All,
First of all, Happy New Year to everyone and then my apologies for being a bit off topic for the VS forum but I would be grateful for the benefit of other's knowledge.
I am connecting an external microphone to a Canon MV100 DV Camcorder. When I do so, I get interference (as well as sound via the ext. mic). I have tried this will more than one mic and still get it. I even get it, even if I only put an adaptor plug into the mic. socket. I can change the interference a bit by moving around within the house (or by touching parts of the adaptor) but I can't get rid of it or even get close to getting rid of it.
Can anyone assist with suggestions of how to get rid of this problem please.
Bill S
External Microphone Interference
The fact that you get noise when you just plug-in the adapter seems to indicate something wrong with the camera's mic connector (socket).
What does the interference sound like? It would be normal to get some backgound hum or buzz with a long cable (maybe over 25 feet) or with an unshielded (or poorly shielded) cable. This type of hum-pickup would get worse if you grab the insulated part of the cable with your hand.
It also could be normal for the noise to increase somewhat when you plug in the adapter alone. If the internal mic shuts-off automatically, the camera's automatic gain control will crank-up to max (since there is no sound), and this will boost the noise from the camera's internal audio preamplifier.
Also, the unconnected input could be more prone to interference due to it's high impedance. (A connected microphone sort-of "shorts-out" the input with it's lower impedance). I would expect this to be offset by the fact that all of the connections are shielded inside the camera case... Normally, a connected mic is noisier.
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I doubt that the following impedance issues are the cause of your problem, but just in case....
Professional microphones are low-impedence balanced ("low Z"). This keeps the noise level low, and you can get away with long cables. An external low impedance mic will have less noise than the internal mic. If your camera can accept low impedance microphones (most can't), it will have "big" XLR connectors that look like this.
If you are using an XLR adapter, you may have a low impedance microphone plugged into a high impedance input, or vice versa. In that case, you may need a special transformer-adaptor. If your camera has XLR connectors, it may have a High-Z - Low-Z switch, or it may work with both. Some Low-Z microphones are also wired to work with both.
What does the interference sound like? It would be normal to get some backgound hum or buzz with a long cable (maybe over 25 feet) or with an unshielded (or poorly shielded) cable. This type of hum-pickup would get worse if you grab the insulated part of the cable with your hand.
It also could be normal for the noise to increase somewhat when you plug in the adapter alone. If the internal mic shuts-off automatically, the camera's automatic gain control will crank-up to max (since there is no sound), and this will boost the noise from the camera's internal audio preamplifier.
Also, the unconnected input could be more prone to interference due to it's high impedance. (A connected microphone sort-of "shorts-out" the input with it's lower impedance). I would expect this to be offset by the fact that all of the connections are shielded inside the camera case... Normally, a connected mic is noisier.
---------------------------------------------------------------------
I doubt that the following impedance issues are the cause of your problem, but just in case....
Professional microphones are low-impedence balanced ("low Z"). This keeps the noise level low, and you can get away with long cables. An external low impedance mic will have less noise than the internal mic. If your camera can accept low impedance microphones (most can't), it will have "big" XLR connectors that look like this.
If you are using an XLR adapter, you may have a low impedance microphone plugged into a high impedance input, or vice versa. In that case, you may need a special transformer-adaptor. If your camera has XLR connectors, it may have a High-Z - Low-Z switch, or it may work with both. Some Low-Z microphones are also wired to work with both.
Last edited by DVDDoug on Wed Jan 03, 2007 12:46 am, edited 1 time in total.
[size=92][i]Head over heels,
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
-
heinz-oz
I had the same issue with my first Panasonic digital camcorder. The reason was this. The socket on the camera had multiple functions and the plug of the mic bridged onto the other functions. I made a special adapter just to find out later that my camera actually did come with one 
Unfortunately, I don't have the camera anymore and can't be more specific.
Unfortunately, I don't have the camera anymore and can't be more specific.
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wywso0
Ext Mic Interference
DV Doug : Thanks for your suggestions. One of the Microphones I used had both high and low impedences settings. Changing the setting had little or no impact on the interference.
Heinz-Oz: Interesting idea, I'll have a bit of a play with the plug etc to see if this might be the cause although the socket has no other use listed for it. Do you remember what you did to the plug on your first Panasoinc (chop the end off a bit)?
Regards
Bill S
Heinz-Oz: Interesting idea, I'll have a bit of a play with the plug etc to see if this might be the cause although the socket has no other use listed for it. Do you remember what you did to the plug on your first Panasoinc (chop the end off a bit)?
Regards
Bill S
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heinz-oz
No, I bought an extension socket to suit the microphone plug and a 4 segmented plug. Connected the right pins by means of a short cable.
I don't think this would do you any good if the socket on your camera is only for use with an external mic. In my case, if I remember correctly, the socket also allowed for a remote control.
I don't think this would do you any good if the socket on your camera is only for use with an external mic. In my case, if I remember correctly, the socket also allowed for a remote control.
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David Latta
- Posts: 70
- Joined: Wed Dec 22, 2004 5:37 am
- Location: Encounter Bay South Australia
Heinz,
You are correct about the Panasonic with regard to the remote. I have a Panasonic GS400 and the connection has this function.
Bill S,
With regard the noise. I have a Rode Videomic which I use with the GS400 and if I run the cam off mains power then an AC hum is introduced. This is due to the internal circuitry of the GS400 and not due to any fault with the Rode Videomic. When the cam is run off batteries then no AC hum is produced.
Are you running your Canon off mains power or battery when you get the hum. Just a thought mate.
Regards & Happy New Year
David
You are correct about the Panasonic with regard to the remote. I have a Panasonic GS400 and the connection has this function.
Bill S,
With regard the noise. I have a Rode Videomic which I use with the GS400 and if I run the cam off mains power then an AC hum is introduced. This is due to the internal circuitry of the GS400 and not due to any fault with the Rode Videomic. When the cam is run off batteries then no AC hum is produced.
Are you running your Canon off mains power or battery when you get the hum. Just a thought mate.
Regards & Happy New Year
David
That'll do me nicely lad
Aye, but that's no how you make porridge Jimmy
Aye, but that's no how you make porridge Jimmy
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David Latta
- Posts: 70
- Joined: Wed Dec 22, 2004 5:37 am
- Location: Encounter Bay South Australia