Dexed Synth vs OB
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Dexed Synth
This app brings a powerful FM synthesizer to your mobile device, offering a vast library of sounds. It integrates with popular DAWs and supports external MIDI controllers for enhanced control and performance.
- FM Synthesizer port
- Over 20,000 cartridges with 32 patches each
- AudioUnit AUv3 plugin support
- MIDI controller input via USB
- Lock scroll and parameter locking
- MIDI CC mapping
Read full descriptionHide full description
A port of Dexed, a FM Synthesizer. Features over 20,000 Cartridges with 32 patches each. Comes with AudioUnit AUv3 plugin for use inside AUM and other DAW apps like GarageBand. Get a camera kit and plug in a midi controller through USB, or get a 5-PIN DIN 1/in 1/out, to: USB and use the camera kit through USB MIDI Spec, NOTE: some devices handle SysEx differently and therefore we cannot promise support for SysEx, so invest in connectors and cables wisely. If you have questions involving making MIDI-USB work the best for your situation, email support. This iOS app was designed especially with small interfaces in mind. Example: an iPhone 5S or a resizable window inside AUM. If one clicks the menu eye, a feature LOCK SCROLL can be –very– important to set knobs, sliders, et cetera: if screen size is limited. LOCK PARAMs in the eye menu locks the parameters for scrolling without knocking loose the preset. In the CARTs menu double tap a cartridge to load a series of patches, the files will have a .syx extension. To use MIDI CC, in the menu eye you must first turn on MIDI CC. When MIDI CC is on it makes the tap events react like a right mouse button click. NOTE: MIDI CC, in eye menu, doesn't have to be on after CC controls are mapped. MIDI CC touch modifier will also turn off after you have successfully mapped a CC control, or when you delete the current mappings. You can turn it on again later to turn off mappings or create new CC mappings. I would suggest setting CC knobs in the bottom section of the screen – above keyboard (if visible). Currently you must save patch in DAW – for instance: GarageBand or AUM. Once we can determine unity and saving/loading between the AUv3 plugin and the StandAlone app, external save will be eventually developed. There is a pathway set to transfer .syx files through iTunes to the StandAlone app, only. Other plans include fixing pixelated images, a quick zoom to set CC mode and updating GUI to a higher degree, make sure midi CC knobs update.
OB
This app emulates the classic Oberheim OB-X synthesizer, offering its rich sound and behavior with added enhancements. It focuses on sonic quality and includes micro random detuning for authentic analog warmth. External effects are recommended to further shape its versatile soundscapes.
- Oberheim OB-X emulation
- Recreates original sound and behavior
- Added enhancements to original design
- Micro random detuning
- Rich and good sound quality
Read full descriptionHide full description
OB-Xd is based on the Oberheim OB-X. It attempts to recreate its sound and behavior, but as the original was very limited in some important ways, a number of things were added or altered to the original design. OB-Xd was designed to sound as good and as rich as the original. It implements micro random detuning. Also, like many synths of the OB-X's generation, the OB-Xd has no internal effects so its sounds and textures can be greatly enhanced by the use of additional processing like chorus, reverb, delay, etc.
Screenshots
Verdict
The clearest difference is price: Dexed Synth at $3.99 against OB's $14.99. OB's advantage is rating (4.4 vs 3.1) and review sentiment (57% vs 29%). On ratings volume, update cadence, ads and in-app purchases 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
Dexed Synth costs $3.99 and OB $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
OB holds the better App Store score, 4.4 against 3.1. Both are backed by a comparable volume of ratings — 43 and 65 respectively. Written reviews point the same way: 29% of Dexed Synth's written reviews are positive against 57% of OB's.
Both ship on a similar rhythm, roughly every 2 months. Both last shipped on October 15, 2026.
| Parameter | Dexed Synth | OB |
|---|---|---|
| Price | $3.99 — better | $14.99 |
| Rating | 3.1 (43 ratings) | 4.4 (65 ratings) — better |
| Positive reviews | 28.8% of reviews | 57.0% of reviews — better |
| Number of ratings | 43 | 65 — better |
| Update frequency | Every 2 months | Every 2 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 105 MB | 25 MB |
| Age rating | 12+ | 4+ |
| Developer | George Rosar | DiscoDSP LLC |
Customer experience
Dexed Synth
OB
Bugs and requests
Dexed Synth
Not enough reviews yet to summarise bugs or requests.
OB
Reported bugs
13 issues- Crashes in Audiobus
- Cannot use in MIDI section of Audiobus
- Preset browser issues (scrolling, cut off banks)
- Automation bug with cutoff freq
- UI issues on iPad Pro (buttons misaligned, text cut off)
Show 8 moreShow fewer
- App suspends on iOS 14
- No virtual keyboard in standalone app
- AUv3 crashes when adding second instance
- UI messed up in AU
- Knobs don't line up with display
- Wonky controls
- Programmer page without menu, cannot save/open patches
- LFOing filter cutoff jerky
Requested features
19 requests- Add last/high priority for mono patches
- Increase polyphony to 8 voices
- MIDI Learn functionality
- Preset browser improvements (categories, scrolling)
- Adjustable keyboard size
Show 14 moreShow fewer
- GUI scaling/layout redesign for iPhone
- Skins for GUI
- MIDI keyboard in standalone mode
- Effects
- Preset manager
- Zoom functionality for AUv3 on iPhone
- Fix knob turning bugs
- Add patch select in DAW apps
- GUI color scheme options
- Manual in settings
- Import presets
- Layering sounds (like original OBXa)
- White pinstripes on blue background (cosmetic)
- Mod wheel customization
In-app purchases
Dexed Synth
No in-app purchases
OB
No in-app purchases









