CO2 sensor vs Frequency Analyzer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CO2 sensor
Monitor CO2, temperature, and humidity levels in real-time using a Bluetooth sensor. Save readings with location data and sync them across Apple devices via iCloud. View historical data on a map.
- Real-time CO2, temperature, and humidity readings
- Bluetooth sensor integration
- Save readings with location
- iCloud sync across devices
- Map view of saved readings
- Open source code available
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Read CO2, temperature, and humidity from your Bluetooth Sensirion SCD-41 sensor in realtime. Save your readings with your current location and have it sync across your devices via iCloud. See previously saved readings with a map of the location that those readings were taken. Works across iPhone, iPad, and macOS devices. Open source code: https://github.com/sighmon/ios-ble-co2-sensor
Frequency Analyzer
Transform your device into a professional audio analysis tool with advanced FFT analysis, SPL monitoring, and detailed visualizations. Record, analyze, and export audio data with precision calibration and multiple weighting filters.
- Real-time FFT analysis
- Calibrated SPL measurements
- 32-bit float audio recording
- Synchronized video recording
- Spectrogram and octave band analysis
- Export WAV, CSV, images, and videos
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Transform your device into a professional-grade audio analysis suite with industry-leading 32-bit float processing, precision calibration tools, and comprehensive visualization capabilities. PROFESSIONAL ACOUSTIC MEASUREMENT • Real-time FFT analysis with configurable window sizes up to 4096 points • Reference SPL measurement with calibrated sound pressure level monitoring • Professional microphone correction with frequency-specific calibration curves • Reference tone calibration for precise frequency measurements • Configurable time averaging (0-1000ms) for stable, accurate readings • Industry-standard weighting filters: dBA, dBC, dBZ, and linear magnitude • Multiple window functions: Hanning, Hamming, Blackman ADVANCED VISUALIZATION MODES • High-resolution spectrum analyzer with peak detection • Real-time waveform display • Professional spectrogram • Octave band analysis • Amplitude tracking over time • Total level monitoring with min/max/average statistics POWERFUL RECORDING & ANALYSIS • High-quality 32-bit float audio recording and playback • Synchronized video recording with audio analysis overlay • Event tracking system with timestamped notes • Playback synchronization with all recorded events and measurements • Location mapping for environmental noise surveys • Export capabilities: WAV audio, CSV data, high-resolution images and videos PRECISION DECIBEL MEASUREMENT • Calibrated SPL measurements with reference level adjustment • Real-time dB monitoring with peak hold functionality • Statistical analysis: Leq, Lmax • Configurable time averaging (0-1000ms) • Frequency-weighted noise exposure calculations • Exposure calculator for NIOSH and OSHA IDEAL FOR PROFESSIONALS • Acousticians and audio engineers • Environmental noise consultants • Musicians and sound designers • Room acoustics optimization • Industrial noise monitoring • Educational and research applications • Live sound reinforcement • Building acoustics assessment Download now and unlock the full spectrum of acoustic measurement capabilities. DISCLAIMER This is a consumer application designed for general audio analysis and educational purposes. It is not a certified measurement instrument and should not be used where legally compliant or certified measurements are required. For professional acoustic assessments requiring traceable calibration or regulatory compliance, we recommend using an external calibrated measurement microphone with certified sound level meters. EULA: https://frequency-analyzer.com/terms-and-conditions/
Screenshots
Verdict
The clearest difference is rating: Frequency Analyzer at 4.5 against CO2 sensor's 3.4. Frequency Analyzer also leads on update cadence (every 8 days vs every 12 months) and ratings volume (169 vs 7). CO2 sensor's advantage is in-app purchases (none vs 11) and device support (4 vs 1). On price and ads 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
Both are free to download. Frequency Analyzer sells 11 in-app purchases, starting at $2.99 per 7 days. CO2 sensor asks for nothing beyond the download.
Frequency Analyzer holds the better App Store score, 4.5 against 3.4. That said, the two scores are not equally well evidenced: Frequency Analyzer has 169 ratings behind it against 7, so its average is the more settled of the two.
CO2 sensor ships an update every 12 months, Frequency Analyzer every 8 days. The most recent releases landed on October 3, 2026 and October 12, 2026 respectively.
| Parameter | CO2 sensor | Frequency Analyzer |
|---|---|---|
| Price | Free | Free |
| Rating | 3.4 (7 ratings) | 4.5 (169 ratings) — better |
| Positive reviews | — | 10.0% of reviews |
| Number of ratings | 7 | 169 — better |
| Update frequency | Every 12 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone |
| Requires iOS | 15.6 — better | 17.2 |
| Further details — not scored | ||
| Size | 0 MB | 35 MB |
| Age rating | 4+ | 4+ |
| Developer | sighmon | Manfred Kuegel |
Customer experience
CO2 sensor
Frequency Analyzer
In-app purchases
CO2 sensor
No in-app purchases
Frequency Analyzer
- Frequency Analyzer Pro Weekly3 Days trial$2.997 Days
- Frequency Analyzer Pro Monthly7 Days trial$3.991 Month
- Frequency Analyzer Pro Monthly$3.991 Month
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- Frequency Analyzer Pro Monthly7 Days trial$4.991 Month
- Frequency Analyzer Pro Monthly$4.991 Month
- Frequency Analyzer Pro Monthly3 Days trial$4.991 Month
- Frequency Analyzer Pro Annual7 Days trial$29.991 Year
- Frequency Analyzer Pro Annual7 Days trial$44.991 Year
- Frequency Analyzer Pro Annual$44.991 Year
- Frequency Analyzer Pro Annual3 Days trial$44.991 Year
- Pro access for lifetime$89.99
Questions
Is CO2 sensor free?
Is Frequency Analyzer free?
Which has better reviews, CO2 sensor or Frequency Analyzer?
Do CO2 sensor or Frequency Analyzer have ads?
Which is updated more often, CO2 sensor or Frequency Analyzer?
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