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Review: Sanken CO-100K 100 kHz Super-Wide Range Condenser Microphone

“The first 100kHz microphone in the world designed for professional recording,” Sanken’s CO-100K is truly a mic to be experienced. 

The conventional wisdom regarding the frequency range of human hearing is that it falls between 20 Hz to 20 kHz. So why on earth would you need a microphone that is capable of capturing frequencies up to 100 kHz? 

I have a number of theories as to why and how the information above 20 kHz really does influence what we hear and perceive, even in a 44.1 kHz world. But I’m not an acoustical scientist and this not a white paper; I’m simply a recording engineer and this is a product review, so onward.

Speaking as a part of the team here at Manifold Studios, it turns out wedidneed some microphones that go that high — especially once we heard them. After spending some time recording and experimenting with a pair of Sanken CO-100K microphones and comparing them to other options in our mic locker, it became crystal clear (pun intended) that these mics capture nuanced detail in a way that our ears—and, more importantly, our clients — will immediately appreciate.


The CO-100K is a 48v phantom-powered omnidirectional condenser microphone with factory-listed specs that reveal a frequency range from 20 Hz to 100 kHz, a maximum SPL of 125 dB, and an equivalent noise level of 22dB (A-weighted). After unpacking the demo set from Sanken, I did a quick glance at the included measurement data. The first thing I noticed was a very flat response from 20 Hz to 10 kHz, then a rise of 6dB from 10k up to 20kHz. Ordinarily, I would be wary of a mic with that kind of high end lift. My previous experience when I’ve seen this kind of curve has been one of a false and hyped top end that I don’t like. So it was with a little skepticism that I fired them up and started listening.

In Use

Well, wow. What I did hear is that the top end just seems to go out to infinity. While it does feel extended, it’s always seamlessly connected to the rest of the sound. I never got the impression of the high frequencies simply being boosted; I was hearing things I hadn’t heard before when a mic was between the source and me. 

After listening for a while, I decided to look again at the specs. With a more careful eye I noticed that the rise was very smooth with almost no deviation from the graceful arc described by the response curve. In other words, pick any point along the mic’s response curve, and the amount of variation within 20 percent above or below that frequency is very small. I don’t know if that is the reason why the high end sounds so natural even with the lift, but the lesson I was reminded of that day is to let my ears decide, in spite of making assumptions based on a list of specifications.

To be sure my impressions were not a result of having more high-end in the generally accepted audible range, Michael Tiemann (the studio owner) wisely suggested that we take the signal from our comparison mic (DPA 4006-TL omni) and — using our most neutral and precise EQ (the 5-band, stereo parametric GML 8200) — attempt to match what we heard from the CO-100K. 

Nope. Not the same. While we could definitely get the output of the high frequency to sound equally loud — and certainly down in the rest of the frequency range they very much agreed — the application of EQ to the 4006-TL sounded like the application of EQ, whereas the CO-100K sparkled in a way that sounded completely natural and completely smooth. Not to just our ears, but looking carefully at the 96k waveforms, it was obvious that the Sanken pair was picking up harmonic information far beyond the “accepted” upper range of hearing (20 kHz). 

Our listening tests convinced us that there is information being captured by these microphones that cannot be duplicated by simply boosting frequencies reachable with an EQ, even if you can match the apparent frequency response. This was even more apparent in a stereo miking configuration. The localization of sounds in the stereo field is completely natural and much more precise than I’m used to hearing with a spaced omni set-up. Even though these mics have very even omni patterns, as you cruise past 20k on your way to up to 100k, physics dictates that the pick-up pattern gets more directional. (A side note: this is one of those previously mentioned hunches relating to how that additional info above 20k makes itself heard.)

These mics sound absolutely stunning on large ensembles, as room or ambient mics, and solo acoustic instruments sound 10 miles deep with them. Most notably, when miking at a distance, everything sounds razor sharp and in focus. There is no loss of clarity as you increase the distance from the source. And if you’ll indulge me stretching that metaphor even more, it really does remind me of looking through a pair of really good binoculars for the first time.


I have absolutely no hesitation in recommending these microphones. It should be understood, however, that these are not the tools for every application. Quite often discretion is the greater art of recording. These mics get everything, good and bad. Use at your own risk in a less than optimal, noisy or unflattering room. You’ll hear it, all of it. 

On many instruments and in many situations, I prefer the sound of the DPA 4006-TL or the Schoeps CM6. While they are in the same class of ultra-sensitive omni condensers as the Sanken, they both (and each in their own way) have a rounder quality to the midrange that I find appealing, especially up close to the source. I wouldn’t trade these old favorites for anything. But, nothing I’ve heard does what the CO-100K’s can do as well as they do it. They are a true benchmark in my book, and are a great addition to our mic locker. 

Ian Schreier is the chief engineer for Manifold Recording, a world-class recording studio/media production facility near Chapel Hill, North Carolina.

Price: $2,685 each, street

Contact: plus24 (US Distributor) |

Audio Sample Commentary: Sanken CO-100K

The provided audio clips — available via the link pasted above — are 96k/24-bit WAV files. The mics went into gain-matched preamps from our API Vision console. The DPA 4006 mics are the TL variety, with a matched pair about a year old. A/D conversion is courtesy of Harrison Premium I/O, clocked by an Antelope 10M, then recorded into Pro Tools at 96k/32-bit. These are the signals just as they came out of the mics. There is no added EQ, compression or processing other than being exported out of Pro Tools at the more universal 24-bit rather than the 32-bit floating point word length.

Audioclip 1: Phil Amalong playing “prepared piano” as part of the chamber music group Conundrum. The mics were positioned as the room mics for the piano and ensemble as a very wide spaced omni configuration about 15 feet away from the piano and 10 feet up from the floor.

Audioclip 2: Lizzy Ross playing acoustic guitar and singing a portion of one of her own songs. Mic positions were relatively close on the acoustic and voice. While this is not a typical use for these kinds of microphones (and that may change for you as it did for me), I felt it would be useful as a reference. Identical DPA windscreens were used on both the sets of mics for this application (as Sanken does not offer a wind screen for the CO-100K). — Ian Schreier