Prism Sound Orpheus - Audio Media

microphones 2008APPLICATIONS+ + + + APPLICATIONS+ + + + APPLICATIONS+ + + +much closer than a cardioid without thistrade-off, and will then be picking up nomore room spill than the cardioid relative tothe wanted source. It will almost certainlyremain pretty close to omni throughout itsfrequency range, so what spill there is willbe clean and real and far less of a problem.I like this particularly on double bass in ajazz session, where drum spill is always aproblem and most cardioids struggle withthe bass sound when up close. A goodomni can be put as close as you like towhichever part of the instrument is givingyou the sound you want, or even wrappedin foam and stuck under the bridge. Goodseparation, clean bass, and the otherspecial attribute of a real omni: ruler-flatfrequency response.Check out graphs for a typicalEarthworks omni and you’ll think eitherthey’re lying or their test gear is broken, butno: that straight line really is what it does,way down to the lows and way up past 20k.No other microphone type can do this.Of course many mics are chosenspecifically for their colour, but I thinkthere’s a lot to be said for using amicrophone from time to time that actuallytells it like it is. Our favourite microphonesalmost never capture the real sound – theyalways impart their own character, which isfine as long as you know that’s what they’redoing, but it can be an eye-opener to usea microphone that is truly neutral. Evenvocals can sometimes benefit from this –I’ve had singers choose an omni in a shootoutwithout knowing anything about whatthey’re listening to. We expect audio andvideo monitors – and video cameras – to beaccurate and to give us an exact renditionof what we’re working on, and it sometimesseems weird that we don’t have the sameexpectations of our microphones.Appealing but FragileElsewhere I’ve gone on at some lengthabout the CAD Trion 7000, a bold newribbon microphone that sets out to bringthe distinctive properties of the technologyto a wider audience. We’re all familiar withthe BBC-designed 4038, although few ofus use them regularly, and of course withbeyerdynamic’s enthusiasm for smallribbons and the applications where theyshine. Royer too, with its updates oninnovative old Bang & Olufsen designs, hastried to evangelise to the world about thespecial appeal of the ribbon. Part of theproblem perhaps is that we’re also familiarwith the inherent downsides of a ribbondesign. You’ll rarely encounter a moremassive magnet outside a loudspeakeror a motor than the one on which a bigribbon mic relies, and as it’s big enoughto be death to tapes and hard drives it’s aworrying thing to have around in a recordingstudio. Stories abound like the one of the4038 ‘accidentally’ put down on top of themultitrack of a project that was going badly,thereby necessitating a complete restart tothe project and a lawsuit to establish whodid it. Even now, the Trion user instructionswarn against using it in an area where theremight be iron filings, as they’ll getpulled inside and gum upthe works.There’s also fragility. Justmoving a 4038 too quicklythrough the air can breakits ribbon, and in fact itused to be part of BBCtraining to be able tomake and fit a new one,crinkling up a little bitof foil and tensioningit across the mountingscrews. As mentioned inthe review, the Trion protectsits ribbon assembly prettythoroughly, but still tells you notto try recording kick drums withit. Phantom power on a ribboncan sometimes destroy it – thelist goes on. And the output levelof old ones can be painfullylow; often they’re such lowimpedance that they canwork over hundreds of yardsof unscreened bell-wire withoutpicking up hum and noise, butthe gain needed in the preamp canstretch its own performance toits limits.So why bother? Simply, because theysound great and have a very predictableresponse that can’t be properly achievedany other way. Much of what was saidabout the omni applies here too, in thesense that a multi-pattern microphonecan only approximate the polar responseof a true figure-of-eight (older engineerswill remember them being called cosinemicrophones because their response, forpretty obvious reasons, should be exactlythe same as a polar plot of a cosinefunction). The same cardioid capsules thatare summed to give an omni are subtractedto give a fig-8, and the success and linearityof the result depends on the accuracy of thecardioid patterns, which as suggested is notusually that great. A ribbon does it properly:sound coming at it from the side simplydoesn’t make the ribbon move, so gives nooutput. Its nulls at the sides are thereforepretty much perfect; and of course it’s notjust the sides, it’s the top and bottom, infact a complete disc surrounding the ‘neck’of the 8.This is the biggest and most reliablearea of rejection exhibited by any micpattern. As long as there’s nothing tooclose directly behind a ribbon,the null area can be pointedpretty much anywhere youwant, isolating a doublebass or singer from anadjacent drum kit orpiano, for instance; seethe Trion 7000 reviewfor how it worked onviolin in a piano trio.Its other big underusedapplication of course isMS work, where a decentribbon as the side miccan be coupled with almostanything you like as the mid –don’t believe anybody who tells youit has to be a cardioid. Anybody withPro Tools has an MS decoder, and thebenefits of recording piano or drumoverheads with in raw MS have to betried to be appreciated. Any stereopair can be narrowed with panpotsof course, although it never seemsquite so convincing as tweaking anMS pair; but it’s not so easy to makeit wider than you originally recordedit – unless you’re working MS, in whichcase it’s a piece of cake. And of courseeven without a dedicated MS decoder youcan ‘make’ one with any mixer – feed theside-fire fig-8 to two channels panned hardleft and hard right, with the right phaseinverted,then add that pair (always set tothe same level as each other) to the frontfacingmid mic panned centre until you hearthe stereo picture you want.Once you’re persuaded of the delights ofMS, you’re ready for a Soundfield……But don’t start me on that.THE INTERNATIONAL MICROPHONE BUYER’S GUIDE 7