In Summary

With a number of mics offering a figure of eight polar pattern, this useful mode of pickup can sometimes get overlooked. Here we look at what figure of eight is, what it can do, and some of the options out there for sounds using one of the oldest polar patterns out there.

Going Deeper

Patterns In History

Back through the mists of time, the all-conquering cardioid polar pattern that so many engineers rely on did not exist. Instead, anything that came out of the mic locker was either an omni or a figure of eight mic. Less by design, and more because of their inherent MO’s, these mics are the ancestors of all the creations that combine omni and figure of eight polar patterns to make them more directional.

In the case of the figure of eight, the earliest were ribbon designs that even now still get their pattern from the ribbon itself. Every sailor knows that their sail needs to face the wind to get anywhere, and likewise, a microphone’s ribbon moves in response to rear or frontal sounds, and virtually not at all to things happening from the sides.

Getting Figure Of Eight

Although a figure of eight pattern is inherent in ribbon mics, other designs later made this bi-directional pickup available with techniques such as using polarity and combining cardioid capsules’ outputs. In the present, engineers can choose mics either for their sound, their pickup pattern (after all, what you don’t record is important too), or both.

If you need a figure of eight pattern, there are slightly fewer choices out there to beat the cardioid’s ubiquity. Broadly speaking there are three options: ribbon mics, multi-pattern large diaphragm condenser mics switched to figure of eight (if available), or specialist smaller diaphragm condenser mics. This last type is harder to come by and more expensive in the form of mics like Sennheiser’s MKH-30 or modular system mic capsules such as Schoeps’ MK8. Slightly more accessible options can be had in Shure’s Beta 181 preamp/capsule combo or Rycote’s all-in-one BD-10.

Using Figure Of Eight

Reduce Spill

The sides of a figure of eight mic offer incredibly ‘silent’ deep nulls that can be steered to ignore other things. This can pay dividends in a number of situations where an unwanted source is clearly audible where it shouldn’t be.

On drums, using a figure of eight as a close mic can be used for a whole range of problem solving. That crash cymbal in the rack tom mic? Turn the mic to ignore the cymbal and it’s gone - the amount of isolation that can be achieved here is impressive! Same goes for keeping kicks out of snare-side bottom mics, or hi hats out of snare shell mics.

Singing acoustic guitarists who like to record as-live can really benefit from the figure of eight treatment. For loud strummers, the instrument is frequently louder in the room than the voice. Tuning the mic position on the vocal can almost completely remove the guitar from the vocal by keeping the instrument in the mic’s deaf spot. Two or three mics can be used for the same trick to isolate the guitar, or even to do stereo at the same time.

Like a figure of eight mic in reverse, there are some sources that radiate principally in two directions and in opposite phase (an acoustic dipole). A cymbal is one, and another is an open-backed guitar cab. Engineers can keep that amp sound out of other mics to a useful extent by steering the quieter sides of the amp towards other things. It’s harder to move cymbals, but knowing that they radiate much less (and with a different timbre) from the sides can help when trying to keep them out of something else.

Lose The Headphones

Figure of eight mics can also be really useful when loudspeaker monitoring must be used while tracking. This can be useful for tracking small vocal groups or similar sources in smaller, drier environments such as control rooms where there aren’t enough headphones to go around. Where small portable monitors are used on stands, either they or the mics can be positioned to minimise spill.

Two Voices, One Mic

It’s been said that air is the best mixer. Anyone who has experimented with recording multiple or complex sources with fewer mics might agree. Recording two things with one mic is a classic technique that can still bring advantages in the modern studio despite its increased input counts and unlimited tracks. Still employed by some, this can glue sounds and a very appealing way, simply by moving the mic to achieve the right balance.

Many have made recordings of two singers facing each other at the same mic. Adjusting the position of singers or the mic can achieve excellent pre-mixed results and a tidier studio floor as well. A related long-lost technique was used by groups of actors in radio drama - walking slowly into the null of the mic while delivering lines achieved the shortest walk off into the distance ever…

Controlled Ambience

Using figure of eight mics’ deep nulls can also be used to control ambience. In the same way that cardioid ambient mics can be pointed away from the source, figure of eight mics can be used in the same way but their deeper rejection at the sides means they can be placed closer to the source. This can provide an alternative ambience that is closer - useful for things like drums where large amounts of close ambience can be faded up without raising the dry drum sound significantly.

In problematic rooms with flutters or other nasties, figure of eight mics’ nulls can again come to the rescue simply by working at 90 degrees to the problem. Using a cardioid like this can be less successful on two counts: the ambience is louder in the mic and might not sound great either depending on the design.

Classic Stereo

Many reading this will be aware of the classic Blumlein stereo technique. This uses two figure of eight mics placed coincidentally and angled 90 degrees apart. Originally conceived as an alternative to the spaced omnis technique, this exploits the figure of eight’s deep side nulls for a greater level difference delivering a wider image than with other patterns at the same distance. It also neatly captures rearward ambience (albeit with the sides swapped over) and allows the array to be used at a greater distance thanks to its narrow Stereo Recording Angle (SRA). This last factor makes it unsuitable for very wide sources as elements at the extreme edges can be picked up in the opposite-polarity rear lobe of the opposite side mic.

Mid-side stereo is figure of eight stereo technique that more engineers will have used. With the figure of eight mic providing the sides signal, the advantages of this technique are threefold: the mid mic is pointed directly at the source, the mono compatibility is also there, and the width can easily be changed in the mix or even in record with no angles or spacing to worry about.

You can read more on mid-side stereo technique here.

Proximity Effect And Fig 8

When used close-up, figure of eight mics have a much bigger proximity effect than cardioid mics. Put simply this is because cardioid mics combine omni and figure of eight principles into one design and a cardioid response is the result. The omni pattern has no proximity effect and its integration into cardioid designs counters the huge proximity effects found in pure figure of eight polar patterns. This makes figure of eight mics a great choice on kick for the brave who want loads of free extra bottom end. Beyerdynamic’s moving coil M380 is great for this if you can find one…

A mic’s Distance Factor describes how far away a directional mic can be placed compared to an omnidirectional microphone to collect the same direct-to-reverb ratio. Both figure of eight polar patterns and cardioids would need to be placed roughly 1.7 times the distance from a source as an omni to get the same amount of ambience. Figure of eight polar patterns will not sound more ambient than a cardioid despite the figure of eight polar pattern’s rear-facing lobe.

Despite expectations, the idealised figure of eight’s performance on paper might be different in real life. As with anything in recording, trying things, listening, and repeating the process sounds a whole lot better than trying to bend the entire process around the enemy of all good recordings: “On this, Thou Shalt Use this”...