Review: Line Audio CM3

Small diaphragm condenser mics are a standard requirement in anybody’s recording arsenal. Be it for recording acoustic guitar and a multitude of other stringed instruments, the bottom of a snare drum, hi-hats, a ride cymbal, overheads, or stereo micing anything at all — the small diaphragm condenser is a prudent choice. But which ‘SDC’ do you buy? Like most audio wares, there are dozens of choices out there these days. Do you shell out a few week’s wages for Neumann KM184s, or do you spend less after wading through the sea of SDCs from Rode, AKG, Sennheiser, and countless Chinese rebrands. Personally, I’ve had a lot of success with the venerable Octava MK102 and keep a number of modified units on hand for anything from drum overheads through to acoustic guitar. But there’s been plenty of times I’ve needed a less ‘pretty’ microphone for acoustic guitar and have reverted to a KM184 — a far more ‘neutral’ sounding microphone and certainly one of the best SDC mics available (pending the depth of your pockets of course).

For those on a budget it’s worth investigating a newcomer to the field from Swedish manufacturer, Line Audio. The CM3 is a minuscule small diaphragm condenser microphone with an equally minuscule price tag. You could own a pair of these and still have rent and food money for the week. 

Spec-wise the CM3 presents a typical cardioid polar pattern with a frequency response from 20Hz through to 20kHz — the frequency plot is flat between 100Hz and 16kHz (±1dB). The diaphragm will withstand up to 135dB SPL using a full 48V phantom power (clipping at 140dB), reducing to 120dB SPL with only 12V of phantom power (phantom voltage accepted runs from 12 to 52V). An older iteration of the CM3, manufactured from 2005 until November 2011 could only operate at voltages down to 24V, and also exhibited a boost in the top end starting from about 7kHz. As mentioned, the revised CM3 is virtually flat, and sounds like it too, but we’ll get to that in a moment. There are no pad or high pass filtering features — what the mic ‘sees’ is what you get. Line Audio have kept to the K.I.S.S. design ethos (keep it simple, stupid)…

A FINE LINE

So how do they sound? As far as sources were concerned all I had the opportunity to record with the CM3s was acoustic guitar and one track of drum overheads. In both situations the mics stood their ground admirably. What’s impressive is the incredibly flat, neutral response from the CM3s — they sound alarmingly natural. What’s more alarming is how these mics perform in comparison with their price. Quite astounding really. For a bit of an ad-hoc shootout I put the CM3, an Octava MC-012 and a Neumann KM184 in front of an acoustic guitar — standard ‘point it at the 12th fret’ mic setup. Often I find the Octavas are too ‘pretty’ for good sounding guitars, but with a slightly lacklustre instrument they can be just right. With better instruments the KM184 will give the best representation of the guitar.

In this situation I used my late ’70s Sigma (read: Japanese Martin). The incredibly flat response of the CM3 actually did a better job of capturing this guitar than the KM184, although the Neumann did have that certain ‘authoritative’ presence about it that only a Neumann can provide (the KM184 does have a slight rise around the 8kHz mark). However, the startlingly neutral CM3 won the day — honest, neutral, real: incredible for a microphone in this price range. Drum overheads did sound great via the CM3s but I went with the Octava MC-012 track as I like what they do to cymbals. But for all intents there was nothing wrong with the CM3 take. In fact, the imaging seemed far superior to the Octava version.

At this price you’d be daft not to add a pair of CM3s to your recording toolbox — regardless of which prestige mics reside in your studio. And for those on a shoestring budget, the CM3 should be your first investment in a versatile, balanced, honest to goodness pair of small diaphragm condenser mics — an utter bargain.