Mathematics · Mathematical Physics

Free-Field Acoustic Distance Attenuation reference source distance Solver

Rearrange the free-field acoustic distance attenuation relationship and solve for reference source distance.

Runs locally
Your numbers

Inputs and results stay in this browser. Change one value at a time to explore the relationship.

Your inputCalculatedPassed forward in chains
reference source distance5
Reconstructed ideal level reduction in decibels12.0412

Calculation steps

  1. Use b=a/10^(c/20) with ideal level reduction in decibels=12.041199826559247 and farther source distance=20.
  2. reference source distance=5.000000000000001.
  3. Substitution into c=20log₁₀(a/b) reconstructs 12.041199826559245.

Understand Free-Field Acoustic Distance Attenuation: solve reference source distance

One idea, three depths

Choose how deeply to explain Free-Field Acoustic Distance Attenuation: solve reference source distance

Free-Field Acoustic Distance Attenuation: solve reference source distance: Rearrange the free-field acoustic distance attenuation relationship and solve for reference source distance.

Age 5Explain it to a 5-year-oldStart with a picture

Imagine using Free-Field Acoustic Distance Attenuation: solve reference source distance to answer this question: rearrange the free-field acoustic distance attenuation relationship and solve for reference source distance? Enter ideal level reduction in decibels and farther source distance; the calculator shows reference source distance. For example: farther source distance=20 and reference source distance=5 produce ideal level reduction in decibels=12.041199826559247. The answer tells you reference source distance.

Age 15Explain it to a 15-year-oldConnect it to the formula

For spherical free-field spreading, sound-pressure level reduction between distances is twenty times the logarithm of their ratio. This page isolates reference source distance and verifies it in the original relationship. The rule is b=a/10^(c/20). Its input values are ideal level reduction in decibels, farther source distance, and the main result is reference source distance. For example: farther source distance=20 and reference source distance=5 produce ideal level reduction in decibels=12.041199826559247.

CollegeExplain it at college levelState the model precisely

This calculator evaluates the stated free-field acoustic distance attenuation: solve reference source distance relation over the valid real-number domain stated below. The implemented relation is b=a/10^(c/20), evaluated from ideal level reduction in decibels, farther source distance to produce reference source distance. For spherical free-field spreading, sound-pressure level reduction between distances is twenty times the logarithm of their ratio. This page isolates reference source distance and verifies it in the original relationship. This excludes reflections, absorption, barriers, source directivity, ground effects, near-field behavior, and changes in source power.

Inputs and valid domain

  • ideal level reduction in decibels must be a finite real number.
  • farther source distance must be a finite real number.

Important boundary: This excludes reflections, absorption, barriers, source directivity, ground effects, near-field behavior, and changes in source power.

The formula

b=a/10^(c/20)

How the calculator works through it

It substitutes ideal level reduction in decibels, farther source distance into the formula and exposes every numerical step above. The main output is reference source distance, accompanied by Reconstructed ideal level reduction in decibels.

Read the result correctly

The reference source distance is the direct answer to “rearrange the free-field acoustic distance attenuation relationship and solve for reference source distance.” Read it with the units shown beside the inputs; a sign, angle, percentage or rate changes what the number means.

A worked check

farther source distance=20 and reference source distance=5 produce ideal level reduction in decibels=12.041199826559247.

Where this model stops being reliable

This excludes reflections, absorption, barriers, source directivity, ground effects, near-field behavior, and changes in source power.

Learn it by changing one value

Begin with the worked example, then change one value while keeping the others fixed. Compare the new result and calculation steps to identify which part of the formula changed.

Dictionary terms behind this calculator

Before studying the codeWhat you should know firstUse the calculator immediately, or check the foundations before reading the implementation.

These foundations help you understand why Free-Field Acoustic Distance Attenuation: solve reference source distance works. They never block the calculator, and “optional” means useful context rather than a hidden requirement.

Hard requirements

  • Reading formulas and substituting values

    Free-Field Acoustic Distance Attenuation: solve reference source distance uses b=a/10^(c/20). You need to recognise what each side represents before substituting the stated inputs or rearranging the relationship.

