headphone trouble - unwanted echoing effect

B

birnbaum

Member
hi there, am very glad to find this forum. had my first experience with a dvx100a and found a problem with sound monitoring:

when using external mics, no matter which mics i tested, but not when using the inbuilt mic, i had an echoing effect in the headphones (i also tested with different headphones) that made it impossible to monitor sound. but the echo is not on the recordings, when putting the tape into another camera and checking, the recordings sound ok, a bit low though, as i could not monitor them.

as to settings, i had the external mic in ch1 and the settings were: no phantom power / mic in / ch1 external / ch2 external (to keep the inbuilt stereo mic from recording)

any idea what went wrong here or if it might be a technical or hardware problem?

i am not an expert, rather just stepping from amateur to a bit more professional and would very much appreciate good advice. hope to not have to send the new camera in for repair so soon!

marion
 
Re: headphone trouble - unwanted echoing effect

nothing wrong , there is a dellay during audio work flow , you hear the sound after it was converted fom analog to digital and versa (you dont heare pb -confidence monitoring ),
the echo is the mix between the real sound which penitrating your headphones and the headphones one .
just buy better isolation headphones , nothing you can do , live with it:-)
 
Re: headphone trouble - unwanted echoing effect

Right -- the echo is a byproduct of recording the audio in 24P mode on a DVX100A. The audio is delayed 2 frames before being written to tape, because the video is buffered before being written to tape (to add the pulldown sequence, etc).

So the net effect is, you hear the audio in the headphones after a 2-frame delay. If your headphones don't adequately isolate you from the "live" audio, you'll hear echo.

The only thing you can do is try to get some completely-isolating headphones, so you won't hear the "live" audio, just the headphone audio.

This issue doesn't occur in 60i mode.
 
Re: headphone trouble - unwanted echoing effect

Barry, I'm living in PAL country and when shooting 25p there is also this echo, although no pulldown etc. is added. Is it possible that, as Oleg mentioned, the camera takes just some time to AD/DA-convert ?
 
Re: headphone trouble - unwanted echoing effect

thats right , the 25 is no different , little bit less dellay
 
Re: headphone trouble - unwanted echoing effect

That's correct. In the NTSC model there was like a 2-frame delay in 24P mode, a 1-frame delay in 30P, and no delay in 60i.

The PAL model's 25P is done the same way as the NTSC model's 30P. So I would expect there to be a small 1-frame delay on 25P footage.
 
Re: headphone trouble - unwanted echoing effect

I think you're hearing the delay in the A/D converter. Happens on anything that records digitally.

-Dave
 
Re: headphone trouble - unwanted echoing effect

hey and thanx all for your helpful comments!

have tried again with a bomb proove headphone and could monitor the sound ok this time, so it seems to have been as simple as you said. thanx!

marion
 
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