KORG MR-1 Portable PCM DSD Recorder

The Korg MR-1 digital recorder captures PCM up to 192 kHz using the Broadcast Wave Format (16 and 24 bit up to 48 kHz, 24 bit only at higher sample rates), as well as records three DSD (direct stream digital) formats at 2.8 MHz streaming rate.
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The Korg MR-1 digital recorder captures PCM up to 192 kHz using the Broadcast Wave Format (16 and 24 bit up to 48 kHz, 24 bit only at higher sample rates), as well as records three DSD (direct stream digital) formats at 2.8 MHz streaming rate. For the space conscious, an option of 192 kbps MP3 is available. In terms of space, the MR-1’s audio storage medium is an internal hard disk drive rather than the flash memory used by most of the current crop of portable stereo recorders. A lot’s packed in this little unit.

Features

The MR-1 is powered either from a supplied 5 VDC wall-wart or an internal lithium-ion polymer rechargeable battery. Korg estimates that you’ll get two to two-and-a-half hours of continuous recording or playback per charge. A run-until-dead test at 16 bit/44 kHz gave me two hours and 53 minutes recording, at which time the MR-1 performed an orderly shutdown, closing its current file so no recorded audio was lost. The LCD backlight and blinking “Record” LED can be switched off to extend battery life.

I never accurately determined the time required for a full recharge, but after about six hours the battery indicator was only at the “two bars” (out of three) level; I’d count on an overnight recharge. [According to the manufacturer, battery charge information is listed in the MR-1’s V.1.5 manual. It states that a full charge will usually take five to six hours of recharging time. — Ed.] The battery isn’t removable, and battery replacement requires a trip to an authorized service shop. But the recorder draws about 450 mA when running, so it wouldn’t be too difficult to assemble an external battery pack for longer recordings independent of commercial power. [Korg plans to offer an external AA battery pack. — Ed.]

When running from an external power supply, the battery (assuming it’s charged) takes over seamlessly with no clicks or pops if the the power supply is removed. Likewise, when power is restored it will switch back from battery for conservation.

Like with most cigarette pack-sized recorders, audio I/O is on 1/8-inch mini-jacks. But rather than the conventional single two-conductor jack for a stereo input, the MR-1 uses a pair of balanced mini-jacks (tip positive) for left and right mic/line inputs.

A switch selects the input gain range between mic or line level. A second switch applies 3.0V microphone plug-in power. Input impedance, specified as 10 kilo-ohms, actually appears to be closer to 100 kilo-ohms for both the line and mic modes.

With neither XLR connectors nor phantom power, a pro user will most likely use the MR-1 with an outboard preamp or feed it from a mixer. There are separate stereo (unbalanced) mini-jacks for headphone and line level outputs, with the level of both (together) controlled by a single pair of up/down buttons.

In addition to manual input gain adjustment, there’s a quite serviceable automatic gain function that works at both ends of the dynamic range. A peak limiter keeps the record level below the preset maximum. A gain boost is applied when the input drops below a preset threshold. The limiter’s attack time and threshold are adjustable, as is the gain boost rate (dB per second) and threshold below which gain is boosted.

Markers can be placed in a recording, either while recording or during playback, for handily and quickly finding specific portions of a recording when playing back on the MR1. The markers, however, are part of the recorder’s unique Project file, so provide no use once the recording is on computer.

The counter (time) display has two modes: absolute time from the start of the current recording, and the remaining recording time available on disk based on the current sample rate and word length. The counter mode can be switched while recording so you’ll know if you have enough “tape” for the band’s third encore.

All things stored on fixed media eventually have to be removed, and a USB port is provided for transferring files to a computer, no special software or drivers required. Just plug it in to a Windows or Mac computer, select USB Mode from the menu and the MR-1 appears as another drive on the computer. Files can also be copied from the computer to the MR-1 for playback and for updating the system firmware.

Most of the action is right up front with a set of five conventional “transport” buttons and a backlit LCD. The buttons are tiny, but comfortably spaced with a good tactile feel even through the clear window in the protective soft case. Power and USB connectors are on the left-hand edge. The right-hand edge carries the power switch, menu access button, scroll/push wheel, a pair of buttons to adjust the playback level and an undocumented hole behind which lurks a master reset (I didn’t have to use it).

Pressing the Record button engages the Record/Pause mode and switches the LCD to Meters/Counter display. From that display, a single press of the scroll wheel brings up the Record Level adjustment screen with the scroll wheel serving as the gain control. The current project can be played back simply by pressing the Play button. To play a previous recording, you’ll need to visit the Library menu, where you can select from a list.

Projects are automatically named as the file format (WAV, DSF, MP3, etc.) followed by a sequential number. Projects can be renamed either character-by-character using the scroll wheel or from the computer keyboard when in the USB mode.

