# GRAB EM Field Synth — Electromagnetic Field Synth

> Experimental synthesizer using iPhone's magnetic sensor to generate sound from electromagnetic waves. (iPhone/iPad app by Hiroya Tanaka.)

- Source: https://appshunter.io/ios/app/grab-em-field-synth/id6773259322 (this page in markdown: same URL + `.md`)
- Developer: [Hiroya Tanaka](https://appshunter.io/developer/1887542375)
- Category: Music, Entertainment
- Price: $3.99
- Age rating: 4+
- Requires: iOS 17.0 · 2 MB
- Languages: American English
- Released: 2026-05-28
- Data updated: 2026-10-11
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/grab-em-field-synth/id6773259322/reviews.md

## What is GRAB EM Field Synth?

GRAB uses the magnetometer in your iPhone as an antenna. It receives the electromagnetic noise around you and turns it into sound in real time. Power adapters, motors, displays, Wi-Fi routers — the invisible field they radiate becomes the source material, and you play it the way you would play a field recording. Move to a different room and the instrument sounds different.

SOUND ENGINE
• Five ETHER-inspired layers: mains hum / PWM buzz / static hiss / high squeal / pulse train
• Three sensor-driven synth voices: saw / square / noise
• With the camera on, light falling on the lens drives a tremolo across level and timbre

EFFECTS
• CRUSH — bit crusher with sample-rate reduction
• COMB — comb filter with feedback
• REVERB — multi-tap reverb with shimmer
• STUTTER — BPM-synced gate
• MUTE — momentary kill switch; tap it repeatedly to articulate a tremolo by hand
• HOLD latch on every effect pad, from the button or a second finger

ABLETON LINK
• Automatic tempo sync with Live, Logic and other iOS music apps
• STUTTER locks to the Link tempo at 1/4, 1/8, 1/16 and 1/32
• Uses Ableton's official Link settings panel
• Plays alongside other audio apps rather than interrupting them

VISUALS
• 3D point-cloud frequency spectrum
• Spectrum bar mode
• With the camera on, a grayscale image sits behind the field in depth

WAYS TO PLAY
• A field-sound tool: walk it past appliances and hear the timbre shift
• An atmospheric noise source to drop into a live set
• A platform for experimenting with electromagnetic noise music

PRIVACY
All audio is processed on the device. Nothing is recorded and nothing is sent anywhere. Ableton Link communicates only within your local Wi-Fi network.

## Key features

- Electromagnetic wave to sound conversion
- Multi-layered sound engine
- Sensor-linked synth voices
- Camera-driven tremolo effect
- Bitcrush, comb filter, reverb, stutter effects
- Ableton Link tempo synchronization
- 3D point cloud frequency spectrum visualization

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/grab-em-field-synth/id6773259322/reviews.md

### 5/5 — A rare electronic instrument and a work of art

*2026-06-11*

An app created with a stroke of genius. It functions both as an instrument for creating experimental music and as a sound art piece.

## Frequently asked questions about GRAB EM Field Synth

### What is GRAB?

GRAB is an experimental synthesizer for iPhone that uses the device's magnetic sensor to capture ambient electromagnetic waves and convert them into sound. It allows users to create music from the electromagnetic noise of everyday electronics.

### How does GRAB work?

GRAB utilizes your iPhone's magnetic sensor to detect electromagnetic fields from nearby devices like power adapters and Wi-Fi routers. These detected fields are then processed and translated into audible sound through its unique sound engine.

### What kind of sounds can GRAB create?

GRAB offers a multi-layered sound engine with five 'ETHER' inspired layers and three sensor-linked synth voices (sawtooth, square, noise). It also includes effects like bitcrush, comb filter, reverb, and stutter for further sound manipulation.

### Can GRAB sync with other music software?

Yes, GRAB supports Ableton Link for automatic tempo synchronization with DAWs like Ableton Live, Logic, and other iOS music applications. The stutter effect can also sync to the Link BPM.

### Is GRAB suitable for live performances?

GRAB can be used as an atmospheric sound effect generator for live sessions or as an experimental platform for noise music. Its ability to sync with other devices via Ableton Link makes it a versatile tool for live setups.

### What are the visual features of GRAB?

GRAB features a 3D point cloud frequency spectrum visualization. When the camera is on, it can also display a grayscale video feed that is integrated with the spectrum for a unique visual experience.

### Does GRAB have ads?

No, GRAB does not contain advertisements. As a paid application, it offers an uninterrupted user experience without any ad interruptions.

### What is the price of GRAB?

GRAB is available for a one-time purchase of $3.99. This price grants you full access to all features and functionalities of the application.

## Version history (last 5 releases)

### 1.0.5 — 2026-09-13

• Rebuilt the SPECTRUM display. It is now a proper log-frequency analyzer that no longer pins to full scale when you lean on the effects, and it draws as a waveform-style line instead of bars.
• STUTTER now snaps to musical subdivisions, with a beat ladder from 1/4 to 1/64 (triplets included) shown right on the fader.
• Ableton Link is now follow-only. GRAB syncs to the session tempo and never changes it for the other apps.
• The Ableton LINK button now uses the same ○ / ● markers as CAM.

### 1.0.4 — 2026-09-11

This update adds an English App Store listing. The app itself is unchanged from the previous version.

### 1.0.3 — 2026-09-10

・MUTEボタンを追加しました。押している間だけ音が消えるので、連打するとトレモロのように演奏できます。
・エフェクトパッドを押さえたまま2本目の指で触れると、HOLDが切り替わるようになりました。
・REVERBから指を離したあとも、残響が自然に消えていくようになりました。
・カメラをONにしたときに低音が消えてしまう問題を修正しました。
・カメラ使用中にエフェクトを深くかけると音が歪む問題を修正しました。
・長時間演奏を続けると音程が下がり続ける問題を修正しました。
・音声処理の安定性を改善しました。

- - -

• New MUTE button. It silences GRAB only while held, so tapping it repeatedly lets you articulate a tremolo by hand.
• Touch an effect pad with a second finger to toggle HOLD — no need to lift the finger already on it.
• The REVERB tail now rings out naturally after you let go, instead of being cut off.
• Fixed the low mains hum fading away when the camera was switched on.
• Fixed distortion when running the effects hard with the camera on.
• Fixed the pitch drifting downwards during long sessions.
• Improved audio stability.

### 1.0.2 — 2026-06-01

【改善】
・他のオーディオアプリ（GarageBand、Ableton Note 等）と同時に鳴らせるようになりました
・起動順に関わらず、Ableton Link で複数アプリのサウンドを重ねて演奏可能に
・バックグラウンド再生の安定性をさらに向上

### 1.0.1 — 2026-05-28

【バグ修正】
・バックグラウンド再生が正しく動作するようになりました
・ホーム画面からアプリに戻った際の一瞬の音量低下を解消

【UI改善】
・LINKボタンの表記を「Ableton LINK」に変更
・CAM/LINKボタンの視認性を向上
・小型端末でもUIが1画面に収まるよう自動調整

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## More apps by Hiroya Tanaka

- [ATMÓS](https://appshunter.io/ios/app/atmos/id6761055879)
- [CLICK(weather drum machine)](https://appshunter.io/ios/app/clickweather-drum-machine/id6776584609)

All apps by Hiroya Tanaka: https://appshunter.io/developer/1887542375

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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 2026-10-11.*