A stereo microphone - Should you want one? What can you do with it?

The Vanguard Audio V44S Gen2 isn't the only stereo microphone in the world, but it's new and interesting.

Where some stereo mics look like a regular pencil mic, but with two capsules behind the grille, this mic is modelled after the classic AKG C24 where one capsule is mounted above the other and is side-address, meaning that the mic is positioned vertically in relation to the sound source, rather than pointed at the source like a pencil mic.

But whatever the style of a stereo mic, the big question is why would you want one in preference to two individual mics, which you can of course use for stereo however you like?

Disadvantage

Let's get this out of the way. You can't use a stereo mic in a spaced configuration; the capsules are always coincident. With individual mics you can space them however you like.

So with two individual mics, in what situations might you want to space them to record in stereo?

The classic example is to record an orchestra, or acoustic band or choir. This gives your recording a lovely spacious sound almost like being there, though there is the risk of a 'hole in the middle' of the stereo image if the mics are spaced too far apart.

Another classic is drum overheads. Likewise, the sound is lovely and spacious, filling the distance between your speakers, headphones, or earbuds.

One more? Ambience mics. Whatever you're recording, it will sound better with stereo ambience recorded with spaced mics. Assuming the room sounds good of course.

You can't do any of these things with a stereo mic, so it would seem that your money might be better spent on two individual microphones.

Advantage

But what might seem like a disadvantage at first can be looked at with a positive frame of mind.

With your shiny new stereo mic, you're forced to use it in coincident configuration - both capsules as close together as possible. Yes, you can do that with your individual mics, but with your stereo mic you're forced to concentrate your thinking and get the best sound you can within its limitations.

And the coincident configuration is not at all bad. You can use it with the figure-of-eight polar pattern, cardioid or hypercardioid. The Vanguard Audio V44S Gen2 misses out on hypercardiod but adds the omnidirectional pattern. This is a little odd because in theory two omni capsules placed close together will capture exactly the same signal. In practice however, with large-diaphragm capsules there will be a certain amount of directionality, which will create a difference between the left and right channels, and therefore stereo.

The sound of the coincident configuration is precise rather than spacious. Record an orchestra and you can pinpoint the location of every instrument on playback, which with spaced mics is much more approximate.

Comb filtering

Aha, the big issue with spaced mics.

With spaced mics recording in stereo, unless the sound source is exactly equidistant from both mics, you'll get comb filtering if you mix the channels into mono, or even just pan them inwards. There's too much to go into detail here but I'll just say that it often sounds bad. This isn't to say that it's so bad it makes spaced mics unusable. You just have to take care and listen closely to the sound you're getting, and check mono compatibility.

But with the coincident configuration, and with a stereo mic, there is none of this. There's a wonderful freedom in the knowledge that comb filtering just will not happen.

Let's take an example here - Imagine you have a singing guitarist to record with two mics. You point one mic at their mouth and one at their guitar, each in the optimum position for its respective sound source.

You'll almost certainly want to pan both mics centre. Bingo! You have comb filtering.

But suppose you use your shiny new Vanguard Audio V44S Gen2. You can set the pattern of the capsules to figure-of-eight, swivel one towards the singer's mouth, the other towards their guitar.

No comb filtering.

OK, that's enough on stereo mics for now. I don't get paid, by the way, to feature individual products but you can take a closer look at the Vanguard Audio V44S Gen2 here.