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Old January 19th, 2010, 01:24 PM   #16
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Pesky Intermittent Phase Errors

Hi Philipp & Daniel:
Correct. Phase cancellations can be introduced at each stage within the chain from microphone, preamp, mixer, recorder, and post production NLE. If the artifact was constant, then it could be quickly identified. Since this tinny sound isn't, then you will have to conduct tests along each stage of the system. Your Nano *may not* be the problem at all, but I've been sitting back here in my chair watching your 2 clips over and over again trying to reason through your chain, and I'm wondering something, but I'm not sure yet. (??)

Philipp could you give us what mic, how it was linked to the recorder, and could you specify if an audio mixer or preamps were being used in the chain *before* the Nano, please ??
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Old January 19th, 2010, 01:47 PM   #17
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hi there.. thank you for taking the time..

Two Setups were used
First one:
Sennheiser ME-66 connected directly to Channel 1 on my XL-H1.. And Recorded to Channel 1 and 2..
So its one Mono Source recorded on both Channels..

Second one:
Wireless Sennheiser EW-100..going to a mixer.. I am not sure which one.. I have to ask.. and then into the camera.. but again only into channel 1.. and again one Mono Source recorded on both channels..

in both cases i had this problem..

Of course your right.. it doesnt mean at all that the error lies with the Nanoflash..Maybe my RCA-Out has something.. Its is not the most reliable or professional way to aquire Audio...

I will find out the type of Mixer tomorrow..
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Old January 19th, 2010, 09:04 PM   #18
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Hi Philip-
Quick question: how are the audio level meters on the nanoFlash during a record? Are the levels, as reported by the nanoFlash, correct, or do they hit the rail?

There could be an issue with our digital audio processing in the nanoFlash or a problem with the audio A/D converter or something alltogether different.

Any additonal info would help us diagnose the problem. We have a Canon XL-H1 in the lab, so we can set up a system and try to replicate tomorrow.

Best-
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Old January 19th, 2010, 10:34 PM   #19
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Hi Philip - I've seen this same phasing issue on HD-SDI audio - so maybe you can rule out your external cabling? (if wired incorrectly with ground switched your two mono channels will be 180 deg out of phase). I think the fault definitely lies within the Nano.

I've listened to my original audio off SD cards from The JVC HM700 and it was fine. The Nano was two frames late and phasing whenever fed dual mono.

I'm hoping the 1.1.154 firmware update which I've just installed will eliminate this. In the meantime if the problem is phasing you should be able to lose it by playing one mono channel only, centered out of your NLE or exporting that way to QT.
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Old January 19th, 2010, 10:57 PM   #20
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Quote:
Originally Posted by John Mitchell View Post
I've listened to my original audio off SD cards from The JVC HM700 and it was fine. The Nano was two frames late and phasing whenever fed dual mono.
Hi John-
So it appears that we may have an time offest between audio channels 1 and 2 as well as time offest with respect to the video. If audio channels 1 and 2 slipped out of sync with respect to each other, than this would cause the phase offset you described.

We should be able to track down this problem quickly (assuming it has not already been fixed). I'll test tomorrow and report back.

Best-
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Old January 20th, 2010, 12:22 AM   #21
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So it appears that we may have an time offest between audio channels 1 and 2 as well as time offest with respect to the video. If audio channels 1 and 2 slipped out of sync with respect to each other, than this would cause the phase offset you described.

We should be able to track down this problem quickly (assuming it has not already been fixed). I'll test tomorrow and report back.

--------------------Mike Schell


Remember I was on the original firmware delivered with the unit. Sometimes a picture is worth a thousand words - the original audio on 3 and 4 and the Nano audio on 1 and 2 - you can see the Nano tacks are out of phase on the waveform whereas the SD card tracks are in phase.
Attached Thumbnails
Metal sound with Nanoflash?-phase-error.jpg  
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Old January 20th, 2010, 05:13 AM   #22
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First..

Thanks everybody for the Help.. and also CD for the support over E-Mail and here in the Forum.

I found the solution to my problem.. Now.. Its probably not going to let me look good.. because its an ovious solution.. I was trying to find the Error in the Hardware..
but some of you suggested to listen to the Monotrack in the Editing Suite, which i didnt so far.. And Mono it sounds alright.. Then I linked the 2 Mono Tracks in Final cut to a Stereotrack with ALT-L.. And its fixed.. The Metal Echo is gone..

but what i cant figure out.. About 90 Percent of the clips sound alright, even when the 2 Monotracks are not linked together!! And its just those 10 Percent which have to be fixed inside the editing suite.. But its good to know a Workaround to my problem..
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Old January 20th, 2010, 08:17 AM   #23
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FCP & Mono Sound

HI Philipp:
What version of fcp are you using ?

