# Self Noise

> Acoustics & Audio Research & Resources (Mike Newton)


## Posts

- [Site updates: Pages on signal processing for acoustics and audio applications](https://selfnoise.co.uk/2024/07/site-updates-pages-on-signal-processing-for-audio-and-acoustics/): I’ve made quite a few updates to this website over the past few weeks. The most-updated area is the Resources section on signal processing for audio and acoustics. I’ve focussed on the topics that I have found most useful in my own teaching and research, and where I’ve observed the most confusion over the years from students learning DSP. For example… Frequency axes and the DFT Even- vs odd-length DFT transforms Amplitude scaling in the time vs. frequency domains
- [Sound & Music Computing Conference 2024: Laser doppler vibrometry for immersive sound design](https://selfnoise.co.uk/2024/07/smc2024/): One of my PhD supervisees, Roderick Buchanan-Dunlop, was in Portugal last week to present research on using laser doppler vibrometry for immersive sound design at the Sound & Music Computing (SMC) Conference 2024. This is in collaboration with my co-superviser, Dr Martin Parker.
- [IEEE Sensors paper on graphene-PMMA membranes published](https://selfnoise.co.uk/2020/01/ieee_sensors_paper/): Our most recent paper on using graphene membranes for acoustic sensing has just been published (early access) in IEEE Sensors. It’s available now via this DOI, and is titled “Realization of Closed Cavity Resonator Formed by Graphene-PMMA Membrane for Sensing Audio Frequency”. It’s also listed on my Publications page.
- [LaTeX and WordPress](https://selfnoise.co.uk/2018/11/latex-and-wordpress/): I recently discovered WP QuickLaTeX, a wordpress plugin, and it’s associated QuickLaTeX service. Together, they appear to permit extremely low-faff use of LaTeX within a WordPress intallation (such as this site). Rendered content looks excellent. For example, here’s the DFT: (1)   from which we compute the complex amplitudes of (where is an -length sampled sequence). The raw code within the WordPress text editor for this page that produced equation 1 is exactly what you’d expect, i.e., We can also express equation 1 as an inner product: (3)   for each of the unique sampled phasors .
- [Fixing export_fig font issues (Matlab figure export)](https://selfnoise.co.uk/2018/11/fixing-export_fig-font-issues-matlab-figure-export/): Export of high quality figures from Matlab, so that they appear on the page as they appear within Matlab, is a surprisingly tricky task. It can be made much more efficient through use of export_fig, a terrific Matlab File Exchange contribution that streamlines high quality figure export to common formats used in academic publishing, e.g., EPS, PDF. However, under MacOS 10.12.6 (Matlab 2018a) I had issues with the usually seamless export breaking, particularly in terms of font embedding. This seems to be resolvable through reinstalling xpdf, via installing Brew, and following suggestions made in this useful thread: Hidden failure mode […]

## Pages

- [Chorizo and bean soupy stew (Spannishy style)](https://selfnoise.co.uk/chorizo-and-bean-soupy-stew/): Description Recipe by: Mike Newton Date first written down: 05 December 2022 Updated: N/A Partly based on recipes here: https://www.bbcgoodfood.com/recipes/roast-chicken-soup https://brindisa.com/blogs/spanish-food-recipes/chickpea-and-chorizo-stew https://brindisa.com/blogs/spanish-food-recipes/tolosa-bean-stew-with-chorizo https://www.theguardian.com/food/2022/jul/25/claudia-roden-recipe-bean-stew-chorizo-bacon Notes on ingredients/swaps: Can swap out the 3-bean mixture for cooked chickpeas as a variation To serve Warm sourdough bread is lush Ingredients 150-200g (ish) of good quality diced pancetta 200g (approx) chorizo sausage (regular, not an extra spicy) – peeled and chopped into chunky slices 2 smallish red onions [finely diced] 2 bell peppers (red and yellow work well) [very finely diced] 4 cloves of garlic [minced] 2x400g tins of good quality whole plum tomatoes 1x400g […]
- [Chicken and pea soup](https://selfnoise.co.uk/other/food-and-cooking/chicken-and-pea-soup/): Description Recipe by: Mike Newton Date first written down: 03 January 2022 Updated: N/A Partly based on recipes here: https://www.bbcgoodfood.com/recipes/roast-chicken-soup Notes on ingredients/swaps: N/A To serve Serve with a dollop of greek yoghurt, and buttered, crusty, and wam sourdough bread Ingredients 1-2L of chicken stock (made from previously roasted chicken, boiled in water for 2-3 hours) Leftover pieces of cooked chicken [shredded (however much to hand)] 1-2 red onions [diced] 3 medium carrots [diced] 1 stick celery [diced] 1 small leek [finely diced (or half a larger leek)] 1 clove garlic (optional) Any other veg to hand (e.g. courgettes, green […]
