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Black magic box

Audio Technica AT4050

Article from The Mix, November 1994

High-quality studio mic

Buyers of good-quality studio mics now have more choice than ever. Coming with an impressive endorsee, the Audio-Technica AT4050 is definitely one to check out, as Bob Dormon discovers

Hmm, another black microphone. Does TV nowadays insist you're invisible, or are unobtrusive looks here to stay? Perhaps there's a more esoteric technical reason for it? Is sound drawn into the microphone like light into a black hole? Could brighter finishes reflect the sound and cause phase distortions? I don't think so. Oh well, 'You can have it in any colour so long as it's black' to paraphrase Henry Ford.

A legendary phrase, and Audio-Technica introduce their AT4050/CM5 Studio Capacitor Microphone as 'the stuff legends are made of'. Well the 'AT4050/CM5...' identity is a little long, so if it does go down in microphone mythology, it might be as 'the big black Jap cap mike'!

Audio-Technica are a venerable Japanese firm who've put in quite a respectable innings as a manufacturer of quality audio products. Thirty-two years ago, hi-fi enthusiast Hideo Matsushita started the company specifically to produce record player cartridges. He did very well, as any veteran vinyl junkie will attest. Furthermore, the company anticipated the decline of vinyl and branched out into the pro-audio field.

Audio-Technica still produce high quality cartridges, but their output also includes headphones, mics, stands, and stereo microphones for video, together with specialised audio mixers. Audio-Technica might not have the pro-audio maturity of Neumann or AKG, but they continue to manufacture products in this highly competitive area which are difficult to ignore.


The fixed (cardioid) polar pattern AT4033, was well received and favourably compared to the AKG 414. This model not only raised a few eyebrows, but raised expectations of what Audio-Technica could and would produce next.

The AT4050/CM5 is the result. Endorsed by musician/producer Alan 'Dark Side of the Moon' Parsons, the new AT4050/CM5 offers a choice of polar patterns. It's the usual gang of three: omnidirectional, cardioid and figure-of-eight.

A -10dB pad and 80Hz (12dB per octave) low end roll-off filter complete the set of white, slightly raised, no-fuss switches, tastefully marked with grey legends. Marginally taller, but otherwise identical in overall appearance, the AT4050 (or CM5 for short) shares its predecessor's matt black metal body. The look and general construction of this microphone inspire confidence. It's weighty (nearly as much as a Neumann U87), rugged and definitely well crafted. Perhaps there is something in the blurb about 'legends', as the CM5 is certainly built to last.

At the business end, the dual membrane large diaphragm capsule is caged in two layers of tough, rigid wire mesh. That's probably just as well, because the AT8441 'cat's cradle' shock mount is a bit of a fiddle to fit. I can envisage many a novice tape-op dropping this audiotreasure as they struggle to squeeze the CM5 through the heavy-duty elastic band that holds it in place.

This is no facetious understatement, as the CM5 has a neat groove encircling its body that the elastic band slots into to prevent it slipping.

Isolastic mounting is not a feature peculiar to Audio-Technica, AKG produce the H30 for smaller microphones. However, most cat's cradles rely on a elastically suspended metal clasp that attaches to the mic's body. But if straining with black rubber doesn't appeal, Audio-Technica do offer a basic mic stand clamp mount (AT8430).

In Use

As a capacitor microphone, the CM5 requires 48V DC phantom power to bring its transformerless circuitry to life. A feature of transformers used on microphones is they help to reduce RF interference, but they can affect the mic's response to transients and low frequencies. Bereft of a transformer output stage, the CM5 presents an improved transient response and overall sonic transparency.

A side-effect of large diaphragm microphone design is that the high frequencies are exaggerated slightly, owing to resonant frequency characteristics of the diaphragm.

However, this kind of high frequency presence was well contained on the CM5. None of your sibilant, squeaky sheen here, that some like to suggest is 'ideal for digital recording'. High frequencies are useful, but an accurate microphone is even more so! And to my delight, the CM5's showing on various instruments suggests that it falls into the latter category.

Getting intimate

On acoustic guitar, the often troublesome low frequencies were detailed, while the top strings enjoyed a distinct lack of coloration. The cardioid setting was intimate, while the omnidirectional polar pattern was a pleasant surprise, as there was no dramatic change in tone or loss of warmth that frequently accompanies this configuration.

