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I've been itching to get my hands on Korg's new palm-size, high-definition audio recorder ever since it was announced last autumn. The hype said the MR-1's breakthrough technology would fundamentally change the way we think about digital audio. While I won't go that far, it certainly got my attention.

(Feel free to jump to the audio examples before reading the entire article.)

The MR-1 records at a variety of resolutions, including several high-definition, 1-bit formats. (Jump to specs table.) It can also record in MP3 format to save space. Behind the handsome metal surface lies a 20-gig hard drive; the sides feature connections for audio I/O, USB 2.0, and the external power supply. Korg says the rechargeable internal battery will last up to 2½ hours. The company plans to introduce an external AA battery pack this fall to extend operating time. According to Korg, any external battery pack with the proper voltage and connector will work; see the MR Juice sidebar for details.

The MR-1 ships with a faux leather case and a remarkably good little stereo mic. It also includes a clever little mic bracket that's threaded to fit standard camera tripods.

While I'm on the subject of portability, the MR-1's AC power supply weighs a hefty 15.5 oz—more than the recorder itself. However, it handles voltages from 100 to 240V to help accommodate the power configurations you might encounter outside of North America. (You'll need to provide local plug adapters.)

So the MR-1 looks like a strong candidate for field recording right out of the box. But why should you consider it when there are so many choices on the market? To answer that, let me talk a bit about bits.

MR-1 Angle

The palm-size Korg MR-1 records in the same format as Super Audio CDs, promising unprecedented mobile audio quality.

Playing the Bits

Digital audio is all about sample rate and bit depth. CDs set the standard at 44.1 kHz/16-bit resolution. In other words, the level of the audio is measured 44,100 times a second and rounded to one of 65,536 levels. (216 = 65,536.) Why this was chosen is beyond the scope of this review, but the short answer has to do with the cost of data storage and the limits of human hearing.

If you've been around for a while, you might remember how excited we got when Alesis released the 48kHz/20-bit ADAT-XT recorder. Why? Because with each increase in bit depth and sample rate the amount of information captured goes up. That translates to greater audio detail.

In standard Pulse Code Modulation (PCM) digital recording, each additional bit doubles the number of values the recorder can use to quantify the level of each sample. (20 bits produce 220 values, or 262,144 levels). That leads to fewer rounding errors, lower noise, and increased dynamic range, the range between the loudest and softest sounds a recorder can capture. The improvements are particularly noticeable in quiet signals such as reverb tails, which sound fizzy at lower bit depths.

Increasing the sampling rate extends the recorder's high-frequency response, producing a clearer sound. (The theoretical maximum frequency a recorder can capture is half the sampling rate, although real-world tradeoffs limit that. For instance, the steep filters necessary to exclude higher frequencies distort the signal.) Today, even my inexpensive consumer audio interface easily handles sample rates up to 192kHz at 24 bits.

So, if more bits are better, why is Korg's 1-bit technology a step forward? In a nutshell, 1-bit technology is to digital audio what RAW is to photography. Instead of rounding the audio level to 16 or 24 bits and filtering, which naturally produces distortion, it uses the single bit simply to describe whether the level of each sample is higher or lower than the previous one. Paired with a sampling rate of 2.8224MHz (64 times the CD rate), this technique can produce a significantly purer sound. Korg's MR-1000 boosts the rate even further, to 5.6448MHz.

PCM vs. 1-Bit Recording

This diagram from Korg shows how 1-bit recording (bottom) avoids the distortion from filtering and roundoffs in PCM recording. (Click to enlarge.)

Incidentally, you may be wondering how this 0-or-1 system represents a signal that's neither going up nor down. According to Korg, the sampling rate is so high that constant levels can be represented accurately by an alternating stream of 1's and 0's.

The technology has actually been around for quite some time; it's used for Super Audio CDs (SACDs). If you are truly curious, take a moment to read Korg's white paper, "Future Proof Recording Explained" (PDF). Even better, check out this video of Korg's Jerry Kovarsky explaining it at the AES Convention.

Hula Band

Once again, it was off to Hawaii for some fiery field recording.

The Field Test

As luck would have it, my review unit arrived as I was leaving on yet another trip to Hawaii, where I'd reviewed the previous three digital recorders in this series. I popped open the box, tossed the recorder in my carry-on, and headed for the airport.

