# SJ-SQUARE - Synthesizer — Analog Poly Synth Keyboard

> Analog Poly Synth Keyboard (iPhone/iPad app by Kouki Yoshimoto.)

- Source: https://appshunter.io/ios/app/sj-square-synthesizer/id6797394418 (this page in markdown: same URL + `.md`)
- Developer: [Kouki Yoshimoto](https://appshunter.io/developer/1884780659)
- Category: Music
- Price: $0.49
- Age rating: 4+
- Requires: iOS 26.5 · 30 MB
- Languages: English
- Released: 2026-08-18
- Data updated: 2026-09-09
- User reviews in markdown: https://appshunter.io/ios/app/sj-square-synthesizer/id6797394418/reviews.md

## What is SJ?

SJ-SQUARE is a Super Jupiter–inspired analog polyphonic synthesizer for iPhone.

A warm brown chassis and amber glow meet a hands-on module layout: oscillators, filter, envelopes, LFO, and effects — built for playing, not menus.

FEATURES
• Multi-oscillator panel with wave, octave, and level controls
• Filter with resonance, envelope intensity, and key tracking
• Filter envelope & amp controls for expressive shaping
• LFO, OSC 2 detune / live layer, chorus, delay, and reverb
• Unison (1–4 voices), tempo / tap, and scale snap
• Full on-screen keyboard with octave shift & range minimap
• MIDI input support for external controllers
• Built-in presets ready to play
• Landscape-optimized performance UI

Craft rich pads, biting leads, and stacked unison tones. Tweak cutoff and envelopes in real time, then perform with the keyboard or your MIDI gear.

From the maker of KG-SQUARE, JP-SQUARE, and DX-SQUARE — hardware-inspired synth apps for musicians who love hands-on sound design.


## Version history (last 2 releases)

### 1.1 — 2026-09-03

・Improved keyboard responsiveness.
・Minor bug fixes.

### 1.0 — 2026-08-19

No release notes.

## More apps by Kouki Yoshimoto

- [WindInstrumentTuner - 管楽器チューナー](https://appshunter.io/ios/app/windinstrumenttuner/id6760515036)
- [TryDiet](https://appshunter.io/ios/app/trydiet/id6760956967)
- [住宅ローン計算シミュレーター](https://appshunter.io/ios/app/id6761039889)
- [Bass Tuner - Bass Guitar Only](https://appshunter.io/ios/app/bass-tuner-bass-guitar-only/id6761100387)
- [Standard Metronome](https://appshunter.io/ios/app/standard-metronome/id6761403036)
- [Vocalist - 歌練習・ボーカルトミュート機能付き](https://appshunter.io/ios/app/vocalist/id6761674601)

All apps by Kouki Yoshimoto: https://appshunter.io/developer/1884780659

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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.*