[Joe Bressler]

OK check it out. I got to the bottom of the problem but now I don’t know how to solve it.

After systematically taking apart the rig and checking how the receiver behaved after the removal of each individual component I finally got to the last three bits: the camera body, the metabones speedbooster, and the canon 24-105. With all three together there was the same RF behavior as before, but after the lens was removed, the RF dropped off and there was no longer an issue! I’ve also noticed that when the camera is powered on and the lens “engages” there is an RF spike and then it returns to about 1/3-2/3 filled on the display.

Any ideas?

[Joe Bressler]

Hey all,

A little update to this story. I have been using the Sennheiser system with the receiver mounted off of the camera (with this setup) with much better results as of the last writing here. I’ve also used other Sennheiser systems with other a7s rigs flawlessly (albeit not mounted to camera) (30 interviews in 3 nights with not one RF hit). I’ve used this system with c300, mounted to camera, no RF hits.

After a call to Sennheiser tech support we determined that my particular camera was acting as an RF antenna that was causing the afore mentioned interference based on this test:

Just camera and cage set up and turned on. Receiver turned on. Receiver exhibits a little bit of RF on the display. When moved away from camera RF goes down and then out completely

Camera, cage, rails, monitor and shotgun mic attached, same behavior only a little more RF is present when the receiver is close to the rig than before.

With the same setup as above, I scanned a new list with the receiver mounted to the camera with squelch on low. No free channels usable.

My question is: are there any a7s users who have had this problem before? Is there a setting on the camera that I can change to stop this from happening (it’s on airplane mode)? Do I need to get a new camera??? This happens regardless of what monitor is bolted to the rig, and I have also noticed strange feedback on sound coming from my rode videomic plugged straight into camera as well.

I want to be able to mount the receiver on or near the camera like I am supposed to be able to and (within reason) not have to worry so much about it!

Thanks for your advice in advance!

[Joe Bressler]

Thank you for your response Brian.

We used an XLR cable with nothing extra in between the mixer and the recorder.

During set up we did monitor but there was not a proper sound check. Meaning we set levels based on pre recorded music that was being played prior to the performance. This audio was below -24db so even if the output doubled once the performance started it would still be well below 0db.

Thanks again for your input!

[Joe Bressler]

Hey Bouke,

I am feeding VLC the wav file straight from the SD card. The file size is 372mb vs a 35:08 duration. When I export the file from audacity or VLC it’s about 100mb less, a loss of which seems proportionate to the amount of data that should account for the missing audio.

[Joe Bressler]

Hey Ty

Yep, got it. Any thoughts on being able to recover the last ten minutes of this audio file if it’s not already coming up in audacity when I import the raw data?

The duration in VLC being correct gives me some hope as well as the fact that it isn’t a 0kb file

[Joe Bressler]

Hey All

I’m in a similar situation- corrupt file because of battery depletion during recording. In fact, I had pressed the stop button and the moment I did, the zoom powered off.

What I have now is a 372MB file that opens in VLC with a duration of 35:08, however it only has audio for about 25 minutes of this. I also can’t export the full length of the file from VLC because at 25 minutes it says File reading failed/VLC could not read the file (m). When importing as raw data to audacity once again all I get is the first 25 minutes, except this time it is at 200% speed.

Anyone have any ideas as to if I can recover the last ten minutes?

[Joe Bressler]

I have noticed in several situations that I will scan for a new list of available frequencies and find that there are several banks with available free channels.

Then i will run into RF interference, scan again, and notice that there are zero banks with any free channels.

Is this explainable? Really starting to think I have a bad kit here with how unreliable these units are. I know that occasionally you have to scan for new frequencies to use especially when changing locations, but I am finding myself with the devices set up properly, in one location, and facing RF hits constantly. It is not practical to switch channels several times during a shoot sometimes.

[Joe Bressler]

Hey all,

Thanks so much for your continuous advice on this. The rig was an a7s with XLR adaptor plugged into the shoe, with the two recievers mounted by Velcro on a movcam cage. I was monitoring sound, and stopped to fiddle with the system upon hearing the issue, but it was quite intermittent and like I said I don’t know what adjustments to make besides finding a clear channel.

The talent was holding a radio and had his cell phone on. This sounds like hell for a radio mic system so I would imagine that wasn’t helping.

The transmitter and receiver that I had been using were pretty much brand new units. Used only once before, with the same issue. So I doubt that the antennae had become un-soldered. Additionally oddly enough the rental transmitter was causing the most problems and was switched from the main talent to his buddy who was also mic’ed but was not speaking much.

How can I find out what frequency I should be operating within in my region?

Thanks again
-Joe

[Joe Bressler]

Hi Peter,

Thanks for your response. What could be done to reduce RF interference besides doing the channel scan and using the bank with the most free channels? We hadn’t changed locations since the initial scan.

Understand nyc would be prone to rf interference but the exact same issue has presented itself outside of the city. Would changing the squelch help?

Thanks
-Joe

[Joe Bressler]

Hi Ty,

All antennae were straight and the receivers were both mounted on the camera rig.

I had another shoot where I used the sennheisers with the same problem. I had tested them before that shoot and had also tested them again before this shoot, but not in similar conditions. They worked fine in stationary, no-stress tests. However after this shoot I tried to test them again walking around outside with the receiver in pocket by myself, trying to get the issue to present itself, but I don’t really think it’s the same.

BOTH mic’s were doing this.

Thanks for your quick response!

-Joe