Testing an IP Cam "Line Level" microphone input?

[triumph202]

So I've got a camera with a "Line Level" input and have tried two amplified microphones and they won't work with it (barely hear the audio with the mic gain up to 100).

I'm trying to isolate the problem. Both microphones are the same brand/ model, so that doesn't help. I've tested them on the line level input of an audio system (home stereo), they work- but the volume needed to be turned up a bit. I've updated the firmware on the camera with no improvement. I don't have any other cameras with mic inputs so can't try them on a known good camera. I've tried different power sources for the microphones with no change.

I'm wondering if anyone can see any problem with using the line level output from home audio equipment and feeding a single mono channel into the camera's line level input to test it? To see if it's still a barely audible signal being recorded or if it then will work.

I don't want to send the camera back to China only to find out something else is the problem.

 

[alastairstevenson]

I'm wondering if anyone can see any problem with using the line level output from home audio equipment and feeding a single mono channel into the camera's line level input to test it? To see if it's still a barely audible signal being recorded or if it then will work.

That would be a good test.
Especially as :

I've tested them on the line level input of an audio system (home stereo), they work- but the volume needed to be turned up a bit.

suggests the microphone output may be a low level signal.

 

[triumph202]

Thanks for the confirmation, I couldn't think of any reason it wouldn't work. It's the best thing I can come up with given the equipment I've got.

(Sending the camera back to China is going to be expensive, so I want to be sure what equipment is at fault.)

 

[marku2]

My mic sevens i use
i run a separate power supply
make sure you have the correct input to the camera from the mic
and with the camera web gui i use mic in

 

[triumph202]

I set it up running off a 12v solar system with 240W panels and a 100Ah battery (but have also used a regulated 12vdc 1000mAh wall plug pack with the same results.)

There's only a "line level" input option, I've tried all the available compression options and gain levels from 0-100.

I've also got two of the same mics and they're both the same.

 

[triumph202]

The microseven is connected to "line input" on the camera via an RCA to 3.5mm mono plug. (I bought two of them as well, so have tried both adapter cables with the same result.)

I'll take the camera down and try feeding a fixed line level audio output from a piece of home audio equipment. My guess is I'll still have low volume levels.

 

[marku2]

Ok you have the mini plug
Not the older green plug with audio in and out?

 

[triumph202]

Yes a 3.5 mm plug for line level I/P, a second for O/P. The Hik specs say "single channel" so I've used a mono plug

 

[marku2]

I have a two cameras that have this mini plug
Do you have a mini stereo plug to try

 

[triumph202]

I've got a twin RCA to 3.5mm stereo adapter (solid plastic type) that I should be able to try with the camera apart. The Hikvision instructions for connecting microphones are woeful- they actually show a 3.5mm stereo and 3.5mm mono plug being used in differing diagrams. The stereo plug has the two channels jumpered together. IIRC in the audio world a 3.5mm mono/ stereo plug are interchangeable, but obviously you will only get the same mono signal to both channels if using the mono plug. (But it has crossed my mind that the mono/ stereo plug could still be the issue.)

 

[triumph202]

The weather has been hot, so I haven't got around to removing the camera for testing.

The seller got an identical camera and tested it with a Hikvision powered microphone- and it works. So I'm buying the tested identical camera with the Hik microphone. I will test the current camera with the Hikvision microphone and see what happens.

(I'm hoping it is the microphones at fault- the two of them would have cost me less than freighting the camera back to China!)