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Author Topic: 4 channel recorders question...  (Read 11846 times)

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Offline BayTaynt3d

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Re: 4 channel recorders question...
« Reply #30 on: September 21, 2008, 08:41:08 PM »
Got that - pretty sure he referenced an R4 - so they are inherently clock synced tracks - so why the need to "shrink"?

Dito for me and recording four track w/ my R4. And for the record I have only had delay issues one time running matrix out side where I was about 45' away from the stage uphill. As long as you are around 20'-25' you should be alright w/o any delay. I use Vegas to render my files together and to take care of delay all you have to do is shrink or expand the two audience tracks. I found it easier to shrink the aud tracks to fit the SDB but when you get it right you will know by the reverb.

^ OK, I see what you mean now Roving Sign.  Doh...

So, Jim, were you using your R-4 or two separate recorders that night where you were ~ 45' away and uphill, and you ended shrinking the AUD source to mix it w/ the SBD? 

I think Roving Sign is pointing out that, theoretically, if it was the R-4 and not 2 separate recorders, the tracks were already sycned and there should not have been a need to correct drift by shrinking a track.

I was using only my r4 and yes I was talking about drift and not delay. I followed these instructions below to correct the show w/ Vegas.
Now, go to the end of your new audio track and compare it visually to your original track.  Hopefully you should see some similar points in each and be able to tell how far off they are.  If your original audio track is distorted too bad or AGC was used it may be almost square.  Use your ears in that case.  Play the tracks together and you should be able to tell if your new track is ahead or behind your original.  You may have to adjust the track volume of one or the other to help out.  Just make sure you set the new audio track back to 0 before you render.  Go to the end of the new audio track and hold your mouse cursor right over the end.  Hold down the CTRL key and you'll see the "~" symbol appear.  Keep that CTRL key held down and move your mouse to the left or right.  You are now stretching or shrinking your audio track in real time.  Move it in small increments and listen and compare your two tracks visually each time.  You might have to zoom in and move in extremely small increments to get it right.  Once you're done both tracks should sound like one when played together. 
http://www.archive.org/details/bts2008-05-03.bts2008-05-03matrix.flac16

But how can there be any drift?

you have an R4 - thats the whole point of that device...4 clock synced tracks...


I'm with Roving Sign. As a multi-year R4 and R44 owner, and as a power user of Vegas for even more years, I can say without question that this is not the right approach. There is also some other info in this thread that is confusing, most of which has been corrected by sporatic other posts, but here's a quick rundown as I see it...

1. If you are using an R4 or R44, there will NEVER be drift, which means there will never be a need to shrink or lengthen any track that was recorded at the same time with one of these units. If you are doing that, you are literally introducing drift yourself by doing so. The exception of course would only be if you had another source you were syncing in that was not recorded with the R44/4 -- say when you are syncing up some video to your audio source. So, for an R4/R44, all you have to do is get any point between the tracks synced, and then the entire tracks will be synced. If you're syncing in a separate source, then the technique above is a great one and represents one of Vegas's amazing features (real time on-the-fly editing WHILE it plays).

So say you are syncing a matrixed source with some video. First, get the matrix synced by delaying the SBD channel (you can either add a delay, or slide the track later, but no stretching/shrinking). Once the matrix is good, then sync it with the audio from the video. Get an early piece in sync, and once that sounds good, go all the way out to the end and listen. It might be OK, but chances are, there's drift. If so, that's where I would shrink or stretch the matrix (I prefer not shrinking/stretching the video piece because that will affect picture quality in a visible way sometimes, and the shrink/stretch of the matrix will be inaudible). Done.

2. If you are recording more than one channel with mics or sources that are significantly distant from one another (e.g., SBD into 2 channels and AUD into other 2 channels way back FOB), then you may need to delay the closer mics (the SBD). The rule of thumb is 1ms per foot, but is much better done by visibly lining things up and listening to them. You need to be careful doing this because once you are close to sync, it is easy to get weird phasing. I prefer getting the SBD just a tiny hair in front of the AUD in these situation (again only if mics far from stage in matrix situation) because that prevents weird phasing and it sounds better with the dry SBD leading my millisecs, and the natural ambient coming millisecs later (I'm talking tiny amounts here, you need good monitors and an even mix cause the tiny difference I'm talking about here really basically all sounds in sync once you're that close).

3. The R4 and R44 can record 4xMono, 2xStereo, and combinations in one or multiple individual files. You have to be careful because some editors can't handle the bundled multi-track files, whereas all editors can usually handle a mono or stereo file. Also, file size isn't too much of an issue because the R4/R44 does seemless splits. That said, I almost always run 2xStereo, whether a few of those channels are really mono or not. It makes for two files that are easily read by any editor, and for me, in Vegas, I can right-click and choose the channel I want on any stereo file in a matter of one second. For matrixes, it's easy this way because I just end up with two stereo tracks in vegas, just slip the AUD back in time, and you're done.

Also, if you're new to matrixing and haven't done so yet, you should read the TaperSection Matrix Guide PDF. Very helpful piece.
« Last Edit: September 21, 2008, 10:54:06 PM by BayTaynt3d »
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Offline stantheman1976

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Re: 4 channel recorders question...
« Reply #31 on: September 21, 2008, 10:21:21 PM »
Dude, that was from a different thread.  If you're using the same recorder then no, there shouldn't be any drift.  My post was about syncing up different recordings from different sources.  My post was not brought into this thread by me and doesn't relate to 4 channel recorders with an internal clock.  Please check the entire thread and see where something comes from before you go calling me out in public.  I don't own and R4 or R44 and probably will never be able to afford either.

I often record video and either a mic or board feed and mix them.  I don't ever stretch the video track when I do that.  I match the new audio to the original and if I have more than one new audio track (i.e. matrix) I match each new track to the one above it and mix to taste.

Offline BayTaynt3d

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Re: 4 channel recorders question...
« Reply #32 on: September 21, 2008, 10:53:04 PM »
Dude, that was from a different thread.  If you're using the same recorder then no, there shouldn't be any drift.  My post was about syncing up different recordings from different sources.  My post was not brought into this thread by me and doesn't relate to 4 channel recorders with an internal clock.  Please check the entire thread and see where something comes from before you go calling me out in public.  I don't own and R4 or R44 and probably will never be able to afford either.

I often record video and either a mic or board feed and mix them.  I don't ever stretch the video track when I do that.  I match the new audio to the original and if I have more than one new audio track (i.e. matrix) I match each new track to the one above it and mix to taste.

That wasn't directed at you, it was directed at the person who quoted it in this thread in this context. I should have left the entire quoted section intact to make that clear. I modified it as such now.
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