very clean signal to which I can add known ...
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2answers
29 views

Combining channels into single FFT left/right vs mid/side

I am creating a spectrum analyser to visualize some stereo audio data in real time. I want to display a single spectrum for the input and a single spectrum for the output. The stereo data is the usual ...
0
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2answers
48 views

How to do the highest resolution FFT?

I wish to do the FFT of streaming audio data coming into a computer. I am just interested in frequencies from 80 Hz up to 1000 Hz but with a frequency resolution of 3 to 4 Hz and no more. Basically ...
0
votes
1answer
44 views

Why is this FFT code not working to extract frequencies from a wav audio?

I'm quite new to audio processing and i'm trying to extract frequencies from a wav file. As research papers stated i put the wav audio into a byte array and segmented and trying to apply FFT to get ...
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3answers
64 views

Performing DFT of streaming audio problem. Is there a limit?

I am trying to write software that will perform the discrete fourier transform of real time data coming from the microphone into the sound card on a computer. I am using Java with the javax.sound ...
4
votes
2answers
136 views

How to deal with low fundamental when using AMDF for pitch extraction?

I am using the Average Magnitude Difference Function to estimate the fundamental frequency of a quasi-periodic audio signal. The AMDF is defined as $$ D_n = \frac{1}{N-n}\sum_{k=n}^{N-1}|S_k - ...
2
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1answer
102 views

Demodulating FSK audio in Python

I am trying to write a Python script that can demodulate an FSK modulated audio file and return the data encoded in the audio. The data being transmitted is GPS NMEA strings which are embedded as the ...
1
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1answer
81 views

How to remove 50 Hz frequency noise from a PCM file?

Are you kind to tell me the odds or the means by which should I grab a clean signal with the $~50 \mathrm{Hz}$ carrier removed using just programming? I managed to make a program in Visual-C that ...
1
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2answers
72 views

How to do 3D audio?

There is the concept of audio played at specific locations relative to the listener, such as in games. What are the details of how this is accomplished in stereo or higher number of channels? I know ...
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1answer
54 views

how to detect short pause in a speech with noise?

I would like to count the number of short pauses in a speech and know the duration of the pauses by loading the signal into Matlab but I am very new to Matlab. Can anyone help and give me some ideas ...
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1answer
30 views

How can I read PCM linear file in Octave? [closed]

I have a pcm linear file (16 bits) collected with a sampling rate 8000 Hz. I want to read the file in octave. Whenever I read it using: ...
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0answers
35 views

Adding two audio files at a predefined SNR level

I have two speech audio wav files. file1 is primary speech, file2 is supposed to be interference. I want to add them so that ...
0
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0answers
42 views

Unable to generate and verify a sound wave of frequency 200 Hz

I am trying to generate a sound that contains low frequency in the range 100-500 Hz. I then record the sound using a microphone and generate a spectrum for the recorded signal using ...
1
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0answers
29 views

Applying DTW on MFCC frames

I want to use MFCC (Mel-frequency cepstral coefficients) and DTW (dynamic time warping) algorithms to make a speech comparison script. I calculated MFCC and got 13 coefficients for each frame. How ...
0
votes
3answers
89 views

Convolution and windowing using a buffer - how do I do overlap add?

I'm reading chunks of audio signal (1024 samples) using a buffer, applying a Hanning window, doing an FFT on it, then reading an Impulse Response, doing its FFT and then multiplying the two ...
1
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1answer
75 views

identification of sounds within audio signals

I am looking for methods to identify sounds within audio files. I was hoping to find some ready-made user-friendly software to do this but haven't found it yet. I am familiar with Matlab and some ...
0
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2answers
49 views

Smoothing an LFO Sawtooth Wave

I'm trying to smooth a Sawtooth wave coming out of my LFO. Effectively the transition from 1.0 to -1.0 in a 1 sample step is causing clicks and pops if I modulate my audio signals amplitude with ...
0
votes
1answer
29 views

How to measure noise, consonance, dissonance of a sound?

How can I make a graph of the noisiness of some audio durations of 100ms - 10s with 100% being white noise and 0% being a sine wave. I have FFT at the moment, are there other ways to know the ...
0
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1answer
39 views

Calculating an exponential curve

I'm developing a synthesiser and have finished the LFO's. I'm wanting to provide a knob on the UI for setting the rate. The minimum value of the LFO will be .01 Hz and the maximum value will be ...
0
votes
1answer
64 views

What is the physical significance of the Fourier coefficients in the DFT of audio signals and how can they be best displayed in a spectrogram?

I am trying to display the spectrogram of an input audio signal (a newcomer to all things spectral here). The amplitudes of my audio signal can be assumed to be normalized between -1 and +1. Suppose ...
0
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2answers
64 views

How to get finer grained spectral decomposition for audio signals?

I am not a "proper" DSP guy at all, so apologies in advance if I am making any basic errors in this question. I would really appreciate it if you could point out any errors I make. I have an audio ...
-1
votes
1answer
26 views

Programming a peaking filter (and how do I FFT?) [closed]

I want to get into audio signal processing. I know how to generate a tone, but I have no idea how filters work. What do I do to a set of samples to boost/cut a frequency with adjustable bandwidth? ...
1
vote
1answer
49 views

Multichannel input/output evaluation board

I'm working on a project at school and the first step is to choose a dsp/evaluation board but I'm having trouble. The project is to create a system that can be used for a variety of audio applications ...
0
votes
1answer
42 views

iZotope RX's FFT processing?

How does iZotope RX handle the FFT (i.e. how does it manage to perform those processes in the frequency domain without creating glitches) since its able to e.g. Apply another DSP process (even ...
0
votes
2answers
70 views

Audio frequency modulation algorithm

I have a digital audio signal (float samples). I need to apply the Vibrato effect to a signal. "Vibrato" is no common term, but it is the same as the frequency modulation. So, I need to modulate my ...
1
vote
1answer
52 views

VIbrato (pitch variation) function

I'm looking for an algorithm for Vibrato audio effect for a cross-platform C++ program of audio processing. Now I use the realization from Chaotic-DAW sources. The problem is that Chaotic-DAW has a ...
0
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0answers
34 views

Multi-band audio delay filter?

I'll be processing stereo music signal. What I need is to first split the frequency range into 2 bands at 50-100 Hz. In the higher band, I need to delay one of the channels by a certain number of ...
0
votes
0answers
18 views

Algorithm to compare audio for similarity? [duplicate]

Right now I am doing the following: For each of the 2 audio files: Compute the Mel/Bark or EBR Bands for every frame. Then find the average of band 1 across all frames, then avg of band 2 across all ...
1
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1answer
47 views

Finding specific spots in an audio signal

In theory, how would one process an audio signal to find the spots marked in the linked picture below. Mel Spectrogram Unfortunately I am not really conform with signal processing and could not find ...
0
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0answers
36 views

How to find the energy of a single frequency from its time-frequency distribution?

I have a non-stationary time series. I am interested in finding the energy content of a single frequency (actually the ratio of that single frequency over the total energy of the signal). The problem ...
2
votes
2answers
55 views

How to know when a sound in a given frequency starts and ends?

I need to detect two sounds (913 Hz and 1370 Hz), knowing the time in which each starts and ends. At this time, I am using a band pass filter (butter), and this is the result: Here is the first ...