Topic: 722 Errors????

[mhibbs]

I think that is called "foldback". It happens when a wavform is sort of over extended. Something was being run really hot here. You can see in mid compression a sample or two jumped completly from positive to negative. The result make a wicked nasty pop from the sudden jump mid compression. You can pencil out those foldback errors. I'm not sure of course if it is a firmware issue or not but from what I can "see" your waveforms are brickwalled. This makes me assume you were running really hot levels. Does this only occur when the waveform is being brickwalled or are there any on quieter passages? If you run your levels lower, underpeak do they still occur?

No, the levels were definitely too hot...I don't see any of this behavior in situations where it wasn't clipping.  It's just unusually nasty behavior.  Those examples I sent before were particularly bad, but look at this one....  It's clipping when it occurs, but some are very short and it's still inverting the waveform rather than just squaring it off.  Fun w/ the pencill time for me.

[it-goes-to-eleven]

Yep. Without a doubt, that is the bug and not any sort of brickwalling. I fixed mine with the pencil.

You can otherwise drive the 722 very hard without distortion. It just clips like you'd expect.  Another exception is when using the bass rolloff filter.  Clipping with the BRO on can cause distortion. I think Justin said that has been improved in recent releases but I haven't tried it lately.

[mmedley.]

It has definitly been fixed in newer firmware. The way clipping was handled was whack..weird pops and whatnot (obviously). Happened to me at the Truckers on firmware v1.68 and has now been resolved.  I can attest. My clips didn't look that bad though as I run a bit conservative going mics > 722 (especially since it was the Truckers )

[cleantone]

No, the levels were definitely too hot...I don't see any of this behavior in situations where it wasn't clipping.  It's just unusually nasty behavior.  Those examples I sent before were particularly bad, but look at this one....  It's clipping when it occurs, but some are very short and it's still inverting the waveform rather than just squaring it off.  Fun w/ the pencill time for me.

Yep. Without a doubt, that is the bug and not any sort of brickwalling. I fixed mine with the pencil.

IMO when your clipping at all your running too hot. I guess some gear you can get away with it without this foldback. I guess I'm wondering if this ONLY happens when your brickwalling? If so I would guess that you would want to run a little quieter and avoid the foldback. If there is a firmware option that will allow you to brickwall a bit without foldback AND that is what you want to do, then you should try that.

[it-goes-to-eleven]

IMO when your clipping at all your running too hot.

I call BS on your gross generalization. I am also surprised that you repeatedly try and characterize a known equipment problem as being 'operator error'.

BTW, have you actually run a 722/744 with the firmware that has this problem?

The *BUG* occurs with the slightest clip. Slight clips are normally inaudible. I record a lot of acoustic music where a performer (or crowd) at any point can blow the levels out by doing something extreme.  Normally those clips are a not a major concern.  But when they result in distortion it ruins the recording.

When you are recording a show where you need 50 dB of gain for the music, you're going to clip when the guy next to you starts clapping 10" from your mics (true even at much lower levels). Even the limiter will not prevent the clips (though I almost never run it).  The A/D should truncate the waveform peak without distortion.  Just like the V3 or countless other pieces of gear.  Just like the 1.46 firmware did and the fixed versions after. Any other behavior is unacceptable.

I guess I don't see the point of running 10dB of gain so I can capture the claps clearly but then have to add 40 more dB in post.

[mhibbs]

IMO when your clipping at all your running too hot. I guess some gear you can get away with it without this foldback. I guess I'm wondering if this ONLY happens when your brickwalling? If so I would guess that you would want to run a little quieter and avoid the foldback. If there is a firmware option that will allow you to brickwall a bit without foldback AND that is what you want to do, then you should try that.

Yes, it ONLY happens when it brickwalls...and sure, in an ideal world it should have been run a little quieter.  But the meters on the 722 leave a bit to be desired in the upper ranges.  You can have it running perfect for 20min w/ the -3db lights blinking only on big drum or transient peaks and still you get an occassional quick spike that jumps over and the majority of the time you don't even notice that it happened b/c it occurred so fast.  There's no clip indicator to reset, and no margin meter, so if you were drinking a beer and not staring at the meters all night, you'll invariably miss a few.  Of course you could drop another 3db and just "play it safe" but that's a matter of preference.  What isn't ok though, is that the 722 is folding the wave over on a minor 4ms clip when it should just square it off like every other converter I've ever owned.  I've had some instances in the past when Schools dropped a huge bass note and FOH jacked the sound up for that section so it clipped HARD for about 3-5sec before I got get it turned down and the ad1000 just squared it off as expected.  These foldbacks sound like someone hit the mics w/ a fuckin hammer.  Bottom line, SD acknowledged that it's a bug and it sounds like it's fixed in that it behaves like you would expect IF/WHEN you happen to accidently clip it (which sometimes is more avoidable than others).


mitch

[cleantone]

Yes, it ONLY happens when it brickwalls...and sure, in an ideal world it should have been run a little quieter.  But the meters on the 722 leave a bit to be desired in the upper ranges.  You can have it running perfect for 20min w/ the -3db lights blinking only on big drum or transient peaks and still you get an occassional quick spike that jumps over and the majority of the time you don't even notice that it happened b/c it occurred so fast.  There's no clip indicator to reset, and no margin meter, so if you were drinking a beer and not staring at the meters all night, you'll invariably miss a few.  Of course you could drop another 3db and just "play it safe" but that's a matter of preference.

 

Understood and agreed.

What isn't ok though, is that the 722 is folding the wave over on a minor 4ms clip when it should just square it off like every other converter I've ever owned.  I've had some instances in the past when Schools dropped a huge bass note and FOH jacked the sound up for that section so it clipped HARD for about 3-5sec before I got get it turned down and the ad1000 just squared it off as expected.  These foldbacks sound like someone hit the mics w/ a fuckin hammer.  Bottom line, SD acknowledged that it's a bug and it sounds like it's fixed in that it behaves like you would expect IF/WHEN you happen to accidently clip it (which sometimes is more avoidable than others).

Understood and agreed again. I just wanted to chime in cause I recognized the problem from the pics. Yes they do sound disgusting. It is jumping from 100% posotive to 100% negative in mid compression motion. Luckily the pencil tool can fix them. Tedious as it may be. I agree that it should not occur.

As for some other comments. I'm sorry. I didn't mean to imply that you guys were doing anything "wrong". I was trying to show a cause and possible solution. I didn't say, nor intend to imply that it was human error as opposed to a firmware bug. The fact remains if the signal was not being brickwalled (which it was), it would not have had foldback (which it did). I'm not trying to tell anyone what levels to run at. Do whatever you like. It's your gear and your recording. Good luck.