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Gear / Technical Help => Microphones & Setup => Topic started by: EmRR on December 27, 2019, 04:06:20 PM

Title: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: EmRR on December 27, 2019, 04:06:20 PM
https://voyage.audio/spatialmic/ (https://voyage.audio/spatialmic/)

Doesn't take a lot of level, borderline for anything close and loud.

USB and ADAT Lightpipe outputs.  No analog. 

USB bus powered via USB-C or external 5v source via micro-USB.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Gutbucket on December 27, 2019, 05:25:14 PM
Interesting. Note the similar configuration to the Core OctoMic - a double tetrahedron with 180° orientation of the overlapping tetra, which makes it a.. looking it up now.. stella octangula?  More importantly, how well-behaved are the 2nd order patterns from these 8 element arrays I wonder?  Anyone come across any AES papers reporting measurements of them with regards to 2nd order spatial performance?

Just based on channel count alone it seems to me this is about where analog out becomes impractical and USB connectivity becomes compelling.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: illconditioned on December 28, 2019, 10:04:37 PM
Those look like "transsound" capsules.  Plastic 3d printing for housing.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Nick's Picks on December 29, 2019, 08:49:47 AM
"too sensitive" seems to be a problem that I've found with every ambisonic mic i've tried.   From my st250, which was $5k new, 20yrs ago....to the $250 Zoom.   
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: EmRR on December 29, 2019, 11:34:12 AM
I’d guess you generally want sensitivity here to overcome the increased noise of mixing so many capsules.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Len Moskowitz (Core Sound) on December 29, 2019, 09:02:56 PM
More importantly, how well-behaved are the 2nd order patterns from these 8 element arrays I wonder?  Anyone come across any AES papers reporting measurements of them with regards to 2nd order spatial performance?

You can see the Core Sound OctoMic's polar directivity patterns here:

www.core-sound.com/OctoMic/2.php

Yes, they are real, measured patterns.

Each OctoMic is individually calibrated. And its capsule mount array geometry is not the same as the microphone from Voyage.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Len Moskowitz (Core Sound) on December 29, 2019, 09:07:22 PM
I’d guess you generally want sensitivity here to overcome the increased noise of mixing so many capsules.

It's not intuitive, but for these microphones, every time you double the number of capsules, the self-noise drops by 3 dB.

That's because the output increases by 6 dB every time you double the number of capsules, but - because the noise between capsules is uncorrelated - the noise increases by only 3 dB. The net result is a 3 dB decrease in self-noise.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Len Moskowitz (Core Sound) on December 29, 2019, 09:08:35 PM
"too sensitive" seems to be a problem that I've found with every ambisonic mic i've tried.   From my st250, which was $5k new, 20yrs ago....to the $250 Zoom.

You won't find that to be the case with Core Sound's OctoMic.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Gutbucket on December 30, 2019, 08:51:10 AM
More importantly, how well-behaved are the 2nd order patterns from these 8 element arrays I wonder?  Anyone come across any AES papers reporting measurements of them with regards to 2nd order spatial performance?

You can see the Core Sound OctoMic's polar directivity patterns here:

www.core-sound.com/OctoMic/2.php

Yes, they are real, measured patterns.

Thanks for posting the link and polars Len.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: EmRR on December 30, 2019, 09:47:40 AM
I’d guess you generally want sensitivity here to overcome the increased noise of mixing so many capsules.

It's not intuitive, but for these microphones, every time you double the number of capsules, the self-noise drops by 3 dB.

That's because the output increases by 6 dB every time you double the number of capsules, but - because the noise between capsules is uncorrelated - the noise increases by only 3 dB. The net result is a 3 dB decrease in self-noise.

Thanks, so that’s a common misconception then. 
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Nick's Picks on December 30, 2019, 10:00:50 AM
I always figured that it was more due to the sound sources a mic like these ambisonic offerings were meant for.
rock concerts is not on the list.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: EmRR on December 30, 2019, 01:01:50 PM
True, though I wonder about SPL's at sports events where they are used for surround.  Those definitely approach concert levels at times.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: heathen on December 30, 2019, 04:39:26 PM
I never had a problem with the TetraMic at loud concerts.  That's the only ambisonic mic I've used.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: morst on December 30, 2019, 09:20:52 PM

#SCIENCE!
Thanks for the informative post, Len!!
It's not intuitive, but for these microphones, every time you double the number of capsules, the self-noise drops by 3 dB.

That's because the output increases by 6 dB every time you double the number of capsules, but - because the noise between capsules is uncorrelated - the noise increases by only 3 dB. The net result is a 3 dB decrease in self-noise.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Len Moskowitz (Core Sound) on December 30, 2019, 10:48:51 PM
I always figured that it was more due to the sound sources a mic like these ambisonic offerings were meant for.
rock concerts is not on the list.