Fast FactsApplications
Remote/location recording

Key Features
10 GB HD, DSD and 192 kHz PCM, USB 2.0 file transfer, DSD-to-PCM software

Price
$899

Contact
Korg USA | 631-390-6500 | www.korg.com

PRODUCT POINTS

Plus

  • Ease of operation
  • Sound quality
  • Large internal drive
  • High-res option

Minus

  • Mini jack inputs
  • Short battery life

Score
The MR-1 offers just the amount of features and ease-of-use to make it a serious remote hand-held recorder.There are two top-level Library folders: “MR_PROJ,” where recordings made on the MR-1 are placed, and “AUDIO” for storing externally created audio files. Each recording type (WAV, MP3, DSF, etc.) has its own folder under MR_PROJ. Starting a new recording creates a new Project folder in which audio files as well as a single Project file are stored. Pressing the Pause button closes and saves the current audio file; a new file is opened when recording continues. When the audio file grows to 1 GB, it is saved and a new file is automatically started. Pressing the Stop button closes the current audio file and the next recording creates a new Project folder. Selecting a recording for playback actually selects the Project (this is what can be renamed) and if the project contains multiple files, they’re played back sequentially and seamlessly, even over the automatic 1 GB split. The only time you’ll see individual audio files is while browsing the MR-1’s folders with a computer.

A folder can display 200 project names. You can record more than 200 projects of the same file type, however only the first 200 will be displayed from the Library menu. Additional files can be accessed by computer via USB port. The AUDIO folder can have four sub-folders. Projects and audio files can be entered on a play list for programmed playback — handy for airplane trips.

In Use

The MR-1 is nearly as simple to operate as an old-fashioned cassette recorder — a good thing for field work without time to plod through menus. The MR-1 remembers the last recording mode and gain settings (including automatic gain mode and parameters) and maintains them until you change something. Going from power-on to recording involves simply pushing first the Record and then the Play/Pause buttons. If you hit Play before Record you’ll start playing the current file and drop a marker into it rather than start recording (which I learned by experience).

The MR-1 feels good in the hand – solid and compact without feeling crowded under the fingers. There are no wobbly buttons or knobs, and I never felt it needed kid gloves lest some essential control break if pressed too hard. And, while I was jumping among recording modes and sample rates while in reviewer mode, the average user will probably settle on standard “house” settings and rarely change, anyways.

While the buttons on the front panel are well-spaced and easy to operate, the mic/line and plug-in power slide switches and the spring-loaded main power switch are recessed. It’s probably good to avoid accidents, but I needed a fingernail to operate them, particularly with plugs inserted.

I recorded a couple of music camp workshops using the supplied stereo condenser microphone. The mic sounds fairly good, but when placed closer than about five feet from the source the stereo image tends to wander; small movements of the subject often translate to large apparent movements in the recording. The mic has about 15 dB greater output level than your run-of-the-mill dynamic mic and there’s plenty of gain to record even quiet ambient sounds. An L-shaped bracket serves as a table stand for the mic, plus a quarter-20 threaded hole in its base allows attachment to a camera tripod or to a conventional microphone stand (with an adaptor not supplied).

The mic’s captive cable is only 3.5 feet long, which I found impractical. It’s too short to put the mic on a table and sit back comfortably with the recorder, and when putting the recorder on the table next to the mic, there’s a bundle of cable to deal with. With the mic on a stand, the cable is too short to reach the floor, so I had to sit by the mic stand holding the recorder.

How good are the mic preamps? Without phantom power, I couldn’t use them with most mics I own, but I found while there was plenty of gain available with dynamic and ribbon mics, hiss became apparent when recording quiet sources. Quiescent noise at 24-bit resolution with the gain set to maximum (+31.5 dB) and inputs terminated in 150 ohms (typical source impedance for a dynamic mic) translates to about -45 dBFS, which is quite audible at a reasonable playback level. If you need this much mic gain, you’d best use an outboard preamp. Quiescent noise for the line inputs at unity gain (0 dB) is a respectable -96 dBFS.

The record gain control works in 0.5 dB steps, so you can’t use it for a smooth fade. And with about 6 dB per thumb-sweep of the scroll wheel, you couldn’t do a complete fadeout without a thumb about a yard long. [According to the manufacturer, “this can easily be done after the fact with the included AudioGate software, allowing the user to try various ‘takes’ with different curves, etc. – much easier and more versatile.” — Ed.]

The good news is that on this recorder the gain adjustment works while recording, and gain adjustment doesn’t generate clicks. Gain controls for the two channels can be linked for stereo operation (this was an added feature in the Version 1.5.0 firmware update) or can be adjusted individually.

Gain adjustment is made on the digital side of the A/D converter, so one must be careful not to feed the recorder a signal too hot for the input stage. In the Line mode, the maximum input level before clipping is +10 dBu. Although you can keep the meters below full scale by lowering the gain, if the signal at the jack exceeds +10 dBu you’ll end up with a high-resolution recording of a clipped audio signal. Many mixers and mic preamps have a maximum output level in excess of +20 dBu, so you may need a pad between a line level source and the input.

