28
votes
Accepted
Does the Nyquist frequency of the cochlear nerve impose the fundamental limit on human hearing?
Does the Nyquist frequency of the Cochlear nerve impose the fundamental limit on human hearing?
No.
A quick run-through the human auditory system:
The outer ear (pinnae, ear canal), spatially "...
- 48.2k
19
votes
Why isn't silence just zeroes in an audio file, and how can I make it?
Full silence is just zeroes.
You likely generated the silence to an audio track which is in some other format than 16-bit PCM, like float or 24-bit or 32-bit PCM.
When you exported it as 16-bit wave ...
- 2,331
14
votes
What are possible reasons a sound may be continually clicking (low amplitude, no sudden changes in amplitude)
There are discontinuities in the waveform.
Please open the file in a program that allows you to zoom in on the waveform.
There is a visible click at 0.9404 seconds, after sample number 20735.
It ...
- 2,331
13
votes
What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?
Especially What is the maximum value of frequency that human speech can have?
This depends on how exactly you define it. Fricatives ("s","f","sh" ...) and plosives (&...
- 48.2k
12
votes
How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?
What you want to do is called "Super Resolution" in the field of imaging.
This is an ill posed problem.
Hence in order to solve it you need some prior / model about your audio data.
For ...
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12
votes
What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?
The fundamental speaking frequency of humans can reach up to around 1kHz, although higher values than, say, 500Hz usually appear only while singing.
The harmonics and non-tonal parts of speech can ...
- 2,383
11
votes
How to compute dBFS?
All the standards define dBFS as an RMS measurement, relative to the RMS level of a full-scale sine wave, so the calculation is:
...
- 16k
9
votes
Transmit data through sound between 2 computers (very close distance)
As you have realized, the hard part of doing digital communications is carrier, symbol and frame synchronization, and channel estimation/equalization.
The bad news is that you can't get around these ...
- 15.4k
9
votes
How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?
While I don't know about tools for upsampling using AI, I am challenging the assumption that the main problem with your sample is lost high frequncies due to resampling from 44kHz to 22kHz, so "...
- 191
8
votes
Accepted
Signal processing for audio and speech
In line with a previous similar question here are my suggestions:
There are so many nice books but I believe you should first have a look at the science of sound from Rossing for getting the most ...
- 28.4k
8
votes
How can one design earplugs so that they provide protection from loud noises, such as explosions or gunfire, while still allowing user to hear voices?
Tricky.
The spectrum of small fire arms (guns & rifles) is about 150Hz to 2500Hz (with a peak SPL at 900Hz-1500Hz). This overlaps a lot of the speech spectrum. Larger weapons sit lower: below ...
- 48.2k
7
votes
Accepted
What is the (approximate) function for amplitude of a plucked string over time? Does it differ between string types?
An exponentially decaying envelope $a\exp(-b x)$ is a good choice, and is used for example in vintage Yamaha FM synthesizers. It has the favorable property that over any constant length time interval, ...
- 13.7k
7
votes
Accepted
Synthesizing piano
Physical Audio Signal Processing by Julius Smith is probably something you'd be interested in! The full book is available online, and there's a whole chapter devoted to piano synthesis.
- 6,814
6
votes
How does Siri recognize me saying "Hey Siri"?
"Ok Google" is described in many publications by Google
Automatic Gain Control and Multi-style Training for Robust Small-Footprint Keyword Spotting with Deep Neural Networks
Convolutional Neural ...
- 1,119
6
votes
Sound absorption coefficients for frequencies higher than 8kHz and lower than 80Hz?
The main reason why the tables don't have it, is that it's hard to measure. The measurement technique in ISO 354:2003 relies on measuring the difference in reverberation times in a reverberation rooms ...
- 48.2k
6
votes
Accepted
Audio Processing Glossary
My own interpretation:
Sound: a mechanical wave that propagates through the air or water.
Audio: sound in the 20 Hz to 20 kHz range; in other words, sound that is (at least in theory) audible to a ...
- 15.4k
5
votes
Accepted
Generating inaudible sound waves using MATLAB
Eventhough the exact cause of those wide-spread line spectra is not very clear to me from the supplied information, it's most probably due to the on-off switching implied by the silence period you ...
- 28.4k
5
votes
Accepted
How to convert a sound signal function to wave file?
i don't consider this a "bad" question. But there is a lot that nano needs to deal with.
first, you must be able to think about conceptually and mathematically converting your continuous-time signal
...
- 21.4k
5
votes
Accepted
Maximum cross-correlation coefficient value for time delay estimation
As your plot shows, the second form allows for the correlation peak to be negative. Now, what does a strong negative cross correlation mean? It means the signals are very similar, except one has a ...
- 2,463
5
votes
Accepted
How are sounds recorded and reproduced (played back)?
A big question. Plz have a look at this first https://en.wikipedia.org/wiki/Sound_recording_and_reproduction.
Sound is highly related to vibration. Sound is generated by vibration of a sound source, ...
- 3,263
5
votes
Why is the reference pressure for dB SPL 20uPa?
It's complicated.
Let's take it step by step:
Sound pressure is a physical quantity that's related to the intensity of the sound field where you measure the pressure. It's measured in Pascal $Pa = \...
- 48.2k
5
votes
How to detect direction of sound using four microphones?
Is it possible to calculate vector from center of box to the source of sound realtime?
Theoretically yes. As long as the microphones are no co-planar or co-linear, 4 is fine.
You can use cross ...
- 48.2k
5
votes
Why isn't silence just zeroes in an audio file, and how can I make it?
What algorithm does Audacity use / can I use to generate "silence"?
Insert zeros in the audio stream.
However:
Microsoft WAV (the typical format for files ending in ...
- 32.5k
5
votes
How can one design earplugs so that they provide protection from loud noises, such as explosions or gunfire, while still allowing user to hear voices?
In your question you asked about the 3M Combat Arms Earplugs, I skimmed there patents and documentation. Here is roughly how they work.
The current gen Combat Arms Earplugs have a rocker to switch ...
- 184
4
votes
Signal processing for audio and speech
But which features of signals reveal differences between piano and guitar
Look at things like timbre; basically, most things when excited to oscillate will not only produce a single tone, but a set ...
- 32.5k
4
votes
Audio time stretching, without pitch shifting
The phase vocoder was first implemented by Flanagan and Golden[1] using analog filters bank, later Portnoff apply the same concept digitally using FFT.
The phase vocoder use the difference of
...
- 2,048
4
votes
Accepted
Why does this video's audio change depending on the playing device?
The 2 stereo channel might be out of phase (near opposites, thus cancelling each other out when mixed to mono).
The human ear-brain doesn't just sum stereo left-right to the 2 ears, but instead uses ...
- 35.7k
4
votes
Accepted
Transmit data through sound between 2 computers (very close distance)
In the end, I used DTMF (Dual Tone Multi Frequency signaling). The original DTMF has 16 signals each using a combination of 2 frequencies. But here I only used "1"(697 Hz and 1209 Hz) and "0" (941Hz ...
- 269
4
votes
Mathematical equation for the sound wave that a piano makes
The best wave form function I found so far is in this video.
In terms of my experience this is the formula:
...
- 41
Only top scored, non community-wiki answers of a minimum length are eligible