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Author Topic: Binaural, dummy head recording with surround sound  (Read 772 times)

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Offline b9audio

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Binaural, dummy head recording with surround sound
« on: April 21, 2021, 09:35:41 AM »
Here is a video showing the possibility to change the microphone polar pattern and pointing direction.
The VR Ball concept, is to add 2 pairs of figure-8 microphone onto the main omni pair on the dummy head. The figure-8 pair is pointing horizontal and vertical orientation. So that the mix can alter the omni stereo pair to cardioid/super-cardioid stereo pair and pointing to the direction as you wish.
https://youtu.be/Twsb19_P5lY

Offline illconditioned

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Re: Binaural, dummy head recording with surround sound
« Reply #1 on: April 21, 2021, 03:36:42 PM »
Here is a video showing the possibility to change the microphone polar pattern and pointing direction.
The VR Ball concept, is to add 2 pairs of figure-8 microphone onto the main omni pair on the dummy head. The figure-8 pair is pointing horizontal and vertical orientation. So that the mix can alter the omni stereo pair to cardioid/super-cardioid stereo pair and pointing to the direction as you wish.
https://youtu.be/Twsb19_P5lY
Wow.  Excellent work.
Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline Gutbucket

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Re: Binaural, dummy head recording with surround sound
« Reply #2 on: April 21, 2021, 05:07:38 PM »
Excellent video example.  Thanks for posting the link here. Its enlightening to be able to switch back and forth and listen for the effect of the altered directivity, which can be heard quite clearly.

Would it be correct to assume that the omnis and figure-8 have identical sensitivities and have been mixed in these examples using identical levels?

If so, the result in the examples which include the contribution of the figure-8s (excepting the first example using the omnis alone) presumably reflect a virtual cardioid sensitivity pattern on opposing sides of the ball-baffle, tangential to it, facing toward the indicated direction of emphasis. 

I mention this to help clarify what is going on for others following.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline b9audio

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Re: Binaural, dummy head recording with surround sound
« Reply #3 on: April 21, 2021, 10:43:25 PM »
Excellent video example.  Thanks for posting the link here. Its enlightening to be able to switch back and forth and listen for the effect of the altered directivity, which can be heard quite clearly.

Would it be correct to assume that the omnis and figure-8 have identical sensitivities and have been mixed in these examples using identical levels?

If so, the result in the examples which include the contribution of the figure-8s (excepting the first example using the omnis alone) presumably reflect a virtual cardioid sensitivity pattern on opposing sides of the ball-baffle, tangential to it, facing toward the indicated direction of emphasis. 

I mention this to help clarify what is going on for others following.
Hi Gutbucket, you are pro! Exactly as you said. I kept the same gain for all microphones, same mix level. Just on or off, polarity normal or invert. (For this video)
This show how the possibility in post stage. The beauty of this setup, is you can change the microphone polar, pointing continuously during the music. I have another one (which I cannot share), that the music start with solo, and then gradually to the choir. I can focus the microphones to the solo at the beginning, and slowly fade to the whole choir and increase the ambience.

Offline kuba e

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Re: Binaural, dummy head recording with surround sound
« Reply #4 on: April 22, 2021, 12:20:47 PM »
Thank you B9audio. The video samples are great. I would like to ask a bit of a theoretical question if you would know how dummy head affects a polar patter with respect to a boundary layer. I know that a dummy head will create an 'acoustic shadow'. But I wonder if the boundary layer also has an effect. Is boundary layer created on the dummy head? If so, it should affect the high frequencies by 6db. Do you have experience with that?
« Last Edit: April 22, 2021, 12:24:38 PM by kuba e »

Offline Gutbucket

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Re: Binaural, dummy head recording with surround sound
« Reply #5 on: April 22, 2021, 12:47:41 PM »
Super cool to arrange things so as to gain this kind of control available after the recording has been made.  Your VR Ball arrangement takes full advantage of this in terms of a spherical-head-baffled array, in a very elegant way.

Speaking generally, I feel this kind of post-recording adjust-ability is particularly valuable for Taperssection style live-music tapers, as we are generally very limited in the control we have over setup, without much if any ability to monitor and make adjustments based on that prior to the performance.  Even though most concert tapers here at TS would not often be modifying directional sensitivity over the course of the performance as you describe in the example of smoothly shifting focus from solo performer to the choir (a truly amazing capability!), the ability to dial in the most appropriate combination afterward while clearly being able to hear what is going on represents an incredible advantage in and of itself.

I encourage other tapers who are recording multiple microphone channels as part of their stereo taping setup to think in terms of arranging the combination of those channels so as to take maximum advantage of this "after the fact" flexibility in a similar way. 

musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline b9audio

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Re: Binaural, dummy head recording with surround sound
« Reply #6 on: April 23, 2021, 02:57:30 AM »
Thank you B9audio. The video samples are great. I would like to ask a bit of a theoretical question if you would know how dummy head affects a polar patter with respect to a boundary layer. I know that a dummy head will create an 'acoustic shadow'. But I wonder if the boundary layer also has an effect. Is boundary layer created on the dummy head? If so, it should affect the high frequencies by 6db. Do you have experience with that?

