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Acoustic science & testing guides
Authoritative, mathematically verified guides on sound reproduction, human hearing biology, signal synthesis, calibration methodologies, and digital audio DSP. Every guide directly connects to our browser-native testing instruments.
Tuning & Perception
Tuning & Reference
- A440 vs. A432 vs. A442: Pitch Standards ExplainedA practical guide to concert pitch standards: ISO 16 (440 Hz), orchestral 442 Hz, and historical 432 Hz, including transposition formulas.
- Bass Tuning Chart: 4, 5 & 6-String FrequenciesFrequencies and MIDI numbers for 4-string, 5-string, and 6-string bass guitars, plus Drop D and Drop C tunings with sub-bass period analysis.
- Guitar Tuning Chart: Standard & Alternate TuningsFrequencies, note names, and MIDI numbers for standard guitar, drop tunings, open tunings, DADGAD, 7-string, 8-string, and 12-string courses.
- Orchestral String Tuning: Violin, Viola, Cello, BassAccurate tuning frequencies and octave relationships for violin, viola, cello, and double bass in equal temperament at A4 = 440 Hz and 442 Hz.
- Ukulele Tuning Chart: Standard, Low G & BaritoneNote frequencies, MIDI numbers, re-entrant high G vs linear low G, baritone tuning, and typical string gauge ranges for ukulele players.
Guides
- Bass Fretboard Notes: Charts for 4-String & 5-String BassComplete bass fretboard notes charts for 4-string and 5-string bass. Full 0–12 neck maps, frequencies, octave shapes, and practice methods.
- Best Free Online Metronome: How to Choose OneHow to judge a free online metronome: the timing engine, background-tab behaviour, the features that matter, and an honest comparison of the options.
- The CAGED System for Guitar: Five Shapes That Map the Whole NeckLearn the CAGED system for guitar: the five moveable chord shapes, how they connect up the neck, and a 5-minute routine to practise them.
- Guitar Chord Chart: Printable Diagrams for Every Common ChordFree printable guitar chord chart: open majors, minors, sevenths and movable barre shapes with fingerings, plus blank grids for teachers.
- Guitar Chords for Beginners: The First Chords That Unlock Real SongsLearn the 8 essential beginner guitar chords with diagrams, fingerings, smooth change drills, strumming basics and a 4-week practice plan.
- Guitar Fretboard Notes: Complete Chart, Diagram & Memorization GuideEvery note on the guitar fretboard: full 0–12 diagram, per-string charts, open-string frequencies, octave shapes, and a 2-week memorization plan.
- Guitar Scales: Charts for Major, Minor, Pentatonic & ModesMaster guitar scales: major scale formulas, 5 CAGED positions, natural minor and relative major charts, mode overviews, and a daily practice method.
- How to Clean a Guitar Fretboard (Rosewood, Maple & Ebony)Learn how to clean and condition a guitar fretboard safely. Step-by-step care for rosewood, ebony, and maple necks, plus oils and common mistakes to avoid.
- How to Learn Guitar Online: A Free Practice RoadmapA complete, free roadmap to learn guitar online without paid courses: step-by-step learning stages, practice routines, interactive tools, and common mistakes.
- How to Read Guitar Chord Charts: Symbols, Numbers & BarresLearn how to read guitar chord charts, diagrams, and fingering boxes. Master strings, frets, finger numbers, O/X symbols, barres, and chord formulas.
- Pentatonic Scale for Guitar: Minor & Major in 5 BoxesLearn the pentatonic scale on guitar: minor and major formulas, the five A-minor box shapes with diagrams, the relative-major shortcut, and starter licks.
- Ukulele Fretboard Notes: Charts for GCEA & BaritoneComplete ukulele fretboard notes charts for standard GCEA and baritone DGBE. Full 0–12 neck maps, frequencies, octave shapes, and practice methods.
- What Is 8D Audio? How the Orbit Effect Works8D audio is a stereo orbit effect, not eight channels. How panning, delay, head shadow and reverb create it, why headphones matter, and how to listen.
Equipment & Buying Guides
- Beginner Guitar Kit: What You Actually NeedCut through retail upsells: what beginner guitarists actually need to start playing, what can wait, and why professional instrument setup matters most.
- Clip-On vs. App vs. Pedal Tuner: Which to ChooseA practical comparison of acoustic vibration clip-ons, smartphone/browser microphone apps, and stage pedal tuners across noise, speed, and accuracy.
