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Line Audio OM1 Omnidirectional Microphone

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Line Audio OM1 Omnidirectional Microphone

PostPosted: Thu Sep 15, 2016 9:05 pm
by Mike Stranks

Setting the Scene

These days most of my recording work is of live concerts recorded either to multitrack for subsequent mixing or a pair of mics straight to stereo. The repertoire ranges from classical quartets, duets and soloists through sacred choir works to middle-of-the road popular material – think ‘Friday Night is Music Night’. The aim is always to capture the essence of the concert with no tricksy stuff afterwards. Maybe some judicious EQ adjustment, some tinkering with the overall reverb, and maybe the slightest of sweetening… what I call ‘my fairy-dust’!

Increasingly over the past three or four years I’ve been conscious of the de facto characteristic of many of the mics in the price-point at which I operate – ie less than £400 when new. That characteristic is either a definite presence peak, a boost of a few dBs above 5 or 6 KHz – or both. The key factor in raising my awareness was the purchase of a pair of Sennheiser MD211 dynamic omnidirectional mics from the 60s. Not only did I love the smoothness of tone that this mic produces, but I was reminded that there is another world than the cardioid one. When I started location recording back in the early 70s the use of omnidirectional mics was considered normal and my first recording mentor owned far more omnis than cardioids. In fact, that’s where I first came across the Sennheiser mic mentioned above. Since buying those mics, not only have I been looking out for mics that avoid the presence and high frequency lift, but I’ve also been slowly accumulating some omnis – a Sennheiser MD21 and a BeyerDynamic 101 have now joined the club.

Line Audio Mics

I first became aware of Line Audio through reading favourable comments about their CM3 wide cardioid (technically ‘hypocardioid’; thank you Mr Robjohns) microphone. Its discreet size and colour were equally as attractive as its claimed ruler-flat response. But I’ve always hesitated; not only do I already have a pair of ‘hypos’, but detailed reading about the CM3 indicated that it was only ruler-flat when used in the near-field – not something I was looking for. I then became aware of their omni mic – the OM1 – and reading the reviews and hearing some recordings persuaded me to buy a pair.

But before I talk about the OM1, a little about Line Audio. Founded in 1989 in Sweden, the company is effectively a single person business run by Roger Jonsson. Being such a small business does mean that sometimes there is a delay after ordering. ‘Custom-made’ can be the name of the game. The company produces the CM3 (hypocardioid) and OM1 (omnidirectional) mics as well as two-channel and eight-channel microphone preamplifiers. As far as mics are concerned, Roger imports capsules from China then puts them through a rigorous evaluation – rejecting a significant number - before incorporating them into his mics with his own circuit design.

Mics and other products may be purchased direct from Line Audio in Sweden, but the mics are very actively promoted by No Hype Audio – another one-person business - in Belgium. In some ways Jon-Pol Gerard of No Hype is the public face of Line Audio. Jon-Pol is active on Facebook and audio forums promoting and explaining the products and actively seeking comments and user demonstrations.

The OM1 Microphone

Having decided to rationalise my mic collection I was able to purchase a pair of OM1s. As everyone who’s seen them says, they’re tiny. As you’ll see from the picture above they are slightly bigger than an XLR plug – exactly the same diameter, but a little longer: 77mm to be precise. They come in a dinky little clear plastic box together with a reassuringly tight-gripping clip and a foam windshield. (You can find a whole set of my pictures of the mic linked-to below)

The specification is as follows:
Type: Condenser microphone (permanently biased 10mm capsule). Polar pattern: Omni. Frequency response: 20-20000Hz +-1dB (on-axis, at 1m distance, 1/12 octave narrow smoothing, 23 C). Phantom power: 12 - 48V (P48 recommended for best performance). Current consumption: 4 mA. Impedance: <100 Ohm. Sensitivity: 8mV/PA -42dB. S/N ratio (DIN/CCIR): 76dB(A)/66dB. Noise level: 18dB(A). Max SPL: 133dB @0.5% THD (130dB@24V, 120dB @ 12V). Size: 77mm x 20mm.

Some may be concerned that the design of the mic with a micro-capsule will inevitably result in a higher than average self-noise. It’s shown as 18dB(A). For comparison, that favourite SDC, the Rode NT5, is 16dBA. The output is shown as 8mV/PA. That’s certainly not a ‘hot’ mic, but it’s perfectly acceptable and you shouldn’t need a stellar mic-pre to get satisfactory noise-free levels from them. Certainly my Zoom H5 gave perfectly acceptable results in my quick test so I’m confident that all will be well when I use my ‘better’ preamps.

