Sound Spectrum Analysis 4+

Audio Frequency Analyzer (RTA‪)‬

Dmitriy Kharutskiy

    • 3.6 • 33 Ratings
    • Free
    • Offers In-App Purchases

iPhone Screenshots


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.

What’s New

Version 2.3.5

• Bug fixes.

Ratings and Reviews

3.6 out of 5
33 Ratings

33 Ratings

jon in alabama ,

Pretty good

My only problem is that I cannot easily select the frequency range I want to look at. The pinch adjustment only works to look at higher frequencies, whereas I want the window to be able to be set not just to exclude low frequencies. Perhaps the ability to set the range manually… type in lower limit, type in upper limit.

I have not yet tried with various calibration files yet, but when I get an external microphone I will do this and see how well it works.

I basically need this app to measure sound sweeps and pink noise from various devices to check flatness of frequency response, and it seem to do ok at this. Price is right, and it has many options that will make most casual users happy.

Developer Response ,

Thank you for your feedback. I realized that you are writing about the logarithmic scale. I did it!

To see each bin, use a linear scale with zoom. If you have any other wishes, be sure to let me know.

Shadow12405 ,

Great for speaker design

I’m a novice speaker builder. I had designed some speakers, used WINISD and Vituix CAD to design the box and crossovers and had the speakers hooked up. I had tried to used Room EQ Wizard, but to no luck. I had problems with a calibrated Mic, getting the software to work right etc. So, I needed some tool to measure the speakers and found this. This tool allows the IMM-6 mic and gives me enough to measure the speakers. The support is fantastic, timely and thorough. I can get the data out, screen grab the graph etc. The price is fantastic, and for those that had problems with the tool not giving them enough for free, it’s only a couple bucks. And for what the designer provides, that’s more than fair. For anyone building their first speakers (maybe even more advanced) this is a great tool.

arg245 ,

Has lots of potential, but......

Somewhat confusing to use. Not enough “tweaking” available to the user, such as allowing the user to select a specific frequency band. Only has 5 pre-selected bands. Also, has no indication or selection of which microphone on the iPhone is active. Doesn’t even explain if it’s using a specific mic, or an average of all the mics. Instructions for use could use better detail and explanations for users not so versed in audio analysis. Still, I like the app, but hope it gets better.

Developer Response ,

Thanks for the suggestions! Please let me know if you have any other ideas for improvement.

App Privacy

The developer, Dmitriy Kharutskiy, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More

More By This Developer

You Might Also Like

Sonic Tools SVM
SignalScope X
Audio Function Generator
SoundTools -Studio Six Digital
SoundMeter X