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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 "...
Hilmar's user avatar
  • 45.3k
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 ...
Justme's user avatar
  • 2,303
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 ...
Justme's user avatar
  • 2,303
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 (&...
Hilmar's user avatar
  • 45.3k
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 ...
Mark's user avatar
  • 357
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 ...
Max's user avatar
  • 2,368
10 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: ...
endolith's user avatar
  • 15.8k
9 votes
Accepted

Why are zero values added in the FFT of a concatenated noise signal?

You're running into a property of the DFT that is usually used in the opposite direction: stuffing zeros between samples in one domain results in replication of the entire sequence in the opposite ...
Jason R's user avatar
  • 24.6k
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 ...
MBaz's user avatar
  • 15.3k
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 "...
Michael Karcher's user avatar
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 ...
Fat32's user avatar
  • 28.3k
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, ...
Olli Niemitalo's user avatar
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.
Jdip's user avatar
  • 6,265
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 ...
Nikolay Shmyrev's user avatar
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 ...
Hilmar's user avatar
  • 45.3k
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 ...
MBaz's user avatar
  • 15.3k
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 ...
Fat32's user avatar
  • 28.3k
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 ...
robert bristow-johnson's user avatar
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 ...
Florian's user avatar
  • 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, ...
ZR Han's user avatar
  • 3,248
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 = \...
Hilmar's user avatar
  • 45.3k
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 ...
Hilmar's user avatar
  • 45.3k
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 ...
Marcus Müller's user avatar
4 votes

Signals cross-correlation

When using a constant tone audio beacon, beware of room echoes causing multi-path interference and distortion, especially around the leading and trailing portions of your received waveforms. Try ...
hotpaw2's user avatar
  • 35.4k
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 ...
Marcus Müller's user avatar
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 ...
ederwander's user avatar
  • 2,038
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 ...
hotpaw2's user avatar
  • 35.4k
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 ...
Dang Manh Truong's user avatar
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: ...
Vinkelman's user avatar

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