# Otosan — ToneGenerator,Simple Gt Tuner

> Frequency generator and simple instrument tuner for audio testing and relaxation. (iPhone/iPad app by HIROSHI SHINKAWA.)

- Source: https://appshunter.io/ios/app/otosan/id6758872739 (this page in markdown: same URL + `.md`)
- Developer: [HIROSHI SHINKAWA](https://appshunter.io/developer/1875457585)
- Category: Utilities, Music
- Price: Free
- Age rating: 4+
- Requires: iOS 26.2 · 102 MB
- Languages: American English, Arabic, French (France), German (Germany), Hindi, Italian, Japanese, Korean, Brazilian Portuguese, Russian and 2 more
- Released: 2026-03-10
- Data updated: 2026-11-05
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/otosan/id6758872739/reviews.md

## What is Otosan?

Enter any value from 20Hz to 20,000Hz to play your favorite frequency, or use the slider to test your hearing range. Frequencies like 432Hz and 528Hz are popular for relaxation, meditation, yoga, studying, and sleep. The built-in tuner also works great for tuning instruments. Simple design with a retro feel. Includes 3 bonus tracks: RetroTone_A440.0Hz / RetroTone_A432.0Hz / RTSHealing_A432.0Hz.

## Key features

- Adjustable frequency generator (20Hz-20,000Hz)
- Hearing range testing
- Instrument tuner
- Supports popular relaxation frequencies (432Hz, 528Hz)
- Includes bonus audio tracks

## Is Otosan safe?

Not enough ratings yet to assess Otosan.

## Is Otosan legit?

Otosan appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Otosan is 65 out of 100 points across 7 verification signals from App Store and developer data.

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/otosan/id6758872739/reviews.md

### 5/5 — ビジュいいね

*2026-03-15*

簡単に周波数が変えられていいと思う

**Developer response:** 爆裂簡単です。ありがとうございます。

### 5/5 — いい

*2026-03-13*

針が動くのいい

**Developer response:** そこです。ありがとうございます。ブラッシュアップして行きますので宜しくお願い致します。

## Frequently asked questions about Otosan

### What is Otosan?

Otosan is a utility app that allows you to generate sound frequencies from 20Hz to 20,000Hz. It also includes a simple instrument tuner and bonus audio tracks.

### What frequencies can Otosan generate?

Otosan can generate any frequency value between 20Hz and 20,000Hz, allowing for precise audio testing and exploration.

### Can Otosan be used for relaxation or meditation?

Yes, Otosan supports popular frequencies like 432Hz and 528Hz, which are often used for relaxation, meditation, yoga, studying, and sleep.

### Does Otosan have ads?

No, Otosan is ad-free, providing an uninterrupted user experience.

### What devices does Otosan support?

Otosan is currently supported on iPhone devices.

### How often is Otosan updated?

The latest version of Otosan was released on November 2, 2026, indicating recent development activity.

### What is the age rating for Otosan?

Otosan has an age rating of 4+, making it suitable for a wide range of users.

### Does Otosan offer in-app purchases?

No, Otosan does not feature any in-app purchases, and it is available for free.

## Version history (last 5 releases)

### 1.6.2 — 2026-11-02

• Added a "Compare" mode to Binaural Beats.
• Microphone permission and other system texts now match all 12 in-app languages.
• Minor improvements.

### 1.6.1 — 2026-10-29

■We've renamed the app from "RetroTone" to "Otosan." It's the same app you know — just a new name.

■New: Binaural Beats — plays slightly different frequencies in each ear to help you relax or focus. Choose from Theta(5Hz)/Alpha(10Hz)/Beta(15Hz)/Gamma(40Hz) presets. Launch from the "Binaural" chip at the top (not intended as a medical device; effects are not guaranteed. Headphones recommended). Minor bug fixes and stability improvements.

### 1.5.4 — 2026-08-18

[JP] ■チューナーに音出し機能を追加：弦をタップすると基準音が鳴り（再タップで停止）、「全弦を鳴らす」ボタンで低音弦→高音弦を一気に確認できます。音を鳴らしている間はマイク判定を自動停止し、誤検出・ハウリングを防止。細かな不具合修正と安定性向上。

[EN] ■Tuner now plays sound: tap a string to hear its reference pitch (tap again to stop), or use "Play All Strings" to hear low-to-high in one go. Mic detection auto-pauses while sound plays, preventing false readings and feedback. Minor bug fixes and stability improvements.

