Rode SVM picks up noise

[mc-racing]

Hi,

I'm using the Rode SVM (Stereo-Videomic) on the HV20 (Pal). But i have a bad noise problem, the SVM pick up a hum at about 5000-7000 and a hissing high frequency noise. I tried also a flash bracket to get the mic a bit away from the cam because of the dead cat which ist a bit to big when the mich is mounted on the shoe, but this had no effect aon the noise.

I think the noise comes from the cam's microphone circuit, because when have the mic on the turned on cam and i plug in the mic in the Computer there is no noise on the computer...

Does somebody know if this how i can fix the Problem, or is my HV20 faulty?

best regards
mc

[CJDaniels]

No I had this too but I ended up in the hospital doing nothing during my 5 week vacation so I tested this. I found the least amount of interference and the best sound with the camera mic turned to "att" and the SVM left on normal.

there are people here that claim that turning the camera setting to "att" only affects the internal video mic but that is not true.

[Worley]

"Att", I can assure you, affects audio recorded with an external mic. I used to use this setting, but found the record volume just a little too low for my needs in most situations.

If you get a program like Goldwave, Audacity, or Audtion/Soundbooth you can create a band stop filter, or apply noise reduction.

[mc-racing]

Do you think that the SVM has a to low output voltage, so the HV20 has to do to much amplification?
Maybe a external mic-amp or step up Transformer will help, i going to do some tests today...
the the VM has 15mv @94db and SVM has only 6,3mv @94db

[mc-racing]

My first test is done, i connected a cd player on the mic jack an recorded........
when the level-control ist in the left 1/3 there is no noise on the recording.
This tell us that the output voltage of the SVM is to small, when i compare it with my older movies let's say about 30-40db to less that the HV20 mic circuit is noise free.
A little mic preamp with about 150-200mv output will do it ift the mic is noise free, this will be my next test.

[mc-racing]

My first test is done, i connected a cd player on the mic jack an recorded........
when the level-control ist in the left 1/3 there is no noise on the recording.
This tell us that the output voltage of the SVM is to small, when i compare it with my older movies let's say about 30-40db to less that the HV20 mic circuit is noise free.
A little mic preamp with about 150-200mv output will do it ift the mic is noise free, this will be my next test.

Sorry, this was not true, i hat the mic-attenuator on, so this will be the same as 15-20mv without the ATT.
@CJDaniels, you are right , i got good results with the SVM, ATT on, the Preamp on -12db, the Hum is completly gone with that settings especially when the mic ist on the flash-bracket far away from the cam.

Now there is only some hiss.
Do you know where this come from and/or how this can be improved (without software editing) ?

[freeflight]

I am thinking about SVM, but rather not get a pre-amp. How loud is the humming without preamp, say comparing to built-in mic?