Math and Measurement Reference
This shelf is the short-answer bench for electrical math, box math, measurement procedures, and the small helper pages that keep a build honest.
Tiny Version
Use this shelf when you need the right number fast and you do not want to guess.
Builder Version
Start with the task that matches the job in front of you: wire and fuse math, box math, measurement setup, DSP number translation, or output checks.
Deep Version
When the quick card feels suspicious or the numbers carry real cost, use the deeper truth page or the formal procedure page sitting underneath the same shelf.
Start By Task
- Wire and fuse math - Ohm's Law and Power, Voltage Drop in DC Circuits, and Battery Runtime Calculation.
- Box math - Box Volume from Dimensions, Ported Box - Helmholtz Resonance, and Sealed Box System Parameters.
- Measurement setup - Measuring Amplifier Gain, Measuring Frequency Response, and Impedance Measurement Procedure.
- DSP number translation - Audio Levels, Metering, and Headroom, Q and Bandwidth Converter, and dB Reference Converter.
- SPL and output checks - SPL Addition, SPL Versus Power Versus Distance, and Measuring SPL Maximum Output.
How To Read This Shelf
- Quick formula - short card for one answer and one check.
- Procedure - step order for real measurement or setup work.
- Standard - formal rule or rating method worth matching when truth matters.
- Helper - browser utility that speeds up repetitive number work.
Core Electrical Math
Use these pages when you need current draw, wire sanity checks, voltage loss, or electrical behavior explained in plain numbers.
- Ohm's Law and Power - Quick formula
- Voltage Drop in DC Circuits - Quick formula
- Battery Runtime Calculation - Quick formula
- Ground Resistance and Noise - Truth page
- Damping Factor - Truth page
- Amplifier Efficiency Classes - Truth page
Enclosure and Speaker Math
Use these pages when the box dimensions, tuning, or driver loading need to make physical sense before you cut wood.
- Box Volume from Dimensions - Quick formula
- Sealed Box System Parameters - Truth page
- Ported Box - Helmholtz Resonance - Truth page
- Bandpass Enclosure - Truth page
- Speaker Impedance Series and Parallel - Quick formula
- Acoustic Power Efficiency - Truth page
Measurement Procedures
Use these pages when you need a repeatable setup order, not just a formula.
- Measuring Amplifier Gain - Procedure
- Measuring Frequency Response - Procedure
- Measuring SPL Maximum Output - Procedure
- Impedance Measurement Procedure - Procedure
- Distortion Measurement Procedure - Procedure
- CEA-2006 Amplifier Rating Standard - Standard
Levels, Metering, and Helpers
Use these when the numbers themselves are getting in the way of the real setup decision.