[简体中文] ■调音器新增发声功能：点按琴弦可播放基准音（再次点按停止），或用"播放全部琴弦"从低到高一次听完。发声时自动暂停麦克风检测，防止误判和啸叫。修复细节问题，提升稳定性。

[한국어] ■튜너에 소리 재생 기능 추가: 현을 탭하면 기준음이 울리고(다시 탭하면 정지), '전체 현 재생'으로 낮은 현부터 높은 현까지 한 번에 들을 수 있습니다. 소리 재생 중에는 마이크 판정이 자동 일시정지되어 오검출과 하울링을 방지합니다. 자잘한 버그 수정 및 안정성 향상.

[Español] ■El afinador ahora reproduce sonido: toca una cuerda para oír su tono de referencia (toca de nuevo para detenerlo), o usa "Reproducir todas las cuerdas" para escuchar de grave a agudo. La detección por micrófono se pausa automáticamente mientras suena, evitando falsas detecciones y acoples. Correcciones menores y mejoras de estabilidad.

[Français] ■L'accordeur joue désormais un son : touchez une corde pour entendre sa note de référence (touchez à nouveau pour arrêter), ou utilisez « Jouer toutes les cordes » pour les écouter de la plus grave à la plus aiguë. La détection par micro se met en pause automatiquement pendant la lecture, évitant faux résultats et larsen. Corrections mineures et stabilité améliorée.

[Deutsch] ■Das Stimmgerät spielt jetzt Töne ab: Tippe auf eine Saite, um ihren Referenzton zu hören (erneut tippen zum Stoppen), oder nutze „Alle Saiten abspielen", um alle von tief bis hoch zu hören. Die Mikrofonerkennung pausiert währenddessen automatisch, um Fehler und Rückkopplungen zu vermeiden. Kleinere Fehlerbehebungen und mehr Stabilität.

[Português] ■O afinador agora reproduz som: toque em uma corda para ouvir sua nota de referência (toque novamente para parar), ou use "Tocar todas as cordas" para ouvir do grave ao agudo. A detecção por microfone pausa automaticamente durante a reprodução, evitando detecções falsas e microfonia. Correções menores e mais estabilidade.

[Italiano] ■L'accordatore ora riproduce un suono: tocca una corda per ascoltarne la nota di riferimento (tocca di nuovo per fermarla), oppure usa "Riproduci tutte le corde" per ascoltarle dalla più grave alla più acuta. Il rilevamento tramite microfono si mette in pausa automaticamente durante la riproduzione, evitando rilevamenti errati e feedback. Correzioni minori e maggiore stabilità.

[Русский] ■Тюнер теперь воспроизводит звук: нажмите на струну, чтобы услышать эталонный тон (нажмите ещё раз, чтобы остановить), или используйте «Проиграть все струны» для прослушивания от низкой к высокой. Во время воспроизведения определение по микрофону автоматически приостанавливается, что предотвращает ложные срабатывания и обратную связь. Небольшие исправления и повышение стабильности.

[العربية] ■أصبح جهاز الضبط يشغّل صوتًا الآن: اضغط على وتر لسماع نغمته المرجعية (اضغط مرة أخرى للإيقاف)، أو استخدم «تشغيل كل الأوتار» للاستماع من الأخفض إلى الأعلى دفعة واحدة. يتوقف اكتشاف الميكروفون تلقائيًا أثناء التشغيل لمنع الاكتشاف الخاطئ والصدى. إصلاحات طفيفة وتحسين الاستقرار.

[हिन्दी] ■अब ट्यूनर आवाज़ बजाता है: किसी तार को टैप करें और उसकी संदर्भ ध्वनि सुनें (रोकने के लिए दोबारा टैप करें), या "सभी तार बजाएं" से निम्न से उच्च तक एक साथ सुनें। बजने के दौरान माइक्रोफ़ोन डिटेक्शन अपने-आप रुक जाता है, जिससे गलत पहचान और हाउलिंग से बचाव होता है। छोटे बग फिक्स और बेहतर स्थिरता।

### 1.5.3 — 2026-08-09

【日本語】
チューナーが大幅パワーアップ。6弦・7弦ギターに加え、4弦・5弦ベースにも対応しました。Drop DやOpen G、DADGADなどの変則チューニングも選べ、弦を1本ずつ選んで合わせる「弦固定モード」、自分だけの音を設定できるカスタムチューニングも搭載しています。

【English】
The tuner gets a major upgrade. It now supports 6- and 7-string guitars plus 4- and 5-string basses, with alternate tunings like Drop D, Open G, and DADGAD. A new string-lock mode lets you tune one string at a time, and custom tunings let you save your own setup.