- [Other](https://selfnoise.co.uk/other/): Food and cooking
- [Food and cooking](https://selfnoise.co.uk/other/food-and-cooking/): Introduction This section collects together food and cooking ideas, including recipes I’ve developed over the years. It’s mainly for my own benefit, when I need inspiration. Recipes Soupy things Chicken and pea soup What it sounds like Chorizo and bean soupy stew Ditto Cakey things Chicken and pea soup What it sounds like TBA TBA
- [Basics of using git and GitHub (on a mac, for Matlab/Python)](https://selfnoise.co.uk/resources/coding-and-writing/basics-of-git-and-github/): Contents Introduction Objectives in getting to grips with git Technical setup/context Main steps I followed to get a working system Further reading 1 Introduction I write a fair amount of computer code to support my research and teaching. Most of it is in Matlab, and some of it in Python. Some of my coding archives are very well organised, and some leave a bit to be desired. In a bid to do better, I recently started using git to help manage and maintain my code. Simultaneously, I wanted to get to grips with how to integrate local version control (i.e., […]
- [Coding and writing](https://selfnoise.co.uk/resources/coding-and-writing/): Introduction Gathered here are a selection of tips and tricks that I’ve found useful in writing and maintaining computer code, and in producing research publications of various kinds. Links to a few of my favourite external resources are also available. Basics of using git and GitHub (on a mac, for Matlab/Python) A diary-style account of how I got up and running Making figures in Matlab for use in publications TBA
- [The Discrete Fourier Transform: Structure for even- vs. odd-length transforms](https://selfnoise.co.uk/resources/signals-and-dft/dft-even-odd-n/): Contents Background DFT structure: Even-length N DFT structure: Odd-length N Coding examples 1 Background Introduction The DFT defined earlier is valid for integer valued . This allows to be either even or odd. For a real valued discrete time signal, , this gives rise to subtle differences in the structure of its DFT, , depending on whether is even or odd. As a side point, it’s worth noting that in many real world applications, the DFT is evaluated using the FFT algorithm, which originally required signals where the number of samples was a power of 2, i.e., even . However, […]
- [The Discrete Fourier Transform: Frequency axes](https://selfnoise.co.uk/resources/signals-and-dft/dft-frequency-axes/): Contents Background The DFT in terms of cyclic frequency (Hz) The DFT in terms of normalised cyclic frequency (cycles per sample) The DFT in terms of normalised radian frequency (radians per sample) 1 Background The DFT defined earlier is agnostic to sample rate — i.e., the concept of `frequency’ is in a relative sense, normalised by the total number of samples, . However, when dealing with real-world audio and acoustics signals it can be helpful to interpret the DFT bins in terms of either cyclic frequency, normalised cyclic frequency, or normalised radian frequency. A couple of foundational points: Define a […]
- [The Discrete Fourier Transform: Amplitude scaling between the time and frequency domains](https://selfnoise.co.uk/resources/signals-and-dft/dft-scaling/): Contents Introduction (TLDR) Amplitude scaling in the time and frequency domains 2.1 Scaling concepts 2.2 DFT scaling computations: N is even 2.3 DFT scaling computations: N is odd 2.4 Amplitude scaling key result 2.5 Caveats 2.6 Example 1: Single frequency cosine wave 2.7 Example 2: Signal with three periodic frequency components (+ Matlab code) 2.8 Example 3: Cosine wave with linear ramping (i.e., a non-stationary signal) (In detail) Amplitude scaling in the time and frequency domains 3.1 Introduction 3.2 DFT of a cosine signal that is periodic in 3.3 Summary Amplitude scaling for periodic signals with a constant phase shift […]
- [The Discrete Fourier Transform: Useful properties to keep in mind](https://selfnoise.co.uk/resources/signals-and-dft/dft-useful-properties/): To be added.
