# Low Frequency Detector — user reviews > 8 indexed App Store user reviews of Low Frequency Detector by TOON,LLC, rated 2.80/5 from 6 ratings. - Source: https://appshunter.io/ios/app/low-frequency-detector/id1196584147/reviews - App overview in markdown: https://appshunter.io/ios/app/low-frequency-detector/id1196584147.md - Rating breakdown: 5★ 1 · 4★ 2 · 3★ 0 · 2★ 1 · 1★ 2 ## Most critical reviews (8 lowest-rated) ### 1/5 — Low Frequency Detector *2024-05-07* This app will not calibrate **Developer response:** To ensure proper calibration, please check the following three points. 1) Check that this app has permission to access the iPhone's built-in microphone. 2) Calibration cannot be completed if the iPhone audio output level is too low or too high. Try setting the iPhone audio volume to the appropriate gain (20%-50%). 3) Calibration cannot be performed if the background noise level is very high in your environment. Try the calibration in a quiet place as far as possible. Please see our app support website for more information on this issue. http://www.toon-llc.com/support/lfd_en.html Thank you. ### 1/5 — Rubbish and a scam *2023-11-11* Pretty sure I previously wrote a review about this, but it seems to have been removed. This DOES NOT detect low frequency. The frequency response of the iPhone microphone is not sufficient to do so. Aside from that the capability of the phone to provide a low pass filter does not exist. SCAM. **Developer response:** As you mentioned, the frequency response of the iPhone's built-in microphone is less sensitive below 100 Hz. In this app, we do not use the simple technique you might imagine, such as direct low-pass filtering the iPhone's built-in microphone signal. This app employs our proprietary digital signal processing technology to detect and analyze only low-frequency components using a specific frequency extraction technology with a reference signal. Therefore, it requires a reference tone output and pre-measurement calibration. It was developed for iPhone devices based on the logical sound analysis technology. Details cannot be disclosed due to our confidential technical information. Thank you for your understanding. ### 1/5 — Rip off - doesn’t actually work as cannot be ‘tuned’ *2020-10-04* Don’t waste your money **Developer response:** In order for this app to work properly, it is necessary to make the microphone access permission settings related to the iOS system. In addition, please check the default settings (tuning and calibration) listed on our support page and try again. ### 1/5 — Doesn’t work *2019-11-03* This app does not work, no support, hard to contact anyone. Don’t buy it. **Developer response:** Our web support desk is available. Please check the email address information on our website again. In addition, there may be a problem accessing the microphone. Please check if you have enabled the microphone input in the iOS settings. ### 4/5 — Pretty good *2020-12-15* This app isn’t as intuitive as other noise detection apps. You have to tune it first by adjusting the volume on your phone, as it sends out a reference signal. The other thing that is not intuitive is it doesn’t show you a live readout of decibels versus frequency like some of the other apps. You have to essentially push “record” and it takes a reading over 60 seconds, then push another button to get the report. I’m giving it four stars though because it seems pretty accurate. When I’m sensing my neighbor’s bass, it reflects in the report as well (the report shows you the decibels versus frequency and is color-coded to reflect low, medium, or high noise levels), and when I’m not sensing it, it reflects that too. ### 4/5 — Works best between 30 Hz and 110 Hz *2020-04-11* It cannot detect 120 Hz or above because it is outside the range, and 20 Hz and below seems to get lost in the background noise. Both 30 Hz and 110 Hz are detected. ### 5/5 — Very useful and it works *2023-01-21* This app had a slight learning curve, but it’s well designed to lead one through what to do. It’s easily well-calibrated enough for my purposes, and getting it to work with the tiny iPhone mic was ingenious. Extremely worth the value. Update: I realized after I wrote the above that it almost looks like a fake review. I’m a meditator who is very sensitive to sound in the environment. LF sound is hard to localize, but I was able to use this app, in addition to my other senses, to walk around and eventually find many intermittent LF sources in my vicinity, made easier by the multimodal sharp peaks in the FFT when I got closer to and farther from different sources. ### 5/5 — Source of low hum identified *2022-02-22* Low sporadic hum seemed to be coming from all directions. App allowed me to pinpoint the room and the source which was next doors bathroom extractor fan coming in via a shared wall. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-04.*