Q: At our church we’ve got a really old mixer kicking around that gets used for portable PA. It has a few inputs, all XLR, that are each labeled microphone input.
Trouble is, we’d like to use one of these inputs with an iPod but are really afraid of messing something up. Can I connect a line-level signal to a microphone input? Will this work?
A: You’re right to be cautious, as mic levels are much lower than (typical) line-level signals.
This means that any equipment designed to work only with a microphone as an input may be overloaded when you hit it with a line-level signal. The likelihood of this varies widely so it’s always best to try it first and see what your results are.
However, just so you know, when we say overloaded we’re really just talking about distortion, not actual damage. So, when trying these steps, your equipment is never in any real danger.
If after plugging the device you do find the input distorts and there is no way to change the input level of the mic-level device (via dip switches, knobs, or other means) then your only alternative is to lower the output of the sending device. However, first I’d absolutely try to change the input level of the channel you’re using, as that may eliminate the problem all together.
As I mentioned, there are a couple of ways to lower the output of the sending device:
1. If possible, simply turn down the output of the sending device until the receiving device stops distorting. This has the advantage of being easy (and free), but it can compromise the signal-to-noise ratio of your signal., so it should be used judiciously.
2. You may be able to assemble various level-matching devices to make the whole thing work — for example, a line-to-instrument level re-amp-type device feeding a direct box, feeding the mic input.
3. If neither of these does the trick, then plan 3 is to buy (or build) a pad to put in the signal path to lower the voltage of the signal coming in.
At the end of the day, you could end up spending more to “make it work” than it’s really worth, but I’d absolutely try some of the free solutions first and see if they don’t solve your problem.
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