Review: Korg MR-1000 & MR-1 Portable DSD Recorders
Just when you thought DSD had bitten the dust, back it comes as a ‘future proof’ archive format.
By Brad Watts
4 February 2007
Upon its release in 2000, SACD or Super Audio Compact Disc, was touted to be the next great leap in consumer audio formats. After 20 years of the CD, Sony and Philips got together (yet again) and came up with a system to deliver audio quality far superior than the PCM-based 16-bit/44.1kHz CD could ever hope to deliver. But SACD was – and is – merely a delivery format for DSD. DSD (or Direct Streaming Digital), when compared to Pulse Code Modulation (PCM), is a completely different method of encoding analogue audio into digital data. Instead of registering the amplitude within the bit-resolution of 16-bit, for example, and sampling that amplitude a number of times per second according to the sample rate – in the case of CD that’s 44,100 times per second or 44.1kHz – DSD samples at an extremely high number of cycles per second – 2.8224MHz or 2,822,400 times per second. It also uses only a single data bit, where instead of measuring the amplitude from zero each time, DSD measures the change in amplitude from the previous sample. If the amplitude is greater than the last sample then a 1-bit is registered, if it’s less than the previous sample then a 0-bit is registered. Consequently a rising portion of a waveform would consist of many consecutive 1-bits, a falling waveform would consist of many consecutive 0-bits and a flat section of waveform would register as alternating 0 and 1-bits. It’s a form of quantum measurement and therefore relies on knowing where the last point was before the next point can be stipulated. The advantages of the concept are a high sample-rate representation of the waveform without requiring mountains of drive space – DSD uses about four times the storage as 16-bit/44.1kHz data. The most immediately obvious disadvantage is that the waveform can’t be edited like PCM data; as soon as you ‘cut’ the waveform, the system no longer knows where zero amplitude is – and the waveform ceases to exist as it was originally captured.
SOWING THE CDs
It’s safe to say that SACD (and DSD) hasn’t supplanted the CD as the generic audio format. While SACD does deliver very realistic audio and is backward compatible with CD players (SACD discs holds both DSD and CD layers), the music buying (and stealing) public became far more enamored with sonically inferior mp3 files and iPod audio players right when this ‘revolution’ was supposed to take place. The Sony and Philips executives must have been livid. Of course anyone can still go out and buy SACD titles and SACD players to play them on, but the iPod-infected public are obviously more concerned with quantity over quality. So that left the DSD consortium wondering just how to get some money back on their R&D investment and license the technology out to the pro and semi-pro recording sector – us, in other words.
Which brings us to a couple of rather interesting releases from Korg: two DSD recorders aimed at the recording market with the promise of capturing the best possible two-track recordings along with future-proofing the data. ‘But why would recording to a DSD format future-proof your master recordings?’ I hear you ask. Well, that obviously depends on a couple of factors… those being: that DSD is definitively the very best way of recording in stereo; and, that nothing better ever comes along. As it stands there are both advocates for and detractors of DSD, with its foes claiming super-high resolution 24-bit/352.8k PCM to be a better alternative, as it dovetails with already established technology. Meanwhile, DSD fans herald the concept to be cheaper to manufacture and providing sampling frequency range of 0 to 100kHz and upward right now. Then there’s the difficulty posed by DSD’s inability to be edited using the current DAW/PCM paradigm. Multitrack DSD editing systems are expensive and very thin on the ground at the moment – so far I’ve managed to find a scant few systems capable of working natively with DSD audio streams, the largest track count equalling a paltry 32-track limit. What is becoming an acceptable alternative is to record and edit at 24-bit/352.8k PCM and then record the final masters to a 1-bit format such as DSD. This is very much Korg’s angle with the MR-1000 and MR-1: create all your work at the highest resolution possible, then record your master to their DSD machine.
So without stirring up the waters any further, we should have a look at these recorders and we’ll start with the pro (short for ‘proper’) MR-1000 then get on to the pocket-sized MR-1.
NEED TO KNOW
The MR-1000 is designed as a portable and desktop two-track recorder. It’ll run on eight AA batteries or the included mains power supply. As a field recorder I was inclined to compare the unit with similar devices from Marantz, Fostex or HHB – the kind used for film location work and reporting journalists. These units usually offer ports for powering via professional battery packs, or at least have a rechargeable powerpack. The choice to go for no less than eight AA batteries may put that sector of the field recording market a little offside but NiMh rechargeable are a valid option, and you can always acquire AA standard batteries pretty much anywhere. Battery life is rated at four hours regardless of the battery type used or whether you’re recording or playing back.
Korg’s musical instrument background shows markedly in the construction of the MR-1000. The enclosure is a black anodised aluminium sleeve with the user interface at one end and the I/O at the other – a pretty standard construction ethic these days. The unit is also incredibly light. At 1kg (without the batteries) it will hardly cause any back pain if you’re lugging it about on your shoulder all day. Korg includes a carry pack with a shoulder strap and Velcro access ports to the I/O section of the unit – not unlike most other professional field recorders. I have already noticed some concern among the online community as to Korg’s build quality, but the MR-1000, despite its light weight, feels sturdy enough to withstand outdoor audio retrieval. My only gripe would be the battery compartment door that looks as though it may require the assistance of duct-tape if it gets overused.
