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ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

3D sound? (1 Viewer)

Jon.Bryant

Well-known member
I have always thought that it is impossible to accurately record song flights of birds correctly. If you record a bird in mono with a directional mic, and track the bird well, it sound like it either doesn't or hardly moves, and it you don'r track it well , if sounds as if it momentarily zooming off into the distance. A stereo recording with mics fixed in location doesn't help, with the 3D flight compressed into a 2D plane - the movement now sounding like the bird is travelling a bit to the left or right and a bit further away or closer again (dependent on relative position to the mics), but not with a hint that the bird is travelling vertically.

I note that there are now a few ambisonic mics available, and that the output an be rendered to binaural audio. Some recording devices are capable of the rendering/decoding onboard, so you can monitor the 3D audio in the field. I have just tried listening with headphones to some binaural recordings (but not of birds), and was surprised by the fact that things did sound front, left, right, and quite weirdly behind and even above me. The science of how two speakers can create such an effect is beyond me!

My question is whether anyone has experience of recording using ambisonic mics to create binaural recordings that capturing bird movement, or if they have ever heard any such recordings. I am dazzled by the idea that I could record a dawn chorus, an environment or song flight in 3D, but suspect that things may not be a simple as a fancy mic and an ambisonic plug in for my recorder.

Regards

Jon Bryant
 

Dave Boyle

Well-known member
I've been wondering about this too - I do a bit of work in busy seabird colonies & being able to capture the 3D sound of 1000s of Sooty Shearwaters calling before dawn would be amazing!

I'm guessing you've seen the Zoom H3-VR? It looks like the most affordable option. I had been put off by some reviews but I stumbled across this the other day which makes it sound more promising -

 

Jon.Bryant

Well-known member
I hadn't seen the review - thanks for the information.

Looks like the Zoom records Ambisonic A and B plus Binaural and Stereo, so a choice for capturing the environment.

I am new to all this, but from the Sennheisser website, I understand Ambisonic A is the 'raw' 4 (or 6?) channel file, B is processed and ready for use in VR, then Binaural is the output for listening to over headphones.

I was amazed to read that with the A format, you can 'turn' the mic. Say you were recording a dawn chorus, and the star of the show started singing to the left, you could post process and 'swing' the sound round, so that the star bird is in front, then render to Binaural (or Stereo) and the bird will sound center stage!

Binaural is confusing and starting to blow my mind. I was looking at some software and it looks like optimum results may be dependent on the size of your head and the position of your ears. The 'off the shelf' binaural sounds I have listed to (not of birds) were impressively immersive, but to 'optimize' the sound, I understand that it may be best to take the Ambisonic B file and render it to Binaural, selecting a virtual dummy head, that most closely fits your own dimensions.

Seems like a fair bit of work, but I think the results could be really impressive.

Regards

Jon
 

Patrick Franke

freelance ornithologist & sound recordist
Hi Jon,

I don't know if you've made any progress on the topic in the meantime. I work with 3D audio on a regular basis and can tell you a lot about it, if necessary recommend hardware and software.
If you are still interested, please let me know!

Best, Patrick
 

Jon.Bryant

Well-known member
Hi Jon,

I don't know if you've made any progress on the topic in the meantime. I work with 3D audio on a regular basis and can tell you a lot about it, if necessary recommend hardware and software.
If you are still interested, please let me know!

Best, Patrick
Hi Patrick,

Sorry, didn't spot your response straight away, hence the time lag.

I decided to 'splash the cash' and bought a Sennheiser Ambio VR mic, then downloaded the Ambisonic plug-in for my Sound Devices Mix-Pre 6 II.

I have a couple of options for processing the recordings. I bought Reaper to process the files, which was reasonably priced, and is the software I have used so far. I have been a long time user of Steinberg's Wavelab Pro, which is my go to sound processing package, and note that version 11 now supports Ambisonic wave processing as well, but I haven't tried this yet.

I have not used the mic that often, but have some questions regarding recording and playback. I recorded what I thought would be a nice aerial display of Common Ringed Plover. The bird started off behind and to the left, then circled directly in front of the mic, flying from left to right. When I listen to the recording, it does not seem that clear when the bird was in front of the mic - I almost get the impression it is passing through my head, rather than in front of me!

My questions are;
1/ Is the height of the mic important? When I recorded the Common Ringed Plover it was a bit gusty, so I set the mic quite low out of the wind. I am wondering if the mic needs to be closer to head height, and whether ground reflection messes with the 3D effect.
2/ Sounds daft, but I have not measured my head and selected a dummy head to match my measurements. The processing of the Ambisonic A-Format file has been done using the default head setup. Can a person's head dimensions have an impact on the 3D effect when listening with headphones? I am wondering if I may be a long way from standard!
3/ Depending on the answer to point 2, how do you share or distribute recordings? I suppose the only possible option is to use the generic head setting, otherwise the end user would need to be able to process the four track Ambisonic-A Format recordings, which seems a tad unrealistic.

I am looking forward to using it more often, particularly in the spring, when I want to experiment with recording song flights of birds.

Any tips on best practice would be appreciated.

Regards

Jon Bryant
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia

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