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I've been assigned to document our class's stage play and I'm having trouble with the audio. I only have one shotgun mic (3.5mm output) and I'm planning on putting it on a tripod and leaving it on the front row. Problem is, my camera's going to be at the back, about 25 feet away. The problem is, how do I bridge the gap between the camera and mic?

I've been thinking of just making a 25 feet long 1/4" plug microphone cable connected to the shotgun mic with a 3.5mm-1/4" adapter. It'll all go into a mixer, which will output to my headphones and straight into the camera. But, won't a 25 feet cable be all noisy and stuff? I've been reading a bit about balanced cables and they seem to be the way to go. However, I've heard that you should never mix unbalanced outputs (the mic) with balanced inputs (the mixer). Are there any possible downsides to this kind of setup?

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    You could also consider keeping the mic where it is and just record the audio to a separate device close to it (laptop, memo recorder). Later you can sync the audio with the video quite easily in post.
    – Saaru Lindestøkke
    Mar 21, 2013 at 23:43

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A balanced mic would certainly help. Another option is to use a direct box to go from an unbalanced mic input to a balanced line (XLR). The best bet would really be to get an actual mic with balanced output. Also, in a pinch, a 25 foot run is totally doable with an unbalanced cable if it is well shielded. It isn't ideal, but it should be workable as long as it isn't near any major sources of interference (like power cables) and there isn't too much RF in the area.

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  • Ah, but I can't get a balanced mic now, so I'm going to have to make do with what I have. So, Unbalanced mic -> balanced cable -> mixer -> headphones + camera will give me usable results?
    – Ken
    Mar 21, 2013 at 13:34
  • @Ken For the cost of a Direct Box (which you would need to go from an unbalanced mic to a balanced cable) you could probably get a balanced mic.
    – AJ Henderson ♦
    Mar 21, 2013 at 13:36
  • The thing is, I only have enough cash right now to get a cable. The question now is, will the combo of an unbalanced mic -> balanced cable -> mixer -> headphones + camera will give me usable results? Or will using an unbalanced cable be better? Also, I have another question with regards to the mixer. In addition to me using the mixer for the mic audio, we will also be using it to play music. Is there a way to output the mic signal just to my headphones and not the entire sound system so it doesn't mix with the music? As you can see, I absolutely have no idea what the hell I'm doing. =D
    – Ken
    Mar 21, 2013 at 13:44
  • @Ken - You can't simply plug an unbalanced input in to a balanced cable. The unbalanced input has 2 conductors, the balanced input has 3. If you can only get a cable, the best bet is probably a decently shielded unbalanced cable since it's your only option.
    – AJ Henderson ♦
    Mar 21, 2013 at 13:49
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    @Ken - as for the output to the camera. It is going to entirely depend on what the capabilities of the board are. If it has aux outputs, you could send the feed from the mic to an aux without sending the music to it. If the aux send is pre-fader, then you can leave the fader on the mic down and it will still go out the aux output. Another option is a PFL(pre-fader level) solo or cue. Most sound boards have an option to send a single channel to the headphone output so that you can listen to just a single input regardless of the fader level for that channel.
    – AJ Henderson ♦
    Mar 21, 2013 at 13:51
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One point needs to be explicitly made. You can't convert an unbalanced signal to a balanced signal with just a cable. Even if you had the right adapter, one that correctly matches the connectors, this does not magically create a balanced signal. For that you do need a direct box (DI), or some sort of transformer.

Another way to say this: you must distinguish between the type of signal, the cable carrying this signal, and the connectors on the end of the cable. You can mix and match these three factors in various ways, to successfully pass a signal (of some quality).

In your case just run an unbalanced line, but buy a quality cable. You will lose signal strength and will be vulnerable to interference from mobile devices and WiFi. But it should work just fine.

Bart's suggestion of a separate audio recorder is a good one. It doesn't sound like you have a budget, but maybe you can borrow a digital audio recorder?

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