# D550 MIDI Controller — Hammered Dulcimer Controller

> Hammered dulcimer MIDI controller app for iPad. (iPhone/iPad app by Michael Eskin.)

- Source: https://appshunter.io/ios/app/d550-midi-controller/id1071138983 (this page in markdown: same URL + `.md`)
- Developer: [Michael Eskin](https://appshunter.io/developer/342739369)
- Category: Music, Music, Education
- Price: $9.99
- Age rating: 4+
- Requires: iOS 16.6 · 67 MB
- Languages: English
- Released: 2016-01-07
- Data updated: 2026-06-01
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/d550-midi-controller/id1071138983/reviews.md

## What is D550 MIDI Controller?

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.

## Key features

- 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

## Recent user reviews (5 of 5)

All indexed reviews: https://appshunter.io/ios/app/d550-midi-controller/id1071138983/reviews.md

### 1/5 — Dusty strings

*2019-11-22*

Dusty strings iPad this download would not work on this iPad Model no. Is mp2h2ll/a every thing worked but it had no sound I had to download sweet midi player to get it to work

**Developer response:** Apparently you didn't actually read the description of the app before purchasing it. It specifically says that this app is just a MIDI controller for other iOS MIDI synth apps and doesn't make any sound on it's own.

### 5/5 — Versatile MIDI Controller

*2016-01-31*

I've been experimenting with this controller and it is opening up new creative possibilities more tan any controller I've ever used. 
It especially shines on creating rich rhythmic patterns using Trilian and many other soft synths. 
I find myself regularly tweaking the Transpose Semi-tones and velocity settings in order to find the right expression. Also combining multiple samples make this a controller that goes far beyond controlling the beautiful instrument it reflects.
Clearly a controller designed by a musician!

### 5/5 — Love this developer

*2016-01-30*

This midi controller helps me get things I haven't gotten out of other controllers.  I like to use it for runs, staccato plucks, etc.  works really good with more percussive sounds like harp, strings, etc....  Thnx!

### 5/5 — Hey! Awesome MIDI controller

*2016-01-30*

Thanks go out to Michael Eskin for creating this unique and awesome controller for MIDI apps. Try it, your apps will be played like you've never played them before. It's pretty cool!

### 5/5 — Unique MIDI controller

*2016-01-30*

As someone who doesn't play dulcimer, using this interface causes me to play notes that I wouldn't normally play on a standard piano keyboard. Using it as a MIDI controller results in unique melodies that change the whole dynamic of a song.

If you're looking for a "different" kind of MIDI controller, check this one out!

## Frequently asked questions about D550 MIDI Controller

### What is D550 MIDI Controller?

D550 MIDI Controller is a paid app for iPad that simulates a hammered dulcimer, acting as a MIDI control surface. It does not produce sound on its own but is designed to control external hardware and software MIDI synthesizers.

### Does D550 MIDI Controller produce sound?

No, D550 MIDI Controller does not produce any sound. Its function is to send MIDI data to other compatible applications or hardware synthesizers that can then generate sound.

### What instruments can D550 MIDI Controller control?

It can control hardware and software VST-style MIDI synthesizers, including those accessed via CoreMIDI compatible interfaces, virtual MIDI instruments like Roland Sound Canvas for iOS, IK Multimedia SampleTank®, and Sonosaurus ThumbJam.

### How does the drag roll effect work in D550 MIDI Controller?

To achieve repeated note "drag roll" effects, users can drag quickly horizontally across the strings. The sensitivity for this effect can be adjusted on the settings screen, determining how far a finger needs to move to trigger the roll.

### Can I customize the MIDI settings in D550 MIDI Controller?

Yes, you can customize settings such as the overall instrument transpose (up to one octave in semitone increments) and set the MIDI channel independently for the treble and bass bridges.

### What is the price of D550 MIDI Controller?

D550 MIDI Controller is a paid application priced at $9.99.

### What devices support D550 MIDI Controller?

D550 MIDI Controller is exclusively supported on iPad devices.

### How often is D550 MIDI Controller updated?

The app was last updated on July 3, 2025, indicating active development and support.

## Version history (last 5 releases)

### 2.2 — 2025-07-03

Bug fixes

### 2.1 — 2021-01-29

Bug fixes and update for iOS 13+

### 2.0 — 2016-02-04

"Trapezoid MIDI" has been re-branded as "D550 MIDI" and is now based on the acoustic "D550 Chromatic Hammered Dulcimer" app.

It expands on the the original Trapezoid MIDI controller app by adding several new features:

Completely new high-resolution graphics based on the D550 Chromatic Hammered Dulcimer.

Extended 3.75 octave chromatic range matching the acoustic D550 Chromatic Hammered Dulcimer instrument.

"Full" instrument and "Treble/Bass-Only" playing modes as in the acoustic D550 Chromatic Hammered Dulcimer app.

"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.

For MIDI channel mapping, 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.

### 1.3 — 2016-01-21

Added optional note label highlights while playing. 

Display of the highlights is based on the "Show Hammer Touches" setting on the settings screen.

### 1.2 — 2016-01-14

Fixed an issue where Note Off messages weren't getting sent consistently for all notes during drag rolls. Was causing stuck notes in some synth apps like Roland Sound Canvas.

Now re-sends the MIDI volume messages to the treble and bass channels when the app is made active.

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## More apps by Michael Eskin

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- [Englitina - English Concertina](https://appshunter.io/ios/app/englitina-english-concertina/id349451473)
- [Uilleann - Pocket Irish Pipes](https://appshunter.io/ios/app/uilleann-pocket-irish-pipes/id353684178)
- [Canntina - MacCann Concertina](https://appshunter.io/ios/app/canntina-maccann-concertina/id360579654)

All apps by Michael Eskin: https://appshunter.io/developer/342739369

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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 2026-06-01.*