BK vs KORG iM1
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
BK
Control and edit the real-time performance parameters of your Roland BK-9 Backing Keyboard directly from your iPad. Enhance your playing, practicing, and composing experience with quick access to tone editing, part mixing, and effects.
- Real-time parameter editing
- Tone editing
- Part mixing control
- Effects adjustment
- iPad touchscreen interface
- Enhanced performance tool
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Use the Apple iPad to display and edit the real-time performance parameters of your Roland BK-9 Backing Keyboard. With the BK-9 Performance Editor, you can use your iPad to directly access the BK-9’s real-time performance parameters as you play the keyboard. Via the iPad’s graphic display and large touchscreen, you have quick and convenient control of a wide selection of parameters, including tone editing, part mixing, effects, and much more. Designed for use alongside the keyboard’s own dual display system and extensive onboard controls, the BK-9 Performance Editor gives you a powerful tool for enhancing your BK-9 experience while performing, practicing, and composing. Communication between the BK-9 and iPad requires either of the following: - Apple iPad Camera Connection Kit (made by Apple Inc.) and a standard USB cable (Type-A male to Type-B male, readily available at retailers that sell computer accessories) - Roland WNA1100-RL Wireless USB Adapter (connected to the BK-9) and a wireless LAN access point with an Internet connection. - BK-9 Version 1.06 or later (available as a free download from the Roland website) is required in order to use this app with the BK-9.
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.
- 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
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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
Screenshots
Verdict
The clearest difference is review sentiment: KORG iM1 at 82% against BK's 33%. KORG iM1 also leads on rating (4.7 vs 3.7) and ratings volume (1K vs 3). BK's advantage is price (Free vs $29.99) and in-app purchases (none vs 2). On update cadence and ads 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
BK is free to download; KORG iM1 costs $29.99 up front. KORG iM1 sells 2 one-off in-app purchases. BK asks for nothing beyond the download.
KORG iM1 holds the better App Store score, 4.7 against 3.7. That said, the two scores are not equally well evidenced: KORG iM1 has 1K ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 33% of BK's written reviews are positive against 82% of KORG iM1's.
BK ships an update every 9 months, KORG iM1 every 7 months. The most recent releases landed on October 8, 2026 and October 17, 2026 respectively.
| Parameter | BK | KORG iM1 |
|---|---|---|
| Price | Free — better | $29.99 |
| Rating | 3.7 (3 ratings) | 4.7 (1K ratings) — better |
| Positive reviews | 33.3% of reviews | 81.5% of reviews — better |
| Number of ratings | 3 | 1K — better |
| Update frequency | Every 9 months | Every 7 months — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Best chart rank | — | #61 — better |
| Devices | iPad | iPhone, iPad, iPod — better |
| Requires iOS | 8.1 — better | 12.0 |
| Further details — not scored | ||
| Size | 22 MB | 200 MB |
| Age rating | 4+ | 4+ |
| Developer | Roland Corporation | KORG INC. |
Customer experience
BK
KORG iM1
Bugs and requests
BK
Not enough reviews yet to summarise bugs or 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
In-app purchases
BK
No in-app purchases
KORG iM1
- M1 Cards Pack$4.99
- T1 Cards Pack$4.99









