9
votes
Accepted
Which transform most closely mimics the human auditory system?
In designing such transformations, one should take into account competing interests:
fidelity to the human auditory system (that varies with people), including non-linear or even chaotic aspects (...
- 31.6k
8
votes
Accepted
Intuitive explanation of subspace
TL;DR: Subspaces are low-dimensional, linear portions of the entire signal space that are expected to contain (or be close to) a large part of the observable and useful signals or transformations ...
- 31.6k
7
votes
Accepted
Slow Down Music Playing While Maintaining Frequency
Yeah some of us can do it, you can speed up or slow down without affect the pitch, some guys call this applications of Time Stretch, there different ways to do it, you can do in frequency domain or ...
- 2,028
7
votes
Intuitive explanation of subspace
Subspaces are a Linear Algebra concepts. The best representative example I can think of is the relationship of the XY plane to XYZ space, The former is a subspace of the latter. Any vector in the ...
- 7,522
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.
- 5,137
6
votes
Accepted
Spectral plot shows more notes than there really should be
Since the notes from a guitar are no pure sinusoids, you should expect to see some harmonics, even when analyzing the dry signal without effects. E.g., the note E is the perfect fifth of the note A, i....
- 88.8k
6
votes
How does Adobe After Effects generate its "audio spectrum" effect?
I've had a try at reproducing the effect, and I think these are some of the key elements:
You need a high-resolution FFT (large size; windows overlapping in time so that this doesn't come at the ...
- 529
6
votes
Is a recording of a chord merely a superposition of recordings of its constituent notes?
Depends to some degree on the instrument: electronic versus mechanical, string versus reed versus pipe, etc. Typical electronic keyboards have no coupling between keys, and the DSP mixer is usually ...
- 35.2k
6
votes
Accepted
MUSIC implementation in Pyroomacoustics library
Why the Code Works
It's important to note that the MUSIC algorithm works on the microphone array dimension only. So it doesn't care how the data on the receive channels (microphones in this case) has ...
- 1,632
6
votes
Can one use MUSIC algorithm to estimate DOA for a circular microphone array with a small radius?
Problem Summary
You have a couple of difficulties with this problem:
The microphone array isn't a uniform linear array (ULA), which is the most straightforward to model steering vectors for.
Unless ...
- 1,632
4
votes
Integration of square wave
If your square wave has a mean of zero (this is important!), then a simple accumulator can do the job. Its operation is described by
$$y[n]=x[n]+y[n-1]$$
where $x[n]$ is the input (square wave) and $...
- 88.8k
4
votes
Slow Down Music Playing While Maintaining Frequency
The tool/theory you describe is really a large area of research in music technology, broadly called audio time-scale modification. A large component of this field is how you might prevent audible ...
- 436
4
votes
Can anyone explain how does CZT (Chirp Z Transform) really help in 'spectral zooming'?
The CZT allows for a fairly general evaluation of the Z transform - the more general evaluation path looks like a spiral, so it has a radial component step size as well an angular step size.For ...
- 2,841
4
votes
Intuitive explanation of subspace
A subspace is just a vector space that's included in a bigger vector space.
Separating a random signal space into two statistically uncorrelated subspaces, a desired signal space and a noise space, ...
- 28k
4
votes
Accepted
MUSIC algorithm terminology
Yeah, notation is not ideal.
It is not - he assumes that each of the $M$ antenna elements is connected to its own RF chain, i.e., there are also $M$ receivers available. If you have fewer receivers ...
- 2,413
4
votes
FFT seems more accurate than MUSIC algorithm?
I created a signal with two sinusoids and added increasing amounts of random noise to it. The results of running the FFT and MUSIC on this signal are shown in the image below.
You are using ...
- 672
4
votes
Why mixing two sines sounds like a triangle?
I tried looking at what your libraries output as just a sine wave by modifying your code:
...
- 25.2k
4
votes
Can one use MUSIC algorithm to estimate DOA for a circular microphone array with a small radius?
The paper 2D DOA estimation with sparse uniform circular arrays in the presence of mutual coupling suggests that the steering vectors are given by:
For your array, it looks like there are 4 sensors ...
- 25.2k
3
votes
what are the Pros and Cons of ESPRIT and MUSIC algorythms?
The prime thing such algorithms aim to do is to make use of more information that you may have about the signal. In this case, the extra information is that you know the number of signals (sinusoids) ...
- 25.2k
3
votes
Can anyone explain how does CZT (Chirp Z Transform) really help in 'spectral zooming'?
This part of that paper suggests the answer:
The issue being that the standard FFT just does linearly-spaced spectral samples from $-f_s/2$ to $f_s/2$ where $f_s$ is the sampling frequency. The CZT ...
- 25.2k
3
votes
Accepted
Simulating musical instruments using their impulse response
there are a lotta people doing research regarding music synthesis and DSP. yes you can sample notes and different key velocities and play them back with different MIDI velocity parameters. if you ...
3
votes
Accepted
What is a note?
the etymology of the word "note" as it applies to music is simply the notation, the note that a composer would make to paper to represent a particular action taken by the musician performing the music....
3
votes
Accepted
Weird note structure on guitar audio waveform
Here are some possibilities:
Transverse waves on a guitar string have two polarized components, one parallel and one perpendicular to the guitar's soundboard. User hotpaw2 mentioned energy exchange. ...
- 13.5k
3
votes
Accepted
DOA estimation; Music (Multiple Signal Classification) algorithm
The receive-signals covariance matrix $\mathbf R$ is by its definition
$$\DeclareMathOperator{\expect}{E}\newcommand{\E}[1]{\expect\left[#1\right]}\DeclareMathOperator{\diag}{diag}$$
$$\mathbf R= \E{\...
- 29.5k
3
votes
Audio Quality Assessment
Audio quality assessment is one of the most critical pieces of audio coding and enhancing applications. The task requires an accurate and objective (mathematical) modeling of human auditory system ...
- 28k
3
votes
What is difference between frequency and pitch?in nutshell and simple words?
Frequency is mathematically defined as the number of cycles per second. So it is a more strict word mathematically. It is represented numerically by the unit called Hertz.
$f=1/T$, where $T$ ...
- 161
3
votes
MUltiple SIgnal Classification (MUSIC) Implementation
I'm going to group number 1 and 3 as related.
For a high level description of MUSIC, you can take a look at MATLAB's overview here. One of the main steps in the algorithm is to find the eigenvectors ...
- 2,326
3
votes
What are features in signal processing using a more tangible or less abstract description
A feature is a number that describes one aspect of a signal.
Signals can be very complex, and the simplest analysis tools (like a time plot, a spectrum, or an energy measurement) don't tell you ...
- 14.9k
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