    Review this foundation about 4 min

Strong support

  • Ratios, units and dimensional meaning

    Tracking ratios and units keeps the Free-Field Acoustic Distance Attenuation: solve reference source distance result physically interpretable instead of merely numerical.

    Review this foundation about 5 min

Optional enrichment

  • Vectors and physical direction

    Vector language extends Free-Field Acoustic Distance Attenuation: solve reference source distance when magnitude and direction must be treated separately.

    Review this foundation about 6 min
Learn the missing foundationsI already know these — show the code

Mathematics → algorithm → program

Implement this calculation in code

These are direct reference implementations of the calculator's principal relationship and first output. They run locally and include a small known-answer check where the language supports it.

Algorithm

  1. Read ideal level reduction in decibels, farther source distance.
  2. Evaluate the principal relationship: b=a/10^(c/20).
  3. Return reference source distance and check the domain conditions described above.
Python
            from math import *

def free_field_acoustic_distance_attenuation_solve_b(c, a) -> float:
    return (a / pow(10.0, (c / 20.0)))

assert abs(free_field_acoustic_distance_attenuation_solve_b(12.041199826559247, 20) - 5.000000000000001) < 1e-6 * max(1.0, abs(5.000000000000001))
          
Current calculator valuesUpdates when you change an input above.
              
            
C
            #include <assert.h>
#include <math.h>

double free_field_acoustic_distance_attenuation_solve_b(double c, double a) {
    return (a / pow(10.0, (c / 20.0)));
}

int main(void) {
    const double expected = 5.000000000000001;
    const double actual = free_field_acoustic_distance_attenuation_solve_b(12.041199826559247, 20);
    assert(fabs(actual - expected) < 1e-6 * fmax(1.0, fabs(expected)));
}
          
Current calculator valuesUpdates when you change an input above.
              
            
C++
            #include <cassert>
#include <cmath>
#include <numbers>

double free_field_acoustic_distance_attenuation_solve_b(double c, double a) {
    return (a / std::pow(10.0, (c / 20.0)));
}

int main() {
    constexpr double expected = 5.000000000000001;
    const double actual = free_field_acoustic_distance_attenuation_solve_b(12.041199826559247, 20);
    assert(std::fabs(actual - expected) < 1e-6 * std::fmax(1.0, std::fabs(expected)));
}
          
Current calculator valuesUpdates when you change an input above.
              
            
Linux x86-64 assembly

x86-64 NASM · System V ABI · Linux · SSE2 with libm where required

            ; double free_field_acoustic_distance_attenuation_solve_b(double c, double a)
; Linux x86-64 NASM · System V ABI · first eight doubles in xmm0–xmm7
extern pow
global free_field_acoustic_distance_attenuation_solve_b
section .text

free_field_acoustic_distance_attenuation_solve_b:
    push rbp
    mov rbp, rsp
    sub rsp, 64
    movsd [rbp-8], xmm0
    movsd [rbp-16], xmm1
    mov rax, 0x4024000000000000
    movq xmm0, rax
    movsd [rbp-40], xmm0
    mov rax, 0x4034000000000000
    movq xmm0, rax
    movsd [rbp-56], xmm0
    movsd xmm0, [rbp-8]
    divsd xmm0, [rbp-56]
    movsd [rbp-48], xmm0
    movsd xmm0, [rbp-40]
    movsd xmm1, [rbp-48]
    call pow wrt ..plt
    movsd [rbp-32], xmm0
    movsd xmm0, [rbp-16]
    divsd xmm0, [rbp-32]
    movsd [rbp-24], xmm0
    movsd xmm0, [rbp-24]
    leave
    ret
          
Current calculator valuesUpdates when you change an input above.
              
            
MATLAB
            function result = free_field_acoustic_distance_attenuation_solve_b(c, a)
    result = (a / (10.0 ^ (c / 20.0)));
end
          
Current calculator valuesUpdates when you change an input above.
              
            
Wolfram Language
            ClearAll[mwCalculate];
mwCalculate[c_, a_] := (a / (10.0 ^ (c / 20.0)));
          
Current calculator valuesUpdates when you change an input above.
              
