Kello vs PFremote2
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Kello
This app analyzes the accuracy of mechanical watches by listening to their ticking sounds through your device's microphone. It compares the watch's rhythm to the precise system clock to reveal timekeeping differences. Supports a wide range of watch frequencies and offers guidance on identifying mechanical timepieces.
- Microphone-based watch sound analysis
- Comparison to iOS system clock
- Automatic detection of 8 common watch frequencies
- Guidance on identifying mechanical watches
- Displays timekeeping differences
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Kello analyzes the precision of mechanical watches against the iOS system clock using a microphone. How Kello works: All mechanically regulated watches are designed to start and stop 1000s of times every hour. A portion of the energy used during this starting and stopping motion is released as acoustic energy, resulting in an audible "tick-tock" sound. The regularity of this sound can be measured against the more precise, internal time-signal of iOS devices, such as the iPhone, and the resulting difference in timekeeping is displayed by Kello. Supported Watch Frequencies: Kello can automatically determine the frequency of the watch being measured based on eight of the most common frequencies used in mechanical watches. These frequencies are standard among low-, middle- and high-grade mechanical timepieces and will accommodate the vast majority of mechanical watches produced in the past 100 years. The following frequencies are supported: * 14,400 bph * 16,200 bph * 18,000 bph * 19,800 bph * 21,600 bph * 25,200 bph * 28,800 bph * 36,000 bph Recommended hardware: Kello works best with an external microphone that has an excellent frequency response between 10,000 and 20,000 Hz. How to know if your watch is mechanically regulated: There are four simple ways to determine if your watch is mechanical and can be used with Kello. 1. Look at the text on your timepiece. If the word "quartz" is featured anywhere on the watch, your watch is not mechanical. If the words "automatic" or "shock-proof" are written anywhere on the watch, there is a very high chance that your watch is mechanical and its precision can be measured by Kello. 2. If your watch has a hand that indicates the seconds, observe how frequently it moves. If the hand moves only once every second, it is very likely that your watch is not mechanical. If this hand moves several times per second or appears to sweep along in a smooth, continuous motion, your watch is most likely mechanical and its precision can be measured by Kello. 3. Turn the crown, that is used to set the hands of the watch, while it is pressed fully in. If the crown turns smoothly, your watch is not mechanical. If you can hear a ratcheting sound as you turn the crown, your watch is most likely mechanical and its precision can be measured by Kello. 4. Place the watch close to your ear and listen. If you hear a noise approximately once every second, it is unlikely that your watch is mechanical. If you hear a constant ticking noise, your watch is very likely a mechanical watch and its precision can be measured by Kello.
PFremote2
Control your acoustic player piano's playback, volume, and all other functions remotely. Connects automatically via Wi-Fi to your Pianoforce Performance Player. An offline view is available to demonstrate functionality.
- Remote playback control
- Volume level adjustment
- Control all player piano functions
- Automatic Wi-Fi connection
- Offline demonstration mode
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The remote control for the Pianoforce Performance player allows you to control the playback, volume levels and all other functions of your acoustic player piano. It automatically connects to Your player piano through Wi-Fi. Note: To use this service - You NEED to have the Pianoforce Performance Player (www.pianoforce.com) V2.50+ connection to LAN and one Wi-Fi access point for iPhone/iPod Touch connection. Or you can press the offline view to see how it works.
Screenshots
Verdict
The clearest difference is price: PFremote2 at Free against Kello's $9.99. PFremote2 also leads on update cadence (every 5 weeks vs every 3 months) and iOS requirement (9.0 vs 13.0). Kello's advantage is rating (2.8 vs 1.7) and review sentiment (37% vs 0%). 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
PFremote2 is free to download; Kello costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Kello holds the better App Store score, 2.8 against 1.7. Both are backed by a comparable volume of ratings — 5 and 3 respectively. Written reviews point the same way: 37% of Kello's written reviews are positive against 0% of PFremote2's.
Kello ships an update every 3 months, PFremote2 every 5 weeks. The most recent releases landed on October 10, 2026 and September 24, 2026 respectively.
| Parameter | Kello | PFremote2 |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | 2.8 (5 ratings) — better | 1.7 (3 ratings) |
| Positive reviews | 37.3% of reviews — better | 0.0% of reviews |
| Number of ratings | 5 — better | 3 |
| Update frequency | Every 3 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 13.0 | 9.0 — better |
| Further details — not scored | ||
| Size | 4 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Coldflower Design Corp. | Pianoforce |
Customer experience
Kello
PFremote2
Bugs and requests
Kello
Reported bugs
10 issues- App crashes on iPhone 5 and iOS 6
- Signal detection fails inconsistently
- Frequency auto-detection varies wildly on same watch
- Unstable signal readings despite strong initial signal
- App hangs on 'determine frequency' step
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- Poor microphone compatibility with external mics
- Results vary significantly between consecutive measurements
- Crashes frequently during measurement process
- Incompatibility with newer iOS versions
- Microphone not detected on some devices
Requested features
10 requests- History log and data storage for watches
- Graphical representation of timing data over time
- Average readings over longer time periods
- Watch profile saving functionality
- Beat error measurement capability
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- Export feature for timing results
- Fine-tuning control for amplification slider
- Improved signal detection algorithm
- Better microphone sensitivity recommendations
- Compatibility with more iOS versions
PFremote2
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Kello
No in-app purchases
PFremote2
No in-app purchases
Questions
Is Kello free?
Is PFremote2 free?
Which has better reviews, Kello or PFremote2?
Do Kello or PFremote2 have ads?
Which is updated more often, Kello or PFremote2?
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