Questions tagged [sound]
The sound tag has no usage guidance.
203
questions
2
votes
3answers
64 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 ...
-1
votes
1answer
22 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 ...
0
votes
0answers
16 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 ...
0
votes
1answer
44 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 ...
3
votes
1answer
138 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 ...
0
votes
2answers
63 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 ...
0
votes
0answers
23 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 ...
1
vote
2answers
35 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 "...
0
votes
1answer
85 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 ...
1
vote
2answers
359 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 ...
0
votes
1answer
23 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 ...
2
votes
1answer
115 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 ...
1
vote
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 ...
0
votes
2answers
83 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 ...
0
votes
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 ...
0
votes
1answer
98 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 ...
0
votes
1answer
84 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.
...
0
votes
1answer
72 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 ...
2
votes
3answers
590 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 ...
0
votes
1answer
42 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 ...
0
votes
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 ...
1
vote
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 ...
0
votes
1answer
36 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 ...
0
votes
1answer
209 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 ...
0
votes
2answers
142 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 ...
3
votes
1answer
249 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 ...
1
vote
2answers
161 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 ...
0
votes
1answer
87 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?
1
vote
3answers
142 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 ...
0
votes
1answer
130 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 ...
0
votes
1answer
172 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 ...
2
votes
2answers
185 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 ...
-1
votes
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 ...
0
votes
1answer
69 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 ...
0
votes
1answer
357 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 ...
4
votes
1answer
275 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 ...
0
votes
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 ...
0
votes
1answer
30 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 ...
0
votes
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) ...
2
votes
1answer
62 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 ...
2
votes
0answers
430 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:
...
0
votes
2answers
116 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.
...
4
votes
1answer
626 views
Polyphase Filter decomposition. It is not working
So, I want to do a polyphase implementation of a filter bank (I had problems with it since the beginning and I already asked for help to the community in the past, indeed: Norm MPEG-1 Layer III (Mp3) ...
12
votes
3answers
2k views
Transmit data through sound between 2 computers (very close distance)
I'm writing an example on transmitting data through sound betwwen 2 computers. Some requirements:
The distance is very close , i.e the 2 computers are basically adjacent to each other
Very little ...
1
vote
2answers
84 views
Custom ringtone sounds good on computer, can't be heard on phone [closed]
I did a ringtone using Audacity and then used this website to convert to mp3. I sent this mp3 file to a friend who said he couldn't hear it well. I have an iPhone so I converted it to m4r. Both the ...
0
votes
2answers
120 views
How to label sound events in noisy .wav files
I'm trying to find a way of automatically identifying birdsong in phone-recorded sound files (1min long). Currently the algorithm I'm using doesn't label all of the events I want it to. (it is ...
0
votes
1answer
2k views
How to transform SoundWave Picture to sound?
I would like to recreate a sound from a picture of a soundwave.
But i see a lot of theorical question.
And im not sure its possible....
I mean, it is possible to create a sound...
But to make ...
0
votes
1answer
439 views
Normalizing audio waveforms code implementation (Peak, RMS)
I have some audio data (array of floats) which I use to plot a simple
waveform.
When plotted, the waveform doesn't max out at the edges.
No problem - the data just needs to be normalized. I iterate ...
0
votes
1answer
903 views
Delay-and-sum beamforming: implementing steering in C
I am currently trying to understand how delay-and-sum beamforming works.
I have found this website which explains the process of this technique very well in which the following C code is provided:
<...
1
vote
1answer
34 views
Why does this video's audio change depending on the playing device?
Yesterday I noticed that if I played this video from my smartphone on speaker, one could barely hear anything. On the other hand, if I used earphones I could hear it perfectly.
Then, I tried with ...
