A while ago I started a project to manage MP3 tracks on a USB stick. It was customised for use with the Numark Mixdeck Express (as it allows browsing tracks by folders, rather than tags). That project is no longer active, but you can still find the code here, should you wish to have a play.
In my endless quest to find a set-up that I’m happy with, I’ve discovered the DVS (that’s Digital Vinyl System for those not in the know…) called xwax (http://www.xwax.co.uk). This is, what appears to be a basic yet rock solid (important, for obvious reasons) solution. For some reason my Toshiba Equium laptop running Windows 7 does not play well with the Native Instruments Audio 4 interface. This is apparently due to dodgy drivers (for devices other than the Audio 4), and you can find more information, and a tool to diagnose the guilty driver, here http://www.thesycon.de/deu/latency_check.shtml. My investigates proved fruitless, however if you’re running into problems with audio dropouts then you may have more luck.
xwax runs on Linux, and this was the perfect excuse to tinker with yet another Linux distribution. I’ve never liked Ubuntu in the past, but I thought I’d give it another try, and I can honestly state that I think its great. I think my main sticking point with Ubuntu in the past was its dreadful color scheme (yeah I know I could have changed it, etc, but first impressions count for a lot…) but this has changed to something that looks a bit less 1970’s, which is nice.
A quick apt-get install xwax sorted the install out. Linux has support for the Audio 4, from Kernel 2.6.30, however you need 2.6.35 if you want to use the high impedance ‘Control Vinyl’ mode (see here : http://www.pogo.org.uk/~mark/linuxdj). This wasn’t a problem, as I already had this Kernel installed. I started xwax with the command line xwax -t traktor_a -a plughw:Audio4DJ,0,0 -a plughw:Audio4DJ,0,1 -l ~/Music (after some tinkering with the options – something to bear in mind here that version 0.7 requires that the options are in the correct order, putting the -t option for the Traktor timecode at the end made the track play at double speed). All appeared to be well.
However, once I’d selected a track, and dropped the needle on the record, it became apparent that something was not quite right. Its difficult to explain exactly how it sounded, but the 2 main characteristics of the problem were a) it sounded ‘digitally distorted’ and b) the track appeared to ‘skip back’ for a fraction of a beat with regularity. Here’s a video to clarify things:
No matter what I tried, different Kernels, installing ubuntustudio-audio (for a real time Linux Kernel), running as root, adjusting rtprio in the limits.conf file, using one deck only, using the other side of the Traktor vinyl etc, nothing seemed to work. This was a little disappointing, to say the least. The guys online via IRC at #xwax on irc.freenode.net were more than happy to help (please be patient if no-one is around, however), unfortunately I could not resolve the issue. If anyone has any ideas, then please let me know.
As a last resort I tried connecting up my old ScratchAmp v1, from the very first Final Scratch system. And, would you believe it, it worked fine, first time! xwax is
I’ll continue to play with xwax, and post my findings here. Its good to know that there’s an open source DVS out there, that requires no special hardware and a free OS!