Tag Archive for: fft

100 Things #80: View Data in Real Time With the Multi-FFT and Multi-RTA

SoundCheck’s powerful virtual instruments let you perform measurements in real time, now with even more multichannel features in SoundCheck 21. Our new Multi-FFT allows for multiple FFT spectra on a single instrument, displayed in real time. The Multi-RTA virtual instrument enables multiple channels of measurement, also in real time. Both instruments can have independent per-channel configuration, perform real time calculations like power averaging, all can all be displayed on a single instrument. Of course, these instruments can be included within a sequence, so you can take advantage of the power measurements with SoundCheck sequence automation.

View Data in Real Time With the Multi-FFT and Multi-RTA

Learn more about the Multi-FFT, Multi-RTA, and more

SoundCheck features a full array of powerful virtual instruments, including the new Multi-FFT and Multi-RTA. Check out SoundCheck’s full features and functionality to learn more.

Video Script:

Did you know that SoundCheck is the first Audio measurement system to offer multi-channel Real Time N-th Octave and FFT Spectrum analyzers that not only displays multiple signals simultaneously, but can also perform basic mathematical operations such as curve subtraction and power averaging in real time?

Both the Multi-RTA and Multi FFT instruments  support any number of channels, limited only by the physical test interface you are using with SoundCheck, and each channel can be configured independently. 

The Multi RTA allows you to analyze a signal using Constant-Percentage Bandwidth filters from Octave to 1/24th of an octave resolution. This is typically used for analyzing non-stationary signals such as speech and music on audio devices (such as smart devices). It can also be used for measuring active noise reduction with pink noise.

The Multi FFT uses  high resolution constant bandwidth filters that enables any number of live FFT spectra to be simultaneously viewed in real time. This resolution is helpful for viewing narrow frequency components such as pure tones and harmonics.

Both instruments offer real time calculations such as channel subtraction, maximum, minimum, average  and power calculations. These are displayed in the instrument in real time. This is useful, for example, for spatial averaging the sound pressure level  of a 6 mic array in automotive cabin measurements, or quickly checking headphone or earbud fit and seal before performing a measurement.

Another thing that’s really slick about this is that the FFT and RTA can be viewed simultaneously, either side by side or superimposed on one another in a single multi instrument. This enables both high resolution spectra and constant percentage bandwidth resolution (e.g. 1/12th Octave) measurements to be viewed at the same time. 

This could be used for analyzing broadband speech signals while accurately identifying single frequency interference tones, or analyzing intermodulation distortion in the presence of speech or music.

Another thing that you can do is drag and drop curves from the multi-channel instruments into another graph, or drag a static curve from another graph into the FFT or RTA to use as a reference. This has many applications such as comparison to a headphone target curve or automotive tuning applications.

We first introduced the Multichannel RTA in SoundCheck 19, added some extra functionality in SoundCheck 20, and introduced the multichannel FFT in SoundCheck 21. So if you’re using an older version of SoundCheck and want to check out this new functionality, contact your sales engineer or local rep to discuss an upgrade.

100 Things #60: Making Real-Time Measurements with Live Curves

Live curves is a new feature in SoundCheck that lets you combine multiple real-time measurements on the RTA and FFT with static curves on the same graph. This lets you compare RTA and FFT curves, as well as comparing either to a static curve. This has applications for live tuning, automotive, and ANC audio testing.

Make Real Time Measurements with Live Curves

Learn more

Learn more about Live Curves in SoundCheck. Information can be found in SoundCheck 21, 20, and 19 new features under RTA and FFT.


Video Script:

‘Live curves’ is a new feature in SoundCheck that lets you drag any real-time measurements from the RTA or Spectrum Analyzer to another graph, or similarly drag any static curve from another graph to the RTA or spectrum analyzer. This lets you compare any live measurement to a static curve, for example, for tuning an automotive cabin, or a headphone response to a target curve.

We introduced the multi-channel RTA back in version 19, and the multi-channel FFT Analyzer in version 21. Both these instruments let you display multiple spectra at once, and also perform calculations such as power summing of multiple sources, subtraction of one curve from another and curve averaging. You can even display both an FFT measurement and an RTA measurement side by side on the same instrument.

When a multi instrument is opened, a live curve is created in the memory list. A live curve is indicated with a green circle. Just like a static curve, you can drag a live curve into any XY display graph [short live shot], and you can also add  a static curve into a multi instrument display [short live shot].

Here I have a static target curve in a graphic display. I can drag my live RTA curve onto this graph. Then I can add low pass and high pass filters to my signal to better match the target curve.

This is incredibly powerful for real time tuning applications. Check it out for yourself! What would you tune using SoundCheck? Let us know in the comments!