Topic: Bottom Half of Waveform Clipping

[VibrationOfLife]

2 mics into a SD 422 into a 32 bit recorder.

On one channel, when I look at the waveform, the bottom half of it is clipped in spots.  Any ideas why?  It's only on one channel and one direction.  Could it be the low cut filter on the pre, or perhaps a limiter?

When I zoom into the wave, I can see the information. 

TIA.

[EmRR]

Many things clip asymmetrically.  If that's the same file, it looks from the timeline like you're zoomed in on a section that isn't clipping.  How does it sound? 

[VibrationOfLife]

That zoomed in section is precisely where it appears to be clipping.  I can't detect any clipping effects from the audio.  Maybe it's a cabling issue.  I'll set up some mock recordings and try to see a real-time waveform on my computer rather than just levels on the pre and the recorder.

[rumbleseat]

If both mics were listening to the same soundfield more or less, then you need to do some troubleshooting.
Swap mics and see if it follows the mic or not.  If not, swap the connections between the SD and the recorder.  Pinpoint which piece of equipment is generating the anomaly.

[VibrationOfLife]

That's all I can think of too.  Process of elimination.

[goodcooker]

Try DC offset removal in Audacity. It's in the normalize window under effects.

Won't explain how it ended up like that but it may fix it.

[VibrationOfLife]

I've got a rig set up now and trying to replicate it.  I was aware of the normalize dc offset, thanks.  I've also got a show to tape tonight, so I'll see if it happens again if I can't figure it out now.  Thanks.

[morst]

low batteries?

[VibrationOfLife]

Nope, plugged in, but I did change them anyway.  My guess is that I had the low cut filter accidentally cranked on one channel.  I'm packing it all up now, and will test it in a real world situation tonight. I'm also wondering if there was something inside my windpro that was cutting off part of the signal.  It was very windy that night.

[EmRR]

Oh….wind.  Windscreen leakage and super low frequency energy hitting one mic but not the other, causing clipping or limiting way down low.  Makes more sense than anything else mentioned. It wouldn’t be a cable issue, even with a dynamic mic, not and have correct sound, plus mic power wouldn’t work at all.  A HPF set really high would make smaller waveforms, not larger.  Hence….wind

[VibrationOfLife]

OK, this is what is showing up.  This is a mostly simple SBD + 2 mic matrix.  The upper 2 tracks are the ones from the mics to the pre where it's flat AF on the bottom half of the waveform.  I recorded a stereo of the sbd, but realized it was mono and just mixed in the mono.  That was straight to the recorder and not the pre (zero gain from the recorder at all from all 4 tracks, I had to ask FOH to lower me 10dB cause it was hot).  I can't detect any clipping whatsoever on the mic tracks and they are both bottom chopped.  Is it a audacity issue?  Cables are great, power is good, mics are fine.  I'm at a loss.  Maybe I should just let it go, but it annoys me not seeing the entire wave form.  I save the project file, of course I have all the wavs.  RRRg.  This is bugging me.

TIA.  Inside venue with some of the best acoustics in the U.S.  This was just a bit over an hour ago.

It seems like if there is a gain variation above a certain number the bottom half gets cut off on the mic tracks.  I think now this is a software problem.  Listen to a portion of it.  I can zoom in and it's all in there.  A solid ass recording if you ask me.  Indeed, it sounds fantastic to my ears.

No HPF and just some foamies on the mics.  And I made sure they were blown out this morning.

https://archive.org/details/trg2025-12-02

[todd e]

can you open in wavelab or try another editing software?  id guess audacity display issue setting, but merely a guess.

shoot me a clip of it, i'll see what it looks like with wL6

[VibrationOfLife]

What is the best way to shoot you a clip, throw a wav file on dropbox?  Whatever you need.  I'd really like to get to the bottom of this.  Thanks very much.

[VibrationOfLife]

Here is a raw untouched wav clip from when it goes from normal to the bottom clipping: https://drive.google.com/file/d/1gp0quiFJSmi5S_ai729sjHbF1jHNWF6G/view?usp=sharing

Any help appreciated.

[al w.]

To me, it looks like an Audacity issue. It looks the same as yours in my Audacity (left), but in Logic (right), it's fine. See attached!