Yes, dummy head (ball) is similar to a baffle, except it is a curve baffle. So that the similar setup as dummy head is a Jacklin disc, which, is a back to back baffle.
Ball (dummy head) stereo is already a very good stereo solution. One step further from it, is that the recording engineer can change it for any orientation bias is a very useful advantage.
The final design of this VR Ball, let the user to mount 4 microphones each side. I am using it with double omni, one flat, and one HF enhanced. That said the HF can also be alter with simple mix.
Further extra mounting is also possible, that the ball can be stand mount, fly suspended, extra mounting points to add a GoPro camera, or a center position super cardioid mic, or any other microphones to be mounted on the surface.

Offline kuba e

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Re: Binaural, dummy head recording with surround sound
« Reply #7 on: April 23, 2021, 07:21:27 AM »
Thank you for the detailed photo. Vr ball is beautiful. It was a great idea to make it wooden. I like wood, it makes things much more pleasant than plastic.

I think Vr ball can also be compared to a boundary microphone. The boundary microphone is on a hard, reflective surface, while the Jecklin disc is made of an absorption material. Boundary microphone uses the effect that an acoustic boundary layer is formed on a solid surface. And in the acoustic boundary layer, the direct sound is amplified by 6db and diffuse sound is amplified by 3db. The geometric dimension of the surface determines which frequencies will be amplified. Vr ball has a hard surface. Theoretically, a boundary layer should be formed there. E.g. if the Vr ball has a diameter of 17 cm, then the boundary layer could influence frequencies around 4000 Hz and higher. Did you notice this effect on the omni microphones? Omnis are right on the surface, there it should be the most visible.

I started thinking more about boundary layer in a connection with the dummy head, that it should also be somehow reflected there. Unfortunately I did not find detailed information about the boundary layer. I don't know if the gain in the boundary layer depends on the angle of sound incidence. I also don't know if the surface shape (e.g. sphere, plate) has an influence. These are theoretical questions, but for boundary microphones and maybe for dummy heads it may be good to know it.

« Last Edit: April 23, 2021, 07:59:02 AM by kuba e »

Offline illconditioned

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Re: Binaural, dummy head recording with surround sound
« Reply #8 on: April 23, 2021, 08:54:37 AM »
Thank you B9audio. The video samples are great. I would like to ask a bit of a theoretical question if you would know how dummy head affects a polar patter with respect to a boundary layer. I know that a dummy head will create an 'acoustic shadow'. But I wonder if the boundary layer also has an effect. Is boundary layer created on the dummy head? If so, it should affect the high frequencies by 6db. Do you have experience with that?

Yes, dummy head (ball) is similar to a baffle, except it is a curve baffle. So that the similar setup as dummy head is a Jacklin disc, which, is a back to back baffle.
Ball (dummy head) stereo is already a very good stereo solution. One step further from it, is that the recording engineer can change it for any orientation bias is a very useful advantage.
The final design of this VR Ball, let the user to mount 4 microphones each side. I am using it with double omni, one flat, and one HF enhanced. That said the HF can also be alter with simple mix.
Further extra mounting is also possible, that the ball can be stand mount, fly suspended, extra mounting points to add a GoPro camera, or a center position super cardioid mic, or any other microphones to be mounted on the surface.

Beautiful work!
Have you considered using just figure 8 at the "ear" location?One Fig8 pointing forward, the other up and down?Perhaps that is what you showed in an earlier post?

Regardless this is a very nice setup, especially the wooden construction.
Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline Gutbucket

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Re: Binaural, dummy head recording with surround sound
« Reply #9 on: April 23, 2021, 09:22:35 AM »
Hi Richard,

That's certainly possible, by simply not using the omnis.  The photo above shows one side of the ball. Pictured is one forward and one downward facing figure-8 along with the two flush mounted omnis (one flat, the other with HF boost). The opposite side is a mirror image of this, placing those two primary groupings of microphone capsules at the "ear locations" on the opposing Left and Right sides of the ball.  There is an additional microphone position centered on the front of the ball, in the "nose" position, which is not in use in the video.

A decade or so back I schemed about incorporating similar arrangement using six channels into a hat!
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline b9audio

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Re: Binaural, dummy head recording with surround sound
« Reply #10 on: April 23, 2021, 11:57:20 AM »
It is certainly reasonable to use any microphone combination, in case using a pair of fig-8, it is like a Faulkner phase array. In case use the pair of fig-8 on the same side, it is Blumlein stereo toward one side, vertical plane stereo.
Also, you can decode a MS pair on one side for stereo...
Meaning, there're too many possibility with this ball.
The nose position was replaced with 12x 3/8" thread around the ball for all kinds of mounting. A center channel microphone, a GoPro camera, or using the top one for fly mount, using the bottom thread for stand mount...
The beauty of this ball: You can take all the microphones out for other application!
« Last Edit: April 23, 2021, 09:09:21 PM by b9audio »

Offline Gutbucket

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Re: Binaural, dummy head recording with surround sound
« Reply #11 on: April 23, 2021, 12:16:15 PM »
Very adaptable, especially by way of the microphones being able to be used separately without the ball.  You've engineered a very elegant system with this arrangement, having made wise choices in the course of it's evolution.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline rocksuitcase

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Re: Binaural, dummy head recording with surround sound
« Reply #12 on: April 23, 2021, 02:54:41 PM »
b9audio- THIS is a winner! GREAT design and functionality, Form FOR Function. Excellent engineering!
music IS love

When you get confused, listen to the music play!

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