Echo/audio delay when monitoring live

veganway

Active member
Audio delay when monitoring live. I heard it clearly in progressive mode on both my DVX100AE and another DVX100. No delay in recorded footage. Also, I hear a slighter delay in interlaced mode. Some users give me right, others don't hear it in any mode, others just hear it in progressive mode, and among them some think it's normal for progressive, some others think it's strange....This is what I learnt from the various forums, so far....What about you? Please help me solve the mistery. Thanks.
 
Re: Echo/audio delay when monitoring live

at least in NTSC-land, there is an audio offset of about 1-2 frames upon playback that can be somewhat easily corrected in an NLE (Final Cut Pro 4.1 actually corrects it during capture now, i believe). it's yet another problem that Panasonic convieniently forgets to mention, but it hasn't been a huge issue for me (of course, i shoot mainly experimental work with no actors/dialogue/sync sound most of the time. if i was doing more narrative work, i'm sure it would irritate me more).

as for a delay when monitoring, the NTSC version is very slight and nearly imperceptible. the LCD display is always a bit stuttery and delayed in the progressive modes, and it actually allows for the audio to catch up with the video! i don't know if pannasonic designed it that way, but it works.

i just shot a two hour theater production a couple of weeks ago & i had no problems monitor the sound, and the sync between voices & lip movement seemed better when i monitored live than when i played back the tape.

sorry to say it, but this sounds like a PAL-only issue, or maybe just something defective with your individual camera. have you had an opportunity to test another PAL camera to see if the results are the same?

and when you say "delay", you are talking about a delay in sync, not an echoing like you hear if you use a microphone through a delay petal, right? if the latter is the case, i might have some suggestions.
 
Re: Echo/audio delay when monitoring live


Thanks Jay.

As I said in my previous post, I did try another camera. A DVX100, beside my 100A. Also, Panasonic technicians here tried other two 100, and told me yes....it's normal to have this delay...they say it's due to the audio being processed. Audio arrives analogically to the camera, becomes digital, and analogue again to get to the headphones/audio out (same on a tv connected with RCA, for instance)...Also, they said it's normal to hear the delay even more in progressive mode, because there's a matter of different speed....even if it actually isn't so...... ??? Anyways, I read on other forums people saying it's normal to have a delay in progressive mode, and some other who hear the slighter one in interlaced mode, too.

"and when you say "delay", you are talking about a delay in sync, not an echoing like you hear if you use a microphone through a delay petal, right? if the latter is the case, i might have some suggestions."

I don't see any sync problem...I mean, let's forget about the LCD for a moment. Let's say: I just turn on the camera, put my headphones on, I close my eyes and make some people speak. I'm in standby mode, I'm not even recording. What I hear is that audio in my headphones comes after live voice....Anybody can hear the issue in progressive mode....But also in interlaced mode, even if it's much slighter, I got people telling me: gee, you're right....
Two sound engeneers I know immediately heard it....

If you read some of the last messages in my thread "DVX100 flaws...." you'll see there's an American guy who advices me to use extreme isolation headphones..... :'(

Cris
 
Re: Echo/audio delay when monitoring live

Veganway (or others),

I'm curious as to the significance to this monitor delay issue. If there is no apparent connection between this and known lip-sync issues during recording, is this somehow a problem/defect in your view.

Just curious.

-Rodger
 
Re: Echo/audio delay when monitoring live

Shot many things live in progressive mode. Concerts, Weddings, etc. Never had a problem ever. Don't see where you care coming from. Hope you get it resolved.
 
Re: Echo/audio delay when monitoring live

Rodger:

"I'm curious as to the significance to this monitor delay issue.  If there is no apparent connection between this and known lip-sync issues during recording, is this somehow a problem/defect in your view."

Sorry, what do you mean?  ??? As I said, several engeneers and technicians heard the delay...! I'm sorry I can't explain the issue better....  :-X

I'll quote Ullanta:

"Hard to say without knowing what's really going on inside... but the report here on DVXUser posted a while back showed, on the DVX100P, audio lag (to differing degrees) for all modes.  You can definitely hear a delay of a single frame, though I'd call it more "fuzz" than echo.

