Happy 6th birthday or why I love my Soundman OKM II binaural microphones

Wednesday, October 29th, 2008 | field recording

I was looking through an old diary from 2002 the other day and noticed that on Thursday 3rd October I ordered my pair of Soundman OKM classic II binaural microphones. I got the set with the a3 preamp which costs extra than buying the mics alone. The whole lot came in at £150.18 which was quite an extravagance for me at that time. A quick look at DACS their UK distributor shows that they are still selling for the same price as 6 years ago. 

I distinctly remember being fairly underwhelmed when I received my purchase in the mail a few days later. The all plastic construction of the mics and the pre-amp was more in keeping with a microphone one tenth of the price of the OKM’s. The mics looked for all the world like a really nasty set of 80’s in-ear headphones and the Pre-amp looked especially delicate and I was concerned that I’d break something fairly soon. 

After this fairly lackluster opening my opinion began to change when I started to test them out. The OKM’s are designed to fit into the ear, their capsules pointing outward. Worn like this sound arrives at the microphones in more or less the same way it arrives at your ears which is a technique known as binaural recording. Because of the physical design of the human ear sounds coming from different directions all sound slightly different to us. Sound coming form behind us for example is filtered through the back of the ear and sounds more muffled than sounds emanating from directly in front (try it by clicking your fingers around your head if you don’t believe me). The OKM’s pick all this up really well with an especially good bass response. I have heard criticism of harsh treble and weak lower mids with the OKM’s but I have never had any problems in these areas with my set up. 

The tiny size and semi-concealed nature of these microphones makes them excellent for field recording where a larger mic may be cumbersome, distracting, or not practical. Recording while riding around on a bicycle springs to mind. Of course you don’t have to wear the mics in your ears, in the time I have had mine I have become quite adept at holding both in one hand and rotating the capsules by rolling their cables between thumb and forefinger to get the desired stereo spread. The mics can also be attached to a dummy head (or any head sized solid object) for recordings where you want a rock solid stereo field. I recently did this for a drum recording where I found that I could not keep my head still enough while playing the drums. 

I think my favorite thing of all about the OKM’s is that they are so easy to carry around and use. Within 15 seconds they can be out of my bag, plugged into my recorder, levels set and ready to record. I’ve captured so many fleeting moments this way that I’m sure I would have missed with a more complicated set-up.

I used to use the OKM’s with a sony mini-disc recorder which sadly died and was replaced by a sharp mini-disc recorder which also died eventually after one to many drops. Both machines gave excellent results although recordings of very quiet sources showed a fair bit of pre-amp hiss. I replaced my dead MD’s with a Zoom H4 recorder which was really horrible and I stopped making field recordings for quite a while as they sounded terrible! Recently I picked up a Sony PCM-D50 which has totally rekindled my love for field recording. It’s solid, dependable, economical, and has proper knobs and switches for all the important controls. The D50’s preamps are much better than in my old mini-disc recorders and they make the H4 sound like a bad joke. 

Despite my initial concerns about the OKM’s build quality they have lasted 6 years without any problems at all. Sounds I have captured using these mics have appeared on all of my albums and have serverd to inspire me to listen to everyday things in new ways.

Here are a few of my recordings – you might try using headphones to listen as it’s the only way to hear the proper binaural effect.

Chimes recorded at quite high gain and played quietly

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The police over Hackney – Perfect summer afternoon

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With the microphones jammed down the back of my fridge

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Drums recorded from the players perspective

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Take care,

Leafcutter John.

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18 Comments to Happy 6th birthday or why I love my Soundman OKM II binaural microphones

October 30, 2008

Hi John,

I have a pair of SoundProfessionals SP-TFB-2 in-ear binaural mics ($69) and they are immense. I have been umming and ahhing over the OKMs for a while, particularly as my pet rat has chewed through the mic cables on mine several times now *shakes fist* and they are on their last legs. The PCM-D50 looks brilliant – I am currently holding a Hi-MD recorder together at the seams… I need an upgrade… Interesting stuff anyway. Binaural is the way forward(backward).

P.S. What headphones do you like? I find the range of stereo image reproduction to be quite broad.

Leafcutter John
October 30, 2008

Hi Matt, I always wondered what the SoundProfessionals were like. Shame about the rat attack. I had a friend who’s rat had a taste for oil paints, when those ran out he turned to audio cables. The PCM-D50 is fantastic, more bulky than a MD but more user friendly.

I had a pair of BEYER DYNAMIC DT 770 closed back headphones which were great sounding and super comfortable. Unfortunately I left them in a hotel in Vienna and have not liked any headphones since them. They were especially good for using on the plane or bus as they really blocked out background sounds.

November 17, 2008

Your concerns about the OKMs build quality were not entirely unfounded on me. Mine have lost the entire enclosure on one channel and half on the other. I hope you are keeping them in a nice little carry case – I used to just shove mine in my bag like a pair of cheap earbuds and now look at me. Oh the shame. I should probably contact DACS to see if I can get them fixed ;)

Also DT770s are the most lovely headphones ever.

