Comparison

Doppler Effect Calculator vs Contact Separator

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Doppler Effect Calculator

This physics and math calculator helps determine the frequency of sound waves when the source or observer is in motion. It provides instant calculations with copyable results and includes reference formulas. The app supports various units and high precision, working seamlessly on iOS devices.

Highlights
  • Instant calculations
  • Copyable results
  • Reference formulas included
  • Supports 16 decimal places
  • Multiple unit support
  • Ad-free and private
Features
Read full description

Doppler Effect Calc is a practical physics and audio calculator designed for students, teachers, engineers, sound designers, and anyone working with waves, frequency, sound level, and distance-based attenuation. The app brings together essential acoustic calculation tools in one clean, fast, and easy-to-use interface, helping you solve common sound and wave problems without manual formulas or complicated spreadsheets. Calculate Doppler effect frequency shifts when a sound source or observer is moving. Enter the original frequency, source speed, observer speed, and speed of sound to quickly estimate the perceived frequency. This is useful for physics learning, classroom demonstrations, audio experiments, vehicle sound analysis, and understanding real-world wave behavior. The app also includes decibel calculation tools for working with sound intensity and sound pressure levels. Whether you are comparing level changes, checking dB differences, or learning how logarithmic sound measurement works, Doppler Effect Calc helps make the numbers easier to understand. With the distance attenuation calculator, you can estimate how sound level changes as distance increases or decreases. This is especially helpful for acoustic planning, speaker placement, field measurements, educational examples, and general sound propagation study. Doppler Effect Calc is built for quick, focused calculations. The interface keeps inputs clear, results readable, and formulas easy to reference. A calculation history lets you review previous results, compare values, and avoid repeating work. Built-in reference and information sections provide useful context for the formulas and concepts behind each calculator. Key features include: • Doppler effect frequency calculator • Decibel and sound level tools • Distance attenuation calculator • Calculation history for reviewing previous results • Clear input fields and readable output • Helpful reference information for physics and acoustics • Support for multiple languages • Clean design for study, work, and quick everyday use Whether you are studying wave physics, teaching acoustics, analyzing sound behavior, or simply need a reliable frequency and dB calculator, Doppler Effect Calc gives you a convenient toolkit for fast and accurate sound-related calculations. Thanks for your support, and do visit nitrio.com for more apps for your iOS devices.

About

Contact Separator

Organize and secure your contacts by separating them from your device's default list. This app identifies incoming callers and provides information in your call history, even for private contacts. It supports vCard import for easy management.

Highlights
  • Separate contacts from standard list
  • Caller Identification
  • Call History Identification
  • vCard Import
  • Privacy protection for contacts
Read full description

Isolate your contacts from the standard contact list and protect them from access by third-party apps. For example, maintain business contacts separately from private contacts and you will still be informed who is currently calling. Calls in the call history are also identified. • Separate contacts from standard contacts • Caller Identification • Call History Identification • vCard Import Privacy Policy: https://it-service-schneider.de/norobots/website-privacy-policy.html Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Doppler Effect Calculator4 screens
Contact Separator4 screens

Verdict

The call

Doppler Effect Calculator and Contact Separator both sit at 5.0 stars, but that hides the real split: 100% of Contact Separator's written reviews are positive against 0% of Doppler Effect Calculator's. Contact Separator also leads on price (Free vs $2.99) and update cadence (weekly vs every 26 months). Doppler Effect Calculator's advantage is in-app purchases (none vs 2). On rating, ratings volume, ads and device support 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

CostPrice · In-app purchases · Ads · Monetization

Contact Separator is free to download; Doppler Effect Calculator costs $2.99 up front. Contact Separator sells 2 in-app purchases, starting at $0.99 per month. Doppler Effect Calculator asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for Doppler Effect Calculator against 5.0 for Contact Separator. Both are backed by a comparable volume of ratings — 1 and 1 respectively. Written reviews are what separate them: 0% of Doppler Effect Calculator's written reviews are positive against 100% of Contact Separator's.

UpkeepUpdate frequency

Doppler Effect Calculator ships an update every 26 months, Contact Separator weekly. The most recent releases landed on October 8, 2026 and October 9, 2026 respectively.

Scorecard5 real differences · 5 level
Doppler Effect Calculator versus Contact Separator: the parameters behind the verdict, then further details
ParameterDoppler Effect CalculatorContact Separator
Price$2.99Free — better
Rating5.0 (1 ratings)5.0 (1 ratings)
Positive reviews0.0% of reviews100.0% of reviews — better
Number of ratings11
Update frequencyEvery 26 monthsWeekly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad — betteriPhone
Requires iOS17.617.0 — better
Further details — not scored
Size1 MB7 MB
Age rating4+4+
DeveloperNitrioLars Herres

Customer experience

Doppler Effect Calculator

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Contact Separator

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews6 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Doppler Effect Calculator

No in-app purchases

2 purchases

Contact Separator

Subscriptions1
  • Monthly Abo$0.991 Month
One-time1
  • Lifetime$5.99

Questions

Is Doppler Effect Calculator free?
Doppler Effect Calculator costs $2.99, with no in-app purchases.
Is Contact Separator free?
Contact Separator is free to download, with in-app purchases available.
Which has better reviews, Doppler Effect Calculator or Contact Separator?
Doppler Effect Calculator and Contact Separator are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.
Do Doppler Effect Calculator or Contact Separator have ads?
Neither Doppler Effect Calculator nor Contact Separator shows ads.
Which is updated more often, Doppler Effect Calculator or Contact Separator?
Doppler Effect Calculator ships an update every 26 months, and Contact Separator weekly. Most recently, Doppler Effect Calculator was updated on October 8, 2026 and Contact Separator on October 9, 2026.

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