Sennheiser ME66/K6 phantom/battery issues with 7D, D7000, Zoom H4n

kitsu

kitsu

Well-known member
A bugger of a problem I'm having with my Sennheiser ME66/K6 mic with 2 dSLRs...

When the ME66 is connected to a Zoom H4n providing Phantom power, I have no problems with audio. Put in a battery and switch phantom power off, no problems either. I've also never had any problems with the mic hooked to my DVX100a with phantom power.

Last week I was without the Zoom so I ran to Radio Shack to get an XLR to 1/4" cable (and then a 1/4" to 1/8" adapter) to plug the mic directly into a Canon 7D but this didn't work. On playback I could hear very faint audio, but it would have been totally unusable. Today I tried the same cable/adapter setup with my Nikon D7000 and had identical poor results.

I know the mic input works on the 7D as plugging the Zoom's output (with an attenuated splitter) worked well.

Any thoughts? Is my problem going from a mono XLR to stereo 1/4-1/8" adapter?
Thanks!

What I was using from the Zoom to 7D: http://www.amazon.com/Sescom-LN2MIC...phone-Monitoring/dp/B004VIOZSK/ref=pd_sim_e_5
 
Sam's recommended adapter should work, providing the mic's internal battery is used. AFAIK, DSLR's only supply plug-in power, which the K6 mic system will not operate on.
Even with a perfect connection in a perfect world, the DSLR's recorded audio won't be great.
 
Sam - Thanks for providing a specific product to look for. I didn't think of that nor did anything I found online specify anything beyond a simple adapter. And I would have gotten a XLR to 1/8" if they had one, but I was in a bind.

Rick - Yes, there was a new battery in the mic and it was switch on.

I know that even with the proper adapter the camera still isn't great for recording audio. Even with the Zoom outputting good audio via attenuation cable, the 7D was applying auto-gain. At least the syncing tools in FCPx are working well.
 
kitsu said:
A bugger of a problem I'm having with my Sennheiser ME66/K6 mic with 2 dSLRs...

When the ME66 is connected to a Zoom H4n providing Phantom power, I have no problems with audio. Put in a battery and switch phantom power off, no problems either. I've also never had any problems with the mic hooked to my DVX100a with phantom power.

Last week I was without the Zoom so I ran to Radio Shack to get an XLR to 1/4" cable (and then a 1/4" to 1/8" adapter) to plug the mic directly into a Canon 7D but this didn't work. On playback I could hear very faint audio, but it would have been totally unusable. Today I tried the same cable/adapter setup with my Nikon D7000 and had identical poor results.

I know the mic input works on the 7D as plugging the Zoom's output (with an attenuated splitter) worked well.

Any thoughts? Is my problem going from a mono XLR to stereo 1/4-1/8" adapter?
Thanks!

What I was using from the Zoom to 7D: http://www.amazon.com/Sescom-LN2MIC...phone-Monitoring/dp/B004VIOZSK/ref=pd_sim_e_5
Click to expand...
You have a phase reversal issue, most likely in the wiring of the XLR to 1/4 adapter, not the 1/4 to 1/8. The XLR has signal hot on pin 2, signal cold (ie, 180 degrees out of phase) on pin 3, ground on pin 1. Your adapter to 1/4 inch very likely puts pin 2 on the tip, pin 3 on the ring, pin 1 on sleeve. That would be correct for going from balanced XLR to balanced TRS but that's not what you need to do here. When it gets into the camera through the 1/4 to 1/8 adapter it puts the normal signal on the left channel and the phase inverted signal on the right channel. Upon playback, if mixed to mono, they cancel each other out. Impedance is not the issue as camera mic inputs are designed to accept low impedance mics which is what you have. Impedance mismatch problems are a very rare thing these days as the situation with solid state electronics is quite different from what is was back in the vacuum tube days. As long as the input impedance is higher than that of the mic plugged into it, thus avoiding loading down the mic signal, you're fine. Your problem stems from plugging a balanced mono signal into a stereo unbalanced input without using proper adapters specifically wired for that purpose. If you want to do it correctly, wire up an XLR to TRS cable connecting XLR pin 2 to TRS tip, XLR pin 1 to TRS sleeve, short XLR pin 3 to pin1, and short TRS tip to ring. The will properly unbalance the mic signal and send it in phase to both the left and right channels in the camera. PS: Don't forget blocking capacitors to prevent the camera's 'plug-in' power from getting back into the mic. Of course your best bet is a Juicedlink or similar box.
 
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It's really common this one, on loads of kit with 3.5mm 3 circuit jacks that are stereo, unbalanced. Certainly not unique to this camera. Steve's explanation is right on the money - very thin, and faint audio being the clue.

The earlier tip about not using adaptors stacked is also very important. A rigid three or even four inches of adaptor stack hanging out of the socket needs very little weight on the end to snap the small 3.5mm socket of the circuit board. The weight can also bend the socket inside, and soon make contacts intermittent.. Don't do it!
 
kitsu said:
A bugger of a problem I'm having with my Sennheiser ME66/K6 mic with 2 dSLRs...

When the ME66 is connected to a Zoom H4n providing Phantom power, I have no problems with audio. Put in a battery and switch phantom power off, no problems either. I've also never had any problems with the mic hooked to my DVX100a with phantom power.

Last week I was without the Zoom so I ran to Radio Shack to get an XLR to 1/4" cable (and then a 1/4" to 1/8" adapter) to plug the mic directly into a Canon 7D but this didn't work. On playback I could hear very faint audio, but it would have been totally unusable. Today I tried the same cable/adapter setup with my Nikon D7000 and had identical poor results.

I know the mic input works on the 7D as plugging the Zoom's output (with an attenuated splitter) worked well.

Any thoughts? Is my problem going from a mono XLR to stereo 1/4-1/8" adapter?
Thanks!

What I was using from the Zoom to 7D: http://www.amazon.com/Sescom-LN2MIC...phone-Monitoring/dp/B004VIOZSK/ref=pd_sim_e_5
Click to expand...

Sounds like a badly wired cable to me.

As far as I remember, the K6 has blocking capacitors inside to prevent plug-in power getting to the microphone.

But to put a balanced microphone into a stereo mic.input on a camera, the cable has to be wired like this:-

XLR pin-1 to mini-jack sleeve
XLR pin-2 to mini-jack tip & ring
XLR pin-3 to mini-jack sleeve (or short to XLR pin-1 inside the XLR)

This unbalances the mic. and puts the signal into both left and right channels.

If you just buy a standard cable it will probably be wired straight through, which is incorrect.

It would likely have been wired:-

XLR pin-1 to mini-jack sleeve
XLR pin-2 to mini-jack tip
XLR pin-3 to mini-jack ring

This would put the +ve mic signal onto left and the -ve mic signal onto right - a very unhappy situation, which you discovered.
 
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