# GMIS - Acoustic Calculator — dB, SPL/SWL, propagation tools

> dB, SPL/SWL, propagation tools (iPhone/iPad app by GMIS Acoustics.)

- Source: https://appshunter.io/ios/app/gmis-acoustic-calculator/id6751337081 (this page in markdown: same URL + `.md`)
- Developer: [GMIS Acoustics](https://appshunter.io/developer/1834658560)
- Category: Utilities, Education
- Price: $9.99
- Age rating: 4+
- Requires: iOS 13.0 · 28 MB
- Languages: American English
- Released: 2025-09-25
- Data updated: 2026-11-08

## What is GMIS?

GMIS - Acoustic Calculator delivers fast, consistent, field‑grade computations for acousticians and environmental noise professionals.

What's inside:
• Fundamentals: Wavelength, Frequency, Speed of Sound, Acoustic Delay, Directivity Index, Doppler Effect, Acoustic Impedance, Blade Pass Frequency, Bragg's Law, Coincidence Frequency, Mach Number, Noise Exposure & Allowed Time, Needed/Potential Acoustic Gain.
• Decibel tools: dB calculator; SPL / SWL / SIL; Weighting Converter (dBZ ↔ dBA ↔ dBC).
• Quantifying noise: Ldn, Lden, SEL, NPL for standardized assessment.
• Outdoor propagation: SWL↔SPL (full/spherical/hemispherical), distance attenuation; point/line/plane source models; barrier attenuation.
• Room Acoustics: Reverberation Time (RT60) with material catalog & frequency chart; Room Mode Calculator with 3D visualizer.
• Resonators: Helmholtz, Perforated Panel, Slotted Panel, Wood Slats & Membrane Panel resonance frequency calculators.
Designed for experts: fast input, metric units, field‑first UX. One‑time purchase, no ads, offline logic.

## Is GMIS safe?

Not enough ratings yet to assess GMIS.

## Is GMIS legit?

GMIS - Acoustic Calculator has limited verification signals. The AppsHunter Legitimacy Score for GMIS is 55 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 2 releases)

### 1.1.0 — 2026-03-20

New modules & improvements
- 8 new calculation modules:
  • Reverberation Time (RT60) with material catalog & chart
  • Room Mode Calculator with 3D visualizer
  • Weighting Converter (dBZ ↔ dBA ↔ dBC)
  • Helmholtz, Perforated Panel, Slotted Panel, Wood Slats & Membrane Panel Resonators
- New categories: Room Acoustics & Resonance
- Performance improvements and UI refinements

### 1.0.0 — 2025-09-25

No release notes.

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## Related topics

[gmis](https://appshunter.io/ios/topics/gmis)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-08.*