The front panel controls are exceedingly simple, with a standard transport section off to the right and rotary/pushbutton encoder and escape button for accessing the operating system options. All the buttons produce a definite ‘click’ when prodded and although slightly ‘spongy’ in feel, look to be up to the task. To the left of the backlit LCD screen are a headphone output and level control, and a dual-concentric record level control. I didn’t like this particular pot as it felt more like the control knob from a synthesiser rather than a ‘pro’ recorder. There was no indent to keep the left and right controls locked together and attempting to turn both knobs while keeping the two in unison often resulted in altering the left and right balance. Plus my chunky Caucasian fingers found access to the record level knobs a tad difficult. The LCD provides ample information with left and right peak level meters, battery level, recording file format and time down to millisecond integers. There is no actual SMPTE timecode functionality.
The operating system itself is a doddle to drive, with the most important menu feature to be the Record mode. Here you can choose which file type you’d like to record in, starting with BWF (Broadcast Wave Format). This can be recorded at 16-bit/44.1k and 48k or 24-bit/44.1k, 48k, 88.2k, 96k, 176.4k and 192k sample rates – comprehensive set of options for .WAV files. The remaining available file types are all DSD format and include standard DFF, WSD and DSF, all of which can be recorded at DSD’s standard sample rate of 2.822MHz and double that resolution at 5.644MHz (that’s double the sample rate required for SACD or over 5.644 million samples per second). Storage is via an internal 40GB hard drive, which should give you 60 hours of recording time at 16-bit/44.1k. But we didn’t come here to record on such an ‘archaic’ format… recording at the full 5.644MHz DSD format will give you 11 minutes per gigabyte, or 22 minutes per gigabyte at 2.622MHz. Make up your own mind as to whether a 40GB drive is large enough, but remember the longest possible recording time is 1 millisecond short of six hours. Markers can be inserted during a recording by re-pressing the record button.
Looking around to the rear of the MR-1000 we find the analogue I/O. There are no digital audio connections at all, which stands to reason. If you can’t send a 1-bit digital signal into or out of the unit there’s hardly much point. There is a USB2 port though, so you can extract recordings to a computer platform. Korg supplies its Audiogate software for converting your DSD files to PCM data. (Have a look at the ‘Audiogate Software’ box item elsewhere in this review for some more info on this cross-platform-savvy program.) The remaining I/O consists of balanced combo XLR connectors for input and XLR outputs operating at +4dBV. The outputs are also present as RCA connections operating at the –10dBu standard. There are a few little slide switches situated on the rear for choosing high- or low-gain input, instigating an input limiter and global phantom power.
Conversion is performed using 24-bit 128x oversampling A/D and the same for D/A. At the highest sampling frequency the frequency response is an incredible 10Hz to 200kHz and 10Hz to 100kHz at 2.822MHz. Dynamic range had me a bit stumped, however, with a quoted figure of 96dB – strange when you consider that to be the theoretical noise floor of 16-bit PCM data… and DSD is purported to offer a dynamic range of 120dB. Perhaps it’s a misprint. Korg? But specifications aside, the real proof of the pudding is how the recordings sound. Does DSD sound better?
THE SOUND OF DSD
To put the sound of these devices to the test, initially I recorded a couple of mixes I had laying around directly to the MR-1000 and at the same time recorded the mix digitally to 24-bit/44.1k on a separate computer. This is my usual regime for final mixes as I always find it gives me a far superior result than bouncing the audio within Logic Pro or ProTools. During the same pass I also bounced the audio within Logic and then compared files. In order to compare each recording alongside each other in the same software I converted the 5.644MHz DSD file and the other 44.1k files to 192k. The internally bounced file didn’t get a second look as is usually the case, but the remaining two files did show remarkable differences. Placement of sounds within the mix seemed much more authoritative and accurate – they seemed to hold their position in space much better. The sense of depth with the converted DSD file was also much greater and more satisfying than the PCM pass. However, the file that was most encouraging was playback directly from the MR-1000. It sounded smoother and more transparent – far more like the original performance. The differences were slight but noticeable nonetheless.
Hoping for something a little more obvious, I decided I should record something live straight to DSD and PCM formats concurrently. Having moved recently and not knowing too many muso’s in Queensland [don’t all email Brad at once – Ed], I decided to resort to nature and record the myriad birds that wake me up each morning at around 4.30am. So, armed with two pairs of Octava MK012s set up in ORTF placement in the backyard, in the dark, I waited for the ornithological fracas to commence. One pair of mics fed the MR-1000 at 5.644MHz while the other pair fed my ProTools HD system digitally via the API A2D [see the review elsewhere this issue] at 96k – which is as high as my ’Tools rig will sample unfortunately. When the cicadas kicked in at daylight, I had about half an hour of audio I figured I could reasonably compare. So what was the upshot? Without question the DSD recording ate the 96k PCM version for breakfast (I had Weet-Bix and some fruit that day, just by the way). The DSD recording conveyed a far greater depth and sense of reality, and honestly sounded far more like ‘being there’. All up, a marked improvement indeed. At this point I was pretty well convinced.
STREAM OF CONSCIOUSNESS
So after my initial scepticism I’ve decided I like DSD. As to how and when this format will permeate our lives completely is another matter, but the MR recorders are definitely the start of something new. I can’t see PCM architecture becoming old-hat for a while yet but as a two-track medium I believe DSD and the MR recorders have a lot going for them. Until now there’s been no way of recording in this format without spending bucketloads of cash, let alone having a unit you can carry from room to room with you. ‘Future proof’? I simply can’t believe that particular piece of marketing propaganda – and I don’t think anyone else who’s been in the industry for a few decades would either – but as a hi-res medium I think we’ll be seeing a lot more of these style recorders.
RESPONSES