Topic: Visualization of various stereo mic configurations

[MIQ]

One thing worth noting is the new version includes a display for the Recording Angle.  The new layout look like this:

-MIQ

[DigiGal]

I'm finally able to use this with a new iOS device. Noticed a bug in iOS 6, once a mid mic is selected from the list the mid mic indicator on the visualizer screen always displays omni no matter what pattern is selected. A feature suggestion for the next update - double tapping the sliders to center them.

It's a nice app, glad to be able to use it now.

Now if someone could port the stereo mic confiuration visualizer to an iOS app.

[MIQ]

I'm finally able to use this with a new iOS device. Noticed a bug in iOS 6...

It's a nice app, glad to be able to use it now.

DigiGal, 

Really glad you are able to use it finally.  We will check out the bug you mentioned and get it sorted out.  Thank you for the heads up. 

Now if someone could port the stereo mic confiuration visualizer to an iOS app.

Ok, here you go.  Our Stereo Mic Tools app just released to day 
https://itunes.apple.com/us/app/stereo-mic-tools/id572383335?mt=8

It has 8 Mic Types from Omni to Fig-8.  The angle between mics can be varied from 0 to 180 deg.  The separation between the mics can vary from 0 to 200cm.  It has six classic configurations stored as presets:

Blumlein
DIN
DINa
NOS
ORTF
XY 90

It displays the Recording Angle and the Wittek - Thiele Recording Angle 75% (RA_75%).  And of course has a geeked out info page.   Here are some screen shots.

-MIQ

[John Willett]

Interesting - but why does it say that ORTF is +/- 48° and not +/- 55° ?

And it would be very much more useful if it included MS as well.

[Gutbucket]

Interesting - but why does it say that ORTF is +/- 48° and not +/- 55° ?

And it would be very much more useful if it included MS as well.

The SRA for ORTF is +/- 48°.

John is aware of what that means, but for anyone reading this who is not I'll explain-
With an ORTF arrangement, the physical angle between cardioid pattern microphones is specified as +/- 55° (indicated below the image on the angle button) which combined with the 17cm spacing results in a Stereo Recording Angle of +/- 48° (which is the angle of pickup for which sources are reproduced between two speakers arranged in a standard +/- 30° playback triangle, sources outside that SRA will tend to emanate from the closer speaker).

[edit] the Sengpiel site explains this better than I can, and allows one to play around with various microphone angles, spacings and pickup patterns in their on-line visualizer.
http://www.sengpielaudio.com/Fragen08.htm

from that site-
The Stereo Recording Angle SRA:
The SRA is not the angle between the microphone axes, but an invisible angle, that gives you information about your stereo image. It tells you how "wide" the recording will sound. Every acoustic sources that are outside of the SRA will be located full at "L" or "R". So a smaller SRA will give you a wider stereo image. Everything inside of the SRA will find a place between the left and the right speaker.

[MIQ]

Interesting - but why does it say that ORTF is +/- 48° and not +/- 55° ?

And it would be very much more useful if it included MS as well.

Hi John,

As Gut mentioned this app is reporting the Recording Angle and RA_75% in +/- degrees.  The angle between mics is shown as well (see the button labeled "Mic Angle"), and for ORTF is correctly shown as 110 degrees.  If you are interested in an MS visualizer please use our Mis Side Mic App.  https://itunes.apple.com/us/app/mid-side-mic-visualizer/id486145346?mt=8

-MIQ

[DigiGal]

I'm finally able to use this with a new iOS device. Noticed a bug in iOS 6...

It's a nice app, glad to be able to use it now.

DigiGal, 

Really glad you are able to use it finally.  We will check out the bug you mentioned and get it sorted out.  Thank you for the heads up. 

Now if someone could port the stereo mic confiuration visualizer to an iOS app.

Ok, here you go.  Our Stereo Mic Tools app just released to day 
https://itunes.apple.com/us/app/stereo-mic-tools/id572383335?mt=8

It has 8 Mic Types from Omni to Fig-8.  The angle between mics can be varied from 0 to 180 deg.  The separation between the mics can vary from 0 to 200cm.  It has six classic configurations stored as presets:

Blumlein
DIN
DINa
NOS
ORTF
XY 90

It displays the Recording Angle and the Wittek - Thiele Recording Angle 75% (RA_75%).  And of course has a geeked out info page.   Here are some screen shots.

