# Questions tagged [speech]

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121 views

### HMM's - Possibility?

I have a basic understanding of HMM's and as a final year project at school wanted to expand my knowledge further. My basic idea was to create an algorithm that determines if someone is saying ...
85 views

### About speech preprocessing in mobile phones

I understand that cell phones transmit speech signals in digital form through 2G/3G or other standards. But I could not find anything about the signal processing method lying in between the analog ...
699 views

### Why discrete cosine transform may not maintain locality

In paper Convolutional neural network for speech recognition, they say I didn't understand the highlighted sentence.
7k views

### MFCC Deltas, Delta-Deltas

I have just a quick question about how to calculate Deltas from MFCC. I have found the formula for calculating deltas here: d_t=\frac{\sum_{n=1}^{N}n\left(c_{t+n}-c_{t-n}\right)}{2\sum_{n=1}^{N}n^2}...
2k views

### How to convert NIST to RIFF wav file

I have a dataset of audios(namely TIDIGITS, collected at Texas Instruments, Inc.) and they are in .wav format. However, when I try to read them from python, I get the following error: ...
1k views

### The minimal signal to noise ratio (SNR) for people to understand a speech in the noisy background

This question seems easy to find an answer but I got lost in the end. I am trying to find the threshold for people to understand speech in a noisy environment. For example, assume the background noise ...
829 views

### Is Cross correlation between stationary random signal and noise zero for all lags?

If $x(n)$ is a stationary random process (let say small 20ms window of speech which can be assumed stationary) and $v(n)$ is said to be uncorrelated noise, can we say that cross correlation of $x(n)$ ...
56 views

### Comparing signals recorded using diffrent methods

Suppose we have two signals( focus to audio) recorded with different methods, or more simply, suppose we have two audio signals recorded with different microphone, and we want to confirm that these ...
103 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 ...
1k views

### MFCC window size at different sampling rates

The general recommendation for window size when calculating MFCC seems to be 20-40 msec. This is most often recommended in a context of 16000 samples per second, so leading to a window containing 320-...
73 views

### Is there a method to combine speech signals recorded by different microphones?

I have 3 speech files of the same speech recorded by 3 different microphones at the same time. I'm only concerned to improve the speech quality (in terms of SNR and intelligibility) by combining the ...
398 views

### audio quality evaluation

I am creating a dataset, where in many speakers are recording their speech signals using different microphones and in different environment. I would like to evaluate the quality of audio and discard ...
69 views

### Why are the observation features of an HMM-based recognition/synthesis system modeled by a Gaussian distribution?

Why are the observation features (namely MFCCs) of an HMM-based recognition/synthesis system modeled by a Gaussian distribution? Even the state duration is modeled by a Gaussian in this paper: K. ...
156 views

### What are good estimates for phonemes length?

I am working in a phoneme recognition project, the language that I am using is "English". I have a tool that converts each written phrase in phonemes. Also I have an estimation of the time length of ...
1k views

### Removing vocoder effect from audio file

There are many tutorials and guides explaining how to create a "robotic" voice by using a vocoder or a mix of filters that change pitch, tempo and maybe add a slight echoed delay. However, is it ...
418 views

### PSOLA how to calculate synthesized Marks

I have successfully extracts all Pitch Markers from waveforms, I used autocorrelation to find my pitch periods, The markers can be observed in the figure below: I want change my signal (Pitch or ...
318 views

### Speech recognition library for detecting phrase in file

I want to find all occurrences of a specific phrase in a set of audio files (it's a catch-phrase in a TV show). The phrase is pronounced by different people with different speed etc. What is the best ...
435 views

### autoregressive moving average code implementation

I am new to DSP and i am trying to take a wav (human speech) file and apply ARMA filter and plot its PSD graph in python. I see that there are a lot of AR implementations but almost none ARMA. I ...
59 views

### peak-to-peak test between two signal

Suppose that we have different signals (Pulses). I would like to study which signal has deterministic peak-to-peak distant (lag). For example A=[1 0 0 1 0 0 0 1 0 0 1] and B=[1 0 0 1 0 0 1 0 0 1] and ...
36 views

### Examples of cases where “invariance to transformation” on signal is important

I realize that this might not be the most well-formulated question, but I figured I'd throw it out there as an open-ended discussion that could turn up some interesting input. I'm relatively new to ...
97 views

### How best to digitize a noisy phone recording for filtering?

How do I digitize an analog telephone recording and filter it with a Chebyshev filter?
187 views

### Speech Recognition - Subtitles

I am looking for ANY advice anyone can give me regarding on this problem. I'm looking to start a project on subtitles, basically, if we take a Youtube video of a breaking news story, subtitles are ...
831 views

### Averaging Different Length Speech Signal

I have around 10 wav audio files all containing same word spoken i.e. 'Hello' but all having different length. So lets say 1st file when loaded consist of 20000 samples, 2nd of 15000, 3rd of 18000 ...
1k views

### Speech Analysis - Zero-Crossing

Basically, (I know I've asked a simular question, but I have been away and really thought about it this time)! Let me try and explain this in the best way possible: Basically, I'm attempting to ...
250 views

