It’s been a few weeks since my last post so it’s time for another update!
Following my test impulse responses I recorded the first HRIRs in the speaker rig with the KU100 dummy head. This is essentially the same process as taking the impulse response measurements from earlier on, except with a stereo dummy head microphone, lined up using the laser guidance system.
Importing these HRIRs into the Ambix VSTs in Reaper enabled me to recreate the soundfield and pan anechoic sounds around in 3D. This has proved that the method is sound and we can now move on to the next stage.
I used Ambix’s binaural decoder, which requires a config file to determine elements such as speaker positions, Ambisonics order and the directory containing the IRs. There was an existing config file for the speaker array that I am using, which I was able to take and amend to feature my HRIRs.
The next stage:
Before I am able to record real, human HRTFs I have one obstacle to overcome, which is microphones.
There is currently one remaining, working pair of in-ear microphones on site, which means I can either go ahead with the listening tests with no backups, or I can assemble some fresh ones. I plan on the latter option.
All of the necessary bits are here, they just need putting together, which will involve a lot of micro-soldering and a large dose of patience. The next post will likely be all about this job.
The listening test is almost complete, which has been made on Max 7. I have decided against using the 3D mouse in my test now and have instead opted for a custom-built controller that features two wheels to adjust azimuth and elevation angles, which should be a little more intuitive to use.
I also will need to create a ‘warm up’ patch which serves two purposes:
1) Help the user learn the controls and understand what they are supposed to do in the test.
2) Kill time, as a few minutes are required to process the recorded HRTFs before the test can begin.