Review of Marantz PMD670: Solid State of the Art?
David Nathan, ELAR
There are now so many recognised advantages of digital sound recording and storage that debates about sound processing are no longer about digital vs. analogue but about data formats, compression, hardware, and techniques. Interestingly, there were also debates about all of these issues in the analogue era, and history tells us that solutions to them were evolutionary rather than absolute, and typically emerged in the form of preferences or standards rather than hard science. Nevertheless, the advantages of solid state over alternative digital recording equipment are compelling.
Solid state digital recording
"Solid state" means, paradoxically, that data is recorded on electronic circuitry ("flash memory") rather than on physical media such as disks or tapes. The technology is not new— - computers have long stored basic start-up data in on-board chips— but is now feasible for consumer large volume storage because the price to volume ratio of flash memory cards has reduced dramatically. A variety of consumer devices are moving rapidly towards data storage on flash cards due to their compact size, reusability, and the fact that no motors or transport mechanisms are needed, which in turn offers potential advantages of robustness, reliability, size, battery life, quietness, and less electrical "noise". In addition, the standard data format of flash memory files provides a seamless path from recording to computer.
Flash cards are available in several physical formats including Compact Flash (CF), SD, Smart Media, and Sony Memory Stick. Following the growth of the digital camera market, the latter types had been gaining ground on CF (the oldest and largest of the formats); however, recently CF is making a comeback because its larger size offers more potential data capacity, and Japanese manufacturers of video cameras—the most data-hungry devices of all—are eager to see flash cards replace disks and tapes. In mid 2004, 512 MB and 1 GB cards, which offer data capacity similar to a CD, became relatively affordable, and now 2 GB cards are starting to appear. An interesting alternative is the IBM microdrive, a tiny hard disk in the physical CF format that can store up to 4 GB, although it has greater power requirements and is probably less robust than cards.
Solid-state digital recording looks like an ideal solution for language documentation where quality recordings are essential but fieldwork can take place under challenging physical conditions. Solid state recording does, however, have some disadvantages, and these may be quite serious for some researchers. Firstly, it is expensive. Flash cards are by far the most expensive recording medium of all, at about 200 times more expensive per megabyte than CDs or DVDs and 50 times more than minidisks. As an example, although the Marantz PMD670 under review in this article is itself expensive, just a few CF cards will exceed its value. Secondly, because flash cards are expensive, the data recorded onto a card will typically have to be moved onto a cheaper medium to allow the card to be reused. In practice, this means that a computer needs to be available to write the data to CD or DVD. Fortunately, most fieldworkers these days will be carrying a laptop computer, and CDs or DVDs are a good solution for cheap short-term storage and distribution of recordings. CF card data is easily copied to the computer’s hard disk via a USB card reader, but a better solution in the case of laptops, is to use a PCMCIA card, which is not only cheaper than a card reader (a CF to PCMCIA card costs around 10 euros), but allows faster data transfer and does not require any cables or objects projecting from the computer. If required, CF data can be written directly to CD without writing the data to the hard disk.
Marantz has a reputation for the quality of its recording equipment, and many researchers have long relied on their sturdy cassette recorders. Such researchers will not be surprised by the appearance of the PMD670. Others may be struck by its relatively large size, and its XLR microphone sockets (also known as Cannon connectors). These professional-level microphone connectors are used instead of the miniplug (also known as 3.5mm jack or maniac) sockets found on typical fieldwork recorders such as Sony Professional Walkman, DAT and minidisk recorders; they offer several advantages including reminding fieldworkers that microphone quality is extremely important. On the other hand, many good quality recorders and microphones do use stereo miniplug, and researchers are likely to have useful microphones of this type, so it seems unfortunate that Marantz has not also provided connectors for them.
Controls and display
The PMD670 offers three arrays of controls. On its front panel are simple recording controls, including a large red slide for starting recording. This allows the machine to be slung in a bag or placed on a table top and operated simply. On the top panel, close to the recording controls, are the playback controls; also on the top are a number of buttons providing advanced functions such as composing edit decision lists. None of the buttons have a particularly pleasing or quality feel. Other controls are for selecting recording formats. The PM670 can record in various formats such as linear PCM (normally the same as ".wav" files) and MP3 at various sampling and bit rates. Unfortunately, there is no support for formats such as the better quality, open source Ogg Vorbis. Providing MP3 recording while not providing miniplug connectors seems oddly inconsistent.
After setting up recording options (the selection of recording format interacts in a confusing way with "Algorithm/File Parameter" selection), I found the PMD670 generally easy to use. The sound quality, as expected, is extremely good. There was a very small amount of background hiss when recording at 16 bit, 44.1 KHz, but this may have been due to microphone compatibility, and was not regarded as a problem. The PMD670 should be useful and flexible in the field - it has a speaker, USB connections, and digital and analogue line-in/out (so it could be used, for example, for digitising analogue sources).
The PMD670’s LCD display panel is disappointing. It offers the expected array of information, but is small in relation to the machine, displays some text too small to read easily, and is in monocolour green; in other words, it is little better than the display of a portable consumer minidisk recorder. Battery life was not as long as would be expected, at between 3 to 5 hours, which, considering that 8 batteries are needed, will worry some fieldworkers.
Flash card compatibility warning [See Postscript]
However, the greatest disappointment that I had with the PMD670 was one that you are unlikely to experience (I hope). During a field trip, following an elicitation session, I found that one track was corrupted and unreadable (both in the PMD670 and using a computer and card reader). While it turned out that the recording was of a speaker reading from a prepared list, and could be repeated the following day, the effects of this failure were more profound, in that I no longer felt secure using the machine, and subsequently used it only in tandem with a minidisk recorder or else did not use it at all. I have never once experienced a similar loss in years of using various recorders, including minidisk. I subsequently discussed the problem with the manufacturer’s agent, who blamed the CF card, a Japanese-manufactured Buffalo 512 Mb card that had been used before and since in other equipment without problem. The agent referred me to the scanty advice about cards on the Marantz Pro website, which neither ruled out the card I had used nor approved of the unbranded card that was originally supplied with the machine. I therefore strongly recommend that you conduct extensive testing of any cards that you buy (and you will buy cards, because the 128MB card supplied with the machine can record only 15 minutes of sound at high quality settings)—and run a backup recorder when recording irreproducible events. [See Postscript]
The Marantz PMD670 has provided a welcome introduction to solid state recording that offers excellent recording quality and is generally easy to use. Its appearance will, hopefully, convince fieldworkers that quality digital recordings cannot be made by recording direct to their computer’s hard disk, which has none of the PMD670’s advantages of dedicated digitising circuitry, a clean electronic environment, portability, robustness, proper recording controls, and ease of operation. On the other hand, the machine has an unimaginative design and feels like a conversion of previous generation machines to solid state, with the addition of some digital functions such as MP3 and track editing which will not be especially useful for most fieldworkers. While the recording quality is excellent and it offers the compelling lure of solid state, this is not yet a state-of-the-art machine.
26 March 2005: Note that the updated version of the PMD670, the PMD671, is now equipped with a "Read after write monitor", to verify that data has been written correctly. This would seem to indicate that there were indeed problems with the PMD670 writing data to flash cards.
This review also appeared in Language Archive Newsletter Vol. 1, No. 4 (December 2004)