When analysing the guitar recordings I was struck by how much it actually sounded like the acoustic guitar I've been fondling for the past fifteen years. Many mics mangle the middle, tweak the top or boost the bottom, but the CM5 just seemed to listen to the guitar! Most refreshing. Switching in the low cut filter produced predictable results by rounding off the bottom end nicely, controlling over-enthusiastic resonances and booms from occasional slaps on the guitar's body.

Talking of slaps, it was time to try out the CM5 on bongos. In cardioid mode and using the -10dB pad, the drums appeared to lack presence, but overall seemed really quite warm and natural. However, it was the figure-of-eight pattern that really scored here.

For those of you that have yet to encounter this configuration, figure-of-eight is a polar pattern that really lives up to its name. The microphone's field of sensitivity extends outward from the front and back. The sides are very insensitive, and the resulting polar pattern resembles a large '8' with the mic itself in the middle.

With the CM5 positioned sideways above the bongos - front and back perpendicular to the drum skins - the figure-of-eight pattern picked up the colourful resonances and bottom end boom splendidly. An improvement in definition was also achieved, as each side of the mic balloons out from the middle, picking up the individual drums.

As for vocals, a pleasing lack of sibilance was immediately apparent. Even though the frequency response graphs provided show a hump around 10kHz (typical for large diaphragm mics), it was the light lift around 2.5kHz that was more obvious on vocals. This mild, middly colouration does set the CM5 apart from the warmth you'd associate with a Neumann U87, while the balanced top end keeps it a safe distance from the general brightness of an AKG 414.

Up close, the pronounced bass due to the proximity effect was warm and reassuring, somewhat reminiscent of the shipping forecast. At this close range (around three inches) popping was understandably pronounced, and thus the optional AT8137 foam 'windscreen' is a must if you revel in this kind of vocal intimacy.

Finally, I enlisted the saxophone skills of Andy Mackay. Once again, the transparency of the CM5 was obvious. An ideal characteristic for an engineer, but for a sax player..? Well Andy's heard his instruments through numerous microphones, and his thoughts on the CM5 were similar to mine.

There was however one notable exception; flattery. Flattery can get you everywhere, and unlike the camera, a microphone sometimes lies. Being an honest sort of mic, the CM5 doesn't try to colour the sound, but musicians frequently find themselves favouring microphones that don't so much honour their sound as add to it. So is honesty the best policy? I prefer to think so. Being straight will guarantee an approving audience, but there's still a place for a bit of a character.


Audio-Technica have produced a fine microphone with a sonic transparency that makes it worthy of its price. The CM5 may well find favour in classical music recording circles and suchlike.

As for the rest of us? Well, it could be the answer to an audio sampler's dream or the new 'all-rounder' for a recording studio, as I'm sure it will perform well on a whole range of instruments. What you think of it will largely depend on the values you place on a microphone's response. Personally, I think honesty is a quality to look for in any character.

The essentials...

Price inc VAT: £925 (or £995 with shock mount.)

More from: Audio Technica, (Contact Details)

Spec check

Elements two externally polarized (DC bias) capacitor
Polar Patterns Cardioid, Omni, Figure-of-eight
Frequency Response 20 - 20,000Hz
Open Circuit Sensitivity -36dB (15.8mV)
(1kHz) ±2dB, re 1V at 1 Pa
Impedance 100 ohms
Maximum Input 149dB SPL, 1kHz at 1%
THD 159dB SPL, with 10dB pad (nominal)
Noise, (A-Weighted) 17dB SPL
Dynamic Range 132dB, 1kHz at Max SPL
Signal To Noise Ratio 77dB, 1kHz at 1 Pa
Hi-Pass Filter (Low-End Roll-Off) 80Hz, 12dB/octave
Power Requirements 48V DC phantom, (+/-4V)
Current Consumption 3.2mA
Weight 480g
Dimensions 188 x 53.4mm (max)

Previous Article in this issue

The Z-plane to Hyperspace

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Crossing over the tracks

Publisher: The Mix - Music Maker Publications (UK), Future Publishing.

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...


The Mix - Nov 1994

Donated by: Colin Potter

Coverdisc: Mike Gorman

Control Room

Review by Bob Dormon

Previous article in this issue:

> The Z-plane to Hyperspace

Next article in this issue:

> Crossing over the tracks

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