Audio, or in terms of signal processing, an audio signal is an analog or digital representation of sound, typically as an electrical voltage.
1
vote
0answers
26 views
Multiresolution discrete wavelet transforms: First steps
I have been looking at trying to use wavelets for multichannel audio dynamic range processor. I am in the very early stages of trying to get decomposition and reconstruction working. In this thesis, ...
5
votes
1answer
61 views
Learning roadmap for the audio signal processing beginner
I would like to start learning audio signal processing. There are numerous books online and academic papers all of which seem to skip the fundamentals of the topic.
I would like to know a rough ...
0
votes
0answers
19 views
Frequency cut-offs for guitar amp tone [migrated]
I am wanting to know what the typical frequency cut-offs are for the bass/mid/treble controls on a pre-1990s guitar amp. I want to simulate them in Java. So basically I have
...
5
votes
1answer
82 views
Measuring time delay of audio signals
Before anyone yells at me I fully realize that this question has been asked numerous times. I assure you that I've read through the existing questions and answers but I am still confused about part of ...
0
votes
2answers
114 views
Removing noise from audio using Fourier transform in Matlab
I'm trying to remove noise from an audio file. This audio file contains speech as well as constant pink noise. I know that I have to use the Fourier transform to convert to the frequency domain then ...
0
votes
1answer
64 views
SineWave generation and BandPass filter : Audio
Can any one suggest me a Bandpass filter in java which I would like to apply on generated sine wave of a particular frequency
5
votes
1answer
116 views
Coloring a waveform with spectral centroid or by other means
Update 5
Some gradient using harmonic series
The color smoothing is ratio-sensitive otherwise it looks bad, will need some adjustment.
Update 4
Rewrote the coloring to happen at source and ...
0
votes
0answers
23 views
algorithm for audio and video separation using matlab [migrated]
sir
i want to design an algorithm which can take a movie clip or a video signal having both audio and video and extract the audio and video part separate using the help of filters, matlab and signal ...
1
vote
2answers
66 views
generating ultrasonic sound in matlab
I am working for my class project on making animal repellent , I need to know how I could go about taking a normal audio file and shift its frequency/Pitch very high to make it an ultrasonic sound.
-1
votes
0answers
56 views
audio signal amplitude
Since we hear the same sound on the left and right channel that mean they should have the same value in the 2 channels but it is not the case with me. The values in both channels are the amplitude of ...
3
votes
3answers
109 views
“Subtracting” one audio stream from another audio stream
I am a long time software engineer but have practically zero experience with signal/audio processing. I am interested in learning about signal processing via a use-case we have for one of our audio ...
0
votes
1answer
53 views
what is probability density function (PDF) of periodic signal
anybody knows what is the best pdf for periodic signal ?
I have signal with 480 samples (16000*0.03=480) but I could not find the exact pdf for that. sometimes it appear like 2 mixed Gaussian.
0
votes
2answers
86 views
Estimating the time offset (delay) between two audio signals in real-time
I'm looking for an algorithm which can accurately estimate the time-offset/delay between two audio signals in real-time. One audio signal is a loudspeaker signal and the other signal is the microphone ...
1
vote
3answers
113 views
Generalized Cross Correlation
What is the definition of Generalized Cross Correlation?
I need it for estimating the delay (time offset) between two audio signals. The time offset between the two signals might be as large as ...
3
votes
1answer
94 views
Hilbert transform filter for audio applications: Using IIR half-band parallel all pass structure
Does anyone have any experience designing wideband IIR Hilbert transform filters with audio applications in mind? I am using the filter for single side band modulation audio effects discussed in this ...
2
votes
1answer
80 views
Question about overlap-add
@Jim Clay: No if the filter varies slowly, then the clicks go away. So I guess the filter needs to vary slowly to avoid audible clicking sounds.
I created a test in matlab where I'm comparing ...
3
votes
2answers
60 views
What is the theoretic difference in the ways to compute the spectrogram?
