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Ribbon Microphone
Published June 2002
By Hugh Robjohns

Built as an authentic replica of one of the all-time classic mics, this premium ribbon model brings a unique character to the modern studio.

There has been something of a resurgence of interest in ribbon microphones in recent years — particularly by those engineers involved in recording string sections and orchestras. Although ribbon mics were largely surpassed by capacitor mics in the recording studio thirty or more years ago, principally for reasons of convenience and fashion, a decent ribbon mic can still deliver a very high-quality signal. In fact, advances in preamp design now mean that the low noise floor inherent in ribbon mic designs can be fully realised to deliver a dynamic range worthy of 24-bit digital systems.

AEA R44C Ribbon Microphone.Advances in preamp design now mean that the low noise floor inherent in ribbon mic designs can be fully realised to deliver a dynamic range worthy of 24-bit digital systems.Audio Engineering Associates (AEA) are an American company owned and run by Wes Dooley — a recording engineer with a long and detailed experience of ribbon mics including the classic Coles 4038 'BBC ribbon'. His company specialises in both familiar and unusual audio-related equipment and services, including a lot of forensic work. Amongst the product line is an intriguing range of specialist microphone mounting equipment, with a clever modular system which can be used for conventional stereo arrays such as ORTF, as well as Decca Tree configurations in various sizes. There are also vintage-style microphones which turn out to be table lamps or empty shells designed to house modern microphones for use on TV presenters' desks!

However, the subject of this review is an authentic recreation of the classic 1936 RCA 44 bidirectional ribbon mic — a much sought-after design in studios around the world, especially in the USA. Ribbon mics such as the 44, and its later siblings the 77 and KU3, were popular not only in broadcasting studios, but also on the scoring stages of most film studios where the ribbon contributed to some fantastically silky string sounds. Indeed, many of the top American scoring stages still use these ribbon mics today.

The AEA R44C version of the RCA classic is hand built by Wes Dooley using the same 1.8-micron ribbon material originally manufactured for RCA. The constituent parts of the new mic are fully interchangeable with original RCA 44B and 44BX models — the recreation is that accurate.

This mic is instantly recognisable for its shape, the black and polished chrome finish, and the huge grille. It is also very large and heavy, measuring 304 x 121 x 86mm (hwd) and weighing over 4kg — few ordinary boom-arm mic stands will support this beast without a severe degree of droop! The mic is fixed permanently into a cradle yoke with an integral stand adaptor and shockmount, and a captive two-metre cable terminated in an XLR.

With such a heavy but delicate microphone, storage and transportation could be a problem, but the R44C is shipped in a custom nylon cordura carrying case lined with a hard protective foam. A cotton bag protects the mic itself while the case holds it in the approved vertical position.

AEA offer some variations on the RC44 theme. The NE option, for example, incorporates some elements of the international version of the original RCA mic, with a lighter case, reduced sensitivity to hum, and a cloth-covered XLR cable. There is also an X option which employs stronger neodymium magnets for a 6dB louder output and a slightly more forward sound quality. Hand-matched pairs are available for stereo applications too.

In The Studio

The review model was an R44CX — the original version, but incorporating the increased output level option to provide around 5mV/Pa (instead of 2.5mV/Pa) which equates to a nominal sensitivity of about -44dBu. The mic exhibited the classic figure-of-eight polar response you would expect from a simple ribbon, with deep, well-defined nulls to the sides and reasonably broad front and rear lobes. The specifications suggest the mic can withstand a maximum SPL of a frightening 165dB and has a source impedance of 270Ω.

The frequency response is far from flat, being both 'ragged' and exhibiting a very characteristic overall tilt in response of around 2dB/octave, with a very strong bass and slightly weaker treble. However, the short-term frequency response variations are not individually audible, and the tilted response provides a lovely, rich quality which easily lives up to the impression given by its attractive vintage appearance.

Like any first-order pressure-gradient mic, the R44C has an obvious proximity bass lift when used too close — and by that I mean anything less than about a metre — and is clearly balanced to be used at a 'more respectful' distance, commensurate with its original studio role, both for speech and music ensembles. Placed at a typical distance from a cello, for example, it gives a fantastically sonorous, weighty sound (boosting the confidence of my daughter considerably in the process!).

The R44C lends all voices a degree of 'scale' and body which is often hard to achieve with more modern designs, technically competent though most are these days. On acoustic instruments the mic reveals a fast, detailed character, with a warm upper bass response and a rich, smooth treble which is musically complementary and easy on the ear. Stringed instruments — orchestral strings, harps, guitars and so forth — simply love the ribbon! Percussion is handled very well too, as is brass, especially trumpets. The accurate polar response allows unwanted spill to be controlled effectively, although care obviously has to be taken with a rear lobe that is as sensitive as the front. In the days of mono radio broadcasts both sides of the original RCA mic would be used, placing the mic between two musicians with their relative positions determining the balance of their instruments. This technique is still useful today, if used thoughtfully.

That this mic is an authentic classic is beyond question. It has a strong and recognisable character which should be used as such. While very expensive in the UK, indeed well out of the range of many, the fact that a mic such as this exists at all is worth celebrating. Recordings made with this mic exhibit a fabulous character which is hard to achieve with more modern fare.

Published June 2002