# Frequency Loom — Acoustic evidence fieldbook

> Acoustic evidence fieldbook (iPhone/iPad app by Robert Corbin.)

- Source: https://appshunter.io/ios/app/frequency-loom/id6771018795 (this page in markdown: same URL + `.md`)
- Developer: [Robert Corbin](https://appshunter.io/developer/1890247992)
- Category: Utilities, Productivity
- Price: $3.99
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-05-20
- Data updated: 2026-09-09
- User reviews in markdown: https://appshunter.io/ios/app/frequency-loom/id6771018795/reviews.md

## What is Frequency Loom?

Frequency Loom is an acoustic commissioning fieldbook for installed sound systems. It turns a listener-area plan into a traceable record of positions, witnessed microphone runs, acceptance results, and handoff evidence.

Start with the job, not a generic meter. Record the site, room, work order, operator, client witness, installed system, microphone, interface, channel, and field calibration context. Lay out one or more listener areas with named measurement positions, microphone heights, plan coordinates, notes, and required repeat counts.

At each position, capture a live evidence run while the installed sound system or another external source plays pink noise, speech-shaped noise, program material, or a sweep; use Ambient only for background capture. Frequency Loom records broadband RMS, one-third-octave band values, active input route, sample rate, captured duration, clipping, and level stability. Short, clipped, unstable, incomplete, interrupted, or route-changing runs are held out of verification instead of being silently treated as valid.

The acceptance matrix evaluates project-defined targets for:

- Planned position coverage
- Listener-area level spread
- Worst cross-position band spread
- Repeat-run agreement
- Optional referenced ambient and commissioned-level limits

Every retained run receives a deterministic SHA-256 evidence seal. Later changes cause an integrity mismatch and exclude the run. Voided runs stay visible as ledger events. Export the complete job as structured JSON, CSV, or a readable commissioning report through the iOS share sheet.

The commissioning workflow requires no account or developer network service and works offline; Methodology links open external reference websites only when you tap them. Microphone samples are analyzed on device and are not saved as audio. Projects remain in private local storage until you deliberately export them. There are no analytics, ads, tracking SDKs, remote flags, or subscriptions.

Uncalibrated work is labeled relative dBFS. A documented reference match can produce referenced dB SPL values, but Frequency Loom does not claim that an iPhone, microphone, calibrator, or input chain conforms to IEC, ISO, ANSI, or AVIXA standards. The app is a commissioning evidence fieldbook, not a class-rated sound level meter or standards certificate.


## Version history (last 5 releases)

### 2.2 — 2026-09-08

Frequency Loom has been rebuilt as a dedicated acoustic commissioning fieldbook.

- Create site-specific jobs with work order, operator, witness, installed-system, microphone, interface, channel, and calibration context.
- Plan named listener areas and measurement positions with coordinates, microphone heights, notes, and repeat requirements.
- Capture live witnessed runs for pink noise, speech-shaped noise, program material, external sweeps, or ambient sound.
- Automatically hold short, clipped, unstable, incomplete, route-changing, or sample-rate-changing captures.
- Verify project-defined position coverage, listener-area level spread, spectral consistency, repeatability, and optional referenced level targets.
- Seal every retained run with SHA-256 and exclude altered or voided evidence from results.
- Export a complete JSON evidence package, CSV ledger, or text commissioning report through the system share sheet.
- Review the measurement boundary, current technical references, and privacy behavior in the in-app Methodology record.

This release gives Frequency Loom one focused purpose: producing a clear, inspectable acoustic commissioning record.

### 2.1 — 2026-06-29

Version 2.1 adds Field Setup, a measurement-readiness workflow for real audio sessions.

New in this build:
- Field Setup readiness score for calibration, external mic, quiet baseline, mounting, FFT size, and export planning.
- Offline Reference Pack with six bundled 48 kHz WAV test signals for playback-path, room, and spectrum checks.
- Profile-specific recommended chains for studio tuning, live-venue checks, noise logs, and vocal range work.
- Copyable session brief for notes, reports, or client handoff.
- In-app source links and clearer reference-tool limits for phone-based SPL and noise-dose readings.
- Safer Noise Log and Hearing Sweep wording to clarify the app is not a certified compliance meter or clinical hearing device.
- Fresh App Store screenshots showing the current RTA, SPL, Field Setup, Reference Pack, and tools screens.

### 2.0.1 — 2026-06-24

This update sharpens the interface: the iPad layout now uses a centered, comfortable reading width instead of stretching edge to edge, plus small display fixes. iPhone is unchanged; still fully on-device.

### 2.0 — 2026-06-21

Frequency Loom 2.0 — five new pro measurement tools, still 100% offline.

• THD / Distortion Meter: plays an internal test tone and reports THD, THD+N, SINAD, and ENOB with a harmonic breakdown and CSV export.
• Dynamics / Crest Factor: live peak vs RMS in dB with a session aggregate and a reference rail.
• Room Mode Calculator: enter L/W/H and see axial fundamentals, mode pile-ups and gaps, and a ratio-quality score.
• Polarity Checker: emits a positive-leading pulse and tells you in-polarity vs inverted.
• Delay / Distance Finder: a click plus cross-correlation gives lag, distance, and confidence.

All DSP runs on-device with synthetic-signal-verified math. No account, no network — your audio never leaves the device.

### 1.2 — 2026-06-20

Version 1.2 - Multiband RT60 per octave band.

New in 1.2:
- Multiband RT60: after any impulse capture, tap "View Multiband RT60" to see T20 reverberation time computed independently for each of 7 octave bands (63 Hz through 4 kHz). Uses IIR biquad bandpass filtering + Schroeder backward integration per band - the same method used by Room EQ Wizard and professional acoustic software. Tap any bar to see its full Schroeder decay curve. Results are compared against EBU R 68 / ISO 3382-1 control-room targets with pass/fail indication per band.

All previous tools (from 1.1):
- Real-time spectrum analyzer with 1/1 through 1/24 octave resolution and NC curve overlay
- A / C / Z weighted SPL meter with Slow / Fast / Impulse integration and LEQ
- Scrolling spectrogram (magma colormap, adjustable FFT)
- Chromatic tuner with YIN pitch detection and cents readout
- LUFS loudness metering (momentary / short-term / integrated, ITU-R BS.1770)
- RT60 room reverberation (Schroeder integration, T20 method)
- Tone generator (sine, log sweep, pink / white / brown noise, impulse)
- Standing-wave heatmap - 12 listening positions
- Audiogram hearing sweep, Crossover designer, Phantom 48V tester
- Hum ID, Time Align, Vocal Warmup, OSHA Dosimeter with CSV export
- Room History, Room EQ Advisor with treatment recommendations
- PDF export from the RTA screen

Real DSP throughout. No tracking. No account. Microphone only.

## More apps by Robert Corbin

- [Daily Word Journey](https://appshunter.io/ios/app/daily-word-journey/id6761548266)
- [Hush Secret Text](https://appshunter.io/ios/app/hush-secret-text/id6761658175)
- [Renew Guard](https://appshunter.io/ios/app/renew-guard/id6761755447)
- [Receipt to PDF](https://appshunter.io/ios/app/receipt-to-pdf/id6761782025)
- [Route Your Pay](https://appshunter.io/ios/app/route-your-pay/id6761783719)
- [Tip Arbiter](https://appshunter.io/ios/app/tip-arbiter/id6761786879)

All apps by Robert Corbin: https://appshunter.io/developer/1890247992

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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 2026-09-09.*