Delays notwithstanding, you get interference between live and headphone sound that often makes headphone monitoring unproductive and/or unpleasant.  So, for live recording of fairly loud performances, isolate! And be happy if you're lucky enough to have an "A" that where it matters - on the recorded signal - you're in sync"

Cris
 
Re: Echo/audio delay when monitoring live

i've got a DVX100e and the sync between headphones and monitored audio is very good (and i'm using a 3€ headphones without any isolation).
Vegan, how long is your delay?
 
Re: Echo/audio delay when monitoring live

Mauro:

It would be a curious thing if you phoned Panasonic Italy to tell them: "hey, I got a DVX100 and I hear a delay between headphones/audio output and live audio." and they would answer: "yes, that's normal...it's because the audio is processed...bla bla bla..." just as they told me....

So, where's the truth? I tried two different cameras, DVX100a, DVX100, heard the same issue. Other people where there with me when I first tried the DVX100, and they all heard it, even three of them that were no technicians....Then I ask Panasonic, and they tell me it's "normal". "Audio processed" in 50i, and "different speed" in 25p. Moreover, they even say they've tried other two cameras....another DVX100 and another A, and heard the same issue.
Result: 2 DVX100 and 2 DVX100A gave the same results, that are even normal to Panasonic Italy.

I don't want to be put in a mental hospital!!!!!  ???  >:(

"Vegan, how long is your delay?"

Hard to tell...I'd say 1 frame in interlace mode and...maybe 3 or 4 in progressive?...  :-X

Cris
 
Re: Echo/audio delay when monitoring live

I think Panasonic have some special 'quality control' for Italy ;)

Just joking :D
 
Re: Echo/audio delay when monitoring live

vegan do you listen a duplicated sound?
i'f i knock on a surface i feel just "knock" and not "knock knock". Maybe that i don't notice the 1/25 delay because it fuse with the original (that's the reason for what i'm not a DJ :P) but even if there was an 1/2" delay this could be "normal" because it's just a monitor for the sound level.
But i'm not listening the delay and there isn't difference in sound between 25 and interlaced.
 
Re: Echo/audio delay when monitoring live

Veganway,

What I mean is you are listening to processed audio as it would sound on the way to tape, or at least I suspect this is the case.  Whether or not you are actually recording would make no difference, only which mode settings you're using could -- At least in NTSC it would.

As this audio must be re-timed and locked to match the pulldown you are using, there will be some differences in live audio and monitor (re-timed audio) which should be noticeable.  And in the NTSC model between 24PA and the other modes, this should be more exaggerated as there is also the stagger frame (dropped in post) to contend with.

This, I believe would have to be the nature of locked audio in the DVX.  Since the PAL version is using a different cadence, delay timing will be different then the NTSC model, but sill there because of locked audio.

If the DVX was not using locked audio, you would most likely not hear any delay between monitor and live, but would run the risk of audio drift and a whole slew of other correctable and non-correctable audio problems.

-Rodger
 
Re: Echo/audio delay when monitoring live

veganway--guess i'm kind of confused here. you said you're not hearing a synch issue, but you're not hearing an echo either?

just a few things that may help:

1) are you monitoring with open ear or closed ear headphones? closed will get rid of any echoing or "double sound" if you are getting any.

2) how were you monitoring, through the LCD or through the viewfinder? is there any difference is the delay between the two?

if it's a really serious delay that's affecting your ability to shoot a scene, i would insist to panasonic that they do something about it.
 
Re: Echo/audio delay when monitoring live

Aejaz...I think you're kinds dramatically right.... :'( But then again, I won't totally blame Panasonic Italian technicians this time, as I heard the issue myself on two cameras.... :-X

Mauro:

"vegan do you listen a duplicated sound?"

