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Problems with slicing @ zero crossing?

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#1

Hey all, hoping to pick the communities brain about a problem that just started happening. I’m trying to slice a piano sample I recorded in pro tools. It’s just single piano notes being played and decaying fully before the next note so there are clear transients here yet the sample slicer won’t slice at the zero crossing point! I checked the slice at zero crossing settings in the menu and both are set to yes.

I tried removing the DC, and checked the files and there isn’t any noise at all between the notes. And even weirder I tried slicing a sample I recorded directly into the 301 and it slices fine! Is this something to do with the rate of the wav file or something? Has anyone else had this problem? Any help is appreciated!

I’m on 0.3.25.


#2

If you drop the WAV file (or part of it) here I can take look.

Can you show with a screenshot (SHIFT+CANCEL) what is happening?
How are you determining that a slice is (or isn’t) at a zero-crossing?

Here is an example where I zoomed the horizontal axis to 70ms and the vertical axis to +30dB. I then inserted 3 slices randomly in front a large onset (from a piano note). The first 2 slices were done with snap-to-zero-crossing turned on and the last slice with it turned off.
0007

One more thing: Have you ruled out phase differences in stereo channels? For example, slicing to a zero-crossing in the left channel obviously won’t necessarily correspond to a zero-crossing in the right channel.


#3

Here are two of the files that were posing the problem. A couple other ones were doing the same thing. All files from the same session. Can’t take a screenshot just now cause I’m away from the 301 but I know it wasn’t slicing at the zero crossing because usually I would just have the marker in the ballpark of the slice and it would slide right to the ZC but last night it was slicing exactly where the marker was. I tried shift+slice and it would move the cursor like -5 samples or something and still not hit the right place.

The context that I’m doing this in is I’m using the 4 poly custom unit and if the slices are off at all it’s pretty obvious as the timing is out of whack. I’d have a metronome going at the same time for reference. I’m note sure if phase issues between L&R would be the issue here. Just took a close look in audacity and they look pretty close to me. Close enough that there wouldn’t be as clear timing issues. But maybe your eyes will see something I don’t!

Thanks for your help Brian! :slight_smile:


#4

On closer listen I do hear some minor noise between the samples, would this be to blame?


#5

Zooming both the horizontal and vertical axis doesn’t reveal anything?


#6

as far as i can see with my wave editor (the one in samplitude)
i can clearly see phase differences in the piano-wav.

working with desktop daws i got used to mark the beginning of a given sample and to
routinely fade it in.
with the er 301 and in cases i am looking for pristine slicing points i do the same!
in this tutorial from @joe’s garage, you’ll find instructions that might help you do this:
http://wiki.orthogonaldevices.com/index.php/Solo_Trumpet_Performance

  1. right now, i suppose you won’t run into the same problem with a mono-recording

  2. another thing is to ask whether some smart algorhythm [cheap pun intended] could and should replace the work i mentioned above, i.e. marking a small portion of a transient and to fade it in.
    i believe most microphonic recordings in stereo tend to have some amount of phase differences. even samples that were recorded in the box, i.e. without external gear, can have those. and since in most cases you just want to get rid of the problem in the transient while preserving phase related ‘features’ in the rest of the sound: at least one workaround is to fade those transients in.
    Are there other possibilities?


#7

There was just enough room to cram the drums in the corner over by the Dodge. :wink:

One of my favorite albums.


#8

Hey Joe,

clearly, we should get back on track to tangolimas original post!
and before we do so we also should add some standard disclaimer along these lines:

“Any resemblance to living people is purely coincidental” :wink:

(Just had to endure “The golden shower must have shorted out his master circuit” :astonished: same album,
i almost forgot WTFunk that really was)


#9

I just tried one of your files (piano_med.wav) and I was able to place the slice just fine and it was snapping to zero-crossings as expected. Although I did have to zoom all the way (in both axes) to see what was going on.

0008

Perhaps what you didn’t realize is that the area just before your piano hit is perfect silence, so every sample is a zero-crossing. So, in order to get the slice right before the piano hit I had to zoom all the way in and place it exactly where I wanted.


#10

I didnt know you could zoom in actually so theres a good start hahaha. This is great though I’m gonna try the methods mentioned tonight. Thanks for everyone’s help with this! I’ll report back…


#11

So still can’t figure out how to zoom in the slice editor. I tried holding M6 and turning the encoder but it just takes me to the menu.

And if perfect silence is all zero crossings, how are other audio files configured so that it detects the correct ZC? Because I’ve never had this problem before. I’d rather not go in and slice as close as I can to the ZC, I’d rather let it auto detect it. So what could I do to the audio to fix this?


#12

Hold the fine/coarse button in while turning the encoder to zoom. The little arrows next to the fine/coarse LEDs indicate which direction you’ll zoom in.