- [The Discrete Fourier Transform: Definition as an inner product](https://selfnoise.co.uk/resources/signals-and-dft/dft-definition-inner-product/): Contents Sampled discrete time signals The Discrete Fourier Transform: Definition as an inner product 1 Sampled discrete time signals Consider an -length finite duration discrete time signal, , specified at integer sample time indices . The signal comprises samples, and therefore runs from . In general, may be complex valued, i.e., , though in most audio-related applications it will be purely real. 2 The Discrete Fourier Transform: Definition as an inner product The DFT, , of the signal is obtained by evaluating the inner product of with an orthogonal set of complex exponentials (1)   where integer , and is […]
- [The Discrete Fourier Transform: Useful maths](https://selfnoise.co.uk/resources/signals-and-dft/useful-maths/): Contents Introduction Vectors in 3D real space Discrete time signals as N-length complex valued vectors Geometric sequences and discrete time signals Sine waves from complex phasors Geometric series 1 Introduction A handful of mathematical tools are particularly useful in understanding the structure and use of the Discrete Fourier Transform (DFT). Several of them are gathered together here on a single page. The other pages within the signals and signal processing section use this page as essential background. 2 Vectors in 3D real space 2.1 Introduction It can be useful to treat discrete time signals, such as sampled audio signals stored […]
- [Signal processing for acoustics and audio applications](https://selfnoise.co.uk/resources/signals-and-dft/): Introduction This section covers a selection of foundational signal processing topics, along with a summary of mathematical tools that I’ve found helpful over the years. Simple coding examples, mainly in Matlab, are included throughout. The focus is on concepts that are useful in practical applications, such as data processing, but perhaps not obvious to those learning for the first time. In short, it’s a summary of things I find useful to remember (but sometimes forget). Links to a few of my favourite external resources are also available. Acoustic and electrical signals Acoustic signals: Basic principles Overview of basic principles, terminology, […]
- [Making figures in Matlab for use in publications](https://selfnoise.co.uk/resources/coding-and-writing/figure-making-matlab/)
- [Electrical signals: Basic principles](https://selfnoise.co.uk/resources/signals-and-dft/electrical-signals-basics/): To be added.
- [Test matlab](https://selfnoise.co.uk/test-matlab/): Test intro text. Nice code below: And some footer-type text
- [Acoustic signals: Basic principles](https://selfnoise.co.uk/resources/signals-and-dft/acoustic-signals-basics/): Contents Overview Sound fields and levels Sound pressure level and the decibel scale 1 Overview This page outlines some of the basic principles, terminology, and concepts that we use when talking about acoustic and audio signals. Many of the ideas (e.g., RMS levels, decibels, etc) translate easily to electrical and other types of signals, too. Where relevant, we will introduce some terminology and concepts used in digital systems, including for digital audio – we often refer to this as a ‘discrete time’ system. 2 Sound fields and levels 2.1 A note on terminology The terminology below is written largely in […]
- [Microphone sensitivity](https://selfnoise.co.uk/resources/acoustics-hardware/microphone-sensitivity/): Contents Purpose of a microphone Types of microphone Basic function of a microphone Specifying the efficiency (sensitivity) of a microphone Environmental condsiderations: Free field vs pressure field vs diffuse field 1 Purpose of a microphone The purpose of a microphone is to transfer acoustical energy into electrical energy. Most microphones do this by having a relatively large and flexible surface, or diaphragm, that moves in response to local fluctuations in air pressure caused by passing acoustic waves. The diameter of this diaphragm is typically on the order of 1cm, though there are a wide range of models either side of […]
- [Acoustics and audio hardware (microphones, vibrometers)](https://selfnoise.co.uk/resources/acoustics-hardware/): Introduction This section focusses on the use of microphones and other transducers in practical acoustics and audio applications, such as laboratory measurements, field recording, and impulse response acquisition. The content draws together practical tips and tricks that might be obvious for a seasoned expert, but less so for those with less experience. Microphone specifications Microphone sensitivity How interpret and use microphone sensitivity TBA TBA