            

Continue in mathematical software

The downloaded file includes your current inputs and first calculated result. It is created locally.

Floating-point answers can differ slightly by language, compiler and processor. Compare within a suitable tolerance rather than assuming every decimal representation will be identical.

Supporting sourcesAcademic referencesPrimary standards, textbooks and complete citations

Standards, reading and academic references

Use the calculator as the worked interaction, then consult the primary standards and academic textbooks listed below. MW SysArc links to the original sources; the explanation on this page is original and does not reproduce them.

University Physics Volume 3

Read OpenStax University Physics: Quantum Mechanics
Cite this book
APA 7
Ling, S. J., Sanny, J., & Moebs, W. (2016). University physics volume 3. OpenStax. https://openstax.org/books/university-physics-volume-3/pages/1-introduction
MLA 9
Ling, Samuel J., et al. University Physics Volume 3. OpenStax, 2016, https://openstax.org/books/university-physics-volume-3/pages/1-introduction.
Chicago author-date
Ling, Samuel J., Jeff Sanny, and William Moebs. 2016. University Physics Volume 3. Houston, TX: OpenStax. https://openstax.org/books/university-physics-volume-3/pages/1-introduction.

OpenStax entries are free to read online. Follow the licence shown on each linked source before redistributing or adapting its content.

Reuse the page responsiblyCite this pageAPA, MLA, Chicago, Harvard, BibTeX and RIS

These formats cite this calculator page itself. They are separate from the academic references above, which support the mathematical method and terminology.

APA 7

MW SysArc. (2026, July 21). Free-Field Acoustic Distance Attenuation reference source distance Solver. MW SysArc Tools. https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver

MLA 9

MW SysArc. “Free-Field Acoustic Distance Attenuation reference source distance Solver.” MW SysArc Tools, 21 July 2026, https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver. Accessed 31 Aug. 2026.

Chicago 17

MW SysArc. “Free-Field Acoustic Distance Attenuation reference source distance Solver.” MW SysArc Tools. Published July 21, 2026. Accessed August 31, 2026. https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver.

Harvard

MW SysArc (2026) ‘Free-Field Acoustic Distance Attenuation reference source distance Solver’, MW SysArc Tools. Published 21 July 2026. Available at: https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver (Accessed: 31 August 2026).

BibTeX and RIS records

BibTeX

@misc{mwsysarc_free_field_acoustic_distance_attenuation_solve_b_2026,
  author = {{MW SysArc}},
  title = {Free-Field Acoustic Distance Attenuation reference source distance Solver},
  howpublished = {MW SysArc Tools},
  year = {2026},
  url = {https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver},
  note = {Published July 21, 2026; accessed August 31, 2026}
}

RIS

TY  - ELEC
AU  - MW SysArc
TI  - Free-Field Acoustic Distance Attenuation reference source distance Solver
T2  - MW SysArc Tools
PY  - 2026
DA  - 2026-07-21
Y2  - 2026-08-31
UR  - https://math.mwsysarc.com/mathematical-physics/free-field-acoustic-distance-attenuation-reference-source-distance-solver
N1  - Published July 21, 2026
ER  -

Clear answers

Frequently asked questions

What does the Free-Field Acoustic Distance Attenuation: solve reference source distance do?

Rearrange the free-field acoustic distance attenuation relationship and solve for reference source distance.

How does the Free-Field Acoustic Distance Attenuation: solve reference source distance work?

The calculator applies b=a/10^(c/20). For spherical free-field spreading, sound-pressure level reduction between distances is twenty times the logarithm of their ratio. This page isolates reference source distance and verifies it in the original relationship.

What can I learn from the Free-Field Acoustic Distance Attenuation: solve reference source distance?

It connects the mathematical rule to your chosen numbers and shows each calculation step. Change one input at a time to see how the result responds.

Does MW SysArc receive or store what I enter?

No. The calculation runs locally in your browser. MW SysArc does not receive or store your calculation inputs.

How should I use the result?

Use the steps to understand the method, then verify important school or professional work using the notation and rounding rules required in your setting.

Last reviewed . Calculations tested .

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