No....It's hard to describe, but I can tell you both sound engeneers described the issue as a "delay". :-/

"But i'm not listening the delay and there isn't difference in sound between 25 and interlaced."

Odd... :o

marjamar:

"What I mean is you are listening to processed audio as it would sound on the way to tape, or at least I suspect this is the case. Whether or not you are actually recording would make no difference, only which mode settings you're using could -- At least in NTSC it would."

Yes, this is what I think technicians here meant.

So you think it maybe normal to have this slight delay when monitoring, right? What do you think about the fact the delay is more noticeable in progressive? Thanks

Jay:

"veganway--guess i'm kind of confused here. you said you're not hearing a synch issue, but you're not hearing an echo either?"

Sorry, maybe I just explained in a bad way...What I'm hearing is a sort of delay/echo, yes...but it's hard to tell if the video in the LCD/viewfinder is out of synch or not...live audio is confusing....I should try to go in another room using long cables to be far from the person talking to the microphone...

"are you monitoring with open ear or closed ear headphones? closed will get rid of any echoing or "double sound" if you are getting any."

I'm using Sennheiser Master HD 200 closed headphones, but they're not completely isolating like some drummers models, so I still hear live sound...

"how were you monitoring, through the LCD or through the viewfinder? is there any difference is the delay between the two?"

See above...I can even close my eyes...and just concentrate on sound....I hear this strange delay/echo....Live audio is distracting, so I really can't tell if live video in the LCD or viewfinder is out of synch... :-/

"if it's a really serious delay that's affecting your ability to shoot a scene, i would insist to panasonic that they do something about it."

In progressive mode I think this is definitely serious. And already annoying in interlaced mode... :(

Cris
 
Re: Echo/audio delay when monitoring live

Don't do PAL, and don't even re-read PAL specs often enough to say more I already have about differences in delay between 25P and 50I.

24PA (full progressive) would have to have a different delay then the other NTSC modes as there is in actuality only 8 full frames in the 10 frame cadence. 2 of these 10 frames are stagger (split) frames and are disposed of in post. Since this is always the case for 24PA (suppose to be anyway), it only makes since that audio will be re-time and locked to the 8 full frames and not to the 2 stagger frames. How Panasonic engineers have chosen to do this I don't know, but it seems pretty obvious to me this is the case.

Unless you have to take part in the ongoing dialog during shooting, I don't quite see the problem. Maybe don't listen so hard?... I don't really have any answers here that could make you feel any better about your DVX. Hope you find some.

-Rodger
 
Re: Echo/audio delay when monitoring live

"I can even close my eyes...and just concentrate on sound....I hear this strange delay/echo"

ok, now we're getting somewhere....

i was thinking this had more to do with the sync issues that all DV cameras, but ESPECIALLY 24p cameras, have. most miniDV cameras have a one to two field (1/2 to 1 frame) off-sync from the video, which is barely noticeable. 24P cameras have a three to four field (1.5 to 2 frame) off-sync, which is subtle, but definitely noticeable.

this gives the feeling of watching a foreign film that's been badly dubbed (think old Godzilla movies), so that a person's lips are moving slightly before you hear their words.

however, your problem is completely different--it's a purely auditory delay. the most obvious cause of this would be a combination of progressive video's sync difference combined with open ear headphones in a loud setting. For example, you would definitely be hearing a noticeable echo if you were wearing open ear headphones while you were recording a music concert.

however, if you're wearing closed-ear, it's a different story. you shouldn't be hearing a noticeable echo because the headphones should be blocking out most of the external noise.

BUT--the DVX has a VERY LOW HEADPHONE AUDIO OUTPUT! This would certainly contribute to an echo effect if the sound in the room around you is louder than what is coming through the headphones. I bought a Boostaroo headphone amplifier for $20, and it helped a great deal.

Here's your test--

1) Have a friend sit in a room. Set up the DVX to record his face & lips moving & close the door.

2) Get a headphones extention cable, and run your headphones & a monitor into another room. Close that door if possible & make sure that you can't hear your friend in the other room with your "naked ears".

