# Knob16 vs Opaline FM

The clearest difference is in-app purchases: Opaline FM at none against Knob16's 1. Opaline FM also leads on iOS requirement (16.0 vs 18.6). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Knob16 sells 1 one-off in-app purchase. Opaline FM asks for nothing beyond the download.

Knob16 ships an update every 8 days, Opaline FM every 6 days. The most recent releases landed on October 28, 2026 and October 21, 2026 respectively.

## The numbers

| Metric | Knob16 | Opaline FM |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (3 ratings)](https://appshunter.io/ios/app/opaline-fm/id6790603368/reviews)** |
| Number of ratings | — | **3** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 8 days | **Every 6 days** |
| Monetization | — | Free |
| Size | 12 MB | 3 MB |
| Requires iOS | 18.6 | **16.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [JURIJS KOSKINS](https://appshunter.io/developer/1888330126) | [Hideki Konishi](https://appshunter.io/developer/6790603370) |

## What reviewers say

### Knob16

[App page](https://appshunter.io/ios/app/knob16/id6761230712)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Knob16 Pro | $11.99 | one-time |


### Opaline FM

[App page](https://appshunter.io/ios/app/opaline-fm/id6790603368)

Create and perform music with a virtual keyboard and advanced sound editing tools. Explore various playing modes, connect external MIDI devices, and manage your sound library. Offers deep control over FM synthesis parameters.

**Highlights:** Virtual keyboard for immediate performance, Detailed sound editing (algorithm, operators, envelopes, LFO, effects), Poly/Mono and Full/Fingered portamento, Single, Dual, and Split playing modes, External MIDI keyboard support, 32-voice SysEx bank management, Built-in reverb, delay, chorus, and tone effects

**In-app purchases:** none


## Frequently asked questions

### Is Knob16 free?

Knob16 is free to download, with in-app purchases available.

### Is Opaline FM free?

Opaline FM is free to download, with no in-app purchases.

### Do Knob16 or Opaline FM have ads?

Neither Knob16 nor Opaline FM shows ads.

### Which is updated more often, Knob16 or Opaline FM?

Knob16 ships an update every 8 days, and Opaline FM every 6 days. Most recently, Knob16 was updated on October 28, 2026 and Opaline FM on October 21, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*