【中文】
调音器全面升级。现已支持6弦、7弦吉他及4弦、5弦贝斯，并支持Drop D、Open G、DADGAD等特殊调弦。全新的"单弦锁定模式"可逐根弦精准校音，还可以保存专属的自定义调弦。

【한국어】
튜너가 대폭 업그레이드되었습니다. 6현・7현 기타는 물론 4현・5현 베이스까지 지원하며, Drop D, Open G, DADGAD 등 변칙 튜닝도 선택할 수 있습니다. 한 줄씩 선택해 맞추는 '현 고정 모드'와 나만의 커스텀 튜닝 저장 기능도 추가되었습니다.

【Español】
El afinador da un gran salto. Ahora es compatible con guitarras de 6 y 7 cuerdas y bajos de 4 y 5 cuerdas, además de afinaciones alternativas como Drop D, Open G y DADGAD. El nuevo modo de bloqueo por cuerda te permite afinar una cuerda a la vez, y las afinaciones personalizadas te dejan guardar tu propio ajuste.

【Français】
L'accordeur franchit un cap. Il prend désormais en charge les guitares à 6 et 7 cordes ainsi que les basses à 4 et 5 cordes, avec des accordages alternatifs comme Drop D, Open G et DADGAD. Le nouveau mode de verrouillage par corde permet d'accorder corde par corde, et les accordages personnalisés vous laissent enregistrer votre propre réglage.

【Deutsch】
Das Stimmgerät wurde deutlich erweitert. Es unterstützt jetzt 6- und 7-saitige Gitarren sowie 4- und 5-saitige Bässe, dazu alternative Stimmungen wie Drop D, Open G und DADGAD. Der neue Saiten-Lock-Modus lässt dich Saite für Saite stimmen, und mit individuellen Stimmungen kannst du dein eigenes Setup speichern.

【Português】
O afinador ganhou um grande upgrade. Agora com suporte a violões/guitarras de 6 e 7 cordas e contrabaixos de 4 e 5 cordas, além de afinações alternativas como Drop D, Open G e DADGAD. O novo modo de trava por corda permite afinar uma corda de cada vez, e as afinações personalizadas deixam você salvar seu próprio ajuste.

【Italiano】
L'accordatore si aggiorna notevolmente. Ora supporta chitarre a 6 e 7 corde e bassi a 4 e 5 corde, con accordature alternative come Drop D, Open G e DADGAD. La nuova modalità a corda bloccata permette di accordare una corda alla volta, e le accordature personalizzate ti consentono di salvare la tua configurazione.

【Русский】
Тюнер стал ещё удобнее. Теперь поддерживаются 6- и 7-струнные гитары, а также 4- и 5-струнные бас-гитары, плюс альтернативные строи, такие как Drop D, Open G и DADGAD. Новый режим фиксации струны позволяет настраивать по одной струне за раз, а пользовательские строи — сохранить свою собственную настройку.

【العربية】
أصبح الضابط أكثر تطورًا. يدعم الآن الجيتار بـ6 أو 7 أوتار وكذلك الباس بـ4 أو 5 أوتار، إضافة إلى أوضاع ضبط بديلة مثل Drop D وOpen G وDADGAD. يتيح لك وضع تثبيت الوتر الجديد ضبط كل وتر على حدة، كما يمكنك حفظ ضبط مخصص خاص بك.

### 1.5.2 — 2026-07-15

・アプリ内の広告表示を廃止しました
・全体的な安定性と操作性を改善しました

広告のないシンプルな画面で、これまで以上に快適に周波数調整やチューニングをお楽しみいただけます。今後ともRetroToneをよろしくお願いいたします。

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## More apps by HIROSHI SHINKAWA

- [おもいでノートまるばつ](https://appshunter.io/ios/app/id6759541700)
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- [Aurio](https://appshunter.io/ios/app/aurio/id6772625082)

All apps by HIROSHI SHINKAWA: https://appshunter.io/developer/1875457585

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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 2026-11-05.*