Posts written by angelofarina

Which bugs?
Please describe the problem, possibly with screenshots...

Audacity 2.4.1 is not compatible with 64-bit versions of Mac OS.
We need to wait that someone manages to recompile the Aurora plugins for the latest version of Audacity.
In the meanwhile, Aurora for Audition 1.5 works fine through Playonmac...

The error is selecting "cross-talk cancel only". This removes the calculation of inverse filters, performing just the cross-talk matrixing.
This option cannot work with real IRs measured, it can only work for Dirac-like pulses (synthetic IRs created with simulation software, or manually).
Just deselect thst option, and a proper set of cross-talk cancelling filters is generated.

We are working on the version 3.0 of Audacity, we hope to release it soon.
Currently Audacity 2.4.1, but also 3.0.2, is a 32-bit version only program for Windows. it is 64 bits for Mac.
see here:
www.audacityteam.org/download/

I think that having all the mikes with the same gain makes the processing easier. However, if you can set the gain in precise steps (as when using a preamp with digital gain control), nothing forbids to set different gains, take note of them, and later on compensating the SPL values applying these offsets. It simply makes it much easier to make errors, so I warmly recommend to fix a preamp gain which is good everywhere, and then keep it unchanged.

the Ir is too long. You should cut it much shorter, typically 300 to 600 samples, containing just the direct sound.
And the inverse filter should be much longer than the IR, say 4096 samples...

You must set an inverse filter length much longer than the IR to be inverted..
You can do this easily adding silence after the IR before invoking Kirkeby....

Disable the autorange and keep a constant gain in the convolver.
Then you can calibrate the Acoustical Parameters or the STI plugin against a calibrated SLM...

Exactly. The site for downloading Aurora with Audacity is: www.angelofarina.it/Public/Aurora-for-Audacity/
Please read carefully the readme.txt file of the version chosen...

Sorry, I cannot see the attachment. You can send me the wav file and the screenshot at my Email address, [email protected]
Did you properly set your computer for using English-UK international settings?
This is mandatory for Aurora...

First of all: why do you use the very old v. 2.0.0, when the newer version 2.4.1 is available?
Said that, I see that you are Italian.
Unfortunately Italians have the bad habit of using nationalised versions of their operating systems, with crap international settings. The most deleterious one is the number format, using a comma instead of decimal dot.
So simply setup your computer with English-UK settings. This is mandatory for most scientific software...

The current version of Audacity 2.4.1 has all the Aurora modules pre-installed and pre-enabled.
Just download the latest release (dated 11/11/2020).

I loaded on my web site a new version of Aurora for Audacity 2.3.3 with Asio. It is v.3.
This bug should be fixed now...

You know that these spatial parameters are quite unreliable, do you know?
Said that, the Aurora Acoustical Parameters module can compute Jlf, Jlfc and Lj.
You should analyze the B-format impulse response, in Fuma format (not Ambix).
So first convert your impulse response to Fuma B-format, then open it with Audacity and use Acoustical Parameters for computing Jlf.
A correct measurement requires that the X axis of the microphone was pointing exactly to the omnidirectional sound source. If the alignment was wrong, you can fix it using a free rotator plugin, such as IEM Scene Rotator, and using O3A Flare for checking that the alignment is correct.
Here an example of computing "spatial parameters" Jlf, Jlfc and Lj with Aurora for Audacity 2.0.0:

Here instead processing the same Ambisonics FuMa impulse response with the old good Audition 1.5 and Aurora plugins in XFM format:

As you can see comparing the two images, the values of these spatial parameters computed in Audacity 2.0.0 are completely wrong, while those computed by the Audition version of Aurora are perfectly reasonable.
Hence we can conclude that, if you are on a Mac and hence forced to use the old version 2.0.0 of Audacity, you cannot rely on the Aurora Acoustical Parameters plugin for computing correctly these spatial parameters.
I warmly suggest that you find and install the very old Audition 1.5, which runs perfectly fine on a Mac using Playonmac.

Edited by angelo.farina - 9/3/2020, 09:46

In your case, as you record a synchronous recording of 4 channels, better to switch back to version 2.0.0, for which we made available the ASIO-enabled version. It is here:
http://www.angelofarina.it/Public/Aurora-f.../2.0.0/Windows/
The password for unzipping the ASIO-enabled executable (which you should copy over the standard version executable) is just my name.
Of course you need to use the Aurora modules fopr version 2.0.0.
Regrading convolution, after recording your 4-channels sweep from the microphones, and imported also the invsweep, your situation will be something like this:



Now you invoke the Aurora Convolver, drag the A-format channels to Data and the invesweep to Filters, and select the "one for All", forcing this single inverse filter to be applied to all 4 input channels:



Press Continue:



Select "full Autorange and presse Calculate! The result will be 4 new mono tracks, containing the deconvolved impulse responses...



Now you can cut short just the portion of the linear IR you need, and export it to a single 4-channels WAV file (of course this 4-channels export is possible only after having disabled the stupid option to downmix to stereo which Audition sets by default).