- [Resources](https://selfnoise.co.uk/resources/): Gathered here are a selection of tips and tricks that I’ve found useful in my own acoustics and audio related work over the years. Links to a few of my favourite external resources are also available. Acoustics and audio hardware (microphones, vibrometers) Coding and writing Signal processing for acoustics and audio applications
- [Resources (elsewhere)](https://selfnoise.co.uk/resources/resources-elsewhere/): Gathered here are links to resources elsewhere on the web that I’ve found helpful over the years. Audio tools and utilities Audio file size calculator (Sound Devices): Useful and quick tool to estimate audio file sizes BirdNet: Excellent online API and upload portal for machine learning powered birdsong identification Auditory research Computational Audiology Network: Comprehensive list of resources for research into sound perception (coding toolboxes, models, etc) Coding MATLAB (learning) Data Science with MATLAB (Computational Data Science Lab, University of Texas at Arlington) MATLAB (toolboxes and 3rd party extensions) Auditory Modelling Toolbox for MATLAB/Octave (Piotr Majdak and team) export_fig (Yair […]
- [Teaching](https://selfnoise.co.uk/teaching/)
- [PhD projects (ongoing and previous)](https://selfnoise.co.uk/research/phd-students/): I have supervised a range of research topics for PhD students since 2012. Ongoing and previous PhD projects, and a brief summary of the student’s research topic, are listed below. Ongoing PhD projects 2024 – Present: Hao Zhang (collaborative supervision with Prof Rebecca Cheung in UoE School of Engineering). Electroacoustic MEMS sensors involving combined piezoelectric and capacitive transduction. 2022 – Present: Roderick Buchanan-Dunlop (collaborative supervision with Dr Martin Parker, Reid School of Music). Laser doppler vibrometry as a sound recording tool for technical and creative audio applications. 2021 – Present: Yun Jiang (collaborative supervision with Prof Rebecca Cheung in UoE […]
- [Research publications](https://selfnoise.co.uk/research/research-publications/): Publication Category: Peer Reviewed Journal Articles Published Conference Proceedings Conference Contributions (abstract or poster only) Peer Reviewed Journal Articles (2024) J. Xu, G. Wood, E. Mastropaolo, P. Lomax, M. J. Newton, & R. Cheung. “A graphene-based capacitive monolithic microphone with optimised air gap thickness and damping”, Journal of Vacuum Science & Technology B. 42(6).DOI: https://doi.org/10.1116/6.0004021 (2023) J. Xu, G. Wood, E. Mastropaolo, P. Lomax, M. J. Newton, & R. Cheung. “A Closed Cavity Ultrasonic Resonator Formed by Graphene/PMMA Membrane for Acoustic Application”, Micromachines, 14(4).DOI: https://doi.org/10.3390/mi14040810 (2021) J. Xu, G. Wood, E. Mastropaolo, M. J. Newton, & R. Cheung. “Realization of […]
- [About](https://selfnoise.co.uk/about/): I’m a senior lecturer in acoustics, audio, and music technology at the University of Edinburgh. I’m based in the Reid School of Music (part of ECA), and a member of the Acoustics and Audio Group. Things I do at the University of Edinburgh: (2024-present) Research sabbatical (2013-present) Co-Director of the Acoustics and Audio Group (along with Prof Stefan Bilbao) Things I used to do at the University of Edinburgh: (2020-2024) Director of Education for Edinburgh College of Art (2019-2020) Director of Learning & Teaching (PG) for Edinburgh College of Art (2012-2019) Organiser of the MusICA Seminars series (2018-2019) Director of […]
- [Research](https://selfnoise.co.uk/research/): My research interests span vibroacoustic sensor design and fabrication, spatial audio, musical acoustics, and machine learning. Further info about my past and present research activities are available via the links below. Publications Publications (via the University of Edinburgh’s Research Explorer tool) PhD students (present and past)
- [Homepage](https://selfnoise.co.uk/): I’m a senior lecturer in acoustics, audio, and music technology at the University of Edinburgh. I’m based in the Reid School of Music (part of ECA), and a member of the Acoustics and Audio Group. Collected on this site are various resources and other bits and pieces related to my research, teaching, and other interests. This includes: A set of resources covering foundational concepts relating to signals and signal processing, microphones and other transducers for acoustics measurements. There is also a short section on coding (e.g., in reference to git) and producing technical content. A few further details about me […]
- [Updates](https://selfnoise.co.uk/updates/)


[comment]: # (Generated by Hostinger Tools Plugin)