D550 MIDI Controller vs Isomorphic Keyboard
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
D550 MIDI Controller
This app simulates a hammered dulcimer as a MIDI controller for iPad. It allows users to play virtual instruments and hardware synthesizers without producing sound itself. Customize transpose, MIDI channels, velocity, and drag roll sensitivity for a unique musical experience.
- Hammered dulcimer simulation
- MIDI control surface
- Transpose up/down one octave
- Adjustable drag roll sensitivity
- Independent MIDI channel control
- Velocity and volume adjustment
- Virtual MIDI port support
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D550 MIDI is a Hammered Dulcimer based MIDI control surface for the iPad. The app doesn't produce any sound on it own. It is designed for playing hardware and software VST-style MIDI synthesizers such as Kontakt via a CoreMIDI compatible interface connected to the dock connector or virtual MIDI instruments like Roland Sound Canvas for iOS, IK Multimedia SampleTank®, or Sonosaurus ThumbJam running on your iPad. The app preview shows the app controlling Hammered Dulcimer, Harp, and Cittern MIDI patches in Sonosaurus ThumbJam. The app has the full 3.75 octave chromatic range of the flagship Dusty Strings D550 Chromatic Hammered Dulcimer, plus can be transposed up or down one octave in semitone increments. To play, just touch the strings on either side of the left (Treble) bridge or the left side of the right (Bass) bridge just like on the real instrument. To get repeated note "drag roll" effects, drag quickly horizontally across the strings. The drag roll sensitivity can be set on the settings screen. The higher the sensitivity, the shorter distance you need to move your finger to get the effect. Touch the iPad icon on the playing area controls to toggle between "Full" and "Treble/Bass Bridge Only" style instruments. "Full" provides the full D550 instrument including the Superbass bridge. "Treble/Bass-Only" focuses on the treble and bass bridges and provides the maximum string spacing for easier play on smaller screens like the iPad Mini. Touch the MIDI connector icon on the upper left corner to show the settings screen where you may: - Set the overall instrument transpose up or down up to one octave in semitone increments - Set the MIDI channel independently for the treble and bass bridges The treble bridge notes include the C#6 and D#6 notes on the accessory bridge at the top left of the instrument and the D#5 on the accessory bridge above the bass bridge. The bass bridge notes include the notes on the Super bridge on the left side of the full instrument layout. - Adjust the MIDI velocity and volume independently for the treble and bass bridges - Use the "Transmit MIDI Port" switch to choose between "Omni" sending MIDI data to all CoreMIDI apps or "Virtual Port" sending to a named CoreMIDI virtual output port. When the "Virtual Port option is selected, D550 MIDI will show up as an input option labeled "D550" in apps that support virtual ports like Sonosaurus ThumbJam and MIDIBridge. "Omni" mode is selected by default. - Show or hide the hammer touches + note label highlights - Enable or disable the drag rolls as well as set the sensitivity for how far you need to drag to get the roll effect - Visit the AppCordions website - Visit the Dusty Strings website Touch the "?" on the upper left corner to show the note names for the strings. Touch the "Shhh" button on the upper right corner of the main screen or on the settings screen to send a MIDI "All Notes Off" message to quiet any stuck notes. The app works most effectively with MIDI patches that have a long release decay time, like harp, guitar, and other plucked instruments. Settings for use with other MIDI synthesizer apps: Sonosaurus ThumbJam: - In "Preferences", under "Options", enabled "Background Audio". If using the "Virtual Port" transmit port option, enable the input port under Preferences / MIDI Control / MIDI Input Connections. Under Preferences / MIDI Control / Input Options, change the "In Channel Start" from "Omni" to channel 1. IK Multimedia SampleTank: - In Settings (touch the gear icon), enable "Background Audio". Other CoreMIDI compatible synth apps will have similar settings. IK Multimedia iRig MIDI Hardware Interface: - For simple direct connection, in D550 MIDI, set the "Transmit MIDI Port" option to "Omni" . - If using a MIDI filtering app like MIDIBridge to modify the data stream, in D550MIDI, set the "Transmit MIDI Port" option to "Virtual Port". Please visit the app website for demo and setup tutorial videos.
Isomorphic Keyboard
Experience a unique hexagonal keyboard layout for music creation. This app recreates the playing experience of a Lumatone keyboard and supports custom soundfonts for diverse sonic possibilities.
- Hexagonal keyboard layout
- Lumatone keyboard emulation
- Custom soundfont support
- Music synthesizer
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This is an isomorphic keyboard and synthesizer recreating the basic playing experience with a Lumatone keyboard. Custom soundfonts supported.
Screenshots
Verdict
The clearest difference is price: Isomorphic Keyboard at Free against D550 MIDI Controller's $9.99. Isomorphic Keyboard also leads on review sentiment (100% vs 80%). On ads, in-app purchases, device support and iOS requirement 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
Isomorphic Keyboard is free to download; D550 MIDI Controller costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | D550 MIDI Controller | Isomorphic Keyboard |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | — | 4.5 (4 ratings) — better |
| Positive reviews | 80.0% of reviews | 100.0% of reviews — better |
| Number of ratings | — | 4 — better |
| Update frequency | Fortnightly | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPad | iPhone, iPad — better |
| Requires iOS | 16.6 | 16.0 — better |
| Further details — not scored | ||
| Size | 67 MB | 23 MB |
| Age rating | 4+ | 4+ |
| Developer | Michael Eskin | Nci Technology Inc. |
Customer experience
D550 MIDI Controller
Isomorphic Keyboard
In-app purchases
D550 MIDI Controller
No in-app purchases
Isomorphic Keyboard
No in-app purchases



