Topic: Visualization of various stereo mic configurations

[MIQ]

We are getting ready to release a new version of Stereo Mic Tools.  We've added some new tools to help get your mics configured to match the recording situation. 

The first is a "Performers Angle Viewer" for measuring the angle of the performers in front of your mics and comparing it to the Recording Angle created by your mic configuration.  We're considering the following explanation in the info page:

Performers Angle Viewer

• Start by pointing the center of the viewer at the middle of the performers and pressing the zero button to set the angle readout to zero degrees.
  
  Holding the camera level, rotate your device from the center to each edge of the performers, noting the angle at the far ends of the performers.  This is the Performers Angle.
  
  Quickly compare the Performers Angle to the Recording Angle of the current microphone configuration by noting when the angle indicated at the center of the viewer equals the Recording Angle shown in red at the bottom of the screen.  The center line and angle display of the viewer will turn red and become thicker when pointed at an angle equal to the Recording Angle.  Any performers at an angle greater than the Recording Angle will appear to come directly from the speaker on that side of the stereo playback sound system.  Performers within the Recording Angle will be distributed between the speakers of the playback system. 
  
  The RA_75% Angle is also indicated in the viewer by the center line turning green and becoming thicker when the viewer is pointed at an angle equal to the RA_75% Angle.  Keep in mind that in many cases the performers located at angles between the RA_75% Angle and the Recording Angle may not be accurately positioned by the playback sound system.

 

Here's a pic simulating an on stage application where the guitar amp is very close to the RA_75% angle.

[MIQ]

The second tool is a Mic Angle Bombsight that allows you to measure the angle between your mics. 

Microphone Angle Bombsight

• Point the bombsight down at your mics while standing directly over your mics. 
  
  Carefully hold your device flat over the mics to make sure the angle you are reading is accurate.  You can check how flat your device is by using the bubble level at the vertex of the angle lines.  Try to keep the solid black bubble within the small center ring.   
  
  The vertex of the angle lines should be directly above the vertex formed by the mic bodies and the angle lines should be parallel with the mics bodies. 
  
  The Mic Angle is displayed in blue at the top of the screen. 
  
  The center line of the bombsight should point directly at the center of the performers.
  
  The angle between a coincident microphone pair can be measured by flipping the display of the device over and placing the bubble level directly over the point where the microphone capsules overlap.
  
  The microphone angle lines can also be dragged to match the angle of the microphones.  Use your finger to drag either angle line and the other line will automatically move along with it. 
  
  The microphone angle used by the Recording Angle Calculator is updated when dragging the angle lines. The new Recording Angle and RA_75% Angle are displayed at the bottom of the bombsight screen as well as in the Recording Angle Calculator. 
  
  In some situations you may be starting your set up by pointing the mics at the venue loudspeakers ("Point at Stacks" - PAS).  By dragging the angle lines to match the microphone angle you have also determined the needed Recording Angle.  The desired +/- Recording Angle is equal to half the Mic Angle.  You can quickly determine the correct microphone spacing by switching to the Recording Angle Calculator and adjusting the Mic Separation so the calculated +/- Recording Angle is equal to half of the Mic Angle.  For example, if the mic angle between a pair of cardioid mics is 110 degrees, the distance between the microphones should be adjusted to 12 cm.  This configuration has a Mic Angle of 110 degrees and a Recording Angle of +/-55 degrees. 

We are considering adding the Mic Separation display to this screen since it is the other aspect of the mic configuration you are adjusting when you are setting their angle.  Here are some pics of the Mic Angle Bombsight in action.  Dig my fuzzy slipper:

[MIQ]

We updated the Recording Angle Calculator with a new layout.  We also added a new preset: AB50 as a starting point for spaced Omni set ups.  Same old Info text:

Recording Angle Calculator

• Preset - Choose one of the following well known microphone configurations: Blumlein, DIN, DINa, NOS, ORTF, XY90, or AB50
  
  Or, independently set...
  
  Mic Pattern - Choose the type of microphone you are using.  Eight pickup patterns from Omni to Figure 8 are available.
  
  Mic Angle - Set this to the angle formed between the bodies of the microphones.  Values from 0 to 180 degrees are possible.
  
  Mic Separation - Set this to the distance between the centers of the microphone capsules.  Coincident microphone techniques use a value of 0 cm.  Separations from 0 to 200 cm can be used.
  
  ...and observe the resultant effect on:
   
  Recording Angle - The Recording Angle is the angle in front of the mics that encompasses the angle of sound sources (performers) that will appear between the speakers when played back.
  
  Recording Angle 75% (RA_75%) - The angle in front of the mics that encompasses the angle of sound sources (performers) that will be accurately and proportionately placed within 75% of the area between the speakers similar to the way the sound sources are arranged in front of the microphones.

Here's a look at the new layout.

[MIQ]

You can see that there are new buttons at the bottom of all the screens that allow you to switch between the different screens/tools and access the info page. 

Please let us know if you see something whack  or want to comment on how it works. 

If it looks OK we'll send it off to approval soon. 

-MIQ

[DigiGal]

Nice looking updates, are they formatted to utilize the extra screen space of the current devices?

[MIQ]

...are they formatted to utilize the extra screen space of the current devices?

Hi DigiGal,

Yes, all the updated versions of our mic apps scale themselves to the screen they are running on, including the new devices.

-Miq

[MIQ]

DigiGal,

Here are some screenshots of the app displayed on the new 4 inch Retina display.  We added the Mic Separation display to the Bombsight view. 

I think (hope) people will find the new tools pretty useful.  Using capabilities built into the device, we wanted to address the complexity in determining the necessary coverage angle (Performers Angle) and the difficulty in accurately measuring the Mic Angle. 

The Performers Angle Viewer is pretty easy to use but really hard to show with a photo.  As you rotate the camera, the angle from center stage to stage L and to stage R is displayed at the top.

The Bombsight is a little trickier to use since you want the device flat (bubble level in the middle) as well as having the camera directly over the vertex of the mics and simultaneously rotating the camera so the angle measuring lines align with your mics.  It takes a little practice but it isn't a big deal after you've tried it a few times.  If someone wants to be anal retentive they can rig up a device mount to hold it in the right spot above the mics, but you can get decent measurements with a steady hand.

The updated Stereo Mic Tools and a less intense update to Mid Side Visualizer are at Apple waiting for review.  We're looking forward to hearing what you think when you get a chance to play with them. 
 
-MIQ

[DigiGal]

Anxiously awaiting the updates, how long doe the apple review process take?  Thanks for the ongoing app development.

[MIQ]

The review processes is about a week but it varies.  It's always a surprise, even for the developers.

[MIQ]

Surprise!!  They released tonight. 

–MIQ

[DigiGal]

Surprise!!  They released tonight. 

–MIQ

LIVE and direct from Network 23, err Apple App Store!  Got the updates this morning perfect timing for an orchestra recording this weekend, thanks.   

[MIQ]

Great DigiGal!  We hope they come in handy at the show.  Please let us know what you think after using them.

-MIQ

[asobriquet]

This looks good.........
Thanks.