### Non human formant frequencies

Some animals are specially trained to repeat human phrases, others just make sounds that people interpret as speech. In this video a rooster seems to say "Cristo Viene" (Christ is coming). Taking ...
2k 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 $\left(16000*0.03=480\right)$ but I could not find the exact pdf for that. sometimes it appear like 2 mixed ...
2k views

### Pitch estimation using the autocorrelation method

I have the following code: ...
2k views

### how can i center an audio signal?

I'm trying to reconstruct an audio signal, and below is what i got after rescaling. How can i obtain centered audio signal such as below? SOLVED: ruoho ruotsi's answer addresses my problem :) i ...
1k views

### The logarithm Energy measure in Speech

I am studying the mel-frequency cepstral coefficient (MFCC) and have downloaded a pdf which is related to MFCC from this link. It is about the "ETSI ES 201 108" ETSI ES 201 108 - Speech ...
2k views

### How to compare vocal words in matlab

We as a group are new to signal processing and speech recognition. We have stored .wav sounds of three different words and we are trying to record a new .wav sound and have the system compare the ...
770 views

### Audio/speech detection, verification

I would like to write a program to compare two '.wav' files, one of which is the original played file with human speech and the other is a recorded '.wav' file. The program I wish to write in python ...
27 views

### Characterization of the amount of modulation in a signal

We have used the ICRA babble noise to generate an 8-talker babble. As a background - babble noise is used as a substitute for competing talkers as babble noise lacks lexical content, but contains the ...
189 views

### Frequency detection in audio and what parameter or set of parameters help/limit frequency detection

I'm trying to learn audio and voice/speech processing techniques out of interest. I intend to learn, experiment with algorithms and design, implementation of such systems, frameworks using programming ...
137 views

### Trying to compare two speech samples that have been recorded by smartphones in pockets

I'm trying to compare two audio samples of speech from two different Android smartphones to determine if the people are co-located. I'm doing this using the frequency bins of an FFT between 300 Hz - ...
353 views

### Raw speech data into spectrogram

I am using Delphi trying to make a very simple speech recognition system. The system collects raw data well, but I have a hard time turning the data into a spectrogram: The system collects an array ...
68 views

### Fine-grained evaluation of speech recognition results

I know that usually ASR systems are evaluated using WER (word error rate), and I was wondering if it makes sense to use a more fine grained approach. E.g. transforming both the ASR hypothesis and the ...
1k views

### Calculating Delta MFCC, correct formula?

I have seen different formulations of how to calculate delta MFCCs. In general, I want to be consistent in such a way that if I have other features to look at other than MFCCs, the way I would ...
113 views

What are the best ways to mask a voice tone, like what they do during news shows on television sometimes? Is there a way that is not reversibile? I think that a ...
44 views

### Matching two video conversations

I have two video where two person having conversation. They begin recording different times. I want to match these two videos' frame numbers, i.e. By matching audio. How can I do that?
61 views

### Bandwidth of time-varying harmonics of speech

For speech signals, do the harmonics have a constant bandwidth above some threshold (arbitrarily, -6 dB dropoffs)? Or does this bandwidth decrease with the upper harmonics? If this is not known, how ...
244 views

### Preprocessing signal before LPC

I have a signal that contains the speaking of three vowels. The signal is contaminated with dc offset and an interference at 60 Hz. I want to perform LPC for the synthesis of the spoken vowels. Do I ...
402 views

### pitch extraction for speech

I am building an LPC analysis tool, and am at the point of needing to do pitch period analysis. I was initially interested in using the Gold & Rabiner algorithm for this, and got a hold of a ...
133 views

### Pesq numbers and clean speech comparison to processed speech

I am trying to evaluate my processed speech for my DSP project. My project is an implementation of an MMSE algorithm proposed by Y.Ephraim and D. Malah, "Speech Enhancement Using a Minimum Mean Square ...
319 views

### Speech discrimination from animal sound

i am looking for discrimination of speech from animal sound if you take a 150ms frame of speech and bird as shown below, what feature can i extract from them so that i can effectively state the ...
2k views

### Relationship between frame rate and sampling frequency in speech signal processing?

While I was going through the short time processing of speech signals, I got stuck at the relationship between the frame rate and the sampling frequency. Is there any relationship between them for ...
171 views

### Format location from LPC magnitude

I am confusing when I find the lpc roots magnitude, f1=0.9313, f2=0.9308, f3=0.91 and f4=0.95 but when I look at LPC envelope the f1 is higher than f4 in term of magnitude in dB. Could anybody explain ...
109 views

### How to compare two speech recognition softwares?

I am working on building speech recognition software for my company. In the meantime however, we will purchase some off-the-shelf commercial speech recognizers until the in-house one is ready. My ...
10 views

### Help in LBG Vector Quantization - Splitting Factor

I'm currently making a program for speech recognition. In the step of codebook generation using the LBG (Linde-Buzo-Gray) algorithm, I've read that the splitting factor $\varepsilon = 0.01$ (generally)...