Mercenary Audio KM69

Unashamedly inspired by the Neumann KM84i, Mercenary Audio have tweaked their KM69 to suit their own tastes. Does it deliver the goods?

I don't know if it is still true today, but at one time if you bought a Rolls Royce car and looked in the handbook for the specifications, the horsepower rating would simply be described as 'adequate'. And that was all you needed to know — because if Rolls Royce said it was adequate, then it was. It seems to be a similar story with the KM69 microphone from Boston‑based audio dealers Mercenary Audio: their web site shows no technical spec and there's no spec sheet in the box. Mercenary have a reputation for talking key manufacturers into building specially tweaked versions of their existing products to bear the Mercenary Edition badge, and on occasions they get products specially built if they can't find what they're looking for elsewhere in the marketplace. They're known for being extremely picky, so if they're prepared to put their logo on a mic, there's every chance that it is going to be a bit special.

New Neumann?

Mercenary Audio were looking for a mic that would perform in a similar way to the now hard‑to‑find Neumann KM84i, particularly for recording hi‑hats, although the mic isn't limited to that application by any means. Apparently, the quest to purchase an original floundered not only on the basis of cost but also because many of the originals are now in very poor condition. The story goes that they talked over the problem with some high‑flying microphone designers they happened to know, then started work on what would eventually become their own KM69 model. I'm told that they got the sound of their mic very close to that of the KM84i but then did some further tweaking to the high‑end response, to pull out a bit more detail but without detracting from the smoothness or depth of the benchmark model.

Mercenary Audio's Fletcher, a very well‑known figure at US pro‑audio trade shows, says that the secret to getting this mic to sound right is in the amplifier design, and they built a number of prototypes with help from some of the respected designers amongst their circle of friends and associates. This makes perfect sense, because for a mic to work well on high‑pitched sounds such as hi‑hats, it needs to produce very low intermodulation distortion, and that, in turn, means that the preamp circuitry has to be very linear. The designers also tried various audio output transformers before settling on a combination they were really happy with. All the metalwork for the microphone, and even the wooden presentation box, is made in China, although it's not clear where the capsule originates from. I put the question to Fletcher, but all he could say is that the capsule is imported from a manufacturer with a long history of superior microphone capsule design — and that at their request Mercenary Audio agreed not to divulge who. He also confirmed that the electronics and assembly are all done in the US, with final testing carried out at their Foxboro, MA facility. The KM69 ships with a simple plastic stand‑mount clip and can be bought singly or in matched pairs.

Fletcher also explained that the lack of published spec is partly due to the lack of the necessary anechoic chamber and other test equipment, but he also believes that other mic specs are often heavily coloured by marketing hype based on such specifications. "I figured,” said Fletcher, "that if we nailed the hi‑hat sound I was trying to achieve, we should be pretty close to the other applications where I would normally employ a KM84i. This has translated into a mic that is also very adept at drum overheads, acoustic guitar, piano applications and even things like congas and glockenspiel. We've used the mic on horns (tenor saxophone, trumpet and trombone) without noticing anything other than a very natural and distinct tone.”

Even though this type of capsule can tolerate a fairly high SPL with no pad switch, the mic preamp circuitry could occasionally be overloaded by close‑up snares or loud guitar amps. Fletcher admits this — but as these aren't the intended applications, he isn't concerned. The mic also needs to be used in a shockmount where possible as, like the Neumann on which it is based, it can be susceptible to stand‑borne vibrations. Essentially, then, Fletcher would like to have you judge the mic by how well it works for you rather than by a spec sheet.

On Test

During the course of this review, I was asked to handle the live sound for a concert featuring Ray Burley and Gordon Giltrap, performing Ray's arrangements of some of Gordon's pieces. They wanted to mic their guitars (nylon-strung classical and steel-strung acoustics) rather than use pickups) and needed a PA system that would produce a near‑studio quality sound in the very reverberant Hollywell Music Room in Oxford. They both brought along their own AKG C414s but I persuaded them to try the KM69s first — and I'm glad they did. Not only did the KM69s deliver a beautifully pristine, well‑balanced sound, but we were also able to get a surprisingly high level before feedback, despite the close proximity of the speakers. I was particularly impressed by the detailed but very smooth high end.

After these initial impressions, I took the mics back to the studio, and they didn't disappoint there either. Although no figure is specified, their background noise was low enough not to be evident during normal recording, and a recorded acoustic guitar sounded beautifully well‑balanced, with a very detailed but refined top end. There was none of the harshness that some lesser mics produce, and the same is true when recording percussion, which is why the KM69 also makes such a well‑behaved hi‑hat mic or drum overhead. It exhibits good rejection of sound coming from behind, as you'd expect for a well‑designed cardioid mic, and because the tonality has no obvious added colour, there are few audio sources that this mic couldn't deal with.

The bottom line is that Mercenary Audio have once again come up with a product that upholds their reputation for audio quality. Some engineers swear by the mic that inspired the KM69, and although this is by no means a budget mic, it's a lot less expensive than an old — and therefore possibly unreliable — KM84.