snap to 0

sometimes works, sometimes doesn’t…?

i have always found “snap to 0” to be a little inconsistent… i’m guessing there’s an explanation, and now i’m searching for it.

i am using build 1980 i’ve starting working on an old project recorded with n-track 3.something…

this particular project consists of all 16-bit 44,100 wav files… some stereo, some mono. in n-track, if i attempt to “cut” segments of the old wav files, the “snap to 0” function seems to have no effect (normally i would expect my selection to move to the nearest 0 crossings… and looking at the wave form, i can tell there are nearby 0 crossings).

now, i’ve recorded a NEW track in that same project. this being a 24-bit 44,100 wav file. if i make a similar selection it DOES snap to 0 where i would expect.

i’ve messed around with the snap settings… can’t seem to make it work on those old 16-bit tracks. one thing that i am curious about is the DC setting… it’s quite possible i had offset issues when i first recorded the project… i believe i was using a soundblaster at the time. the new track i added went through much nicer and newer equipment.

also… i’m not sure if snap worked when i originally recorded this project because at the time i did not know about the wonders of “snap to 0” and was using volume evolutions all over the place (where i could have used a simple cut).

any ideas?

one more question i’ll add… anyone know how snap to 0 works (or doesn’t) with a stereo track?

Beats me, dude. I don’t use snap to zero (perhaps you could tell me what it is, and why I should use it?). However, what you said about the original file sounds plausible. Have you tried rerecording the file? In other words, doing a live playback/record dump of one of the files and see if you could edit it then? Or you could try even simply opening a new n file and importing one of the files in and then mixing down to create a new file. Perhaps that might help nail down the issue?

whenever you’re doing edits of wav segments in a track (for example, comping a track made of up multiple takes), you will find yourself making a selection on that track to either cut, copy, or delete it. most often for me, it is even just to delete a portion of unwanted noise at the beginning of the track.

if you have “snap to 0” enabled, n-track will make sure to start/end your selection at a point where the waveform crosses 0 (the vertical “center” of the waveform). if your segments start/end at a 0 crossing, this prevents a “click” from ocurring at these points.

i don’t know how to explain it any better than that.

i will have to do a bit more testing as to why it’s not working on the older files. i still suspect DC offset, though i don’t know why DC has anything to do with it… the waveform still crosses 0 at some point even if there is an offset problem. but if the snap to 0 settings have DC offset stuff, it must be possible.

i have tried creating a new n-track project and re-imported the old wav files and it didn’t help. next i will try removing the dc offset from one of those files. there are so many files in the project, i don’t see doing this to all of them if this is the issue.

Quote (dimmer77 @ Nov. 07 2005,12:29)
if your segments start/end at a 0 crossing, this prevents a “click” from ocurring at these points.

Correction: it makes a click less likely. Any sharp corner in a waveform will cause a click. Splicing at a nonzero value will always cause a click (unless the next section of wave file starts immediately, near the same value, and with nearly the same slope).

Snap to zero makes clicks quite a bit less likely, and it’s a good feature whenever you splice where it’s not silent. But I usually edit any splice point manually to pick the best spot (zooming way in), and based on whatever comes before or after the splice, so I don’t bother using it much.

However, when I did use it, I noticed that there seems to be two cases: when it snaps and when it doesn’t. I got the impression that if I drag a selection, it jumps. But when I adjust a selection, it doesn’t. Or something like that – I didn’t investigate it thoroughly.

Never noticed a difference between 16-bit and 24 bit files.

I’m using V3.3, btw.

thanks for the clarification.

my selections are almost always done the same way… made at the beginning or end of a wav segment: i drag from a point inside the segment, ending my selection just outside of the segment. i will normally see the selection jump/snap somewhere inside the wav segment. this is just not working on these old wav files.

i’m not sure the difference is the 16-bit to 24-bit, that’s just how i’ve tested it in this situation.

it doesn’t look like there are any dc problems with my old files either (by examining visually)… is there a way to scan a wav file and read the dc offset value?

DC offset wouldn’t really cause a snap to zero problem, except when you’re cutting at silence (because then, with no waveform, there are no zero crossings).

If you record silence on a mono track and the red line lines up with the green line for volume automations (before doing any), then you don’t have much of a DC offset problem. To get closer, two ways:

1) Use RMAA (rightmark audio analyzer) and really scope out your soundcard
2) record silence using a short plug, drag a section of it, pick “Normalize”, and then scan. There’s always some noise, and you can’t tell DC offset from the noise, but the scan value gives you the upper limit – you know any DC offset you may have is lower than that.

yeah, none of that will really helps as i am working with files recorded long ago on equipment i no longer have connected. i think you’re right that it probably isn’t dc offset causing the problem. perhaps i will have to go back a few versions and see if the problem still occurs.