Tutorials Articles
Architectural Acoustic Design: The Student Guide (With Free Calculation Tools)
Written for architecture and engineering students, this guide covers sound behaviour, absorption, reflection, diffusion, the Sabine and Eyring equations derived from first principles, common assignment types, and a fully worked lecture theatre design example using free tools.
Acoustic Treatment vs Soundproofing: Why Most People Get This Wrong
The definitive explanation of the difference between acoustic treatment (controlling sound within a room) and soundproofing (blocking sound between rooms). Covers the mass law, decoupling, the 1% rule, STC vs NRC, and when you need each approach — with cost comparisons and worked examples.
Building Acoustics vs Room Acoustics: What's the Difference?
Building acoustics blocks sound between rooms using mass and decoupling (STC/Rw). Room acoustics controls sound within a room using absorption (RT60/C80). Here is when you need each, how they interact, and the standards that govern them.
How Do Acoustic Panels Work? The Physics of Sound Absorption
Acoustic panels absorb sound by converting kinetic energy into heat through viscous friction in porous materials, membrane vibration, or Helmholtz resonance. Learn the physics behind all three absorber types, why panel thickness determines low-frequency performance, and how mounting position changes everything.
How to Calculate RT60 Step by Step — From Room Dimensions to Compliance Check
Calculate RT60 manually in 5 steps: list surfaces, assign alpha values, calculate absorption, apply Sabine or Eyring, check compliance. Full worked example with a 180 m³ conference room. Every number shown.
How to Acoustically Treat a Home Studio for Under £500 (Step-by-Step)
A complete home studio acoustic treatment guide for under £500. Priority order: ceiling cloud first, bass traps second, side wall panels third. Exact product specifications, placement guide, and before/after RT60 calculation.
NC Curves Explained: Understanding NC-25, NC-35, NC-45 Background Noise Ratings
A comprehensive guide to Noise Criteria (NC) curves: how they work, how to determine an NC rating, target values for every room type, and the differences between NC, NR, and RC rating methods. Includes ASHRAE recommended levels and step-by-step calculation examples.
Deriving Sabine's and Eyring's Reverberation Time Formulas from First Principles
Step-by-step mathematical derivation of Sabine's T60 = 0.161V/A and Eyring's T60 = -0.161V/(S·ln(1-ᾱ)) from the diffuse field energy balance. With worked examples showing why Sabine fails at high absorption and when Eyring is the better choice.
Speech Privacy Index (SPI): How to Measure and Achieve Acoustic Privacy
A technical guide to the Speech Privacy Index (SPI) per ASTM E1130: how it relates to STI and AI, the three elements that determine privacy, privacy classification thresholds, and practical design strategies for offices, healthcare, and open plan environments.
What Is a Sabin? The Acoustic Absorption Unit Explained
A sabin is the unit of sound absorption equivalent to 1 square foot of perfectly absorptive surface. Learn how sabins relate to absorption coefficients, how to calculate total room absorption in sabins, and why thinking in sabins instead of alpha values prevents acoustic design failures.
The Acoustic Design Process: From Brief to Handover in 8 Steps
Acoustic design follows a structured 8-step process: establish criteria, model the room, calculate the baseline, identify deficiencies, specify treatment, verify compliance, document, and measure post-construction. Here is each step explained with the specific deliverables and ISO references.
A Practical Guide to Acoustic Materials: Foam, Mineral Wool, Wood, and Everything In Between
Acoustic materials fall into three categories: absorbers, reflectors, and diffusers. Each type works differently at different frequencies. Here is a practical guide to selecting the right material for your room — with NRC values, octave-band data, cost ranges, and fire ratings for every major product type.
How to Measure Room Acoustics: Equipment, Methods, and What the Numbers Mean
Measuring room acoustics requires a sound source, a microphone, and analysis software — but the method you choose determines whether your results are valid. Here is a practical guide to acoustic measurement: from balloon pops to dodecahedron speakers, from smartphone apps to ISO 3382-compliant equipment.
Noise Criteria Explained: NR, NC, and RC Curves — Which One Does Your Project Need?
NR (Noise Rating), NC (Noise Criteria), and RC (Room Criteria) all rate background noise levels in buildings — but they use different curves, different frequency ranges, and are required by different standards. Here is how each system works, when to use which, and the specific values your HVAC engineer needs to hit.
Room Acoustics Fundamentals: How Sound Behaves Inside a Room
Sound in a room does not simply travel from source to listener. It reflects off every surface, arrives at the listener hundreds of times with different delays, and creates a complex acoustic signature. Here are the fundamentals of room acoustics — from direct sound to late reflections to standing waves.
Understanding Octave Band Analysis: Why Single-Number Ratings Hide the Truth About Your Room
A single RT60 value or NRC rating averages across frequencies and hides critical problems. Octave band analysis breaks sound into 6 frequency ranges — revealing that your room might pass at 500Hz and catastrophically fail at 125Hz. Here is how octave bands work and why every acoustic assessment should use them.
Understanding Sound Insulation: STC, Rw, and Why Walls Don't Block All Frequencies Equally
STC (Sound Transmission Class) and Rw (Weighted Sound Reduction Index) both rate how well a wall blocks sound — but they use different standards, different frequency ranges, and can give different results for the same wall. Here is what each rating means, how they are measured, and which one applies to your project.
What Is NRC (Noise Reduction Coefficient) — The Number on Every Acoustic Panel Datasheet
NRC is a single number rating from 0.00 to 1.00 that describes how much sound a material absorbs. But NRC hides critical information about low-frequency performance. Here is what NRC means, how it is calculated, and why you need octave-band data for any serious acoustic design.
What Is RT60 — And Why It Determines Whether Your Room Sounds Good or Terrible
RT60 is the time it takes for sound to decay by 60dB after a source stops. Too long and speech blurs. Too short and rooms feel dead. Here is what RT60 means, why it matters for every room type, and the optimal targets that acoustic standards have established over 100 years of research.
What Is STI (Speech Transmission Index) — Can People Actually Understand Speech in Your Room?
STI measures how much a room degrades speech from source to listener, on a scale from 0 (unintelligible) to 1 (perfect). An STI below 0.50 means one in four words is lost. Here is how STI works, what scores you need, and why reverberation time alone is not enough.