Comparison

KORG iM1 vs FM Essential

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

KORG iM1

This app faithfully reproduces the legendary M1 synthesizer, offering its iconic sounds and expanded features for modern music creation. It provides a vast library of presets and intuitive performance tools, making it accessible to both experienced musicians and beginners.

Highlights
  • Faithful reproduction of original M1 sound
  • Expanded filter resonance and 18 effects
  • Gigantic library of 3,300 sounds
  • Intuitive KAOSS pad for performance
  • Smart Sound Browser for quick sound selection
  • Compatible with KORG Gadget
Features
Read full description

A complete reproduction - and more - of the legendary M1 that defined an era. Mobile Digital Synthesizer for the iPad. ● Selected by Apple as "App Store Best of 2015" ● Ranked #1 on the App Store on Top Paid Music category in more than 20 countries! (15/5/27) Since it went on sale in 1988 the legendary M1 music workstation rapidly achieved record-breaking sales, becoming a mainstay of the music scene from the late 1980s and beyond. The common element of electronic instruments that have left their name in history is that they had a unique sound that was difficult if not impossible to replicate. Sounds such as the “M1 Piano” is instantly recognizable and have appeared on countless hit records over many years, and yet these are sounds that could only be produced by the M1. And that’s what you can now have on your iPad! ● A faithful reproduction of the original M1 Sound The PCM data provides the library of the original M1. For the hardware, we analyzed the circuit diagram of the original design, and completely replicated it in software down to the last detailed parameters. Engineers with an exhaustive knowledge of the M1 made careful adjustments in order to obtain the sound of the original unit, something that cannot be obtained simply by sampling the original sounds. ● A continued evolution of the M1 Not content with simply reproducing the original, iM1 provides further evolutionary developments. Synth parts now have the Filter Resonance that was requested at the time of the original. The effect parts, originally consisting of only two effects, have been powered-up to 18 effects. The user interface has also been refreshed with additions such as a KAOSS pad. iM1 is the ultimate version of the KORG M1. ● A gigantic library encompassing 3,300 sounds and 34 cards* In addition to all 19 of the ROM cards originally released for the M1, iM1 also covers the sounds of the M1EX which expanded the internal PCM of the M1, as well as the sounds of the T-series which appeared as an evolution of the M1. There’s also “BEST OF M1”, a selection of 100 great M1 programs. The new “Smart Sound Browser” makes it quick to find the desired sound. You can also view the sounds ranked by how often they are selected by iM1 users around the world. *with all the expansion card installed via in-app purchase ● KAOSS pad lets anybody perform iM1 features a KAOSS pad from the popular KAOSSILATOR, allowing you to perform intuitively just by touching the screen. By using the dual KAOSS pads to play phrases or adjust the sound, even people who are not accustomed to keyboard instruments or knowledgeable about synthesizers can enjoy performing the iM1. There’s also a conventional keyboard, as well as the “Smart Keyboard”, which lets you specify a scale setting and play phrases with a single finger. ● Use with KORG Gadget for song production iM1 can be used together with Gadget, the music production DAW app that won the App Store Best App of 2014 award in Japan. If both apps are installed, you can use iM1 as a sound module within Gadget, taking advantage of the program sounds in iM1 for music production. iM1 also supports Audiobus and Inter-App Audio, so it can also be used for GarageBand etc. ● Connect a MIDI keyboard and use as a sound module In addition to enjoying iM1 on its own, you can connect a USB MIDI keyboard* via a Lightning adaptor and play the iM1 as an external sound module. You can easily take along an even more powerful workstation sound module as part of your iPad-based compact mobile system. *microKEY, nanoKEY etc. ● Interchangeable with the KORG Legacy Collection and the original M1 Sounds that you create in iM1 can be sent from your iPad via iTunes to a Mac/PC. If you have the Legacy Collection M1, you can use those sounds in a DAW. More info at korg.com

About

FM Essential

This app is an FM tone generator and synthesizer for iPhone and iPad, offering real-time performance capabilities and voice editing. It includes a variety of presets, arpeggiator patterns, chord pads, and scales, along with drum functionalities. The app also supports external hardware integration and advanced sound manipulation through effects, EQ, and a ball controller.

Highlights
  • FM tone generator
  • Real-time synth performance
  • Voice editing
  • Arpeggiator and chord pads
  • Effects and EQ edit
  • Ball controller for sound modulation
  • Step sequencer
Read full description

Featuring an FM tone generator, FM Essential is a synthesizer app for the iPhone and iPad that provides for real-time synth performances and also lets you edit voices. [Spec] -FM sound ・Tone Generator: FM ・Part: 1 ・Polyphony: 16 ・Preset Voice: 271 ・Arpeggiator patterns: 64 ・Chord pads: 20 ・Scales: 25 -Drum Part Tone Generator: Audio Part: 1 Drum Pad: 16 Drum Pad Set: 3 Functions Plug into MX! -You can play full 271 voices and voice store function if you connect your iOS with Yamaha music synthesizer MX BK/BU series. Effects/EQ edit -You can adjust parameters to edit effects and equalization. Ball controller -Touch and drag in ball controller to modulate the sound by simultaneously changing multiple parameters based on the ball position. Step sequencer -We can store the ball position in the currently selected scene box. Arpeggiator and chord pads -You can play Arpeggiator and Chord pads in addition to keyboard with various scales. What's MX BK/BU/WH series? Find more here: http://jp.yamaha.com/products/music-production/synthesizers/mx_bk_bu/?mode=series [Support] -Compatible with Audio Unit Extentions -Compatible devices: iPhone 5S, 6/6 plus, 6s/6s plus and SE, iPod touch 6th Generation or later, iPad Air 1st Generation or later, iPad mini 2nd Generation or later,iPad Pro

