From an on-the-fly matrix - This sounds like a brief static zip - I thought maybe the singers mic channel overloaded...but this looks different.
Im thinking pencil tool...
What is happening at each of those peaks? A drum hit, singing?
I'd guess analog clip.
I believe the 722 suffered the same issue at one point. When you'd hit digital 0/over, it would invert the signal instead of the "table top" look. They fixed it in firmware:
1.67
fixed - bad overload behavior from 1.60 fixed
fixed - CF no longer erroneously shows "full" after deleting files and emptying trash with a Mac
fixed - time remaining now changes properly with ext word clock
fixed - linked units now advance take simultaneously with file split
fixed - user bits now properly track take number on both hard drive and compact flash
changed - FireWire screen now says "...don't disconnect firewire cable..."
added - upon update, it now prompts the user to update the date/time
released March 24, 1006
Just to expand a bit...
This was using the JB3s A/D...fed from my mixers RCAs...
Overall - the levels look fine, in not a bit conservative. There is no obvious looking clip.
The segment above (where the zap occurs) is actually just a fraction of a second of singing - check the times
Its definitely associated with the vocals...Im thinking this actually came from the soundmans mixer - the vocal channel may have red-lighted.
Another competing theory...dont laugh (actually do!)
The sound man had one of those little rotating pizza ovens and was running it off the same electric as the PA.
I hear a few pops in this recording that Im certain are the pizza oven cycling on and off.
Im wondering if an oven pop combined with a vocal peak might make this happen. (I haven't examined any of the pops yet...if they are similar, that might be it...)
here's an mp3 sample of the moment...
overall view of the whole song...(this is the version that was normalized 3.3 db)
JB3 is HD...
I must say - Audacity Pencil tool rules! Cleaned this up very nicely...
Im really thinking this pizza oven may have been the culprit...
Here's the fixed segment...
http://www.rovingsign.com/hexbelt2008-07-12t12fix.mp3
Here's the original just for comparison - note the first blip doesnt really seem to sync with the vocal as much...(right after the "handful of pills" line)
http://www.rovingsign.com/hexbelt2008-07-12t12prefix.mp3
I've had that exact type of inverted spike before on a couple of my recordings - both SBD feeds. One of those times, I am certain it was analog clipping from one of the drum (tom) channels on the SBD. The other time, I think the output levels from a SBD feed I received were too hot and were clipping my R-4 Pro at the analog input stage.