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Audio Technica ATM89R

Back-electret Microphone By Paul White
Published September 1997

Paul White tries out a reincarnation of one of his favourite budget mics, and finds that the best has just got better.

There's no shortage of good capacitor studio mics around if you've got the budget to pick and choose, and there's certainly no shortage of dynamic models, but where do you look when you want capacitor‑mic quality on a dynamic‑mic budget? The answer is to be found in the back‑electret sector of the market, but this covers everything from naff camcorder mics up to top‑end Audio Technica and B&K studio mics so, unless you know exactly what you're looking for, it's all too easy to make the wrong choice. Fortunately, every so often, something comes along that challenges your preconceptions of what you can realistically expect for your money.

A couple of years back, I reviewed the Audio Technica 873R microphone, which I've been recommending ever since. However, some users are put off by its small size. The good news is that Audio Technica have taken the capsule assembly from the 873R and used it as the basis for the ATM89R, which looks, on the outside, much like a good‑quality dynamic stage microphone. This resemblance is deliberate, because Audio Technica want the mic to appeal to live vocalists as well as studio owners; to that end, they've built in a new shock‑mount system, which I have to say is one of the very best I've tried at rejecting low‑frequency handling noise and rumbles.

The ATM89R is a fixed‑pattern, hypercardioid mic, though it is possible to fit different capsules for cardioid, sub‑cardioid or omni operation, as you can to the ATM873R. Unlike some back‑electret mics, which can operate from either battery or phantom power, the ATM89R runs on phantom power only, which is one reason the designers have been able to make it so sensitive.

Those unfamiliar with the theory of back‑electret mics may be interested to note that it is quite possible to build these mics with the same characteristics as their conventional capacitor counterparts; the main difference is that the electrical charge on the capsule is provided by means of a permanently charged electret material fixed to the back plate, rather than by an applied DC voltage. The charge will eventually drain away, which means that the capsule will have to be replaced, but as this typically takes several decades, it isn't an immediate concern — and to our older readers, no concern at all!

If your budget is strictly sub‑£200, the ATM89R stands capsule and basket above the rest of the crowd.

Another feature of this microphone is a properly thought‑out windshield, which is rather more sophisticated than the perfunctory systems fitted to most hand‑held mics. In addition to the usual outer mesh basket and inner foam sleeve, there's a further foam element positioned right over the capsule on a lightweight plastic frame. This does improve matters, but in the studio, stand mounting and an external gauze pop shield are still recommended.

Technicalities

At the heart of the capsule is a very low‑mass diaphragm — just two microns thick — with a thin layer of gold applied to its surface to render it electrically conductive. This low mass enables the mic to react more quickly to transient sounds, and its frequency response of 70Hz‑20kHz equals that of most studio capacitor mics. In side‑by‑side tests, the mic is also far more sensitive than conventional dynamic mics; with an output of almost 8mV per Pascal, it also compares well with typical studio capacitor mics. This extra sensitivity helps when you come to record quiet acoustic instruments that would otherwise have your mixer input gain set at maximum, and the practical benefit is that recordings are quieter. The signal‑to‑noise ratio of the mic itself is quoted as 67dB, and with a maximum SPL handling of 138dB, you don't have to worry that it will overload when close‑miking percussion. Output impedance is 100Ω, making it suitable for use with all low‑Z mixer inputs.

Most vocal mics are 'doctored' at the high end to give them a slight presence lift, and this mic is no exception, but the presence peak is both gentler and higher up the spectrum than it would be on a typical dynamic model. There's also a very slight rise at around 150Hz, which gives the mic warmth in the 'chesty' region of the vocal spectrum. Like all cardioid mics, if the ATM is used close to the source it will give you a rising bass response, which is one of the reasons the designers have chosen to roll off the basic response at 70Hz rather than letting it extend lower.

Final Impression

I think Audio Technica have got it just about right with the ATM89R: at the asking price, it has to be one of the best bargains around at the moment. For vocals, the sound is clean and natural, with a pleasant warmth, while the high sensitivity makes it useful as an acoustic guitar mic, or for working with ensembles further away from the mic. The extended high‑end response also makes it suitable as a drum overhead, and the handling noise is as good as for any mic I've tried — particularly impressive is the way low‑frequency handling noises and cable noises are attenuated. Similarly, the pop shield has been designed to be more effective than most, and the overall feel of the mic is pleasingly solid, without it being too heavy for extended periods of live performance. The option of purchasing alternative pattern capsules is useful, though most project studio mics seem to be left permanently set to cardioid. If you can afford to spend £300 to £350, the Rode NT1 is my best buy at the moment, but if your budget is strictly sub‑£200, the ATM89R stands capsule and basket above the rest of the crowd.

Extras

  • ACCESSORIES: Soft zip pouch and stand‑mount clip.
  • OPTIONAL ACCESSORIES: AT853C‑ELE Cardioid capsule; AT853O‑ELE Omni capsule; AT853SC‑ELE Sub‑cardioid capsule; shock mounts; AC‑powered external phantom power supplies; mic cables; high‑Z matching transformer.

Pros

  • Warm, natural sound.
  • Low noise with good sensitivity.
  • Attractive, solid styling.
  • Very low handling noise.

Cons

  • No battery alternative to phantom power, which may limit

Summary

The best sub £200 back‑electret mic I've tried in recent months.