Topic: strange uneven waveform from live akg mod recording ... seeking opinions

[cpscps]

i recorded a show last weekend and discovered a strange/uneven waveform while editing in post.  i've recorded from the same location in the same venue with the same mount and similar gear.  the only differences were the capsules and newly built cables.

30 second clip:
http://dl.dropbox.com/u/19262848/partial_sample_24bit.44k.flac

complete song:
http://dl.dropbox.com/u/19262848/complete_sample_24bit.44k.flac



is this normal?  do you hear any distortion?

edit: revised title
thanks!

[JonG]

 

There's a bit of distortion in both channels that's a bit more obvious in the right, and for one reason or another snare hits and drum kicks are considerably more intense than the left. The left channel is about 2.75dB quieter than the right, but the funky intensity imbalance is still there.

Considering the circumstances (an assumption) you taped in, I'm not terribly surprised. I for example, was at one of these shows and my seat had the right mic with a more or less clear path to the right stack, while the left was impeded by so many bodies. Balancing the channels was a bit of a challenge because of the same sort of issue, but not to the same extent in your pull and without distortion.

Where about in the venue were you and what gear did you run?

[cpscps]

Where about in the venue were you and what gear did you run?

i was seated 10th row, 4 seats off center. 

thanks for the feedback!

[JonG]

I would think something with the capsules and their sensitivity, seeing as the cables aren't likely to have caused the issue.

The intensity imbalance is all of the bodies acting as baffles that the sound had to go around before reaching the mics, but the distortion definitely ought not to be there.

[anr]

My attempt

http://www.sendspace.com/file/zuixiv

There is a huge amount of bass which I confess I don't like.  And as I'm old and the top end of my hearing is shot, you may think this a bit "trebly".  But it is better balanced and the distortion is less noticeable (IMO).

[cpscps]

the distortion is less noticeable (IMO).

thanks for the feedback.  it seems distortion is the primary problem.  i will try to post more details for further analysis.
 

[OOK]

I need to know bout the recording chain.  what mics, pre and recorder were you using?      peace ook

[cpscps]

I need to know bout the recording chain.  what mics, pre and recorder were you using?      peace ook

modified akg ck93 capsules > 9v batt box > sony pcm-m10

[cpscps]

fyi - the capsules & cables were wired according to schematics from this thread:
http://taperssection.com/index.php?topic=144716.msg1864340#msg1864340

wired as:

Pin 1: shield
Pin 2: Hot +
Pin3: Cold -

here are photos for reference:

pic1 pcb wiring :
http://i188.photobucket.com/albums/z48/igene_01/PCBwiring.jpg

pic2 pcb pinout :
http://i188.photobucket.com/albums/z48/igene_01/PCBpinout.jpg

pic3 blueline lav reference:
http://i188.photobucket.com/albums/z48/igene_01/bluelinelavPCB.jpg

pic4 pcb top :
http://i188.photobucket.com/albums/z48/igene_01/CK91PCBbottom.jpg

pic5 pcb bottom :
http://i188.photobucket.com/albums/z48/igene_01/CK91PCBtop.jpg

pic6 :
http://i188.photobucket.com/albums/z48/igene_01/100_5451.jpg



any comments?

[OOK]

Ok now it makes a little more sense to me.  Depending on where you were set up in the venue the uneveness could be due to more signal being picked up in that channel.  You recording chain just has a battery box going right into a m10.  You had no means of adjusting balance on your incoming signal.  You would be surprised how just being a few feat in either direction off center will throw your balance off in your recording.  As for What I hear...I am hearing some bass bombs but nothing really distorting aside from maybe a little pa distortion, again its slight.  To me it just looks like one channel is louder than the other.  I don't see any brickwalling or any other abnormalities.  once you are able to place a preamp in the chain and have some control over balance you will see the diference. 

peace ook

[rhinowing]

Ok now it makes a little more sense to me.  Depending on where you were set up in the venue the uneveness could be due to more signal being picked up in that channel.  You recording chain just has a battery box going right into a m10.  You had no means of adjusting balance on your incoming signal.  You would be surprised how just being a few feat in either direction off center will throw your balance off in your recording.  As for What I hear...I am hearing some bass bombs but nothing really distorting aside from maybe a little pa distortion, again its slight.  To me it just looks like one channel is louder than the other.  I don't see any brickwalling or any other abnormalities.  once you are able to place a preamp in the chain and have some control over balance you will see the diference. 

peace ook

agreed

[F.O.Bean]

Ok now it makes a little more sense to me.  Depending on where you were set up in the venue the uneveness could be due to more signal being picked up in that channel.  You recording chain just has a battery box going right into a m10.  You had no means of adjusting balance on your incoming signal.  You would be surprised how just being a few feat in either direction off center will throw your balance off in your recording.  As for What I hear...I am hearing some bass bombs but nothing really distorting aside from maybe a little pa distortion, again its slight.  To me it just looks like one channel is louder than the other.  I don't see any brickwalling or any other abnormalities.  once you are able to place a preamp in the chain and have some control over balance you will see the diference. 

peace ook

agreed

[cpscps]

i appreciate all the feedback, thank you. 

[Church-Audio]

i appreciate all the feedback, thank you.

Who did the mod on your mics and what was done? It could also be a bad or weak battery. I get many bad akg mods sent to me and when I end up measuring the distortion its not good.  I had one pair sent to me by a customer that was 10% thd at 1k at 114 db thats a huge amount of distortion. But if you have never had an issue before I would look at the battery. Dont worry too much about one side looking different or being at a higher amplitude chances are these mics are not matched and the stereo field in a live event is NEVER symmetrical.

[cpscps]

i appreciate all the feedback, thank you.

Who did the mod on your mics and what was done? It could also be a bad or weak battery. I get many bad akg mods sent to me and when I end up measuring the distortion its not good.  I had one pair sent to me by a customer that was 10% thd at 1k at 114 db thats a huge amount of distortion. But if you have never had an issue before I would look at the battery. Dont worry too much about one side looking different or being at a higher amplitude chances are these mics are not matched and the stereo field in a live event is NEVER symmetrical.

akg blueline capsules were modified according to the specs from a thread here:
 http://taperssection.com/index.php?topic=144716.msg1864340#msg1864340

i used a brand new 9v battery in batt.box.

thanks for the feedback.