Audio Dropout Near End of Tape at DVinfo.net

Ron Anderson · August 13th, 2008, 10:54 AM

I shot a wedding/reception this past weekend with my VX-2100 and when I captured the video with Vegas 8 I noticed audio dropout near the ends of both tapes. On both Sony DVC Mini DV tapes around the 55 min mark there was noticable audio dropout. Absolutely no problems with the previous 55 min, just that last 5. Is this a tape issue? Do you folks record all the way to the end of the tape or do you switch it out before? Thanks.

Ron

Don Bloom · August 13th, 2008, 02:35 PM

While I don't use Sony tapes in my 150 or 170 or before in my dsr250 or my JVC5000, BUT I RARELY go all the way to the end of the tape (just an old habit) and I black 2 or 3 seconds on the front end. Just another old habit, to get off the leader.
However, I would kind of doubt it's a tape thing only because you still had 5 minutes left on the tape. I would take another fresh tape FF it about 6 minutes left and then start recording to the end. See what happens. You can always rewind to that mark, black it and use it again for B roll or something. It would be surprising if it's a tape issue but then whadda I know? ;-)

Don

Bob Hart · August 13th, 2008, 10:40 PM

Ron.

If your camera has about 150 hours in runtime and load cycles, it might be a good time to have a service done on it while the technicians still have the smarts on the camera type.

The PD--- family has a slightly more robust tape transport than the later Z1 but things still go off with time. In my case the backtension on the tape was off and this was leading to occasional dropouts which went away after I took it in for a clean and alignment when it got dusted at an outdoors music gig.

From the point of view of the tape cassette itself, when the outroll spool gets small in diameter and the inroll spool gets wide, this is the condition which provokes any potential fault in the transport towards the end of the tape. The resistance of the outroll friction is at its highest leverage over the draw of the tape through the transport and likewise for the recovery of the tape over the power of the inroll spool direct drive motor.

The inroll is unlikely to be the cause of your problem unless the tape is building and creasing in the path from the capstan to the inroll spool. Faults from this problem are usually more dramatic, damaging and likely to set off a shutdown and error report by the camera

I suspect you have had the odd bad capture now and again recently when you have been doing a lot of shuttling back and forth.

Sometimes a tape develops a crush ridge through a few layers close to the centre hub on the outroll spool which will not conform to the drum as it passes over and will introduce dropouts. The build quality of modern MiniDV cassettes is such that this should be a rare occurrance and bad backtension on the camera's tape transport is the more likely culprit.

Ron Anderson · August 14th, 2008, 06:00 PM

Thanks both of you for the valuable info. It looks like a service is required. I hope I can get this done in Hawaii. I really don't want to have to mail it somewhere. Thanks again.

Ron

Jim Andrada · August 17th, 2008, 08:49 PM

We call the tendency of the tape to pick up ripples etc near the reel "imprinting". There's always a very slight discontinuity between the reel and where the tape starts to wrap and it can create a very small bump that can telegraph through several layers of tape that are wound closest to the reel. As more tape is wound over it, the tension at the center of the reel increases more than you might think and several tape wraps can get a very slight permanent bump. In general it's best to avoid recording within a few wraps of either end of the tape.

Having said that, I doubt the effect would be apparent 5 minutes away from either end of the tape. 30 seconds or so wouldn't surprise me, but 5 minutes seems a bit much.

August 13th, 2008, 10:54 AM	#1
Ron Anderson Regular Crew Join Date: Aug 2006 Location: Waipahu, Hawaii Posts: 45	Audio Dropout Near End of Tape I shot a wedding/reception this past weekend with my VX-2100 and when I captured the video with Vegas 8 I noticed audio dropout near the ends of both tapes. On both Sony DVC Mini DV tapes around the 55 min mark there was noticable audio dropout. Absolutely no problems with the previous 55 min, just that last 5. Is this a tape issue? Do you folks record all the way to the end of the tape or do you switch it out before? Thanks. Ron

August 13th, 2008, 10:40 PM	#3
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Ron. If your camera has about 150 hours in runtime and load cycles, it might be a good time to have a service done on it while the technicians still have the smarts on the camera type. The PD--- family has a slightly more robust tape transport than the later Z1 but things still go off with time. In my case the backtension on the tape was off and this was leading to occasional dropouts which went away after I took it in for a clean and alignment when it got dusted at an outdoors music gig. From the point of view of the tape cassette itself, when the outroll spool gets small in diameter and the inroll spool gets wide, this is the condition which provokes any potential fault in the transport towards the end of the tape. The resistance of the outroll friction is at its highest leverage over the draw of the tape through the transport and likewise for the recovery of the tape over the power of the inroll spool direct drive motor. The inroll is unlikely to be the cause of your problem unless the tape is building and creasing in the path from the capstan to the inroll spool. Faults from this problem are usually more dramatic, damaging and likely to set off a shutdown and error report by the camera I suspect you have had the odd bad capture now and again recently when you have been doing a lot of shuttling back and forth. Sometimes a tape develops a crush ridge through a few layers close to the centre hub on the outroll spool which will not conform to the drum as it passes over and will introduce dropouts. The build quality of modern MiniDV cassettes is such that this should be a rare occurrance and bad backtension on the camera's tape transport is the more likely culprit. Last edited by Bob Hart; August 13th, 2008 at 10:52 PM. Reason: error

August 13th, 2008, 02:35 PM	#2
Don Bloom Inner Circle Join Date: Jan 2003 Location: Chicago, IL Posts: 6,609	While I don't use Sony tapes in my 150 or 170 or before in my dsr250 or my JVC5000, BUT I RARELY go all the way to the end of the tape (just an old habit) and I black 2 or 3 seconds on the front end. Just another old habit, to get off the leader. However, I would kind of doubt it's a tape thing only because you still had 5 minutes left on the tape. I would take another fresh tape FF it about 6 minutes left and then start recording to the end. See what happens. You can always rewind to that mark, black it and use it again for B roll or something. It would be surprising if it's a tape issue but then whadda I know? ;-) Don

August 14th, 2008, 06:00 PM	#4
Ron Anderson Regular Crew Join Date: Aug 2006 Location: Waipahu, Hawaii Posts: 45	Thanks both of you for the valuable info. It looks like a service is required. I hope I can get this done in Hawaii. I really don't want to have to mail it somewhere. Thanks again. Ron

August 17th, 2008, 08:49 PM	#5
Jim Andrada Inner Circle Join Date: Feb 2007 Location: Tucson AZ Posts: 2,211	We call the tendency of the tape to pick up ripples etc near the reel "imprinting". There's always a very slight discontinuity between the reel and where the tape starts to wrap and it can create a very small bump that can telegraph through several layers of tape that are wound closest to the reel. As more tape is wound over it, the tension at the center of the reel increases more than you might think and several tape wraps can get a very slight permanent bump. In general it's best to avoid recording within a few wraps of either end of the tape. Having said that, I doubt the effect would be apparent 5 minutes away from either end of the tape. 30 seconds or so wouldn't surprise me, but 5 minutes seems a bit much.