Screenshots

KORG iM14 screens
FM Essential4 screens

Verdict

The call

The clearest difference is price: FM Essential at Free against KORG iM1's $29.99. FM Essential also leads on in-app purchases (none vs 2). KORG iM1's advantage is rating (4.7 vs 3.0) and review sentiment (82% vs 40%). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

FM Essential is free to download; KORG iM1 costs $29.99 up front. KORG iM1 sells 2 one-off in-app purchases. FM Essential asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

KORG iM1 holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: KORG iM1 has 1K ratings behind it against 70, so its average is the more settled of the two. Written reviews point the same way: 82% of KORG iM1's written reviews are positive against 40% of FM Essential's.

UpkeepUpdate frequency

KORG iM1 ships an update every 7 months, FM Essential every 15 months. The most recent releases landed on October 30, 2026 and October 22, 2026 respectively.

Scorecard8 real differences · 2 level
KORG iM1 versus FM Essential: the parameters behind the verdict, then further details
ParameterKORG iM1FM Essential
Price$29.99Free — better
Rating4.7 (1K ratings) — better3.0 (70 ratings)
Positive reviews81.5% of reviews — better40.0% of reviews
Number of ratings1K — better70
Update frequencyEvery 7 months — betterEvery 15 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS12.0 — better16.0
Further details — not scored
Size200 MB88 MB
Age rating4+4+
DeveloperKORG INC.Yamaha Corporation of America

Customer experience

KORG iM1

All ratings1,007 ratings
Positive93.8%
Neutral2.3%
Negative3.9%
Written reviews487 reviews
Positive81.5%
Neutral7.4%
Negative11.1%

FM Essential

All ratings65 ratings
Positive43.1%
Neutral12.3%
Negative44.6%
Written reviews40 reviews
Positive40.0%
Neutral12.5%
Negative47.5%

User reviews

KORG iM1

From 1K App Store ratings

What we love

  • 👍 Authentic M1 sound reproduction
  • 💰 Great value for money
  • 🎹 Faithful recreation of the original hardware
  • 🎨 Powerful sound customization options
  • 🔗 Works well with MIDI controllers

Room to improve

  • 🐛 Occasional crashes or stability issues
  • 🔇 Low output volume compared to other apps
  • 🤔 Confusing UI for patch editing and saving
  • 🔴 Missing AUv3 support for integration with DAWs

FM Essential

From 70 App Store ratings

What we love

  • 🎶 Fantastic sound quality
  • 👍 Easy to use
  • ✨ Amazing synth capabilities
  • 💡 Great FM synth app
  • 🎵 Wonderful, flexible, intuitive synth

Room to improve

  • 🔓 App locked by hardware
  • 🔌 Connection issues
  • 💸 Expensive hardware required
  • ❓ Deceptive free app
  • 😩 Limited functionality

Bugs and requests

KORG iM1

Reported bugs

3 issues
  • Disappearing or missing purchased sound cards
  • Bluetooth MIDI connectivity issues
  • Compatibility problems with certain iOS versions or devices

Requested features

4 requests
  • Add AUv3 support for better DAW integration
  • Improve preset management and saving capabilities
  • Increase master volume control options
  • Expand sound library with more cards/expansions

FM Essential

Reported bugs

6 issues
  • Does not unlock with USB-C adapter
  • App crashes when loading combinations
  • Preset menus crash the app
  • Combined Sounds no longer read from keyboard after iPad update
  • Instruments stop working if effect filters are turned off
Show 1 more
  • Incompatible USB Device on MX displays

Requested features

9 requests
  • Unlock without hardware purchase
  • Allow in-app purchase to unlock
  • Bring back Tenori On apps
  • Fix LFO delay parameter
  • Add separate volume control for drums
Show 4 more
  • Allow app to be used as a plugin
  • Fix AU host preset recall
  • Make app compatible with more devices
  • Fix instruments disabling when effects are off

In-app purchases

2 purchases

KORG iM1

One-time2
  • M1 Cards Pack$4.99
  • T1 Cards Pack$4.99
None

FM Essential

No in-app purchases

Questions

Is KORG iM1 free?
KORG iM1 costs $29.99, and also offers in-app purchases.
Is FM Essential free?
FM Essential is free to download, with no in-app purchases.
Which has better reviews, KORG iM1 or FM Essential?
KORG iM1 is rated higher. KORG iM1 averages 4.7 out of 5 from 1K ratings, while FM Essential averages 3.0 from 70 ratings.
Do KORG iM1 or FM Essential have ads?
Neither KORG iM1 nor FM Essential shows ads.
Which is updated more often, KORG iM1 or FM Essential?
KORG iM1 ships an update every 7 months, and FM Essential every 15 months. Most recently, KORG iM1 was updated on October 30, 2026 and FM Essential on October 22, 2026.

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