The first thing I noticed was how easy the MR-1 is to use. Hit the large slider to power it up, and then use the Menu Button and P-dial (a multifunction wheel) to navigate and make selections. All the necessary transport functions are conveniently located on the front panel. No matter where you are in the menus, pressing "Record" arms the unit and brings up the meter screen. It is so well laid out that I was recording before I cracked the manual!

A pair of balanced/unbalanced 1/8" inputs handles a variety of levels. (See spec chart.) Although Korg supplies a wiring diagram so you can solder your own mic cables, I wish they had included adapters. But, as I said, the bundled single-point stereo mic is first rate. Here is a recording I did while checking out a friend's luau band. It's crunched down to MP3 for Web playback, of course, but you can get an idea of the spaciousness.

I also made some tests outdoors while at the Aloha Music Camp; alas, the lack of a windscreen ruined most of the recordings. This is the second field recorder I have tested that did not include such a basic element.

Recording Sax

The MR-1 distorted while recording loud bagpipes and sax.

With no clipping indicators, it is easy to overload the MR-1's preamps, as I discovered the hard way when recording a bagpipe and saxophone ensemble:

The mic/line switch functions as a "pad" for lowering excessively loud signals. That's handy, though not intuitive. One more reason to read the manual!

Each input supplies switchable +3V phantom power for mini-microphones; you will need your own power for studio-grade condenser mics. You set levels via submerged menus. Bummer, but at least the meter screen pops up with a single press on the P-dial when the MR-1 is record-ready. Did I mention the lack of clip lights?

MR-1 Sides

The MR-1 is extremely easy to operate. On the far side is a data wheel for navigating menus.

Korg thoughtfully incorporated a fair amount of control into the Auto-Gain settings. (Auto-Gain is simply a dynamics processor inserted in the signal chain to level out the differences in loud and soft signals.) In many small recorders, automatic gain control is either on or off, and the results are anything but subtle. Although the effect here is not 100% transparent, the MR-1 is one of the few recorders on which I would consider using this feature. Perhaps it would have saved my bagpipe recording from distorting.

I want to emphasize again how simple it is to operate the MR-1: while on my trips I was able to set it up and record at a variety of different formats under all kinds of conditions and then back up the files to my laptop. And I never opened the manual until I returned home.

File This


You'll hear the tiny bubbles in your maitai with the MR-1.

The MR-1 keeps track of your work by time- and date-stamping your files and placing each kind (WAV, MP3, and three different 1-bit formats; see sidebar) in a clearly labeled folder. You can rename, protect, or erase files or arrange them into playlists.

Even better, you can drop markers into a file during recording or playback—handy for navigating interviews and other long files. Maximum song length is six hours, which ought to cover most jam bands.

USB operations for backing up and restoring audio files are a snap, which is the way USB is supposed to work. Should you care to, you can import audio files from your computer and use the MR-1 as a rich man's iPod for playback.

AudioGate Software: The Missing Link

Professional mastering houses and high-end studios have the equipment to play back 1-bit audio files. But what about the rest of us? I'm not about to spring for a multi-kilobuck Pyramax or Sonoma workstation just so I can listen to my band's rehearsal.

So why record in an audio format you can't play back easily? Actually, I can think of a ton of reasons. How about recording every subtle nuance of a pristine high-mountain soundscape as a thunderstorm rolls in? Or archiving a mix at the highest possible resolution, ready to be translated into half a dozen different delivery formats? How about capturing the last performance of an endangered musical style in a form that won't be obsolete next month? How about creating your own hi-def CDs? Again, the parallels to camera RAW are instructive.

The MR-1 plays back 1-bit files natively. To listen on your computer, just fire up the included AudioGate software, open the file, and hit Play.


AudioGate software converts the MR-1 files to standard formats and offers basic editing.

Like the MR-1, AudioGate is simplicity itself. To convert a 1-bit audio file to PCM format, you just choose the output resolution and hit "Export." AudioGate also functions as a simple playlist-style editor: snip unwanted audio, create fade-ins and -outs, or combine several audio files into one. (Although you can load different species of files into a play list, you can't combine, say, a WAV and a WSD file.) The program also includes a filter to remove DC offset, a shifting of the waveform that can cause distortion and loss of headroom.

