View Full Version : Interference Occurs w/ Mic Input When SD Video Cable Plugged In
Chris Barcellos May 29th, 2009, 12:02 AM I ran into a problem while testing out a new Juiced Link CX231 today. Its not attributable to the Juiced Link. It appears that when you have the SD monitor cord attached to the camera, whether connected to a monitor or not, there is a rogue signal generated that cause a high pitched squeal. For those that are looking for a cheap way of generating tone, the squeal actually serves that purpose. I am wondering if Canon failed provide for shielding..
This is a real bug, because many of us depend on SD out.
Has anyone else had this happen ? Anybody with the HDMI cord ?
Chris Barcellos May 29th, 2009, 12:20 AM I was able to locate my HDMI mini cable, and tested with output from that, and it appears the issue is only with the SD output.... I will be sticking with HDMI from here on out, unless we go separate sound.
John Harvey May 29th, 2009, 01:10 AM I posted the same thing back in January,
http://www.dvinfo.net/conf/canon-eos-5d-mk-ii-hd/142395-sound-recording-issues.html
no one had confirmed it until now, so it's just not our individual cameras, but probably all of them.
So I had to go to the expense of an HDMI LCD, works fine now, I record dual sound anyway though. Camera sound is not that bad really, makes a great guide track.
Now if I could only figure how to sync sound closer than one frame!
jh
Jon Fairhurst May 29th, 2009, 01:22 AM Chris, when testing the iPod into the 5D (16 kHz @ -3dB, Shuffle volume set at roughly halfway), the noise floor was about -36dB. After applying a 16kHz cut, I get it down to about -45 dB. With 24dB of additional noise reduction (using Sound Forge 9), I get down to about -63dB, but the voice is warbly.
On the other hand, I was getting -74 dB noise floor out of the box with the MicroTrackII.
That said, nothing is calibrated just yet. I haven't optimized or matched gains, so it's apples and oranges at this point.
But still, the 5D still had some AGC, and I could hear rogue tones, even after the EQ. The NR noiseprint had a few spikes in it that I didn't like. I'm probably getting harmonics, aliasing and interference signals with the 16 kHz pilot tone.
Next week I should have time to fine tune things and make some more meaningful measurements.
Chris Barcellos May 29th, 2009, 10:02 AM I posted the same thing back in January,
http://www.dvinfo.net/conf/canon-eos-5d-mk-ii-hd/142395-sound-recording-issues.html
no one had confirmed it until now, so it's just not our individual cameras, but probably all of them.
So I had to go to the expense of an HDMI LCD, works fine now, I record dual sound anyway though. Camera sound is not that bad really, makes a great guide track.
Now if I could only figure how to sync sound closer than one frame!
jh
John:
Sorry I missed your post. It would have saved me some headache.
Jon:
I will try to get a bit more techincal in terms of readings on my tests. I hope my special addition Sound Studio will provide same calibrations as you are dealing with.
Chris Barcellos May 29th, 2009, 11:50 AM Chris, when testing the iPod into the 5D (16 kHz @ -3dB, Shuffle volume set at roughly halfway), the noise floor was about -36dB. After applying a 16kHz cut, I get it down to about -45 dB. With 24dB of additional noise reduction (using Sound Forge 9), I get down to about -63dB, but the voice is warbly.
On the other hand, I was getting -74 dB noise floor out of the box with the MicroTrackII.
That said, nothing is calibrated just yet. I haven't optimized or matched gains, so it's apples and oranges at this point.
But still, the 5D still had some AGC, and I could hear rogue tones, even after the EQ. The NR noiseprint had a few spikes in it that I didn't like. I'm probably getting harmonics, aliasing and interference signals with the 16 kHz pilot tone.
Next week I should have time to fine tune things and make some more meaningful measurements.
Again, not sure of your exact set up, but this is how I do it. I feed mic and player into the JuicedLink. I use an XLR to miniplug adapter for the player, and play out of the headphone jack (only output I have on the IRiver). On Front of JuicedLink, I pan right on one track, and left on the other, to eliminate signals being mixed. So I am settling for mono on the voice track, which is standard anyway. Depending on how hot your mic is, I would use medium setting on the gain for starters on the mic input (switch at rear) and I am leaving trim at 12 oclock position. On the mp3 player track, I haven't settled yet, but it will be set either at medium or low gain.
Jon Fairhurst May 29th, 2009, 12:21 PM Again, not sure of your exact set up, but this is how I do it. I feed mic and player into the JuicedLink. I use an XLR to miniplug adapter for the player, and play out of the headphone jack (only output I have on the IRiver). On Front of JuicedLink, I pan right on one track, and left on the other, to eliminate signals being mixed. So I am settling for mono on the voice track, which is standard anyway. Depending on how hot your mic is, I would use medium setting on the gain for starters on the mic input (switch at rear) and I am leaving trim at 12 oclock position. On the mp3 player track, I haven't settled yet, but it will be set either at medium or low gain.I didn't have a 1/8-inch to XLR connector handy. I drove the pilot tone signal straight into one channel of the 5D with the preamp feeding the other channel. I would have rather patched the pilot through the preamp.
That said, I was amazed at how much signal I had to crank into the 5D to get the noise level down! Being a headphone output into a mic input, I figured that I'd be running the volume at five or ten percent. I ended up cranking it to 50 percent!!!
I'm really looking forward to Tramm's firmware update for gain control (or, at least, a maximum gain limit control - some AGC for controlling extremely loud sounds isn't necessarily a bad thing for one-man-band shooting.)
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