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05-24-2021, 03:23 PM | #1 |
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Ambisonic IR
Hi, I am trying to figure out how to create the best and easiest ambisonic impulse responses for software like ambi verb and wwise convolution.
I would like to 1. record IR for a specific place in the sphere wehere I will pan my monophonic sound source. 2. record IR to be used more freely across the whole sphere. Should I for no. 1 place the speaker with the white noise/sine sweep at the position I want to place the virtual sound source and record it there? For no. 2 record several IR around the location and combine them? Or fx recording it from a 2 m distance and use that for the entire sphere? Does anyone have experience with this? |
05-25-2021, 09:55 AM | #2 |
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If a "true stereo" IR reverb is four IRs (2*2 matrix), a "true 1st order" IR reverb would be 16 IRs (4*4 matrix). It's been on my "to experiment list" for the past ten years...
https://www.avosound.com/en/tutorial...ono-and-stereo |
05-25-2021, 11:02 AM | #3 | |
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Quote:
Anyways, for number 1 you do want to place the speaker at the location you want the emitter at and the mic in the spot you want the listener to be located. In my understanding, if you move that emitter around the listener it will be like rotating the entire room as you can't virtually move that speaker after the fact. However...Zylia just did a very interesting demo of synthesizing multiple ambisonic recording positions in a room. I assume the same idea could be used to synthesize multiple ambisonic IRs, especially since they used wwise and unity to do it. That is my answer to question 2. It is labor and processor intensive so make sure it's going to pay off in the end.
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05-27-2021, 03:03 AM | #4 |
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My main goal is to do a 360 video and audio recording and then ad sound sources with a reverb that is coherent with the space.
Knowing that I can make an ambisonic IR of the speaker placed at the right position of the panned mono source, must be my primary focus after getting into the complexity of this problem. Ambi Verb and Wwise Convolution lets you import a 4 channel ambisonic IR recording. Regarding panning a sound source in the entire sphere it seems to be the course of action to use one IR and trust that the localization information from the direct sound source will overshadow the mismatch with the spatial reverb. AudioEase is offering a set of ambisonic reverbs in their 360 pan suite, but I just thought it would be great to enhance the realism with the correct reverb information. I have also heard of examples where you can re-render the IR using a decoder plugin and then do a soundfield rotation and process the next mono sound source at the new position. And that some are blurring the localization of the direct sound if it clashes with the reverb. Is it possible at all to create a 16 channel IR file and use it with a 360 panner in any software today? Last edited by Jensus; 05-27-2021 at 06:25 AM. |
05-27-2021, 05:16 AM | #5 |
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How to create the 16 channels IR file I don't know, but to process it you can use X-MCFX Volver or the MConvolutionEZ from MeldaProduction, both free :
http://www.angelofarina.it/X-MCFX.htm https://www.meldaproduction.com/MFreeFXBundle |
05-27-2021, 08:02 AM | #6 | |
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For the IR capture and processing, I would use Logic Pro's Impulse Response Utility with the "Quadraphonic" preset for an A-Format mic or "Quadraphonic B-Format encoded" preset for a B-Format microphone. Both have 16 IRs. For the convolution with the IRs, I would probably use X-Volver Essential. Signal flow: For A-Format microphone IRs: B-Format -> Decode to position of emitters -> A-Format IRs convolution -> B-Format encoding B-Format microphone IRs: B-Format -> Decode to position of emitters -> B-Format IRs convolution |
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