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.
App Overview
Audio Spectrum Analyzer
Spectrum Pad turns your iPad, iPhone, or iPod Touch into an audio spectrum analyzer
$3.99
PRICE
$3.99
No in-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 3.9
53 ratings · Top 50%
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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Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
What's included
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.
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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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Audio Spectrum Analyzer: map the core Utilities workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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App evidence
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
Screenshots
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App Store description
Spectrum Pad turns your iPad, iPhone, or iPod Touch into an audio spectrum analyzer. Frequencies up to 20 kHz can be displayed. You can control the displayed frequency span, as well as the FFT size, from 1024 to 262144 bins. A logarithmic display of the entire 10 Hz to 20 kHz frequency range is available, and the graph fill mode can be turned on and off, as well as the display of up to five frequency markers. Filtering (averaging) can be applied to the spectrum, to smooth out variations. You can turn on the Peak Hold to make it easier to see transient events, as well as adjust the decay rate. Swiping with two fingers lets you adjust the brightness of the spectrum or the graticule grid overlay. Tapping three times with two fingers will save a screenshot to your Photos. One of several user selectable window functions can be used: Rectangular Hanning Hamming Tukey Cosine Lanczos Blackman
Written user reviews are not shown here. Check current App Store reviews >
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 to include streaming sources and Bluetooth devices.
Assumption to check: Limited audio source support (only local files)
Validate with people who use this workflow before building.
Hypothesis 2
Implement saving and exporting features for user convenience.
Assumption to check: No ability to save or export analysis sessions
Validate with people who use this workflow before building.
Hypothesis 3
Focus on simplifying the UI for better user experience.
Assumption to check: Interface can be cluttered with too many features
Validate with people who use this workflow before building.
Hypothesis 4
Optimize audio processing for better performance across all devices.
Assumption to check: Occasional performance issues on older devices
Validate with people who use this workflow before building.
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
React Native
Expo
react-navigation
@react-native-community/slider
expo-av
react-native-reanimated
BUILD KIT DIFFICULTY
Not assessed in a Build Kit yet.
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.
