Topic: Visualization of various stereo mic configurations

[Gutbucket]

That's right, and when you input a different +/- value in the 'orchestra angle' input box, the result is visually indicated by changing the spread of the colored lines superimposed on the mic pattern display.  Those colored lines in the mic pattern display indicate the actual position of individual live sound sources on stage, within that particular orchestra angle.  Those won't move if you change other mic configuration parameters.

The other colored lines in the playback speaker display show where in the stereo image those actual sound sources will be reproduced on playback, so that set of colored lines will shift around depending on all the other mic setup parameters you enter.  The relationship between the colored lines on the speaker display and those on the mic display indicates the source image position distortions on playback  - distortions that can be good, not necessarily bad! For instance: if most of the colored lines are shown as bunched around the two speakers without many in the middle, you might expect the 'hole in the middle' situation (see footnote).  Conversely if all the lines are bunched in the center, it indicates that the playback will probably sound predominantly mono.  Play around with it and it will make sense.

footnote: Keep in mind that this colored line display is modeled after and mostly relevant for situations where the sound is coming from the actual sound sources on stage, not from speaker stacks on either side of the stage.  Think things like recording on stage, from the stage-lip or an orchestra or something without a PA.  Recording a PA reinforced band from the section where a much smaller portion of sound arrives directly from the actual instruments on stage is a very different beast.  In particular, the 'hole in the middle' condition indicated on this display may not apply if the PA is mostly mono and your recording position is pretty much centered between stacks.

[ethan]

I SO need this as a phone app.

[ScoobieKW]

I SO need this as a phone app.

HTML and Javascript, but doesn't work with the touch interface of the iPod Touch. Any iOS programmers on this board?

[ethan]

I SO need this as a phone app.

HTML and Javascript, but doesn't work with the touch interface of the iPod Touch. Any iOS programmers on this board?

I'll see how my droid does.

I'm thinking something a little different though for a phone app. You'd want the ability to visually input the orchestra angle somehow by lining up your location and the sound stage and have it come up with angle between the mics and spacing recommendations.

Edit: or better yet have some way the gyro's on the phone can be used for input. Something like point it at center then rotate left side through right side.

[ethan]

So I just noticed the CopyLeft on the page. I wonder if this means we can get the source code for this.

[ScoobieKW]

It's Javascript and HTML, the sourcecode is in the page.

If it's copyleft we should be good to go.

Steve

[DigiGal]

It would be great to see this made into an iOS App, any board members capable of doing that???

[ethan]

I don't think the accelerometers on smartphones will work for data input but perhaps the compass

[ethan]

It would be great to see this made into an iOS App, any board members capable of doing that???

Well if I were to take it on it would be android...don't have an iphone and I'd prefer writing in Java to  Objective C anyways.

First things first I've got to digest the javascript code so i can get an idea of what it does.

[ScoobieKW]

http://www.rycote.com/images/uploads/The_Stereophonic_Zoom.pdf

Michael Williams in this paper, lists the AES papers that have the math and physics behind this if you want to dig in deeper.

He also has some handy precalculated graphs in it. Been meaning to laminate these and keep them in my gear bag.

[Gutbucket]

I've posted this link at TS previously, but it should be here for this discussion-
http://www.mmad.info/MAD/Ch_n_cov.htm
^^^
Link to Michael Williams' web page accessing a large number of his mic array charts, both 2 and multi-channel.  This is a link driven configurator that gets you to a specific stereo zoom chart, depending on your desired recording angle, mic pattern, number of mics, etc.  It's missing information on 3-channel configs which I would really find useful and hasn't been further updated in a number of years, yet is an outstanding resource.

He previously had all his AES papers posted on another page at that site for anyone to download, many containing the background information on the development of the data and methodology for deriving the charts (as well as the math behind the apps were talking about) as well as additional charts not linked on the page above such as his 'Magic Arrays'.  However, I just checked and it looks like all those links have now been removed. The papers are still listed, but the reader is directed to the AES site- a pay to download provider.   Bummer.

[MIQ]

I've been working with a friend who is an iApp developer on some stereo mic apps.  As an easy first step to get some of the building blocks in place we developed a Mid-Side mic visualizer.  I know it's not exactly what we've been discussing in this thread, but it is another tool that I think many of you will find useful and fun to play with.  You can find it in the App Store by searching for "Mid-Side Mic Visualizer".  It was released on the 8th.  I've been traveling for work and didn't even know it was released until last night.   

The basic idea of the app is to allow you to see the relationship between the polar patterns of the Mid and Side mics and the resultant Left and Right polar patterns as you vary the Mid to Side signals' ratio (levels). 

We included a couple of ways to change the mid mic type.  There is a selector menu button at the bottom where you can choose from most of the standard mic types (Omni, Card, Subcard, Hyper, Fig 8, etc).  The slider on the left will also allow you to vary the polar pattern continuously from Omni to Fig 8.  At the bottom of the visualizer there is a polar plot that displays the Mid and Side mic polar patterns.  As you vary the mid mic type, the changes are displayed in this polar plot.

