Pro Audio

From smooth to savage: the story of the Coles 4038

Like other studio classics we’ve come to know and love, the Coles 4038 was born out of practicality. Commissioned by the BBC for broadcasting purposes in the 1950s, the microphone was originally developed by Standard Telephones and Cables (STC) before landing in the Coles Electroacoustics factory in the 1970s.

Affordability and strength were high on the list of requirements from the BBC when they requested a new microphone. The 4038 delivered, proving to be consummate vocal performer, forever associated with the sound of the preeminent broadcaster. Yet, its future use in a recording studio context transcended its utilitarian origins, cementing its reputation as an elegant allrounder, which has more than a few tricks up its sleeve.Coles 4038 Close Up

Affectionately known as the “waffle iron”, the Coles 4038 has risen from humble beginnings to become one of the most recognisable symbols of recording quality.

In Ye Olde Times

In the lead up to the STC 4038, another microphone had left its own indelible imprint on the history of the BBC. The Marconi Type A was the sound of the broadcaster from the 1930s until the inception of 4038 in 1952. It too was a ribbon microphone, though the ribbon was quite thick by modern standards, which proved detrimental the performance of its first incarnation, the Type A.

Subsequent Marconi models saw improvements in ribbon technology. A Ticonal magnet was added to the AXBT model to increase the sensitivity by a sizeable 6dB. Though there were evolutionary leaps in the Marconi’s designs, the microphones themselves were prohibitively large and heavy. In fact, the Marconi shared a similar squarish aesthetic and proportion to the great RCA 44-BX from across the Atlantic.

While this wasn’t necessarily a problem for radio, the BBC was moving into the burgeoning field of television. This meant the need for a leaner, low profile microphone – that was also portable and suitable for TV production. Enter the 4038.

Its striking design wasn’t merely for the purpose of catching the eye. The microphone was an assemblage of a nickel-copper-iron alloy internal screen – which protected the aluminium ribbon and counteracted the resonances that afflicted Marconi microphones. This was subsequently shielded by gauze of varying coarseness and encased in its trademark perforated brass shell, all contributing to a design that captured sounds with minimal internal reflections.Coles 4038 Drum Kit

Moving into the Studio

While the 4038 had an immediate and long lasting influence on broadcasting, it has had a equally seismic impact in music recording. It was introduced in the early 1950s – which was a pivotal epoch in the evolution of pop music and a turning point in the history of recording.

Not long after its implementation in the BBC, the microphone became popular in recording studios across England. In the 1960s, British pop music was dominating the world and the competition for bands to outrank each other on the charts was fierce. This in turn fuelled advancements in multitrack recording technology and innovative production techniques. To catch up with the demand, engineers needed a reliable but classy microphone to turn to.

One such early champion of the 4038 was Glyn Johns. This is a guy whose drum sound was so influential that his miking technique has a name of its own: “The Glyn Johns Method”. This technique involves just three microphones – one in front of the kick drum, another above the drummer’s head, facing the snare and the other facing the snare too, but out to the right, beyond the floor tom.

This miking setup played a significant role in shaping sound of modern rock drums – the 4038 was  one of Mr Johns’ key weapons of choice. No doubt this is due in part the rock solid build quality of the microphone, not to mention that one of his main guinea pigs was John Bonham – drummer for Led Zeppelin and one of history’s finest. Others factors include the mic’s ability to represent the relative fullness of the bottom end and represent the primal beatings that Bonham would deliver on the kit in all their glory. So much for BBC politeness.

Smooth Response

Interpreting a microphone’s frequency response graph is an exercise in relativism. A perceived exaggeration in one area might simply be because another area isn’t unnaturally hyped. This kind of response is widespread among ribbon microphones – the Coles 4038 is no exception. It’s graph is remarkably flat from about 4oHz to approximately 15kHz.

As a result, it doesn’t skew the sound toward attention grabbing upper mids, the way that a condenser microphone might. It also doesn’t exhibit a low end rolloff, like some dynamic models do. Its thickness across a massive swathe of the spectrum was the perfect compliment to Bonham’s bombastic groove.

Beyond the maverick techniques of Glyn Johns, the 4038 has become one the first choices for stereo drum overheads in more conventional setups. It doesn’t accentuate the sizzle of cymbals and hats, which means gives the engineer more option when it comes to positioning.Coles 4038 Piano

Away from the Kit

The 4038 goes hand in hand with the guitar amp cabinet as well. The bitey mid range of the amp is tamed by the mellowness of the ribbon design. So, rather than exacerbating the resonance of and upper harmonics that amp speakers can sometimes put out, the 4038 has a cooling effect, presenting the full meatiness of the mid range. This principle also applies when miking lively brass instruments. Finding a balanced position which can offer up brassy cut through as well as a thick mid range and bottom end is a natural fit for the 4038.

Of course, its first purpose was for recording voice and it would be remiss of us not to mention its capabilities in tracking singers. The large diaphragm condenser has long been the archetypal lead vocal sound. And anyone that has grown accustomed to the glassy top end of a condenser would find it a challenge to get used to the sound of a 4038 on vocals. What it lacks in the hyper details of pop, it makes up for in low mid velvety warmth. Make sure your pop filter is handy though, ribbon mics do not being blasted with air.

Remarkably, in spite of the significant advances in ribbon technology since STC first developed the microphone, there’s been no changes to the design since the first one rolled off the production line in 1952. 2o years afterward, when the 4038 shifted production to Coles Electroacoustics, the bosses of that company – two former STC engineers – saw no reason to change a winning formula. Why would they?

It’s not often that a single piece of design has remained intact for almost 70 years and counting. The enduring popularity of the Coles 4038 is testament to the rigorous experimentation that went into its first build. More importantly though, its lives on through the engineers who have taken what was meant to be utilitarian and elevated it to the artistic.