- Headphones for Hearing Tests and Critical ListeningHow transducer design, acoustic seal, driver matching, and frequency neutrality affect home hearing screening accuracy and critical audio monitoring.
- How to Fix a Speaker Buzzing at Low FrequenciesA step-by-step diagnostic isolation procedure to find whether low-frequency rattle originates from room objects, loose cabinetry, voice coils, or cables.
- Metronome Apps vs. Hardware: Features & TimingCompare acoustic pendulum metronomes, dedicated electronic hardware, and browser/mobile apps across timing jitter, audio latency, and practice features.
Equipment & Calibration
- Bluetooth Audio Latency Explained: Codecs, Buffer Delays, and Sync FixesWhy wireless audio delays video and games: codec latency benchmarks, buffer physics, operating system delays, and how to measure and minimize Bluetooth lag.
- How to Test Speaker Channels and Stereo Imaging: Polarity, Phase, and CenteringMaster stereo listening: isolate channel balance, verify electrical polarity, diagnose phase cancellation, and anchor phantom-center imaging.
- Subwoofer Calibration Guide (10–200 Hz): Crossover, Room Modes, and PlacementLearn how to calibrate your subwoofer from 10 Hz to 200 Hz: optimize crossover points, eliminate room mode bass nulls, and master the subwoofer crawl.
Signal Generation & Calibration
Digital Signal Processing
Hearing & Psychoacoustics
- Fletcher-Munson Curves Explained: Equal-Loudness Contours, Phons, and Why Volume Changes ToneEqual-loudness contours show why ears hear bass 10 to 30 dB quieter at low volume. ISO 226 numbers, phon vs sone, and why mixing at 85 dB SPL matters.
- Normal Human Hearing Range: Frequencies, Limits, and Age-Related LossExplore the 20 Hz to 20,000 Hz human auditory spectrum, equal-loudness Fletcher-Munson curves, presbycusis aging patterns, and safe exposure guidelines.
How-To Guides
- How to Check Your Hearing Online (and When to See a Doctor)What an online pure-tone hearing screening can and cannot tell you: uncalibrated audio limits, safe listening levels, and when to see an audiologist.
- How to Count Odd Meters: 5/4, 7/8 & Additive RhythmMaster counting odd time signatures: additive rhythm principles, subdividing 5/4, 7/8, and 9/8 into groups of 2 and 3, and keeping steady time.
- How to Eject Water from iPhone Speakers: 165 Hz Frequency Guide and PhysicsMuffled iPhone speakers after liquid exposure? Use 165 Hz sound waves to eject trapped water droplets safely. Physical acoustics, steps, and safety limits.
- How to Practise with a Metronome (and How Not To)Effective metronome practice strategies: subdivision techniques, incremental speed building, developing internal pulse, and common timing mistakes.
- How to Tune a Guitar for BeginnersA step-by-step beginner guide to tuning an acoustic or electric guitar: peg mechanics, string order, pluck-and-wait technique, and tuning up to pitch.
- How to Tune a Guitar by Ear: Relative & HarmonicsMaster relative guitar tuning by ear: hearing acoustic beats, using the 5th-fret method, 5th/7th fret harmonics, and reference pitch pipes.
- How to Tune a Ukulele: High G and Re-entrant SetupLearn how to tune a ukulele properly: explaining why the re-entrant high G confuses beginners, tuning pegs, string stretch, and octave checks.
- How to Tune a Violin Without Breaking a StringTune your violin safely: friction peg technique, fine tuners vs pegs, tuning order, avoiding bridge collapse, and preventing string breakage.
- How to Use a Tuner with a Band: Rehearsal & LivePractical guide to band tuning: eliminating ambient noise, pickup vs mic isolation, tuning order, temperature drift, and muting unplayed strings.
Acoustics & Physics
- Room Modes and Standing Waves Explained: The f = c/2L Formula, Worked Example, and Placement FixesRoom modes explain boomy or dead bass in a rectangular room. Use the f = c/2L formula with a worked 4.0 x 3.2 x 2.6 m example, then fix seat and sub placement.
- Why Smartphones Physically Cannot Reproduce 20 Hz: The Acoustic Limits of Micro-TransducersA deep dive into acoustic physics: Hoffmann's Iron Law, volume displacement, acoustic short-circuiting, and why phone speakers cannot produce true sub-bass.