The other slider at the right side of the app allows you to vary the ratio of Mid to Side mic signal used in the Mid-Side matrixing.  This slider allows you to vary the levels of the signals anywhere from 100% Side to 100% Mid.  The changes to the Mid to Side relative levels are displayed in the Mid and Side polar plot at the bottom.  The polar plots of the post matrix Left and Right signals are displayed in the polar plot display at the top of the app.  It is interesting (and informative  ) to see the Left and Right polar patterns change in shape and orientation as you slide the Mid to Side ratio slider up and down.  Either of the sliders can be moved in one step increments by tapping the buttons at the top or bottom of the sliders. 

Also included is an information (geek) page where I've written a short description of the Mid-Side microphone technique and how it works.  Below are a few screen captures of what the app looks like.

I'm excited for you guys (and DigiGal  ) to check it out since I know a lot of you use Mid Side and also want iApps to play with.  Please let me know what you guys think and feel free to send me feedback about how the app can be improved or corrected.  I hope you dig it.

-Mike (aka MIQ)

[DigiGal]

I've been working with a friend who is an iApp developer on some stereo mic apps.  As an easy first step to get some of the building blocks in place we developed a Mid-Side mic visualizer.  I know it's not exactly what we've been discussing in this thread, but it is another tool that I think many of you will find useful and fun to play with.  You can find it in the App Store by searching for "Mid-Side Mic Visualizer".  It was released on the 8th.  I've been traveling for work and didn't even know it was released until last night.   

The basic idea of the app is to allow you to see the relationship between the polar patterns of the Mid and Side mics and the resultant Left and Right polar patterns as you vary the Mid to Side signals' ratio (levels). 

We included a couple of ways to change the mid mic type.  There is a selector menu button at the bottom where you can choose from most of the standard mic types (Omni, Card, Subcard, Hyper, Fig 8, etc).  The slider on the left will also allow you to vary the polar pattern continuously from Omni to Fig 8.  At the bottom of the visualizer there is a polar plot that displays the Mid and Side mic polar patterns.  As you vary the mid mic type, the changes are displayed in this polar plot.

The other slider at the right side of the app allows you to vary the ratio of Mid to Side mic signal used in the Mid-Side matrixing.  This slider allows you to vary the levels of the signals anywhere from 100% Side to 100% Mid.  The changes to the Mid to Side relative levels are displayed in the Mid and Side polar plot at the bottom.  The polar plots of the post matrix Left and Right signals are displayed in the polar plot display at the top of the app.  It is interesting (and informative  ) to see the Left and Right polar patterns change in shape and orientation as you slide the Mid to Side ratio slider up and down.  Either of the sliders can be moved in one step increments by tapping the buttons at the top or bottom of the sliders. 

Also included is an information (geek) page where I've written a short description of the Mid-Side microphone technique and how it works.  Below are a few screen captures of what the app looks like.

I'm excited for you guys (and DigiGal  ) to check it out since I know a lot of you use Mid Side and also want iApps to play with.  Please let me know what you guys think and feel free to send me feedback about how the app can be improved or corrected.  I hope you dig it.

-Mike (aka MIQ)

Great I purchased this app to give it a try.  Big suggestion though, please make it compatible with iOS version 4.2.1.  My device won't support iOS version 5.xxx so I can't actually use the app as it is now  .  I was curious if you included a shotgun pattern for the Mid too.

Hopefully, you guys can make it compatible with 4.2.1, I'm not planning on replacing my device until the next major hardware bump from Apple.

[MIQ]

Hi DigiGal,

I'm sorry you are not able to check it out even after you purchased it.     I have asked my friend how difficult it would be to make a version that is compatible with older versions of iOS.  I'll let you know what he says.  Currently it will work on iPhone 3GS, iPhone 4, iPhone 4S, iPod Touch 3rd generation, iPod Touch 4th generation, and the iPad, but you must have iOS 5.0 or higher to use it.  I know it is too late now but this is shown in the "Requirements" text in the apps store.  PM me with your address and I can send you a dollar back in the mail if you are really bummed.

We have not included a shotgun pattern for the mid mic.  As a start we concentrated on only "first order" microphone patterns.  I'll take a look at how to derive the pattern for a shotgun mic.  I imagine it may be different from manufacturer to manufacturer but I haven't explored shotgun mics at all.  Thanks for the suggestion.

-MIQ

[MIQ]

I heard from my friend (Rob) today.  He said making a version for iOS 4.2.1 is doable.  He is cranking on some other projects right now but thought that after New Years he would likely have some time.  Also, we will hopefully have some other feedback we could incorporate at that time.  Sorry for the wait.  I really wish you could use it NOW.

I've been researching how to derive shotgun polar patterns.  I've got a good start on it.  I'll see if we can get them into the app at the same time.  I'll post a pic of the shotgun pattern I'm thinking of using in a few.  I need to make sure it looks like the ones that are published for common shotguns first.


-MIQ