The other night, <a href=”http://www.quadrantcrossing.org/blog/” target=”_blank”>Tobias</a> treated me to a demonstration of <a href=”http://www.native-instruments.com/index.php?id=traktorscratch” target=”_blank”>Traktor Scratch</a>, a digital DJ setup. Basically, it involves the usual two turntables and a mixer, plus a digital interface and a laptop. The DJ uses special records striped with timecode, special needles and a digital interface reads the timecode off the records and uses it to control digital music files playing off a laptop’s hard drive (which could be as simple as an iTunes library).
The setup has a few main advantages: the DJ no longer has to cart around boxes of records and can presumably have more access to music (by carting around a laptop with a full hard drive and the relatively small interface instead). The setup also allows for the use of all sort of digital effects, again giving the DJ much greater flexibility. And, for the first time, the DJ’s collection can be “backed up” so even if the laptop were to disappear before or after a show, the person could have another copy of his or her collection. Finally, because it uses traditional DJ technology (two turntables and a mixer), the DJ can still use his or her skills — manually beat matching, scratching, starting and stopping music.
But that’s where there are some interesting differences. On a regular analog record, the DJ can see the breaks and can learn to see where, exactly to drop the needle. Because the timecode records are in timecode, the DJ now has to make an extra step of intellection: “the break I want is at 3:53” and then drop the needle onto the corresponding part of the timecode record. There is, of course, also the matter of the additional visual interface of the laptop screen, which is somewhat more involved than simply thumbing through a stack of records. Spontaneity in song selection works quite differently. The timecode records “like” a certain kind of needle, and though this needle can play records, it’s not necessarily the needle a given DJ would want if analog records were also to be played.
And then, of course, there’s the sound.
We did a few unscientific tests. Most notably, the high end coming off the laptop and off an analog version of the same track was different. There could be lots of reasons for this that have nothing to do with “digital” and “analog” — the traktor-scratch needle, the D/A conversion of the laptop, an EQ setting we missed, etc. The mids and lows were basically indistinguishable. But the place where the difference really came through was when it got down to things that DJs do: stopping records, slowing them down, playing them backwards, scratching, etc. Drag the needle backwards over the timecode record and the digital file sounds very different from the analog record. Slow it down and the bass takes on a different character. I won’t say that digital sounded worse, because I don’t think it did. But as we “abused” the file like a DJ would “abuse” a record (and by that I mean simply “not playing it like you’re supposed to” even though at this point records more or less <em>are</em> “supposed to” be manipulated by DJs), it broke down in a completely different way.
The differences between .wav and high bandwidth .mp3 versions (at least I <em>think</em> it was 256k though I never checked) of the same song were much more subtle. They also “broke down” slightly differently, but the difference was had to perceive. Tobias pointed out that with 20,000 watts behind it, the difference may be more noticeable, but we didn’t have an opportunity to do <em>that</em> test. Whether it would affect people’s enjoyment at a show is also questionable.
What does all this mean for the arguments about analog vs. digital? Not a whole lot. I’ve never claimed the two storage modes sound exactly the same, only that the ontological arguments for digital’s inferiority are based on faulty premises and misreadings of the sampling theorem. That said, it’s interesting to hear the different modes of decomposition: the different formats and storage media <em>reveal</em> themselves differently when under duress. You can sort of hear the sampling theorem breaking down as the record slows to a stop–the apparatus is revealed. And that difference, unlike the difference between a 320kmp3 and a .wav file, is plain for anyone to hear.