This is the predicted response from the back sub at the 4mt mic position at the back of the array.Īnd a compare between both responses (2 subs front red trace and 1 sub back blue trace at the 4mt mic position). This is the predicted response from the 2 front subs at the 4mt mic position at the back of the array. This is the predicted response from the back sub at the 2mt mic position at the back of the array.
This is the predicted response from the 2 front subs at the 2mt mic position at the back of the array.
The screenshots in the first part of this post were done in 2 day’s so i ended up with slightly different levels in the comparing screenshots sorry). This has to do with a Gaussian program algorithm implemented within the Mapp program. (you might notice the level differences between the first 2 screenshots and ”the compare screen shot”. This is the predicted response from the back sub at the 1mt mic position at the back of the array.Īnd a compare between both responses (2 subs front and 1 sub back at the 1mt mic position). This is the predicted response from the 2 front subs at the 1mt mic position at the back of the array. Within Mapp you’ll see the same thing at the 1mt mic position. So with the”back sub” at 1mt and the front subs at 2mt the front subs will have 6dB more level but travelling twice the distance they also loose 6dB. Has to do with the Inverse Square Law (with each doubling of the distance the SPL level reduces with 6dB). This means there is a 6dB offset between them so at the 1mt mic position you will see a pretty good cancelation due to the fact that the sound from the front subs has to travel around the array and assuming this is +/- twice the distance compared to the sound travelling from the back sub to the 1mt mic position you’ll end up with both parts of the array having matched level. The problem with this array: If you phase align the “back sub” with the front subs with the mic at 1mt from the array and then polarity reverse the back sub you’ll get a pretty good cancelation at that mic position but in the far field you get to deal with a level offset between the 2 front subs vs. The mic’s are positioned at 1mt 2mt 4mt 8mt and 16mt (so each time the distance is doubled). The front-back-front set-up consists of 3 900LFC with the middle one reverse (shooting back worth). So here’s the start: A front-back-front set-up (3 x 900LFC Meyer Sound) In this post I’ll take a peak at what happens at different mic positions at the back and not at just 1 mic close for getting the maximum cancel. (if you have Mapp on Line installed on your computer here are the ZIP-files from MAPP used to do this post CSA cue2016-3 CSA 2subs cue2016-3 CSA 2subs mics front cue2016-3) I will be updating this post but it’s a start. In the posts on this kind of an array before this one I was mainly interested in getting as much cancelling on the stage side and as much level possible in the audience area. So I decided to do a little more research on what i know as a CSA array or Cardioid Sub Array.
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