Last edited by Mark Job; January 20th, 2010 at 09:37 AM. Reason: For purposes of clarity
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Old January 20th, 2010, 08:39 AM   #24
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7.0.1 German Version
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Old January 20th, 2010, 10:08 AM   #25
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Are we sure that the 2 separate mics are causing phase problems?

Sometimes recording a shotgun on a boom and a wireless mic on talent can result in phase problems.
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Old January 20th, 2010, 12:32 PM   #26
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Quote:
Originally Posted by John Mitchell View Post
[I]
Remember I was on the original firmware delivered with the unit. Sometimes a picture is worth a thousand words - the original audio on 3 and 4 and the Nano audio on 1 and 2 - you can see the Nano tacks are out of phase on the waveform whereas the SD card tracks are in phase.
Hi John-
This is extremely useful! I think the problem is fixed in our new beta code. We are testing today to confirm. We will look at the audio tracks out of the NLE as well as the audio as played out of the nanoFlash (monitoring on our scope).

I'll report back shortly.

Best-
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Old January 20th, 2010, 05:37 PM   #27
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Quote:
Originally Posted by Philipp Steiner View Post
First..

Thanks everybody for the Help.. and also CD for the support over E-Mail and here in the Forum.

I found the solution to my problem.. Now.. Its probably not going to let me look good.. because its an ovious solution.. I was trying to find the Error in the Hardware..
but some of you suggested to listen to the Monotrack in the Editing Suite, which i didnt so far.. And Mono it sounds alright.. Then I linked the 2 Mono Tracks in Final cut to a Stereotrack with ALT-L.. And its fixed.. The Metal Echo is gone..

but what i cant figure out.. About 90 Percent of the clips sound alright, even when the 2 Monotracks are not linked together!! And its just those 10 Percent which have to be fixed inside the editing suite.. But its good to know a Workaround to my problem..
Philipp, the thing about mono audio is that it is, well, mono. You only need 1 track centered to give you sound out of both speakers (assuming both mono tracks are identical and reading your original post they are). You can trash your second mono track altogether. This will ensure no phasing. Perhaps that is what you are doing in FCP - but your solution sounded strange to me? In most audio applications and NLEs you have a pan control that pans your audio left to right. Use this control to centre the mono track and delete the other alotgether. Do this for everything as the fault could just be less pronounced on some of those clips.

If I read what you did correctly (and I don't use FCP regularly) the problem with what you've done is your audio is still out of phase and when combined back to mono on playback it will start to phase again.

cheers John
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Old January 20th, 2010, 07:41 PM   #28
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Quote:
Originally Posted by Mike Schell View Post
Hi John-
This is extremely useful! I think the problem is fixed in our new beta code. We are testing today to confirm. We will look at the audio tracks out of the NLE as well as the audio as played out of the nanoFlash (monitoring on our scope).

I'll report back shortly.

Best-
Mike if you remember my original post in another thread the problem is more than that. I will do a test with the latest firmware to confirm that it is solved but at least with the JVC 700 video was 3 frames early which resulted in audio being two frames late. If you match video streams on timecode (rather than vision) the audio actually appears to be a frame early. (ie 2-3 = -1) This is not the case. In reality the audio is all two frames late.

So for example on matching video with identical frames
SD card stream : timecode 00:17
CD card stream : timecode 00:14

Audio 2 frames late from Nano compared to SD card. I pointed out in my original post that I couldn't be sure that this was a Nano fault or whether the JVC had a timecode differential between the SDI port and SD cards (does seem unlikely).

I checked the audio in Adobe Soundbooth and the right channel is 6/1000 sec earlier (or 3/500 if you want to simplify). A frame in PAL land is 40/1000 so it is 15% of a single frame.

That's as accurate as I can get with my equipment.

best John
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Old January 24th, 2010, 01:23 PM   #29
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Experiencing the same sound issue

Hi

This is my firts post here. I have this "bucket" sound on my recordings also.
I use an EX1 and the NanoFlash. Linked together with a sdi cable. No mixer or external mic. I dont use external mic because i record mostly noise from machines.
I have a clip on YouTube where this error? can be heard clearly.
YouTube - MiniFlex FeedLine press tending performing assembly with Fanuc robots
One clip starts at 0.47 and second clip at 3.46.
I have the latest firmware 1.1.154 and the serial number on the unit is 080930209
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