I loaded up a variety of files, converted them, and then listened to the results back-to-back with the originals. As I would expect, 1-bit files brought down to 16-bit/44.1kHz did sound different. But I could not hear any file conversion artifacts. In fact, I thought the files converted from 1-bit to WAVs sounded subtly smoother than similar WAV recordings I'd made as a control.

The Sound of One Bit

HummelGuitar, dulcimer, and hummel.

To get a handle on the differences between the various audio file formats, I set up a pair of omni mics in the middle of my small studio and recorded my big Taylor 4141K guitar and my trusty Swedish hummel, an unusual folk instrument with six drone strings and acres of top end. I did multiple passes at various WAV resolutions and the three 1-bit formats.

I then listened back, first via headphones on the MR-1 and then after routing the audio through the AudioGate software (which converted the high-definition files to 96kHz for playback.)

Could I hear a difference? You betcha. In every case, the 44.1 WAV files sounded like, well, 44.1 WAV files. That's not to say they were bad; in fact, I would recommend the MR-1 to anybody for field recording just based on these tests. But direct comparison of the WAVs to the 1-bit files was eye-opening.

MR Juice

Tekkon Battery PackOne of the drawbacks of a portable recorder with a fixed internal battery is that keeping it powered up limits your mobility. The MR-1's 2½ hour maximum battery life can keep you on a pretty short leash. (Like an iPod, the MR-1 also requires a trip to the service center once the battery wears out; Korg estimates the procedure will cost $80.)

Fortunately, Korg says that any external battery pack that provides 5 volts and has the right pin connector can work. Third-party batteries they've confirmed to work include these:

Korg will also be offering its own external AA battery holder this autumn. Watch the MR-1 information page for availability.

Even at 44.1kHz/24-bit, the guitar tracks seemed dull. The top end had some of that graininess we've come to accept from CDs, and there wasn't much of a sense of place, despite my pains to capture as much room sound as possible. Even when I bumped up the sample rate, the WAVs were noticeably inferior to the 1-bit files. My notes say it all: "Lots more detail; it sounds like I'm standing in front of the guitar right here in the room! Great subtlety as the notes fade off. I can really hear the notes fade below my breathing."

The hummel recording really sold me. All those high-pitched strings, squeaks, and pick slaps make it notoriously hard to record. The WAV files accentuated an ugly upper-mid harshness, making me long for analog tape. But the 1-bit files were a revelation! The sound of the pick hitting each individual string stood out as an independent event. As the sound faded, I could hear all the clangorous overtones as the various drones wavered slightly in and out of tune. (Yes, we folk musicians live for that stuff.)

I have never heard better audio from a digital recorder.

For completeness, I also tried to make out differences between the three 1-bit formats. This is one of those places when I am going to have to be brutally honest. Although I thought the WSD files had a slightly more open feel than either the DFF or DSF formats, I do not know if I actually heard anything or if I only thought I perceived a difference. Korg confirmed that there are "no significant fidelity differences" between the three 1-bit formats; they were included for compatibility.


After using the MR-1 for a couple of weeks, I am very impressed. Nevertheless, I do have a couple of doubts. Yes, it is extremely easy to use and it sounds amazing. In fact, I have a feeling it is capable of far better audio quality than can be captured by any of the mics and preamps I have at my disposal.

However, with only about 2½ hours of useful life, the internal battery is potentially troubling. I also fail to understand why Korg could not find a better way to set recording levels. Even though the unit feels solid, I would be nervous about taking any portable device with an internal hard drive deep into the bush.

Korg MR-1 Hi-Def Portable Recorder

MSRP: $899


  • Sounds great
  • Easy to use
  • Mic is good value
  • Amazing technology for the price


  • Relatively short battery life
  • Setting levels is a chore
  • No clip indicators at input

Should you buy one? That depends. Unless you add a battery pack, it may too limited for serious field use. In addition, the honking big AC adaptor is so last-century. Nonetheless, enterprising recordists will find ways around these limitations. (See the MR Juice sidebar.)