-MIQ

Great timing on the new app, grabbed it right away, had been hoping someone would do this for a while now. 
Both are fabulous apps for our community.  Much appreciated, great job guys !!!   

Edit to add:
Extra credit for including DINa

[John Willett]

Interesting - but why does it say that ORTF is +/- 48° and not +/- 55° ?

And it would be very much more useful if it included MS as well.

The SRA for ORTF is +/- 48°.

John is aware of what that means, but for anyone reading this who is not I'll explain-
With an ORTF arrangement, the physical angle between cardioid pattern microphones is specified as +/- 55° (indicated below the image on the angle button) which combined with the 17cm spacing results in a Stereo Recording Angle of +/- 48° (which is the angle of pickup for which sources are reproduced between two speakers arranged in a standard +/- 30° playback triangle, sources outside that SRA will tend to emanate from the closer speaker).

[edit] the Sengpiel site explains this better than I can, and allows one to play around with various microphone angles, spacings and pickup patterns in their on-line visualizer.
http://www.sengpielaudio.com/Fragen08.htm

from that site-
The Stereo Recording Angle SRA:
The SRA is not the angle between the microphone axes, but an invisible angle, that gives you information about your stereo image. It tells you how "wide" the recording will sound. Every acoustic sources that are outside of the SRA will be located full at "L" or "R". So a smaller SRA will give you a wider stereo image. Everything inside of the SRA will find a place between the left and the right speaker.

Thanks GB - I only had a quick look and missed that.

Well, they seem cheap enough at only £5 for the two, so I now have them both.

John

[Gutbucket]

Seems useful and the price is right.  If I was an I-phone user I'm probably try them out.

[MIQ]

Thanks DigiGal, John, and Gutbucket!  We appreciate the positive feedback.

I want to mention one thing that may not be obvious unless you have the apps on your device.  If you hold your phone (or Pad, or iTouch) running the apps above your mics with the screen pointing straight up to the sky, you can sight down the Recording angle lines and see how the recording angle relates to the performers (or sound sources) in front of the mics.  You have to hold the phone still and move your head to sight down each line but it gives a quick approximation.  There are better ways to implement this with the device (think camera and gyros) but that will require considerably more effort.  We hope to be able to work more on these apps but I wanted to mention the simple method for now. 

-MIQ

[noahbickart]

I love the m/s app, and use it all the time.

Now all i want is an AU plugin that allows me to vary the relative M and S gain proportionally with the same interface.

If you could make a double m/s plugin so that someone running 2 figure 8's and an omni could select polar pattern and angle, that would be really good.

(I know about the schoeps double m/s plugin. It has two problems. One it is VST only. Also the model assumes that you are using a pair of mk4v microphones for the M signal and not an mk8 and mk2 [or in my case a mk3]).

[MIQ]

Hi Noah

Glad you continue to get good use from the M/S tool. 

Double M/S using 2 Fig-8s and and Omni is interesting.  By varying the ratio of Fig-8 to Fig-8 you can steer the angle between the resultant L and R patterns, and by combining them with the Omni you can control the patterns shapes, right?  That's cool. 

I wish we knew more about writing AU code for you.    

-MIQ

[John Willett]

Double M/S using 2 Fig-8s and and Omni is interesting.  By varying the ratio of Fig-8 to Fig-8 you can steer the angle between the resultant L and R patterns, and by combining them with the Omni you can control the patterns shapes, right?  That's cool. 

This is basically the same as a Soundfield mic. without the height information.

[noahbickart]

Hi Noah

Glad you continue to get good use from the M/S tool. 

Double M/S using 2 Fig-8s and and Omni is interesting.  By varying the ratio of Fig-8 to Fig-8 you can steer the angle between the resultant L and R patterns, and by combining them with the Omni you can control the patterns shapes, right?  That's cool. 

I wish we knew more about writing AU code for you.    

-MIQ

Yup. You could always do a real 5.1 mix as well: put a variable lpf on the omni for the subwoofer channel, and create a separate rear channel pair for the surrounds.

Yes, I wish you could code AU for me! Know anyone who can?

[MIQ]

Yes, I wish you could code AU for me! Know anyone who can?

Sorry Noah, I don't.