H4N line out to GH2 mic in

B

Boon

Well-known member
I'm using a friend's GH2 and my H4N.
Here's what we did. Connected the AT 875 to H4N XLR mic input. The sound recorded was good enough for our project. We set the mic level to 50.

We then connected the headphone/line-out of the H4N to the GH2 mic input with a 'normal' short length 3.5mm cable and a 3.5mm to 2.5mm mono adapter.
We lowered the headphone level to about 20, the volume of the GH2 was set to level 1. When we played back the recorded clips, the noise level was pretty high.
I understand that this is due to the GH2 AGC kicking in. We then dropped the headphone level to 10 but the noise level was still loud.
We experimented with different level and realized that even dropping the H4N headphone level to 0, the noise was still very audible.

So I was thinking of buying the Sescom GH2 cable with a -25db pad http://www.bhphotovideo.com/c/product/746644-REG/Sescom_LN2MIC_ZMH4_GH1_LN2MIC_ZMH4_Line_Out_to.html
Will this help to minimize the noise level? I'm a bit puzzled because even dropping the H4N headphone level to 0, I still hear pretty bad noise. So whats the advantage of using the Sescom cable in this situation?
I don't think my no brand 3.5mm cable and 2.5mm adapter is the problem as it sounded fine with other equipment.

By the way, we don't intend to use the camera recorded sound but more of a backup purpose.

One last puzzle, the GH2 will not recognized a Stereo 3.5mm to 2.5mm adapter as mic input, it will only recognized a mono 3.5mm to 2.5mm adapter.
I'm trying to get both channel from the H4N to Gh2.

Very sorry for the basic questions, I 'm new to audio and still learning.




I
 
Boon said:
I'm a bit puzzled because even dropping the H4N headphone level to 0, I still hear pretty bad noise. So whats the advantage of using the Sescom cable in this situation?
I don't think my no brand 3.5mm cable and 2.5mm adapter is the problem as it sounded fine with other equipment.
Click to expand...

The problem is that you're sending a line-level signal to a mic-level input, so you're overdriving that input by up to 50dB. Connector type has nothing to do with the kind of signal that's running through it. Your "no brand" cable works, but you've probably had it connecting devices that have the same or similar impedance.

The inline pad on the Sescom cable will drop the H4n's headphone/line output to proper mic level for the GH2.
 
What type of "noise" are you referring to when you say the "the noise level was pretty high?" Are you talking about noise from the camera's preamps, ie, electrical hiss or are you talking about the harsh noise of a signal clipping due to overloading or are you talking about "noise" as in the background sounds of the location itself being louder than expected?

The camera would be expecting a mic level signal on its input. There's no way you can plug a line level signal into it without risking overload and neither turning down the output level on the line level source nor reducing the recording gain the camera can compensate for it. No matter how low you set the dial (without turning it off completely) the H4n can still send a hot enough signal to overload the mic input. Remember, the mic input electronics themselves can be overloaded into distortion before the signal ever gets to the camera's level controls

Those numbers you quote, "we set the mic level to 50, we lowered the headphone level level to about 20, the volume of the GH2 was set to level 1" are meaningless. They're just arbitrary dial markings. You need to cite signal levels and meter readings for discussions of level settings to mean anything at all

I hate manufacturers who don't give complete meaningful specifications or make their full manuals available online. I haven't been able to locate any numbers as to the rated sensitivity of the GH2's input but adding an attenuating cable couldn't hurt. My only hesitation is the 25dB pad on the cable you're looking at might not be enough - one can only try it and see. The recorder's output is around -10dBv while the typical DSLR external mic sensitivity is around -50dB - a 40dB difference. If it doesn't work out you can always send it back. In any case, it won't help any problems introduced by the AGC and I don't know if the GH2 allows you to disable AGC or not.
 
Last edited:
A number of people in the "Panasonic GH Cameras" forum reported that they get good results using a Sescom cable. As to the technical explanation of why it works well, I can't really say. But the -25dB attenuation in the Sescom cable does seem to be enough in most cases.

I would ditch the sub-mini to mini adapters you're using, and go track down a Hosa GMP-467. It works really well with the GH2. It gets both channels into the camera without fail, and it's $3.50.
 
guys, thanks a lot for your insight.

I didn't get the sescom cable in the end. My SD MixPre D arrived and I use the Mixer TA3 -36db mic out to the GH2 and it's now all sounding good.
 
You must log in or register to reply here.
Back
Top