Audio Technica AT873R

Paul White tests Audio Technica's latest low‑cost back‑electret mic and discovers that its performance is out of all proportion to its size.

Only a few short years ago, Audio Technica was just one amongst many microphone companies fighting for a place in the big league, but the launch of their AT4033 professional vocal mic changed their market position almost overnight. Here was a relatively low‑cost mic that seemed to 'out‑classic' the classics — in fact, many of the big names who'd been asked to try out the AT4033s refused to part with them. The success of the AT4033 was followed by the more recent introduction of the AT4050 multi‑pattern studio mic, which again compared favourably with established models, many of which were considerably more expensive. Having forced themselves into the collective consciousness of the pro market, Audio Technica have now turned their attention to the live and home recording arenas.

Home recording has become very sophisticated of late, and most people realise that in order to obtain professional results you have to use good microphones. Studio professionals use capacitor mics for most serious vocal and acoustic instrument recording, and over the past few years, we've seen the development of several fine‑sounding low‑cost capacitor mics based on the back‑electret principle. The AT873R is one such microphone, and although its compact format and hypercardioid response make it ideal for live work, its attractive price, combined with a very solid audio performance, puts it squarely in the frame as a home‑recording mic.

There are numerous back‑electrets already on the market, ranging from very cheap models designed to be stuck on top of camcorders, to top‑end mics, such as Audio Technica's own AT4033 and Bruel & Kjaer's ruthlessly accurate studio mics. The very cheap models tend to suffer from low sensitivity, and although they have a better high‑frequency performance than most dynamic mics, they have little else to offer. The AT873R is unusual in that it is one of the least expensive back‑electrets around, yet its sensitivity is considerably better than a typical dynamic mic, and closely approaches that of a quality studio capacitor mic.

Let's Get Physical

The AT873R comes complete with soft case and stand clip. Physically, it is a very unassuming mic, but you only have to pick it up to realise that it's very solidly put together. Unscrewing the tough wire basket reveals the capsule, which is supported on a shock‑resistant mounting; the preamp circuitry is hidden away in the handle and operates from conventional 48V phantom power. Being a hypercardioid mic, the AT873R exhibits a proximity effect, which results in an increase in bass end when used close up. To prevent this becoming excessive, the low end of the mic's response is gently rolled away, resulting in a nominally flat frequency range of 70Hz to 20kHz. The sensitivity is quoted as 14.1mV at 1Pa, and as a guide for comparison, a budget back‑electret mic might make it up to 5mV/Pa, whereas a really good studio capacitor mic can belt out around 20mV/Pa. The signal‑to‑noise figure of 67dB at 1kHz at 1Pa is also quite respectable, as is the dynamic range of 113dB. There's no built‑in pad, or even an on/off switch for that matter, so you can't expect this mic to give of its best when placed half an inch from a heavy metal snare drum, but it does work well as a drum overhead mic, as well as for general acoustic instrument work (including guitars).

The 100Ω output impedance of the AT873R means that it is suitable for any mixer or multitracker that has been specified for low‑impedance mic operation, but as there is no battery power option, the mic can only be used in systems where phantom powering is available.

The Sound

There is one school of thought which says that mics shouldn't have a sound, they should just tell it like it is — but I've been around long enough to know that in a blindfold test, the honest mic (if there is actually such a thing), rarely turns out to be the preferred one, especially when it comes to recording vocals. What we tend to go for is a mic that presents the sound in a slightly idealised fashion, giving the impression of honesty, yet still flattering the sound being recorded — rather like a portrait photograph taken with sympathetic lighting.

As the AT873R employs a relatively small capsule, I was expecting it to sound somewhat clinical, but its inherent top‑end clarity is combined with a degree of low‑end warmth, resulting in what I call a very 'comfortable' and open vocal sound. Inevitably, I did a direct comparison against one of my AKG C1000s, and was surprised to find the AT873R significantly more sensitive. Tonally, the AT873R is generally brighter and crisper‑sounding, but isn't in any way brittle or aggressive.

The hypercardioid response doesn't seem to cause any problems in the studio, provided you don't work too close to the mic. In fact, the (slight) additional separation you get from using a hypercardioid mic can actually be very welcome in multi‑player sessions. The AT873R's only weakness seems to be its susceptibility to popping — an element shared by just about every small mic I've come across. It's all down to physics Jim — to make a mesh pop filter work effectively, it has to be at least a couple of inches away from the mic, so add 50p to your overall budget for a chip pan splash guard to use as an external pop filter.

Summary

Despite its unassuming appearance, the AT873R is a very serious little mic, which combines good sensitivity with a workable balance of warmth and crispness. The handling noise is reasonably low (should you be thinking of taking it on gigs with you), and as well as making a great vocal mic, the AT873R is a particularly good choice for acoustic instruments — especially nylon‑strung acoustic guitars and other difficult instruments that low‑sensitivity mics tend to struggle with.

If price is no object, then you can find any number of better mics than the AT873R. If, however, you're looking for a mic that can turn in a studio‑quality performance for less than the VAT on a classic capacitor mic, then I have no hesitation in recommending that you put the AT873R right at the top of your short list. There's no doubt in my mind that this mic has what it takes to become established as a firm project studio favourite.