Engine Sound Analyzer:RPM Calc

Contains ads
2.7
192 reviews
50K+
Downloads
Content rating
Everyone
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About this app

It is an application that estimates the engine Revolutions Per Minute [RPM] from the exhaust noise of a motorcycle or car when idling. By all means for maintenance of vehicles without tachometers such as scooters !


The idling sound includes the sound of the engine exploding, the rotation of the crankshaft / motor e.t.c., and the sound of various parts.
This application divides the sound measured by the microphone for each frequency and calculates the rotation speed [rpm] from the loudest frequency.
* Measurement results may vary due to various factors such as ambient sound, vehicle type, terminal used, and distance from the sound source. Please treat the measurement result as a reference value. In addition, it may not be possible to measure correctly depending on the model, rotation speed, and microphone performance.


• Set the number of engine strokes and cylinders
• Start measurement with “RUN” or “▷”
• Adjust the Gain and Threshold to place the peak value above the Threshold line
• Select any peak with "<" and ">"
• Stop at “□”
* Measurement will stop when the count is exhausted. You can extend the measurement time by seeing the reward advertisement or restart.


* Never use it while driving. There is a risk of accidents.
* Do not touch the heat source, keep away from it. There is a risk of burns or terminal failure.
* Securely fix the vehicle or machine so that it does not move. It may fall or move suddenly, leading to an unexpected accident.


For a long time, DIY has always liked to maintain motorcycles as a hobby.
When deciding the idling height while thinking "Is it like this?" When repairing an engine malfunction or carburetor in winter, or when adjusting the air screw, ask "Where is the number of revolutions high?" I was setting the settings while feeling. Then I had the opportunity to study the Fourier transform in another case, and if I analyze the engine sound with this, I think it can be quantified. What I thought was interesting was the reason I decided to do DIY.

I hope this app helps someone somewhere in the world.
Updated on
Aug 20, 2024

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
This app may collect these data types
Location, App activity and 2 others
Data is encrypted in transit

Ratings and reviews

2.7
190 reviews
steven s
June 13, 2025
I dont leave app reviews often but this one didnt have any and it deserved it for the utility it provided. I used it to set the governors on some small engines (think lawnmower). with the gain, filters and engine type set correctly it works awesome. It struggled a little at idle but was dead on the money at full throttle. I could tune to 3600rpm +- 20 easily. i also appreciate the ad system. not super obtrusive, you watch ads occasionally to get more rpm readings. dosent blast you every time
4 people found this review helpful
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Nolan McCann
July 19, 2022
This app exceeded my expectations. The interface is minimal and works easily, allowing the user to tune the filters and thresholds for accurate speed detection. It matched my dash tachometer within 50 rpm - the error was probably from the dash. Perfect. Thanks!
3 people found this review helpful
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Emi 20
June 8, 2025
the measurements was between 4 and 12 times the true value. tested with two motorcycles with different engines. completely useless for me.
1 person found this review helpful
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