PolyHarp vs Trapezoid
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PolyHarp
This app offers a virtual musical instrument inspired by chorded zithers, featuring extensive chord customization, multi-string capabilities, and massive polyphony. It serves as a platform for harmonic theory exploration and a powerful MIDI controller, with numerous presets and the ability to create unique instruments.
- Extensive chord customization
- Multi-string and polyphony support
- Harmonic theory testbed
- MIDI controller functionality
- Large preset library
- Audiobus 3 and IAA support
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PolyHarp is a virtual musical instrument and a thought experiment. It takes the basic idea of a chorded zither and extends it to large numbers of chord choices, made out of any kinds of intervals, multi-string courses, fretting, and massive polyphony. It's a testbed for harmonic theory as well as a great multi touch simulation of the good old "idiot zither" you have in the attic. PolyHarp can translate many of these innovations to MIDI and is a powerful MIDI controller. PolyHarp comes with a large number of presets, exploring many variants on stringed instruments, but its real power is its ability to build strange new chords, layouts, and controls into otherwise impossible instruments. PolyHarp supports Audiobus 3, including saving setups, and IAA.
Trapezoid
This virtual instrument app offers an authentic hammered dulcimer experience on iPad. It features a full range of notes, customizable tunings, and realistic playing mechanics like drag rolls. Advanced users can connect MIDI controllers for enhanced performance and control.
- Authentic hammered dulcimer sound and playability
- Full range of a 15/14 instrument
- Standard and Michigan (octave) tunings
- Drag roll effects for repeated notes
- Hard or soft hammer sound options
- MIDI keyboard support with velocity sensitivity
- Adjustable volume, panning, and strike zones
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Trapezoid is an amazing Hammered Dulcimer for the iPad. Written by an experienced Hammered Dulcimer player, this virtual dulcimer sounds and plays like the real thing! The app has the full range of a standard 15/14 instrument and supports both Standard and Michigan (octave) tunings. 15/14 means there are 15 bridges on the Treble (left) side of the instrument, 14 bridges on the Bass (right) side of the instrument. 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. Toggle between Hard or Soft hammers sound by touching on the "Hard" or "Soft" label on the upper left corner of the screen. The app also may be played from a MIDI keyboard connected to a hardware MIDI interface or other MIDI controller or MIDI file player apps. When playing via MIDI, the app is velocity sensitive based on the velocity sent with the Note-on events. Lowest MIDI note is A2 (MIDI note 45). MIDI range is fully chromatic from A2 to D6. When playing via MIDI, the volume is based on the Treble bridge notes volume. The app will respond to MIDI volume messages on the selected MIDI channel. Touch the "?" on the upper left corner to show the note names for the strings. Touch the "i" on the upper left corner to show the settings screen where you may: - Adjust the volume and right/left panning for the bass and treble bridges - Choose between "Traditional" or "StrikeZones" instrument styles The new "StrikeZones" instrument style shows you exactly where to touch on the screen for each note. The zones light up when touched. It is an excellent tool for understanding or teaching the layout of the instrument. - Choose between Standard or Michigan (octave) tunings - Show or hide the hammer touches - Show or hide the note name highlights (when note labels are displayed) - Enable or disable the drag rolls as well as set the sensitivity for how far you need to drag to get the roll effect - Set the MIDI channel. Lowest MIDI note is 45 (A2) - Using the "Soft Hammer Filter" control, choose between equalization of the soft hammer sounds for best sound through the iPad speaker or through headphones. The "iPad" setting optimizes the soft hammer equalization for playback through the iPad speaker. The "Headphones" setting optimizes the soft hammer sound equalization for headphones or for use when connected to an amplifier through the headphone jack. The "Headphones" setting allows more of the low frequency content of the sound to pass through for best quality. On the iPad Pro, with its amazing stero speakers, set the "Soft Hammer Filter" to "Headphones" for best quality sound when playing with the soft hammers. - Learn more about ThumbJam or visit the AppCordions website Touch the "Shhh" button on the upper right corner to quiet all the ringing strings. To truly experience the full stereo spread of the instrument, plug in a set of headphones or amplified speakers. Audio samples of Wes Chappell's amazing dulcimer provided by Jesse Chappell from ThumbJam.com. The instrument was built by James Jones, from Bedford, VA. I have played and taught the Hammered Dulcimer for over 20 years. This app sounds and plays as close to the real instrument as I'm capable of doing on a touch screen. Be sure to visit the AppCordions.com website to watch the demo videos!
Verdict
The clearest difference is rating: PolyHarp at 4.9 against Trapezoid's 3.9. PolyHarp also leads on review sentiment (100% vs 91%). Trapezoid's advantage is update cadence (every 4 days vs every 4 weeks) and price ($2.99 vs $4.99). On ratings volume, ads, in-app purchases and monetization model 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
PolyHarp costs $4.99 and Trapezoid $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
PolyHarp holds the better App Store score, 4.9 against 3.9. Both are backed by a comparable volume of ratings — 11 and 7 respectively. Written reviews point the same way: 100% of PolyHarp's written reviews are positive against 91% of Trapezoid's.
PolyHarp ships an update every 4 weeks, Trapezoid every 4 days. The most recent releases landed on September 30, 2026 and October 13, 2026 respectively.
| Parameter | PolyHarp | Trapezoid |
|---|---|---|
| Price | $4.99 | $2.99 — better |
| Rating | 4.9 (11 ratings) — better | 3.9 (7 ratings) |
| Positive reviews | 100.0% of reviews — better | 90.9% of reviews |
| Number of ratings | 11 — better | 7 |
| Update frequency | Every 4 weeks | Every 4 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPad | iPad |
| Requires iOS | 12.4 | 10.0 — better |
| Further details — not scored | ||
| Size | 16 MB | 73 MB |
| Age rating | 4+ | 4+ |
| Developer | Henry Lowengard | Michael Eskin |
Customer experience
PolyHarp
Trapezoid
In-app purchases
PolyHarp
No in-app purchases
Trapezoid
No in-app purchases