I have noticed that the spectrogram for a audio signal is often calculated in different ways when the result from the DFT is transformed into real numbers; some tend to compute $|k|$ or $|k|^2$ while ...
1
vote
1answer
45 views
Detection of regions of voice in music
I want to detect the regions of voice in a song. Currently, I am using the fact that the vocals in the song are recorded as center panned. So, I am removing all center panned audio from the song. ...
7
votes
2answers
182 views
Can you represent an audio signal in any other domains besides time and frequency?
Maybe a stupid question, but if there is a time-domain representation of audio signal, and also frequency-domain, so is there any other domain that signal can be represented in?
0
votes
1answer
72 views
How to calculate the energy levels of frequency intervals of an audio signal?
Using the Fourier transformation I can translate a signal from the time-domain to the frequency-domain. If I divide the frequency axis into intervals, how can I calculate the audios signals energy for ...
2
votes
1answer
77 views
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 ...
2
votes
0answers
41 views
Are there any measurements or test for whether an audio signal is stationary?
I need to divide an audio signal into frames in which the signal can be assumed to be stationary. How can I measure whether an audio signal is stationary in a frame?
1
vote
1answer
110 views
How to get fundamental frequency of a signal using autocorrelation?
I am trying to get the fundamental frequency of a signal that only has a single pitch. I coded out the autocorrelation function using FFT and already got the autocorrelation result. Unfortunately, I ...
0
votes
0answers
62 views
How to measure the short-time change in an audio signal?
The choice of frame length for calculating the Mel Frequency Cepstral Coefficients of a signal, depend on the how much the signal change over a small time scale.
I guess that human speech change ...
4
votes
2answers
118 views
Low Pass Filter Artifacts
I have created a Low Pass filter (I am trying to understand the topic of DSP, and it's hard.. But moving along with samples, books and a nice post on Stack Overflow).
I am saving the 'output' to a ...
1
vote
0answers
21 views
Length of frames for calculating cepstral coefficients
For audio classification we are using the cepstral coefficients and their derivatives. Which I calculate using the Matlab libary voicebox.
I am looking for some literature for how to choose the frame ...
1
vote
1answer
35 views
How to apply convolution on a buffer
I'm trying to do some simple filtering for an audio signal using a window-sinc low pass filter. Supposing that my buffer has M values and the filter kernel size is N, after convolving these two arrays ...
1
vote
1answer
53 views
How can frequency dispersion in a vibrating string be modelled using an LTI filter?
According to JOS on stiff-string synthesis, stiff strings (like on a piano) introduce inharmonicity (i.e. the harmonics of the tone are not all in tune) due to different frequency components of the ...
2
votes
2answers
88 views
How to stitch together MFCCs from multiple frames?
I am trying to record a sound two times and compare the two recordings. I am playing exactly the same sound both times (for example, play a small .wav file twice and record it each time), so I hoped ...
4
votes
0answers
93 views
How does Songify work?
Does anyone know how does the "Songify" app algorithm work?
There are 2 inputs:
speech (or amateur singing), and
underlying music.
Somehow the speech is altered and mixed into the music. Which ...
0
votes
1answer
66 views
How to resample in MATLAB one signal that is supposed to be convolve with another one?
i have two audio signals .wav and i want to convolve them, the trouble is that the frequency do not fit, they aren´t just the same frecuency-lenght in the wavread arguments. i am supposed to use the ...
3
votes
1answer
64 views
Equal loudness curves: any good numerical approximation equations?
What might be, if any, some good numerical approximation functions to the ISO 226 family of human perceptual equal loudness curves? Is there a polynomial fit of reasonably low degree?
1
vote
2answers
201 views
Adding echo to audio sample
I have recorded my own voice in Matlab and I intend to add some echo to it.I came up with one solution for getting the desired echo effect:
Delay the sampled audio in the time domain and adding it ...
0
votes
2answers
82 views
Find out when an audio file is actually recorded?
Is there any technology to help find out when an audio file is actually recorded?