November 18, 2008

Awesome recording quality and great binaural sound. Absolutely love this drum sample – is it licensed in any way? I’d like to use it in a mixdown (Creative Commons)…

Leafcutter John
November 19, 2008

Asaguare, If you credit me then I’m happy for you to use the drum recording. I’d be really interested to hear what you do with my wobbly drumming skills too.

November 25, 2008

Hi John, actually I intended to create a ballad (kinda Tom Waits style) to use your drums for, but today I stumbled upon such loverly Gospel acapellas… well, your drums had the perfect BPM for that (just had to twiddle some millisec areas). So they make a nice tune even nicer ;o)
The song has also been published on Jamacast; of course I explicitly credited your sample.

[…] although I got a better sound without the low cutoff filter enabled. For some other examples visit this post on Leafcutter John’s Leafcutter John’s […]

c. todd [phylum_sinter]
December 14, 2008

Hi John,

Very much enjoy the quality of the field recordings on your albums, i had always wondered how they were captured — to be honest i had guessed a boom condenser and some fancy DAT setup.

Recently i’ve been playing around with my md recorder and a soundpro sp-spsm1 (which is a single point stereo mini-condenser) in cahoots with a aa-battery module i built to extend the headroom of the mic, but i’m still wishing i had proper gain adjustment. Do you think the OKM (or the D-50) are a good investment for someone that mangles field recordings pretty thoroughly inside a computer, or should i just stick with putting various layers of stockings over the mic like i am now to prevent clipping?

Also curious if the D-50’s included mics configure to pick up in proper binaural?

cheers and thanks for the informative post,

Leafcutter John
December 14, 2008

Well the OKM pre-amp has a 20db pad but i’ve misplaced it at the moment so I’m relying on the D-50 to power the mics and I use the gain control on the D-50 to get the right level. I’ve had no problem with clipping.

Does your MD recorder not have a mic/line in gain control? That’s where i would start trying to avoid clipping. If it’s your mics themselves that are overloading then yes you are stuck with the stocking solution.

I’m not sure what you mean by your last question – do the D-50’s mics record binaurally?? If that’s what you mean then the answer is no. They record in Stereo but they can be positioned like shown near the start of this video: http://uk.youtube.com/watch?v=8dLLLyNMXCg

because they are attached to the D-50 body they cant be used for binaural recording where the microphones are arranged either side of a head or dummy or in the case of the OKM’s placed directly into the ears.

If you are happy with your current set up then I don’t see why you should change – though with your current mic you are NOT doing binaural recording – If you want mic’s for binaural recording you’ll need something like the OKM’s where the L & R elements are separate.

Best wishes,


Winter Recordings
January 11, 2009

[…] in trying out some binaural recording myself. So, after a little research, including discovery of a good post over at Leafcutter John’s web site, I bagged the OKI Soundman binaural mic’s for some […]

[…] song is truly experimental in nature. I started of by recording the instrument using my little sony d-50 and my binaural Soundman mics. I gave myself the rule that I could not use my fingers directly to […]

Daniel Jewesbury
March 21, 2009

Hi John
Was wondering what happens if I want to use OKMs with a larger field recorder with phantom powered XLR mic inputs (I use an Edirol R4). What’s the situation on the power supply then?
Perhaps this comment trail is dead now.. but would love to hear if you have any info on this, i’m confused at the moment.

Leafcutter John
March 21, 2009


I think you need something like this: http://www.kmraudio.com/catalogue/product_info.php/cPath/1/products_id/2316

It seems a bit pricey though!


April 26, 2009

Nice! As for minidisc, it is incredible how good the preamps are in those things. One still cannot buy any digital recorder that small that sounds that good… incredible! For a solid state recorder I ended up going for the FR-2LE and have used it a bit, but the size is a bit much sometimes.

May 26, 2009

Do I need the OKM pre-amp with the D-50?
Or does the D-50 built-in preamp even sound better?

June 2, 2009

It’s always useful to learn from other’s experience, so thanks for this post.

I recently saw you performing at Village Underground and was interested in the mic and boom you were using. Any chance of another post in the ‘microphone’ tag?

July 8, 2009

I currently use a Zoom H2, and I am Thinking about upgrading to a Sony PCmd50. I use the Sound Professionals In-Ear Binoral Microphones. Basicly I am thinking on switching recorders because I get some Random RF noise when using these mics with the zoom, and no I don’t have a cell phone in my pocket when I record. Also, I would like it if there wasn’t as much Pre-amp noise in quiet recording situations. If anyone has this combination: Pcmd50 and Sound Professional In-ear Mics, and could share some sample recordings with me, I would be very greatful. Drew.

February 13, 2013

Hi john, thanks for that article I stumbled over right now. I use the okms since 2003 and i m totally happy with them, but also i dont have any comparison with other binaural mics..
I use them now with an xlr adapter on a tascam dr.100 , but thats big and cumbersome and i m looking for a smaller solution. ist the plugin power of the mic in of the sony d50 working well? do you know if there are some other recorders in that price range you can recommend? Often the new recorders do not have the plugin power the okm refers to anymore.. thanks!

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