The Scoop on Mini-disc Recorders

A young man sent us an e-mail asking about mini-disc recorders, if he should buy one and if he did, what kind? Flawn Williams, one of our Next Generation Radio Technical Advisers, responded to his question. Flawn has a more substantial piece on recording and equipment.

Hello and thanks for writing to us.

You wrote:

A professional sound person I just talked to said the new SONY Minidisc recorders were "lossy" and only recorded at 28Khz rather than the 48Khz of SONY D7 and D8 digital tape recorders.

I think that person is confusing kHz (sampling rate in kilohertz, which affects frequency response) with kbps (data rate in kilobits per second, which affects overall sound quality).

It's correct to say MiniDiscs are lossy: they use a data reduction algorithm called ATRAC to take an incoming sound signal and encode it in a smaller amount of data. DAT recorders like the D7 and D8 don't do this. But ATRAC has been improving over the years that MiniDisc has existed, and many recordists now put it on a par with the linear 16-bit recordings of DAT.

Further muddying the issue, though, is that lately Sony and others have been introducing MiniDiscs with multiple options for data reduction, answering users' pressure for fitting more and more music running time on a MiniDisc. These use more aggressive data reduction to squeeze more music into less data. More running time--twice, or even four times as much!-- but poorer sound quality. That may have been what your sound pro person was referring to. But those extra options only degrade the sound if you use them! All the new models I've seen still have the option to use the regular ATRAC algorithm with good fidelity and store 74 or 80 minutes of stereo audio.

It seems like the technology is moving towards recording on disc. I wonder if the quality is there?

The technology is actually moving PAST disc recording now...much of the innovation is happening in hard disc recorders or flash memory recorders. But MiniDiscs are still hard to beat for the cost of the recorder, battery efficiency, cost of media. They DO have some occasional problems in terms of susceptibility to corrupted Table of Contents (TOC) files when recording in motion. But so far there is no perfect recorder: DATs have problems, memory chip recorders have problems too.

Is there a 48Khz portable Minidisc recorder?

MiniDisc's native sampling rate is 44.1 kHz, the same as CDs. The D7 DAT recorder records at 48 kHz; the D8 DAT records at either 44.1 or 48. Quality difference between these two sampling rates is negligible. Some newer hard disc recorders offer 24 bit 96 kHz sampling rate recordings, which is a noticeable quality jump from either MiniDisc or DAT. But these decks are pretty pricey and not terribly power efficient either.

The stores (e.g., The Wiz) are drastically reducing the price of their D8s. I presume they are not being made anymore and I do not want to buy into a technology that is obsolescing. What are your suggestions for dealing with this situation?

If they're really drastically reducing prices on the D8s, you'll probably find me standing in line to buy another one. Since NPR's studios (and I personally) have a large library of DAT tapes, an installed base of DAT production capability, and all the appropriate accessories to support the D8, it'll be useful to us for some time to come. I believe Sony has announced it is discontinuing the D8, but retaining the PCM-M1 and TCD-D100 portable DAT recorders.

On the other hand, for someone just starting out as a recordist, MiniDisc is a much cheaper way to get almost the same sound quality. Some drawbacks? Portable MiniDisc recorders lack digital outputs, though they have digital inputs. "Lossy" MiniDisc audio doesn't hold up as well as linear DAT recordings through several generations of transfer from one device to another; that's a problem for us, but may not be for you.

You may also want to look at recorders that convert sound directly into MP3 format digital audio. If you keep the data rate high (at least 128 kbps, which is similar to regular ATRAC, or preferably 160 kbps), these can also sound pretty good.

And on the horizon, watch for products using the MPEG-4 "AAC" (Advanced Audio Codec) algorithm. This offers better sound quality at lower data rates than MP3 or any similar system.

As you can see from the plethora of options I've outlined for you, EVERY technology available to you now is obsolescing. Choose what you need for current work, and plan on transferring anything you want to save for the future into new storage formats at they appear!

--Flawn Williams
NPR Next Generation Radio trainer