Here is the problem:
Given an audio file, how can we find out when it is recorded? File creation time is useless ...
1
vote
1answer
31 views
Establishing Phrase Frequency in Audio Files
Is there any Application, Programming Library or Theory that could be used to identify human language phrases in a set of audio files, so as to calculate the frequency of occurrence of each such ...
2
votes
1answer
53 views
Convolving With half-Hanning
The goal is to get a 200ms decaying delay of an audio signal while preserving the sharpness of attacks to mimick human perception of sound. The paper I'm following convolves a 200ms half-Hanning ...
2
votes
0answers
35 views
Compressing A Range Of Decibel Values to One “Representative” Value
Don't have any formal dsp experience - sophomore in college.
Working on constructing a 25 band bark spectrogram for psychoacoustic analysis of audio FFT data. To do this, I'm grouping all FFT ...
3
votes
1answer
59 views
pitch vs playback rate
Let's say I have an audio sample, whose pitch is known to be C4 (don't wanna go in detail here, let's say I just sampled a tuned piano playing the C4 key).
The rules of the game are: I can only ...
5
votes
1answer
240 views
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 ...
0
votes
1answer
57 views
get amplitude difference via cross correlation?
im currently comparing 2 signals:
A = some music
B = A + noise
and ive implemented cross correlation in frequency domain via complex multiplication to determine the time offset, which works ...
3
votes
0answers
72 views
how to extract telephone audio only from an mp3
I have mp3s of radio talk shows in which the host interviews people on the phone. The host uses a microphone, and the interviewee uses either a landline phone or a cell phone.
I want to save just the ...
0
votes
2answers
115 views
eliminate signal A from signal B
i have 2 audio signals, both available in time and frequency domain:
A: Noise
B: Noise(A with minor variations) + Additive sounds (C)
i want to eliminate Signal A from B to leave only C.
C is for ...
4
votes
2answers
156 views
Logarithmic fourier transform(LFT) on audio signal
I am trying to analyze the musics as possible as precisely.
Of course I tried FFT, but got some problems.
I found low frequencies have very low resolution than human's hearing. I tried very long time ...
1
vote
1answer
97 views
Speech comparison algorithm for rating on similarities
I am trying to compare 2 speech samples and rate them on similarities. Think of someone trying to repeat a phrase, and then comparing those 2 audio files.
I started by implementing the MFCC ...
0
votes
1answer
70 views
Dynamic time warping in percentage
I'd like to compare 2 speech similarity and show it in terms of 0-100%.
Here's my approach:
1: Convert 2 audio waveform into audio spectrum by Fast Fourier Transform (FFT)
2: Use Dynamic Time Warping ...
0
votes
1answer
134 views
Skype's SILK Codec
Let me start by clarifying the terminology that I will be using in the following.
A codec packet is the compressed data which an encoder returns when it is called once.
An RTP payload can consist of ...
5
votes
3answers
242 views
Common methods of transmitting digital data through an extremely noisy audio signal?
I am developing software for transmitting data from a computer to a mobile device using audio. Specifically, from the computer's speaker to the device's microphone. (I am developing both the sender ...
3
votes
2answers
99 views
What audio effects, filters, distortions, etc. create a “vinyl” effect?
I want to make any song sound like it's being played on a gramophone record in the 1920s. What specific filters would I apply to make this happen?
I'm looking for technical details, not some magical ...
0
votes
4answers
265 views
How to generate a good Sinus audio signal of specific SampleRate, DataBits and Chunnels in a time frame
I encountered a problem when I tried to generate by a program an sinus audio signal.
My parameters are
Sample Rate: 44100 Hz
Data Bits: 16 bits
Channels: 2
I need to create a WAV file ...
5
votes
1answer
121 views
How to mix two signals without changing the overall loudness?
I have two audio signals that I want to mix at various mixing ratios. Initially, I simply went for something like
$y(t) = \alpha \cdot x_1(t) + (1-\alpha) \cdot x_2(t)$
where $\alpha$ is the ratio ...
