SPLnFFT Noise Meter vs Mosquitone Detector

SPLnFFT is a sound level meter (noise meter) for your iPhone or iPad with many advanced features: frequency analyzer, frequency meter, test signal generator, dosimeter, ... This soundmeter App is the only one for iOS recommended by the "Laborers' Health and Safety Fund of North America". Here are extracts from other reviews: "our favorite sound measurement app" SafetyAwakenings.com "SPLnFFT is comprehensive, easy to use" TapeOp.com You will find more reviews here: https://www.facebook.com/SPLnFFT For daily use, a very simple interface displays the level of exposure: if orange or red, protect your ears ! Professional users will take advantage of a wide range of accurate and reliable measurements: Leq, peak, L10, L95, taktmaximal, frequency analysis, histogram, dosemetering, ... A&C weightings are compliant with ANSI® S1.42 standard. "468" refers to ITU-R 468-4 *** Some KEY INFORMATION *** : - you absolutely need to allow access to microphone to use this App - screen rotation must be un-locked - there are built-in help messages (speech bubble). Need more ? Contact us !: email, blog, Facebook,... - do not expect to measure as low as 0dB(A) in a quiet room, for these 2 reasons: 30-130dB(A) is the standard usable range for sound level meters and anyway a standard quiet room is around 30dB(A) whereas a typical anechoic chamber is 10 to 20dB(A) Top digital display is for measurement of sound power in 'slow' mode (averaged on 1s). Central analog display is for 'fast' mode (averaged on 1/8th s). But it can display 'slow' mode as well on request: just click on 'fast' label. Peak and average values are displayed below and are held until you touch the 'reset' label. The videos on Youtube reveal more details. Bottom view is a real time FFT (frequency analysis). You will notice that predominant frequency and next one are highlighted. Their frequencies and relative power are displayed on the right. If your input signal is a pure tone then this App will lock on its frequency and display a very accurate result. Green line is the result of a real time FFT done with 1024 points. Purple line is the averaged FFT (exponential filtering done on power of each frequency). Blue line is a copy of what the purple line was when the user froze the display the last time. A test tone at 1kHz or a white noise or a pink noise can be generated and sent to right and/or left outputs (select the type you want in BEEP tab). This FFT view - more precisely an upsized version of it - can be exported as a picture in your own photo library, using the camera button (when display is frozen only). This picture can be exported in a mail as well. The display can be flipped upside-down to ease reading: just rotate your iPhone while holding it vertically. As for ALL sound meters (thus including this one and all others at any price), calibration is suggested if you want to reach extreme precision. This is enabled in this App thanks to a slider to apply some compensation and to three non volatile memories (choice to be made in MIC. tab). How to ? For calibration, you need and external reference, either a calibrated sound meter, or a calibrated noise source. Note as well that the tiny embedded loudspeaker cannot reproduce extreme frequencies. Thus if you want to hear a real white or pink noise, you will need to use a quality headphone or HiFi system. This App was designed seriously for our own needs, by a signal processing expert, and is regularly updated to maintain accuracy and reliability. ***** Any comment, any feedback ? Click on 'support' in iTunes: there is a blog for this. You can even contact us directly by email or through the dedicated FaceBook page (note 'send email' top right) *****

"Mosquitone Detector" is a sound measurement app that detects high frequency noises and ultrasonic sounds hard to hear for human ears. The human audible range is generally said to be 20 Hz to 20 kHz, but sounds above 10kHz gradually become harder to hear with age. On the other hand, prolonged exposure to noise at excessively high sound pressure levels has been pointed out as potentially harmful to health, including hearing. You may be unknowingly exposed to artificially generated dangerous high-frequency noise. This app can detect and visualize such noises. For example, there are increasing cases where high frequency noise generators are installed in various places as a purpose of repelling young people and beast pests using very high frequency mosquito noises, which are inaudible to general adults. Young children, in particular, may be exposed to very loud noise in an uncomfortable environment because adults cannot recognize it. Use this app to find high frequency noise and quickly get away from the bad spot or remove the noise source. Two operating modes are available in this app, Detection Mode and Search Mode. Detection Mode can detect if there are high frequency noises and ultrasonic sounds. Search Mode can pinpoint the direction of high frequency sound sources. Features: - Detection of high frequency sound and ultrasonic wave, display of the peak frequency of the highest level. - Search for sound source direction: 360 degrees horizontally - Detectable frequency range: 8 kHz - 16 kHz / 16 kHz - 23 kHz (2 band division) - Function to switch the gain range: 0dB - 100dB / -10dB - 90dB / -20dB - 80dB (in Detection Mode) - Measurement screen rotation function (Rotate) Operating procedure: 1) Selection of detectable frequency band Select the frequency band as more than 16kHz or less than 16kHz. 2) Selection of Operational mode - Detection Mode (Detect) It finds an inaudible high frequency and ultrasonic sound in the frequency band more than 16 kHz (or less than 16 kHz). Tap START button and it starts the detection function. If high frequency or ultrasonic sound exist, it will be displayed on the graph as the peak frequency. You can make the graph display easier to see by switching the gain range. - Search Mode (Search) It finds the direction of occurrence of the high-frequency sound source that detected the peak frequency. Search mode can be used only when high frequency or ultrasonic sound is founded in Detect mode. Please make sure to hold the bottom built-in microphone of iPhone so that it faces outward. If you measure with the microphone facing inward, microphone sensitivity will deteriorate, and accurate measurement will not be possible. Tap Start button, and firmly hold the iPhone terminal, please turn slowly clockwise. Recommended that the time required for a rotation is about 15 seconds and the rotation speed in the graph is approximately 4 rpm. The measurement is completed by one revolution, and the signal strength of the peak frequency is displayed on the pie chart. You can find approximate direction of the high-frequency sound source relative to your standing position. 3) Snapshot Measurement results can be saved as image files in “Photos,” and a timestamp is embedded in the image. Note: If the frequency changes periodically or randomly, it is not possible to determine the direction of occurrence in "Search". Ultrasonic measurement depends on the sensitivity characteristics of the built-in microphone, so the measurement result may vary. Peak frequency measurements (dB) conform to general noise levels. Remarks: It is still under study about health effects on human body by listening to high frequencies including ultrasonic sound. If the high frequency noise of high level is detected daily, we recommend that you consult an expert. Please visit our iOS App Support page for more information on this app.