I'm going general on this, because there are many specific mics that will fall in here and fit the general description. Some omni dynamics (OD) of note--the EV 635a/PL-5, EV RE-50, Beyer M-101, Sennheiser MD-21, and the Shure-built Realistic 1070. A couple of those are still in production or reissued, and there are other offerings by Shure and Audio-Technica that I know of.

Advantages? A couple are obvious. Most will take SPL as well as any other dynamic mic. And of course they have an omni pickup pattern, although there can still be somewhat of a directional tendency at higher frequencies.

A couple of things aren't so obvious. Some of this becomes clearer when drawn into relief with a typical cardioid dynamic (CD) mic. Most CD's will have a presence boost up top as well as the proximity-boost effect--close micing a guitar speaker is pretty effective at getting a simulated Fletcher-Munson effect when doing control-room volume, keeping some of the loud-amp-in-the-room character. An OD doesn't play this game, so it's nice for contrast--lets say you don't want a mid scoop, but want a more midrangey sound for slide guitar. Most OD's have a pretty flat frequency response within their ranges, so you can often get very flat and accurate mids. Also, if the response goes deep enough, bass on an pressure-gradient omni (dynamics and most small-diaphragm condensor omnis) is generally flatter and truer than on a directional mic. Limited band-width with pure mids can be nice for sounding old-timey or intentionally lo- or mid-fi--the 635a can be great for carving out a niche for a sound in a mix.

The other element is that OD's have the omni pattern advantage with less sensitivity than an omni condensor--less reach, less truck-rumbling-by-two-blocks-away, less computer fan, and so forth. That and their SPL handling generally makes them work quite well for difficult percussion like triangles, tambourines, and so forth--if your omni condensor fails the "car-keys test" your OD might save your but on that type of application.

Definitely a good way to diversify the tool kit--compared to another flavor of the same-old, you can use them differently and do more things when tracking.

Bear

I'm a big fan of the 635a - I've got a 60s one and a 70s one, the 60s one is in better nick and seems to have a clearer high end, sounds great on drums and percussion, the 70s one has a slightly more aggressive mid range that sounds good on rockin' acoustics and electrics. if i could only afford to own one mic in the world it would be the 60s ev635a. you can really do the lot with that one mic.

The conventional wisdom with old EV's like the 635a and the RE series is that they lose high frequencies with abuse, so it makes sense that the one in better condition has more highs. Yeah, they are tough enough to hammer nails, but there is a consequence . . .

Bear

I've got a pair of 80's vintage 635a's and an old 635. The old 635 looks like a phaser gun out of a 50's B movie but I am told that it is essentially the same mic just in a different package. I know I definitely prefer the sound of the 635a's 99% of the time. I have always assued that it was because the 635 had degraded too much over time.


Jason A.

Good call Bear's Gone Fission on the omni dynamics as gear of the month.

Today, we think of omni dynamics as one off dilys. But, I've heard of them being used as the original overhead mics on drum kits. I've heard of them being used in diferent arrangements for recording Classical music. Seriously. I'm not saying I've seen it done. Just heard of it.

a 635a can sound great on acoustic guitar or snare.

also worked well as a spaced pair in a room.

FOO - Fear of omnis
LOO - Love of omnis

Some other advantages of omnis.

Low cost especially used. Basically omni dynamics are relatively cheap new and the used market can be substantially less.

Can be used in close because no proximity effect.

First choice for recording outside when wind noise can be a problem. I put a foam wind screen on a dynamic omni and get less wind noise than any cardiod or any condenser I've tried.

Great harp mics.

A few nice dynamic omnis so far unmentioned

EV PL9
EV 649b - lav mic for video studios similar to 635a
EV 631 - Kind of like a high impedance 635a with a screw on connector. Double plus for funky.
Shure SM61

And a few I'm interested in that I haven't tried yet. Comments appreciated.

EV RE55
Shure SM76
Shure 576

Omnis can be a great choice for stereo recording if the room sounds good. I like to use two omnis in a spaced pair or Jecklin Disc configuration. Both can give really good stereo images.

Thanks,

Hairy Larry

I'd like to know more, too.

Bear

i just missed a deal on some EV RE-50's as i fell asleep and forgot to get back on ebay: (~