Mic Cable wired out of phase

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busted kitty

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Some dude told me that he had a mic cable wired out of phase so that when he used it to mic a kick drum, he wouldn't pick up nearly as much of the snare through the kick mic.

Could somebody explain how the hell this works? Or if it wirks?
 
An out of phase cable can be very useful.Say you are miking a snare top and bottom.The sound waves going to the two mics are going to be exactly 180 out of phase so you use an out of phase cable on your bottom mic and line them back up.Same thing if you mic an open backed guitar cab front and back.The speaker cone moves foreward and pushes air at the front mic,where the rear mic gets its sound energy from the cone's backward movement.Were you to add these two out of phase signals together and listen to them,most of the bass energy would be cancelled out and the resultant recording would sound thin and weak.That is the charactoristic out of phase sound.
Music History phase trivia.Jimi Hendrix hand wrote on his pre-masters "Do Not Phase Adjust" because otherwise the industry engineers of the day would have "corrected" his phase-shifted psychodelic sound.
Tom
 
While we're at it, a slightly different question:

How do you make y-cables for mics (to use on the mid mic when M-S recording)? Do you use a quad cable with two leads soldered to each pin in the female end, and then simply attach the two male connectors using only one lead to each pin (phase reversing one male connector for M-S use)? If so, how do I solder the shield?

Or is it better to make a small box that has one in, two out?

Thanks
/Henrik
 
IMNSHO, it's better still not to split the mic at all: go straight into one channel, and then patch the direct out from that channel to the line in of the next channel with a polarity-flipping patch cable. It's less noise, and better loading for the mic...

You can do that trick with an insert steal as well. In fact, on many boards the insert send is inverted already (a positive-going voltage on pin 2 on the mic in will yield a negative-going voltage on the insert send), just because of the circuit design of the board. if that's the case, a straight cable into the line in will do it for you.

It's always useful to find out if your inserts are inverting or not: nothing dictates that they be noninverting, and low-cost boards often don't keep track of the number of inverting stages on these oh-by-the-way auxiliary functions. Chalk that one up to Stupid Mixer Tricks...

If you have to Y the mic, you'll need to Y the shield as well. The times I've done this, I've just shoved two cables into the female connector, and paralleled everything. It gets snug, but can be done. I'd much prefer to use the buffered direct-out signal, though.
 
Hey Skippy,
thanks for this! Actually, I don't have a console at all, I just use standalone mic pres and then mix everything in the computer. But some of my pres have double outputs, so this will work anyway. Plus I won't have to solder. (Come to think of it, the extra outs may be unbalanced. But this shouldn't be a problem, right?).

Next step is to get some good mics for M-S...I'm considering the Beyer 160 and 130. Other suggestions are welcome.

Sorry about changing your thread, Kitty!

Cheers
/Henrik
 
That's better by far than Y'ing the mic cable: let the preamp buffer the signal *first*, and then make a TRS Y cable to do the phase inversion trick (swap tip and ring) on one channel between the pre outs and your soundcard ins.

Mic signals want to be mucked with as little as possible. But once you've come out of the pre, you can do all manner of disgusting tricks with it without affecting the signal quality very much at all.

If your pre outs are single-ended, and your soundcard ins are balanced, this will still be easy. Build your Y cable as follows: tip on the pre out goes to tip, and sleeve on the pre out goes to ring on one leg of the y, and sleeve goes to tip and tip goes to ring on the other leg (leaving the shield floating at the soundcard ends). That'll give you the phase inversion on one leg, and break any ground loops to boot: you are driving the hot and cold legs of the balanced inputs with the opposite phase between the two legs, even though the source is single-ended...

Have fun!
 
Hi again,
aha,so you mean that instead of connecting the out of the first mic pre channel with the in of the ssecond one, I could make a Y-cable from the output of my mic pre and connect the two ends to two inputs of my soundcard? And thus not use a second channel at all?

This sounds even better, as this will save me the trouble of matching the levels of the two pres.

Thanks
/Henrik
 
Exactly: splitting on the output of the pre guarantees the levels will match. Everybody wins...
 
Cool! Looking forward to trying that. How I love this bbs.

Thanks
/Henrik
 
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