3) Have your friend read something. Listen with the headphones, no video. See if you hear the echo. Then watch the monitor while listening to the headphones--see if you notice it, or any synch issues.

If the answer is "no" to both of these questions, then it's just the peripheral ambient noises during the live recording that are giving you these problems. get some better closed ear headphones & a Boostaroo. If the answer is "yes", there is definitely something wrong with the camera.
 
Re: Echo/audio delay when monitoring live

i did a web search & your headphones seem more than appropriate for that kind of shoot. have you tested other headphones however? there's always the possibility your headphones are messed up.

just playing the devil's advocate here....
 
Re: Echo/audio delay when monitoring live


Jay, I'll surely do that test as soon as I get some long cables. I already wanted to try something like that. :)

"i did a web search & your headphones seem more than appropriate for that kind of shoot. have you tested other headphones however? there's always the possibility your headphones are messed up."

Yes, I tried other phones. From cheap walkman auriculars to studio headphones from my friend sound engeneer...Same issue. Also, I tried to directly hear the audio through a tv monitor. I could just hear the live audio plus "more volume" with my old Digital8 camera, for instance, if I connected it to a tv while recording someone speaking in the room.
But with the DVX100 it's something different....you can immediately hear there's something strange... :'(

Moreover, as I said Panasonic technicians here tried other cameras and heard the same issue...they surely used different headphones and TVs than mines....And they keep on saying it's *normal*....I won't get tired repeating this... :-/

Of course this problem can be solved someway...by getting Direct Sound extreme isolation headphones as Ullanta suggested, and/or buying a Boostaroo...maybe...But.....why do some people hear the delay and others just don't? And if the issue is really there at least on some cameras, why do I have to buy some other accessories to solve a Panasonic's problem? Same discussion we where having about progressive, you know. :-/

Cris
 
Re: Echo/audio delay when monitoring live

I hear the delay! I hear the delay! did I just say that twice.
I think some people don't hear the delay because the don't realize it. I didn't notice the echo until I was pointing my camera at something, while wearing closed headphones, and I started talking. It was a really wierd experience. Since I couldn't hear my actual voice I could only hear what the dvx picked up, my voice was just a split second behind normal. I started speaking and suddenly I felt like my toung was really heavy. I must have sounded like a moron because it was like I was talking and waiting to hear what I just said at the same time. Try it, it's pretty cool. I solved the talking problem however. I took one earphone off my head while I speak, it's much easier that way. everyone should try it at leas once. Oh, and by the way, I was not recording, I was in 24pn. I changed the dial to 30p while talking and the echo was much less. I then turned it to 60i and it all but dissapeard. I don't think it's a flaw, just a fact of life for 24p ;)
 
Re: Echo/audio delay when monitoring live


Thanks so much Scharky. :D

Of course you can immediately hear the weird issue when it's you speaking, wearing the headphones. But then again the issue is noticeable even when other people are talking to the camera...this makes it very annoying not to say hard to work in progressive mode (flickering lines apart... :-X :P )...
But I can tell you (or maybe it's just on PAL models?) the delay is there in interlaced mode, too. If you switch from progressive to interlaced, you'll say: hey, no delay now!!! But if instead you take another camera, like for instance the Canon XL1 and listen to audio live, then try the DVX in interlaced mode, you'll soon hear the difference....and you'll notice that weird delay/echo is always present, even if in 60i/50i it's much slighter...Believe me....You could run a test with any other camera...even cheaper ones, and you'll notice it as much as you've noticed it now for the first time in progressive. ;)

So, anyways, why do you think this could be a fact of life for progressive, while other people say it's impossible...there has to be no delay...? ???

Cris
 
Re: Echo/audio delay when monitoring live

Hi Cris I've tried again and with more attention. With a cheap and open headphones, just with one ear... listening music or voices...:
there i'snt delay and there isn't difference switching between progressive and interlaced.
:-/
 
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