Echo in return when monitoring sound being recorded on the camera.

S

SJane

New member
Sometimes I find that when I monitor the audio being recorded on a camera (I've worked with many different cameras; I use a FP33 mixer--yeah, perhaps old school, but it's been a good work horse through the years : ), it sounds echo-y.

Does anyone have an explanation for why this is?

Thanks for your input,

SJane
 
Any chance you could describe exactly how you have things hooked-up? (i.e. what is the audio signal chain from microphone to mixer to camera; to your headphones?) What settings are you using on the Shure mixer, and what/where are you monitoring from (mixer or camera)? Could you describe "echo-y" with a little more detail?

GJ
 
Sjane,

You didn't mention what camera you are using, but some of the older generation Panasonic cams had a hitch in the gittyup in the headphone circuit. This drove a lot of folks really crazy when monitoring since it seemed out of sync and created a echo. It was not an issue for recording as the issue was in built into the headphone circuit. No longer an issue on the newer cams.

Grant
 
If its hooked up to some camera's it may be that you are listening to the return after all the record electronics or on tape based cameras from a playback confidence head, as it takes longer for the signal to go through all of this you will get a delay and it will sound echoey!

Int old days when we used nagra tape recorders on location you always listened to the playback head so you always heard the world out of sync but at least had the confidence that you could hear any problems with tape drop out etc.

My own cameras have two monitor outputs available, the headphone socket which is pretty much real time and some RCA phono's which are delayed to match the SDI and video outputs.
 
That actually would have been my first guess (it sounded like some kind of record/repro head issue, depending on the definition of "echo-y"), but SJane's description of the gear didn't seem to indicate that. Gary and Grant's comments make perfect sense in that context though.

So, bottom line, if it's not affecting synch on playback, and you can learn to live with it...

GJ
 
I have experienced simple delay in the headphone output when monitoring live recording. This is a result of the digital processing. Careful observation may reveal that the video in the viewfinder is also delayed (although this is not nearly as easy to perceive). This has nothing to do with the FP33, that was tossed in as a red herring.

The bottom line is that is an artifact or side-effect of the method of recording and does NOT affect the audio/video sync of the recording. Certainly, it is annoying, but I would rather have an "E-to-E" confidence output from the camcorder than simply an amplified version of what is coming in to the camera.

"E-to-E" is a term from back in the analog days which describes the output from the recorder after it has gone through all the record electronics, encoding, modulating, etc., and then back through the demodulating, decoding, etc. electronics. The purpose is to give a complete end-to-end sample to show that the entire path is operating correctly. To be sure, there is even a processing delay through old analog equipment, but was is so small it wasn't worth worrying about. Modern users don't appreciate the amount of raw computing that is going on even in an ultra-cheap digital camcorder. Encoding, and especially compression takes time.

Over in another forum discussing the Blackmagic Design ATEM video switchers, there is much discussion about how to deal with the video processing delay. The only solution is to delay the audio by a corresponding amount to restore a/v sync.
 
I concur with Richard, the FP33 has nothing to do with it, some cameras just inherently have 'slower' processing no matter what output you use for a return, it usually doesn't affect final picture/sound sync though.
And yes, some 'old' analog (Betacam SP) decks had a 'confidence' monitoring mode. Akin to monitoring off the PB head on a reel-to-reel tape machine.
 
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