Want a 1-bit mixdown deck for your studio for under $700 street? Wire up a couple of cables and Velcro an MR-1 to your console. The AudioGate software is terrific and offers a real-world method for making multiple copies of your mixes at different resolutions. But, if I were in the market for a pro-level recorder, I'd have no trouble justifying the extra cash for the MR-1000. That bigger model has numerous professional features and offers higher resolution for archiving, albeit at almost twice the price.

Admittedly the MR-1 is overkill if you just need to record voice for podcasts or make casual field recordings of live music. Sure, you can record direct to MP3 and at a variety of PCM sample rates and bit depths, but then you can find plenty of recorders that do so at half the price. I do give it high marks for the coolness factor, and the included mic and its nifty stand are solid values.

Ultimately, if you want the best-sounding vest-pocket recorder you've ever heard, look no further. Heck, buy two and double the battery life.

Audio Examples

Because it's unlikely many readers will have the technology to play back 1-bit audio, I've converted all of these examples to MP3. You'll have to take my word for it that they sounded terrific.

MR-1 Specifications

2.52" (W) x 4.72" (D) x 0.94" (H)
Number of Tracks
2 tracks, 2-track recording/playback simultaneously
1-bit audio formats
DSDIFF, DSF, WSD: 2.8224MHz @ 1-bit
PCM audio formats
WAV, BWF: 44.1kHz @ 16/24-bit, 48kHz @ 16/24-bit, 88.2kHz @ 24-bit, 96kHz @ 24-bit, 176.4kHz @ 24-bit, 192kHz @ 24-bit
MP3 format
Recording: 44.1kHz/192kbps
Internal Hard Disk Drive
20 GB
Recording Time
Max Approx. 30 Hours (44.1kHz @ 16-bit, 2-track
100 points per song (no marker names)
Song Editing
Rename, Delete, Protect
160 x 104-dot LCD with backlight
Frequency Response
10Hz–20kHz ±1dB @ Fs 44.1/48kHz
10Hz–40kHz ±1dB @ Fs 88.2kHz/96kHz
10Hz–80kHz ±1dB @ Fs 176.4kHz/192kHz
10Hz–100kHz (1-bit)
Signal to Noise Ratio
90 dB (typical) @ IHF-A input-output
0.0018% (typical) 20Hz–20kHz
A/D D/A Conversion
2.8224MHz (1-bit), 24-bit (PCM)
Mini Phone Jack (balanced)
Nominal Level
LINE -6dBV, MIC -39dBV
Maximum Level
LINE +6dBV, MIC -27dBV
OUTPUT (analog)
Stereo Mini Phone Jack
Nominal Level: –6 dBV
Maximum Level: +6 dBV
Stereo Mini Phone Jack
USB 2.0 High-Speed device, USB mass storage class
Type B (mini) connector
Included Items
AC adaptor (also operates as charger), Owner's Manual, Protective case, Stereo mic (CM-2M), Mic clip stand, "AudioGate" audio file conversion application on CD-ROM
AudioGate Software
Supported OS: Windows XP Home Edition/Professional Edition Service Pack 1 or later/Vista, Mac OS X 10.3.9 or later (Intel-based Mac supported).
Supported Computers: [Windows] Intel Pentium III 1 GHz or faster [Macintosh] Apple G4 800 MHz or faster (Intel-based Mac supported)
CM-2M Mic Specifications
Element: electret condenser
Polar Pattern: stereo, directional
Frequency Response: 100Hz–12kHz
Sensitivity: 58dB ±3dB, 1kHz at 1 Pa
Cable Length: 3.28 feet

Supported Audio Formats

The MR-1 records 1-bit audio at a sampling frequency of 2.8224MHz in three different formats. DFF (or DSDIFF, for Direct Stream Digital Interchange File Format) is the standard for SACD (Super Audio CD). DSF is a file format used in some Sony VAIO personal computers. WSD (Wideband Single-bit Data) is a file format defined by the "1-bit Audio Consortium," a group founded in 2001.

Supported WAV resolutions include 44.1 and 48kHz at 16 bits, and 44.1, 48, 88.2, 96, 176.4, and 192kHz at 24 bits. The only supported MP3 resolution is 192kbps. Recording time varies depending on the format and resolution; for 1-bit recording, the 20-gig internal drive should yield about 7 hours.

Which One's for You?

See how this recorder stacks up in our
portable recorder comparison chart.