Accurate and effective frequency analysis - source ID and rapid complaint resolution
We have tested many apps. This is a detailed guide to using a very effective free Keuwl Android app for narrow band tonal noise analysis and identification (FFT noise analysis - download for free). Note: it is not available in the Playstore, you have to download using the above link.
Why use old fashioned 1/3 octaves that are not good at identifying tones and that throw away so much useful identification and diagnostic information when a smartphone FFT app can provide an accurate evaluation?
There can be no valid excuse to rely on subjective impressions or third octaves when tonal noise may be involved.
This is a simple process that dramatically improves noise complaint resolution, source identification and, with our help, BPM/BAT evaluation.
Once you've analysed, what next?
The results of your instant field narrow band analyses may be sufficient. You can determine if there is/isn't a tone or identify whether the tone is from a particular item of plant.
If you need help with tonal noise source ID or the mitigation options, then you can contact us to make use of our free remote analysis service.
Download your free copy of the guide here >> How to use a free Android narrow band frequency analysis app
Other narrow band apps - what to look out for?
Any useful FFT/spectrum analysis/narrow band analysis app should at least include the following:
- Resolution: ability to change the frequency resolution. This will often be described as the "FFT size" as x number of points. We would suggest you need to be able to select at least 4000 points (around 1Hz resolution for a 0Hz - 1kHz display.
- Max frequency: be able to reduce the frequency range for the analysis down to 0Hz - 1kHz as this is the range required for most environmental noise issues.
- Linear X axis: able to select linear rather than logarithmic as this allows you to see harmonics of a tone as a series of equally spaced peaks.
- Y axis: select dB
- Linear weighting: select this, not "A" weighted (if "A" is available)
- Cursor: to select and read the frequency of peaks. Ideally with a "snap to peak" function.
- Store setup: so you don't have to reenter the above to use the app.
- Export noise signature: ideally export as csv file so you can pull it into a standard Excel spreadsheet you've created to display spectrum graphs and overlay signatures. Better than the screenshot option.
Apple Apps
Whilst we haven't carried out testing on iOS apps, the following seem to meet the above requirements. We cannot vouch for their performance however...
