Sound Spectrum Analysis vs SmarterNoise Pro

The application is designed for analysis of a sound spectrum in real time (with a microphone). Besides, the application can be used as a measuring instrument of noise level (not for exact measurements). • Sound wave. • Fast fourier transform (FFT). FFT size: 2048 (the accuracy of determining the frequency of ±12 Hz), 4096 (±6 Hz), 8192 (±3 Hz), 16384 (±2 Hz), 32768 (±1 Hz), 65536 (±0.5 Hz), 131072 (±0.2 Hz). • Linear and logarithmic frequency scale. • Linear frequency scale with maximum details (there is a choice for the displayed frequency range). • Linear and logarithmic amplitude scale. • Octave bands (1/1, 1/3, 1/6, 1/12). • Window functions (Blackman, Hamming, Hann (Hanning), Blackman–Nuttall, Gaussian, Flat top). • A- and C-Weightings. • Peak hold. • Exponential spectrum averaging. • Peak frequency detection. • Values of any point (for frequency scale and sound wave (at maximum detail)). • Sound level meter (dB SPL). You can calibrate your microphone by launching a signal generator with a sinusoid frequency of 1000 Hz on another device and making the volume very low. When the sound is almost inaudible, it is necessary to find the amplitude for the frequency of 1000 Hz on the spectrum (FFT size: 16384). This value should be multiplied by 1.2 (to compensate for spectral leakage). It will be the reference value for your microphone. ESTIMATE THE TOTAL NOISE LEVEL BY USING THE SOUND WAVE MODE AT THE MAXIMUM VALUE. • Sample rate: 48000 Hz. • Taking a screenshot by lightly touching the screen. • Export data to a WAV or text file ("Y=[y1 y2... yn]", "y1;y2;... yn", "x1;y1\nx2;y2;..."). Number of points is adjusted via "FFT size". • Automatic stop in the sound wave mode (when increasing or decreasing signal strength). • Automatic stop in the spectrum mode. Now you can stop data collection when the start of the fading signal reaches the end of the FFT buffer. The beginning of the signal is not calculated accurately (just like with an automatic stop in the sound wave mode). • Test wave. • Saving the measurement results in the application. Files with saved data (SavedData_[date]_[time].txt) can be copied to a desktop/laptop computer or transferred to another iPhone using iTunes. There are buttons for quick loading and comparing saved files. • Dark theme. • List of frequency peaks. If several peaks have a common base, then they are considered as one peak. The minimum height of the peak for octave bands is 2 dB. • Interpolation of frequencies in the list of peaks. To interpolate the frequency of the peak, select the Gaussian window (the accuracy of determining the frequency can increase by 10-100 times). The calculation is not done for the extreme bins or if the adjacent bin is zero. • Calculation of the amplitude (in the list of peaks) using neighboring bins (to compensate for spectral leakage and use of the window). The number of bins used for calculation is written in brackets. • Collecting recent data (last minute). You can move over all collected data. The amplitude of the waveform can be changed in the sound wave mode. • Calibration file. The app recognizes only files for the UMIK-1 microphone, but you can specify which microphones you need support for.

SmarterNoise Pro is the most advanced edition of the SmarterNoise recording sound level meters. SmarterNoise Pro edition is developed especially with more advanced measurements in mind, and includes many requested features such as a frequency spectrum display, export of measurement data, A-, C- or no weighting for sound level measurement, and full screen audio mode. SmarterNoise Pro edition does not contain any advertising, and performs accurately and fast. Features: • Sound level measurement in video mode • Sound level measurement in audio mode • Sound meter snapshot camera • Record video and audio files (paid function) • Recording timer • Sound level activated audio recording • Frequency spectrum display (paid function) • Peak frequency detection • A-, C- or no frequency weighting • Export of measurement data in CSV format • Full HD (paid function), HD and VGA video resolution • Three video quality settings • Archive for saved files • Sharing of saved files • Calibration • Save location of measurement (optional) • Time and date • Continuous Leq, LAeq, LCeq value • 10 second sound level average (Leq, LAeq, LCeq) • 60 second sound level average (Leq, LAeq, LCeq) • Maximum and minimum decibel level About decibels and sound level measurement The unit for measuring sound is called a decibel. Because the decibel scale is logarithmic, a sound with an intensity that is twice that of a reference sound corresponds to an increase of about 3 decibels. The reference point of 0 decibel is set at the intensity of the least perceptible sound, the threshold of hearing. On such a scale a 10-decibel sound is 10 times the intensity of the reference sound. Highlighting this is important as already a few decibels higher or lower makes a noticeable difference in how noise is perceived. The preferred method to describe sound levels that vary over time, resulting in a single decibel value measuring the total sound energy over the period, is called Leq. It is however common practice to measure sound levels using A-weighting, which attenuates lower and higher frequencies that the average person cannot hear. In this case the value is called LAeq. A- and C-weighting The A-weighting is a standard, commonly used filter that attempts to alter the measured sound pressure levels to more closely match the perception of the human ear. A-weighting makes the sound level meter less sensitive to very high (over 8000 Hz) and low frequencies (below 1000 Hz). C-weighting also attenuates low and high frequencies, but the attenuation of low frequencies is much less severe compared to A-weighting. Calibrate: Calibrate the application using the calibration tool found in the settings menu. Phones and their components vary in quality and setup so you need to calibrate the app in order for the results to be relatively comparable. One suggestion is that you close the window and door to your bedroom or bathroom, turn off appliances, and once its very quiet calibrate the app so the reading is about 30 decibel.