App Overview

FFT icon

FFT

Andrew Smith · Music

FFT is a high-resolution audio analysis tool for the iPhone and iPod touch

$10.99 · In-app purchases

PRICE
$10.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.0
6 ratings · Top 30%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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A product spec, screen plans, and build steps for your coding agent.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for FFT: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Expand supported formats for better user experience.

Assumption to check: Limited audio file format support

Validate with people who use this workflow before building.

Hypothesis 2

Integrate sharing options to enhance user engagement.

Assumption to check: Lack of social sharing features

Validate with people who use this workflow before building.

Hypothesis 3

Add features for users to analyze together.

Assumption to check: No collaborative analysis features

Validate with people who use this workflow before building.

Hypothesis 4

Offer tiered pricing or a free trial to attract more users.

Assumption to check: High price point for features offered

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

FFT is a high-resolution audio analysis tool for the iPhone and iPod touch. It uses the Fast Fourier Transform to analyze incoming audio, and displays a very detailed graph of amplitude vs. frequency. Use this app with the built-in iOS device microphone, or upgrade to our iAudioInterface2 or iTestMic for a complete professional solution. *** Designed for Acoustical Analysis This application has been designed for acoustics work, and so the bins have been normalized to octaves, to get a display that will show a flat line for pink noise. You can control both the level of graph smoothing and decay time, to get as much or as little detail as you require. You can also control the dB resolution of the graph, as well as the frequency range that is displayed. *** Includes Signal Generator Included in this app is the engine from our Generator app, which is a low-distortion, artifact-free signal generator. The signal generator appears as a heads-up display when you tap the icon, so you can see the graph while you adjust the generator. Generate sine waves, square waves (within limits), white noise, and pink noise, optionally in psuedo-balanced mode. All waveforms are generated in real time using high-precision algorithms. *** Cursor Readout Move your finger across the screen to get a cursor to read out exact dB levels and frequencies. *** Touch-GUI Controls Use a vertical pinch-open gesture to expand the dB scale. Use a horizontal pinch-open gesture to expand the frequency scale. *** Graph Smoothing Smooth the graph by octave, 1/3, 1/6, 1/12, or 1/24 octave. Adjust the decay time from 0.5 seconds, for a very fast fluid display, to 8 seconds, or use Peak Hold or Average mode. Average mode is a true equal-weighted average, which can run continuously. *** Peak Tracking Turn on Peak Tracking to have FFT automatically find a label the frequency of the highest peak on your graph. *** Tune the Parameters Set the FFT size from 4096 to 32k points (depending on iOS device) , or select Equal Points Per Octave mode, for high-resolution analysis, even at low frequencies. *** Calibration FFT comes calibrated for the typical iPad, iPod touch, or iPhone microphone, and you can adjust the calibration. Microphone compensation files tailored to each iOS device are automatically applied. *** Save and Recall When your analysis is complete, you can save the graph image to your photo roll to include in a report, or export the data in an XLS file. *** Display Multiple Graphs Show a recalled graph on the screen in a different color. *** Difference Mode Use a stored graph as a baseline that is subtracted from the current graph in real time. *** RTA or FFT? If you are wondering if you should download this app or our FFT app, check out our website, we have a page devoted to this topic. *** Other Audio Apps Also, check out our other great audio and acoustics apps: AudioTools, our premier suite of audio and acoustics analysis apps, SPL, SPL Graph, for recording SPL over time, RTA, RT60, Generator, and Speaker Pop.

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
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BUILD KIT DIFFICULTY
Advanced

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.