The Auto gain can’t prevent the input stage from clipping, but it does a good job as long as the input level doesn’t exceed +10 dBu. However, it’s important thing to understand you can’t just set it on Auto, plug it in to an unknown source and walk away.

With the output level set to maximum (this gives the best signal-to-noise ratio on playback) a full-scale digital recording represents +8.5 dBu at the Line Output jack. THD+N at the analog output clocks in at 0.02-percent at close to full scale.

As far as how it sounds, I have only compliments. I used it only as a field recorder, recording with the included mic, a Studio Projects LSD-2 stereo mic through a Mackie Onyx preamp and from PA consoles. Other than some strange imaging with the Korg microphone, the MR-1 produced excellent results. This is a good recorder, and requires little fooling around to use.

Most of my recordings were made at 44.1 kHz, 16 or 24 bit, with excursions to the higher sample rates for comparison. Given the material and the environment in which I was recording, I found no practical need for anything above 44.1 kHz, but it’s nice to know that higher sample rates are available if needed (or requested). Some users have reported that a DSD recording converted to a lower sample rate sounds better than a direct PCM recording at that sample rate, but I couldn’t confirm it with my recordings.

The AudioGate program supplied with the MR-1 converts between DSD and PCM formats. It also seamlessly joins multiple files created when an MR-1 recording exceeds 1 GB, and the joined files can be exported to a new, continuous file. It also provides playback and playlist functions, but other than format conversion the pro user will probably have little use for this program. [The manufacturer states, “Allowing the user to play back DSD files without conversion for quick reference on a computer is an important tool that we feel pro users would appreciate, as is the DC cut and fade/gain controls when used on the DSD material.” – Ed.]

Now for a few minor annoyances: if the Library gets too large, it’s difficult to locate a particular recording. Default file names seem to appear in alphanumerical order; but once you start renaming projects there seems to be no particular order in which they appear in the Library list, and I could swear that they move around. A Sort function (either manual or automatic) would be a welcomed addition. [A Sort function was added in V.1.5 software update for the MR-1 and can be toggled on or off for convenience. — Ed.]

The power icon on the LCD roughly indicates charge level when operating on batteries, with its bars changing to a sine wave when receiving external power. It would be nice if the AC/charging icon appeared when the recorder was off yet connected to external power, indicating that the battery was being charged; it is only visible, however, when the recorder is switched on.

The Broadcast Wave Files that the MR-1 creates are indeed time-stamped as per the BWF specification; however, the time stamp of every file is 00:00:00:00. When a new file in a project is created once the current recording exceeds 1 GB or when recording is restarted after pausing, I expected that the files would be time stamped sequentially, with the second file’s time stamp being the ending time of the first file. But they aren’t. Korg told me that they would discuss this with the engineers and perhaps include it in a future firmware update.

Summary

Overall, I’m very pleased with the MR-1. It looks and feels great, provides all the functions I need, it’s easy to use, and it sounds just fine. It is, however, a bit on the expensive side.

Second opinion

Since it is rather pricey at $899, you would expect the Korg MR-1 to be a cut above many low cost recorders — and it is. It is the only portable offering DSD (Direct Stream Digital), a 1-bit digital scheme operating at 2.8 MHz sampling frequency with fewer conversion steps than PCM. It is the basis of commercial SACDs, which many pros swear superior to PCM and well suited for transparent archiving.

Ergonomically, the MR-1 is the easiest portable I have ever used, and is smartly packaged with balanced operation via space-saving stereo mini-jacks. The 10 GB built-in hard drive means not having to change flash card drives while filling it with DSD or PCM tracks. Of course, high bit rate recording sucks the battery very quickly; I got less than an hour at 192 kHz.

Now the sound quality: Via line input, the MR-1’s high-res record/playback via DSD is excellent. I tracked acoustic guitar with a mixer and two Audix SCX-25s and found the detail, clarity and sense of acoustic space, as well as the transients, to be very real. After recording, you will need the included DSD-to-PCM software to do anything with the DSD files other than straight machine playback, unless you have a very expensive Sony Sonoma DSD workstation or Pyramix.

The Korg’s PCM at 192 kHz or 96 kHz sounded good, but not as detailed as the DSD. The reverb decay of recorded Martin guitar did not have the separated detail of DSD. And the Korg’s 24/96 PCM recordings were not quite as detailed as from the M-Audio MicroTrack (tracking the same recording simultaneously), nor the bigger, more expensive TASCAM HDP2.

Even with PCM transferred to computer and playback via external Benchmark DAC-1, the MR-1-recorded PCM did not sound quite as detailed as other PCM portables I have tried. In my opinion, the DSD-to-PCM-converted Korg audio sounded better than straight PCM.

Overall, the Korg MR-1 is a nicely built, good sounding and easy-to-use handheld ... with the high-res DSD feature. But at $899 retail, it is pricey for most people looking at handheld portables. I realize that adding DSD increases the cost, but the market is too competitive to keep the price so high.

— John Gatski