Interference Occurs w/ Mic Input When SD Video Cable Plugged In

[Chris Barcellos]

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]

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]

I posted the same thing back in January,

http://www.dvinfo.net/conf/canon-eos...ng-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]

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]

Originally Posted by John Harvey

I posted the same thing back in January,

http://www.dvinfo.net/conf/canon-eos...ng-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]

Originally Posted by Jon Fairhurst

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]

Originally Posted by Chris Barcellos

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.)