# Tag Info

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 "...
• 32.8k
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### Does our brain constantly ifft to hear?

No. Why do you think it would? First of all, the human brain works very different then any human constructed computer (to date); so the assumption that it runs mathematical "algorithms" is somewhat ...
• 32.8k

### What are the audio equivalents of images like "Lena", "Mandrill", and "Cameraman"?

The closest example I can think of is the beginning of Suzanne Vega's "Tom's Diner" which has been used for the mpeg-1 layer 3 development, and is still occasionally used to demo audio codecs.
• 19.1k

### What are the audio equivalents of images like "Lena", "Mandrill", and "Cameraman"?

Audio processing is a large field, but specifically in speech processing, an open database of samples known as Harvard Sentences is widely used. Harvard sentences are phonetically balanced collections ...
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### 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 ...
• 415

### 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 ...
• 1,872

### 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 (&...
• 32.8k
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### 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 ...
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### 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 "...
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### 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 ...
• 26.9k

### 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 ...
• 13.9k

### Are there libraries for extraction of sound wave features?

From the ones I've been using I can recommend: YAAFE - very pleasant to work with in Python ESSENTIA - another one I like particularly due to Python integration aubio FEAPI Aquila - friend of mine ...
• 10.5k
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### 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, ...
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### 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

### 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 ...
• 32.8k
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### 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 ...
• 13.9k

### 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: ...
• 15k

### What are the audio equivalents of images like "Lena", "Mandrill", and "Cameraman"?

I also think that NIST database is very popular when it comes to speech recognition tasks. In fact it is a standard for comparison of new algorithms and techniques during yearly challenges. ...
• 10.5k
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### 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 ...
• 26.9k
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### 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 ...
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 ...
• 2,288
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### 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, ...
• 2,628

### 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 = \...
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### What are the audio equivalents of images like "Lena", "Mandrill", and "Cameraman"?

The European Broadcasting Union's (EBU) Sound Quality Assessment Material (SQAM) resource is pretty popular. https://tech.ebu.ch/publications/sqamcd
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### What does MATLAB display when plotting a sound signal?

What you are observing is the digital representation of the voltage, which in fact represents the acoustic pressure. Workflow would be something like: Vibrating larynx is producing ...
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### 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 ...
• 34k

### 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 ...
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### 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 ...
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### 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 ...
• 34k