LABWhat happens from vibration to hearing, from a digital sample to a loudspeaker, and from electrical power to room acoustics? SWORD LAB is not a collection of short glossary entries but a structured technical knowledge base whose articles build on one another.
The order is deliberate: first we examine vibration, sound and human hearing; then measurement, power transfer, electroacoustic conversion, crossovers, space, digital audio and finally the complete DJ signal path.
What do we actually hear?
From vibration to auditory perception - the physics and physiology of human hearing, and how hearing changes with age
HEARING · ACOUSTICS · READ →02Decibel, sound pressure and SPL
What +3, +6 and +10 dB actually mean
SOUND ENGINEERING · READ →03WATT, power and loudness
Why the WATT rating does not tell you how loud a loudspeaker is
SOUND ENGINEERING · READ →04How does a loudspeaker work?
From electrical signal to mechanical motion and acoustic power
ELECTROACOUSTICS · READ →05Impedance in sound engineering
Resistance, reactance, phase angle, power and amplifier loading
ELECTRICAL ENGINEERING · READ →06Crossovers and frequency bands
Electrical filters, acoustic slopes, phase, delay and directivity matching
ELECTROACOUSTICS · READ →07Phase, polarity and interference
Why bass disappears, what comb filtering is, and what delay really changes
ACOUSTICS · READ →08Why do we need a subwoofer?
Excursion, volume velocity, enclosure loading, crossover, placement and low-frequency arrays
SOUND ENGINEERING · READ →09Room acoustics in practice
Reflections, modes, decay, critical distance, measurement and what EQ cannot fix
ACOUSTICS · READ →10Digital audio from first principles
Sampling, Nyquist, bit depth, quantisation, dither, jitter, latency and clocking
DIGITAL AUDIO · READ →11WAV, FLAC, MP3, AAC and CD
Containers, codecs, lossless and lossy compression - what actually happens to the music?
DIGITAL AUDIO · READ →12The complete DJ signal path
From the music file through mixer, DSP and loudspeaker - then through the ear to the brain
DJ TECHNOLOGY · READ →Professional and legal notice
I prepare the technical descriptions, calculations, examples, diagrams and other information published in SWORD LAB for educational and informational purposes. When compiling the material I aim for technical accuracy, correct presentation of the underlying relationships and careful use of the available professional knowledge.
Nevertheless, the information may contain inaccuracies, errors or simplifications that cannot be applied unchanged to a specific system or environment. The calculations and engineering examples are generally based on stated or implicit assumptions. Real systems are also affected by the actual parameters of the equipment, system topology, environmental conditions, measurement method, installation practice, applicable standards, legislation and manufacturer requirements.
The material I publish does not constitute design documentation, an expert opinion, an installation instruction, a safety instruction or individual professional advice. It does not replace manufacturer documentation, current regulations and standards, or - where required - the examination, measurement or design work of a suitably qualified and authorised professional.
Technical standards, product data and technologies change over time. Before design, installation, measurement, operation, repair or equipment selection, I therefore recommend checking the current primary and authoritative sources.
I make every reasonable effort to prepare the material carefully; however, to the extent permitted by applicable law, I accept no liability for direct or indirect damage, loss, malfunction or interruption resulting from the use, misinterpretation or incorrect application of information published on this site, or from interventions carried out on that basis.
The purpose of SWORD LAB is to help explain engineering relationships and the physical and technical processes behind sound reinforcement, electroacoustics, digital audio and DJ technology. It is not intended to replace on-site investigation, measurement or engineering design of a specific system.