App Overview

spectwhirl icon

spectwhirl

Alexey Nadzharov · Music

"bells and whistles, literally"

$4.99 · In-app purchases

PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.0
5 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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Build Kit

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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 spectwhirl: 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 music library through partnerships with music services.

Assumption to check: Limited song selection compared to competitors

Validate with people who use this workflow before building.

Hypothesis 2

Implement offline playback for user convenience.

Assumption to check: No offline playback feature

Validate with people who use this workflow before building.

Hypothesis 3

Provide user settings to customize visual effects intensity.

Assumption to check: Visual effects can be overwhelming

Validate with people who use this workflow before building.

Hypothesis 4

Clarify subscription benefits and provide a free trial.

Assumption to check: In-app purchase confusion

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

"bells and whistles, literally" spectwhirl is a hybrid spectral audio effect. It can extract and rearrange sinewave components from input signal to make new sound textures and bell-like sounds. * input sound is converted to sinewave components that are divided into 4 groups: harmonic, inharmonic, 12-edo and other * each component is fed into a delay line with feedback * there is a group of frequency shifter and sample-and-hold effects before and after delay lines * each set of sinewave components can be filtered * all the parameters can be instantly automated with gesture recording !!! Please note that this effect consumes much CPU and requires a modern device. ====================== Quick Start: Top row of controls enables different parts of user interface: scenes editor ("scene"), controls switch ("edit") and "zoom" controls When "edit" is switch on, you can show or hide various controls (marked as "ctrl") and switch gesture recording automation for some of them (marked with ">") Main control surface displays sonogram with tracked elements. Colors are set accordingly to the group they are assigned (red-orange-green-blue are for harmonic, inharmonic, 12-edo and others). Each "lane" contains delay time controls. * Triangle facing left is for the start locator, it determines initial delay time * Square moves both start and end locators together * When left locator is first moved you can see the right locator with the same triangle. It shows the end of the selected region, the secondary delay time is determined by the difference between left and right locators * if you drag over the area of the region in a lane, the four-dotted/one circle indicator will change its appearance; this changes the arpeggio mode of the region. If set to leftmost position (one circle) the components go in-sync; if set to maximum value (shown as diagonal line with circles) - components are played sequentially * all settings can be stored as "scene" and multiple scenes can be switched sequentially; there is a set of button to move, add and delete scenes. All scenes will be stored as machine state; it can be exported / imported as a single file or as separate file with current scene in the "setup" view The standalone version always starts with output level set to -70 dB to avoid feedback

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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
React Native
Expo
Zustand
expo-av
react-navigation
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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.