Digital audio
Sampling theory made simple. Online simulation of sampling, demonstration of aliasing, oversampling.
Testing bit-depth and quantization is really simple.
Does high-resolution audio sound better than CD? Investigation of the optimal sampling frequency and bit depth of distribution audio formats.
Measurements of a fixed-point decoder and a floating-point decoder. 16-bit & 24-bit tests.
Acoustical simulation
Online simulation of a speaker mounted in an infinite baffle.
Simulation of early reflections from the floor, ceiling and from the wall behind the speaker. Baffle step and speaker directivity are also simulated.
Prediction of the audibility of noise in audio systems with "flat" noise floor from SNR.
Psychoacoustics of sound reproduction
What is the "ear-perceived" dynamic range of 16bit/44.1kHz and some older formats? Why is the typical answer ("dynamic range of 16 bits = 96 decibels") wrong? Why doesn't Signal-to-Noise Ratio and "dBA" tell the whole story? What is the dynamic range of an audio system in which low-level signal transmission is affected by noise? - Dispelling the misconceptions about SNR, dynamic range and noise perception... The article also contains a comparison of noise audibility threshold of popular audio formats (16/44k, vinyl, reel-to-reel tape).
Loudspeakers
Approximation of the frequency response of a speaker cabinet on the rear axis with a first-order low-pass filter. With this method, the reflection from the wall behind the speaker can be calculated simply and with sufficient accuracy.
Measuring the sound radiation of different types of woods used in speaker cabinets. The effect of cabinet damping material on sound radiation.
The placement of sound absorbing materials is critical to achieve maximum sound absorption in speaker cabinets.
Headphones
How does high output impedance affect the sound of headphones; some notes on the damping factor; output impedance and nonlinear distortion.
Audio cables
Main topics: Calculation of the minimum cross-section. Shielded and twisted speaker cables. Speaker wire plugs. Table with recommended cable length. Calculation of the inductance loss.
Guitar amplifiers & speakers
Pre & post distortion filter measurements of a classic digital amp modeler.
Popular misconceptions about tube guitar amplifiers and tube distortion.