Static noise with external mic

M

magicant

Member
I have a Sony EX1R and a Rode NT4 external stereo mic with a shock mount, mounted to the camera. I haven't had the camera long and at first the sound seemed fine. I just filmed a party and some of the video has a static noise in the background. It seems louder in one channel. I just plugged headphones in the camera and there is a constant static hissing sound. I tried changing a few settings but nothing seems to work. Some of my recorded video has no static at all. But now with the headphones there is constant static. Any ideas??

Ok I noticed now that if I only plug in one XLR input, the sound is fine. I tried 2 different cables and tried both left and right plugs in each left and right XLR input, all one at a time only have one plugged in. The sound is find in both channels. As soon as I plug in both plugs the static starts (I am monitoring through headphones, and the headphones are fine). So is this a problem with the camera or with the mic?

Thank you.
 
Last edited:
Make sure the audio automatic gain control is turned off all the time. It will bring up audio levels when its quiet to the point you get a hiss.

Make sure the manual audio levels is no more than half way up, often times a bit less.

I don't know that specific mic, but if it has a battery check it to make sure its inserted the right direction. Also check the phantom power switch.
 
Thank you. I do not see an OFF option for automatic gain. Only low or high. I have it on low. I kept the volumes a little more than half but sometimes adjusted a little lower. Now with the headphones on no matter what I put them on I hear the static unless I put it to zero. Mic has an option for batteries or phantom. I am using 2 XLR inputs with phantom.

Funny thing is I just tried now and there is no static. Also as I mentioned above, most of the party I taped has no static. So it seems to come and go. Before when testing at home it was constant. Now it was on, I unplugged one XLR and plugged back in and no static. Before that did not help.

When I had static, I tried adjusting the triim levels and it helped a bit, but not enough. Something was definitely wrong. I also tried adjusting Limiter, Mic AGC, etc, but no settings got rid of the static.

These are my settings:


SWITCHES ON BACK OF CAMERA:
-----------------------------------------------------
Audio Select
CH1: MANUAL
CH2: MANUAL
AUDIO IN:
CH1: EXT
CH2: EXT

SWITCHES NEAR XLR INPUTS:
----------------------------------------------
CH1: MIC+48V
CH2: MIC+48V

MENU SETTINGS:
--------------------------
TRIM CH1: -41dBu
TRIM CH1: -41dBu
INT MIC LEVEL: 0db (should not effect this as I'm using external mic)
Limiter: OFF
Mic AGC: LOW (only LOW or HIGH as a choice)
AGC Link: LINKED
1KhZ Tone: OFF
Wind Filter CH1: ON
Wind Filter CH2: ON
EXT CH SELECT: CH-1/CH-2

It bothers me that there is no static now. I don't have any different settings than from before.
Oh well, it's back again.

---------------
UPDATE: I just unplugged the mic and noticed that the plate with the pins at the end of the mic is loose. I guess this could be the problem. Now how did it get loose? I have plugged and unplugged the mic a few times but should it be this fragile or was it defective??

I guess I will get it replaced and see if that fixes the problem...grrrr.
 
Last edited:
Its been awhile since I looked at it, but my recollection is audio AGC is a menu item to turn off. That's the bad thing about AGC it overrides your settings and changes them mid-stream dependent on the location, so I'd still check the AGC.
 
If that socket is loose, it sounds like you got a defective unit. It should NOT have worked loose this soon....or ever, actually. Call Sony.
 
Well I called B&H photo and they replaced the mic for me. Got the new one today and shipping old one back tomorrow. Static is gone so that is the problem. Now I'm afraid of it happening again. But hopefully it will not. I put a little electrical tape on the mic/xlr connection so the plug will not come out or move. When I need to disconnect the mic I will disconnect the cables from the camera instead of the mic.

Regarding my settings, it seems if the external switches are set to manual then I have full control of audio, as opposed to setting them to auto. Only other reference to AGC in the manual is the high/low setting and the linked setting (whether the gain is synchronized between both channels or separate). I didn't see anything else but I think the manual turns it off. Again, below are my settings. Do they look ok?

One thing I tried changing was the trim setting from default -41dBu to -38dBu and it seems to get rid of some normal slight background hiss sound. Do you think that is a good setting?

Thank you.

SWITCHES ON BACK OF CAMERA:
-----------------------------------------------------
Audio Select
CH1: MANUAL
CH2: MANUAL
AUDIO IN:
CH1: EXT
CH2: EXT

SWITCHES NEAR XLR INPUTS:
----------------------------------------------
CH1: MIC+48V
CH2: MIC+48V

MENU SETTINGS:
--------------------------
TRIM CH1: -41dBu
TRIM CH1: -41dBu
INT MIC LEVEL: 0db (should not effect this as I'm using external mic)
Limiter: OFF
Mic AGC: LOW (only LOW or HIGH as a choice)
AGC Link: LINKED
1KhZ Tone: OFF
Wind Filter CH1: ON
Wind Filter CH2: ON
EXT CH SELECT: CH-1/CH-2
 
Last edited:
I have two Rode NT4 mics, each attached to and EX1 and EX3 and none of them exhibit this behavior. Earlier, you said the recording is fine and you only hear it in headphones.

Just to be sure, while monitoring the headphones, try wiggling the mic cable at both ends. Does the static follow the cable movement? If not, there could be a problem with the headphone amp block in the camera. Static is a sign of 'avalanche' in one or more semiconductors inside the IC amplifier. You might need to have the camera serviced.

Note that the NT4 requires BOTH channels be plugged in and BOTH phantom power sources ON. The NT4 won't work if only one channel is powered with 48V, as it is a shared connection between mic capsules.
 
Sorry if I wasn't clear. The problem is fixed now that I have the new mic. I was getting static in the headphones and on the recording during playback of the videos. It turned out that the pins in the mic for the XLR cable were loose. Must have been defective or it just broke. New mic is fine, both in headphones and recordings.

Yes I do have both plugs connected with phantom power.

What trim setting do you suggest for the NT4?

Also, the NT4 came with a little blue rubber washer. I couldn't tell what that was for?

Thank you.
 
Last edited:
Glad to hear that you got it sorted. Intermittent connections would make a lot of static on any phantom powered mic, because you're talking about a potential 48 volts peak to peak swing between make and break of the connection!

For general use, I set my attenuation at -35dB for the NT4 mics. If I know I'm recording live music up close (jazz ensemble, I might set it to -29dB. For fireworks, I dial it all the way down to -11dB. Realistically, there's no need to dial in anything more sensitive than -35dB, as the preamp noise and mic noise will start to come above the ADC conversion noise and you will only lose headroom and gain nothing on the bottom.
 
You must log in or register to reply here.
Back
Top