Rock concerts recorded with a Core Sound OctoMic (a second-order ambisonic microphone):

https://archive.org/details/fotb2019-05-22.2019-05-22-octomic
http://core-sound.com/temp/BTTG1969-11-3-2018-SomebodyToLove-VVStereo.wav

There are more recordings at: www.core-sound.com/OctoMic/13.php
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Voyage Audio on February 12, 2020, 08:03:15 PM
Hi all,

I am the creator of this microphone and heard there was a little chatter over here about it. Let me just touch on a couple items that may have got lost in translation somewhere or improved with the latest firmware update.

1. This mic can take up to 131dB SPL before ADC clipping in 'pad mode'.
2. USB - 8 channels streaming to computer or mobile device up to 96kHz and 2 channels playback up to 96kHz.
3. ADAT Lightpipe - 8 Channels Streaming up to 48kHz.
4. Stereo Analog Out (HP or turn down for line output). This is binaural decode at sample rates up to 48kHz and MS decode at 88.2kHz and 96kHz.
5. This mic stores sensitivity calibration in the front end so you are recording with a balanced array.
6. We tested many different capsules in the design phase and chose the ones that made the most sense for this mic — you would be surprised how many look-a-like capsules there are out there.
7. Body construction is strong, lightweight aluminum and nylon made here in Southern California!

I've used the mic to record extremely loud drums up close without clipping — sounds awesome as an OH and you have the ability to aim virtual mics after the fact.

Thanks for taking a look and don't forget to check out the Reaper session we have for download on the site.

-Colin
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: EmRR on February 12, 2020, 09:55:12 PM
Thanks Colin!
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: morst on February 12, 2020, 11:54:32 PM
the latest firmware update.
Thank you for checking in here with some specs and insight, and thanks also for updating the firmware on your device! Too many pieces of kit end up becoming stranded in time, but it seems like yours won't be!
 :laugh:


Also thanks for making the bodies in USA. #AmericanJobs
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: rastasean on February 13, 2020, 01:33:35 PM
Hi Colin,

What were you recording into for the field recordings on your soundcloud?
https://soundcloud.com/voyageaudio/sets/field-recording-with-spatial

Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Voyage Audio on February 13, 2020, 02:39:39 PM
Hi Colin,

What were you recording into for the field recordings on your soundcloud?
https://soundcloud.com/voyageaudio/sets/field-recording-with-spatial

Those recordings were made with Spatial Mic connected to an iPhone, running the app "Multitrack DAW". There is actually a journal article, along with some 360 videos and bill of materials on our blog. Here is the link:

https://voyage.audio/360-field-recording-with-spatial-mic/ (https://voyage.audio/360-field-recording-with-spatial-mic/)

Remember that your final format from this mic can be anything you wish — it doesn't necessarily have to be for 360. You can decode to binaural, aim different polar patterns for stereo or mono, pretty much whatever you'd like. Some of the field recordings are in our downloadable Reaper session, detailed in this article:

https://voyage.audio/listen-to-spatial-mic/ (https://voyage.audio/listen-to-spatial-mic/)

Keep in mind that little, if any (think low-cut for wind, etc) processing has been done to these sound samples besides running them through the Voyage Audio plugin that is included with the mic.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Voyage Audio on February 13, 2020, 02:41:57 PM
the latest firmware update.
Thank you for checking in here with some specs and insight, and thanks also for updating the firmware on your device! Too many pieces of kit end up becoming stranded in time, but it seems like yours won't be!
 :laugh:


Also thanks for making the bodies in USA. #AmericanJobs

I hear ya! We tried to stay local for as many of the components as possible.

We want to keep improving the product and getting feedback, so if there are any feature requests that can be done in firmware, or even thoughts on connectivity for future models please let us know!
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: rastasean on February 13, 2020, 03:35:23 PM
Those recordings were made with Spatial Mic connected to an iPhone, running the app "Multitrack DAW". There is actually a journal article, along with some 360 videos and bill of materials on our blog. Here is the link:

https://voyage.audio/360-field-recording-with-spatial-mic/ (https://voyage.audio/360-field-recording-with-spatial-mic/)


Thanks for the links! You must be invisible. Even with 360 degree video, you're not in it.
Title: Re: Another 2nd order Ambisonic mic: Votage Audio Spatial Mic
Post by: Voyage Audio on February 13, 2020, 03:36:51 PM
Those recordings were made with Spatial Mic connected to an iPhone, running the app "Multitrack DAW". There is actually a journal article, along with some 360 videos and bill of materials on our blog. Here is the link:

https://voyage.audio/360-field-recording-with-spatial-mic/ (https://voyage.audio/360-field-recording-with-spatial-mic/)


Thanks for the links! You must be invisible. Even with 360 degree video, you're not in it.

HA! You definitively need to be strategic about finding bushes / posts to hide behind if you don't want to be in the videos!