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Old January 14th, 2010, 06:02 AM   #1
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Metal sound with Nanoflash?

Hi,

very odd behaviour with my Nanoflash..
some of the recorded Material has some strange metal echo in Audio, other material is ok..
Tape Footage is always ok..

recorded with 50mbit HD ... Xl-H1.. old one.. sound output camera over rca.. input in Nanoflash over 3,5mm socket... Audio Source is sometimes Microfone and sometimes Mixer..

thank you...
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Old January 14th, 2010, 08:53 AM   #2
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Hi Philipp-
Does the audio from the headphone jack sound OK? Just trying to determine if the audio problem is caused by analog or digital processing.

Thanks-
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Old January 14th, 2010, 12:56 PM   #3
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Hi Mike.. Thanks for the quick help..

I have to find out.. The last few clips were alright.. I keep you updated..

cheers..
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Old January 18th, 2010, 04:04 AM   #4
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Hi..

Here is an example of what happens..

YouTube - VW Loeffelmann 5008.m4v

Between the 2 Closeups there is a significant difference in sound...
Its like the Sound of the Film Robocop 1 ;)

I would say about 10 percent of the clip have this metal noise..

In my opinion the sound over the Headphones is always ok.. but i had crappy Headphones.. just little ones and lots of noise around me.. but today i will to a test in a quiet room..
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Old January 18th, 2010, 07:45 AM   #5
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It sounds to me like there is a difference in the ambient noise due to change of mic location and ambient sound time change (recorded later, second take, not continuous recording).

There also sounds like there may be more than 1 mic, and that can lead to a "plate" or tunnel sound, a fast single echo.

This is just listening to my MBP. But it sounds like the mic placement was bad.

A shot like that should probably have been done with a shotgun mic on a boom just above talent aiming away from ambient noise, I often have a sound absorbing panel just out of the shot that the mic is aiming at, and more panels to block ambient sound.

Good audio is an art.
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Old January 18th, 2010, 09:37 AM   #6
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Sound Shifts

Hi Philipp:
It sounds to me like the digital audio sampling rate is shifting back and fourth. (??) I don't think the differences in microphone placement should make that much of a difference. However, good audio *is* an art. and depending on the characteristics of the mic being used there (looks like it could already be a shotgun in the zeppelin, but who knows ?) you could get a shift in audio quality. Although, I'm hearing a great deal of background noise in the wide angle shots, which could possibly indicate an omni-directional mic use. (???) An omni mic will give you horrible sound shifts if you change from close proximity to a few feet back as well. This example of your audio shift is inconclusive Philipp.
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Old January 18th, 2010, 11:31 AM   #7
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Thanks for the help..

I must also agree.. Good Audio is art.. And doesnt always get the recognition it should.. Sadly... Luckiliy in this case it wasnt necessary to have good Audio.. Its just me who wants to know whats wrong with the Audio.. For Future Projects.. It is definitly not the Mic.. Because the Footage recorded on Tape is ok.. Its just the clips on the Nanoflash, which have this metal sound to it.. just a few. not all of them.

I was wondering if anybody else had this problem ?
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Old January 18th, 2010, 07:12 PM   #8
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Different on Tape

Hi Philipp:
Could you put up the footage from tape for a direct comparison ? If you're claiming the audio is different on tape, then I'm really curious to listen to the tape footage.
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Old January 19th, 2010, 05:01 AM   #9
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Hi there..

I exported directly from the Timeline.. One is HDV Codec... The other Nanoflash 50mbit..
Just to make sure there is no further compression on it..

MyDrive - Ihr kostenloser Online-Speicher
usr: Nanoflash@tet20
psw: nanoflash

(case sensitive)

This strange sound is not very often.. I would say.. Every 10th clip or so..

I did actually write about this to the Convergent Design Support a few months ago.. And i got an answer immediately.. very good support.. but Tommy Shell couldnt help me.. I did a lot of editing in the last few months and not much camera and this Sound Error didnt occur again.. I thought the update took care about this so i didnt investigate further..
but it didnt.. I am just posting this to find out if anybody else has this problem.. Its maybe just a human error I am making..

I am recording unbalanced Stereo...
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Old January 19th, 2010, 08:42 AM   #10
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Can't View Second Video

Hi Philipp:
Can you post that second video example to Youtube or Vimeo and direct link that ? This website wants to collect my info so they can sell it to someone else. I won't register or give them any of my data just to view a video.
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Old January 19th, 2010, 10:42 AM   #11
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registering shouldnt happen with mydrive..

anyway..here is the footage on vimeo...

tape

nanoflash

cheers..
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Old January 19th, 2010, 11:25 AM   #12
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You definitely have problem on the NanoFlash audio.

It is very obvious now, with the two clips.

What does CD have to say?

You may have a defective unit or there may be a problem with your SDI/HDMI out on your camera.

OOPS I see you are using the RCA audio out to Nano unbalanced in. Have you discussed this with CD?

Can you use audio over HDMI or SDI to test?
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Old January 19th, 2010, 11:58 AM   #13
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hi..

i will get my hands on an ex-3 tomorrow and will do some further testing..

Just tested..Audio over Headphones connected to Nanoflash is always ok..
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Old January 19th, 2010, 12:07 PM   #14
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I'm Hearing Audio Phase Cancellations on the Nano Footage !

Hi Philipp:
Yup. You most definitely have a problem with the audio in your Nano Flash unit. I can clearly hear audio channel Phase cancellations ! Uuuhhhh, that's not good my friend. :-( If the problem is intermittent, then this is an even more miserable situation, since if it was constant you could just send back your unit and get it fixed or replaced or whatever they will do for you at Convergent Technology. The fact that it is *intermittent malfunction* **could** indicate a microphone preamp issue or a mixer issue prior to the input on the nano Flash itself. I would return your unit to CD and ask them to check it and see if it meets spec. Also, please try more testing with a different microphone and cable or wireless setup, or do your audio through the camera and take it in embedded into the HD-SDI or HDMI signal. Sorry to learn of your problem. Very irritating for you I'm sure.
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Old January 19th, 2010, 12:51 PM   #15
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Assuming Mark is correct about the phase issue do you have the same source going to each channel or is it from two different mics? Try playing just one of the channels and see if it is correct. Phase errors can creep into the system from several sources. Can you playback the files from the Nano flash and mix them together into a mono signal to see if the problem originates from there or is it only when you get them into the edit system that you have the problem.
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