On Test

As I don’t have any concert recordings in the pipeline and am some distance from my contacts with decent musical instruments and who can play them, my testing has been confined to some voice tests – both male and female – and recording ambience in the garden. All tests were made using a spaced pair (42cms) straight into the Zoom H5, using the recorder’s onboard 48-volt phantom power and with no limiting, compression or anything else in the recording chain. Given that this was a rough ‘n’ ready test and that the H5 wouldn’t be my first choice for critical evaluation work I was very pleased. The voices came across very naturally – some of the most natural voice recordings I’ve heard – and the garden sounds showed that the claimed ruler-flat response is probably true. On headphones, the twittering of birds, the bark of a neighbour’s dog and the rumble of passing traffic were all faithfully recorded. Certainly the low-mids and bass were there as they should be; the claimed flat response down to 20Hz seems fully justified. These are not mics to put in any old clip on any old stand. The bass extension is such that good isolation is a prerequisite; fortunately I’m well-served by a selection of Rycote Invision clips.

A link to one of my crude tests is given below. For those who want to explore the sound in more detail there’s an excellent and intelligent thread, with numerous examples at:

Value for Money

In the UK these mics may currently be purchased for £99 inc VAT each. To me that’s astounding value for money and I don’t hesitate to recommend them. If you’re a concert or classical recordist then they would form a useful addition to your mic collection – even if you usually inhabit loftier regions! Because they are so neutral I’d imagine they be brilliant as overhead mics on a kit or as room mics.

A Final Warning!

As I’ve discovered, quality omnidirectional mics are ruthless at exposing rooms and venues with iffy acoustics and are not very tolerant of poor positioning… but it helps us raise our game doesn’t it!



Line Audio:

No Hype Audio:

Sound Test to Download:

Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Sat Sep 17, 2016 2:43 am
by Tim Gillett
Thanks Mike for the great review. I'd not heard of these mics.

I looked up the website details of the OM1 and the frequency response plot.

Re listening tests, I suspect that we will struggle, just listening, to confirm whether the plot is accurate as published. Sure, by experienced listening, we can confirm in general terms that the mic's response is not greatly inaccurate, but a proper mic measurement test facility - which most of us will probably never have at home, or learn the test techniques and protocols to interpret the data validly - can measure the mic's response to a far greater accuracy than mere listening tests. And that's not to belittle the great analyzing abilities of human hearing. It just has its limits.

That's my understanding at least. I know you didnt say otherwise. I'm just adding this as a comment.


Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Sat Sep 17, 2016 10:47 am
by Mike Stranks
Of course you're right Tim and I readily acknowledge that my very rough and ready test proves absolutely nothing! :lol:

Well, that's not strictly true, but probably any half-decent mic would have done a similar job. However, I was able to judge that the upper boost which some of my other mics have wasn't there and equally the low extension is impressive.

The examples in the extended Gearslutz thread are excellent - and not all using stellar outboard. It was those above all that persuaded me to splash the cash.

(and in passing... a delight to read an intelligent 'open' discussion on GS which doesn't descend to grandstanding and dogmatism...)

Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Mon Oct 10, 2016 9:52 am
by Mike Stranks
So.... finally had the opportunity to do a decent recording of a village church & choir evensong last night. Just an ordinary church and an ordinary choir in the sense that they were not professionals or linked to a 'known' church with a musical reputation. Good, but not great...

But the mics... a very open and unhyped sound with a real sense of 'being there' because the mics were not drawing attention to themselves in any way at all.

And of course, as was to be expected with decent omnis... they picked up every cough, foot-shuffle, footstep, door-click etc etc etc.... but that's the joys of live recording... :)

Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Mon Oct 10, 2016 10:34 pm
by blinddrew
Mike Stranks wrote:And of course, as was to be expected with decent omnis... they picked up every cough, foot-shuffle, footstep, door-click etc etc etc.... but that's the joys of live recording... :)
Presumably also the unintentionally ironic "Sssh!" that's the loudest part of the recording? ;)

Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Tue Oct 11, 2016 10:50 am
by James Perrett
Thanks for this review Mike - I've been wondering about asking for a pair of their mics for Christmas...

Re: Line Audio OM1 Omnidirectional Microphone

PostPosted: Wed Mar 29, 2017 3:48 am
by philharmony
I find these are lovely mics and have been using them 22" apart with a Zoom H4nPro recorder. Here is a link to a rehearsal recording of Bloch's Schelomo. ... s-10-22-16