[LAU] ?? Dmix is enabled as default

Hi! In accordance with http://alsa.opensrc.org/index.php/Dmix "For ALSA 1.0.9rc2 and higher you don't need to setup dmix. Dmix is enabled as default for soundcards which don't support hw mixing". Ok, I starts 'aplay file.wav' at two consoles. The second one says: aplay: main:608: audio open error: Device or resource busy I have tried asoundrc examples from that page without any success. Alsa 1.0.20, hdsp/RME9632 are in use under Kubuntu Karmic. Other aplay info is: $ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: DSP [Hammerfall DSP], device 0: RME Hammerfall HDSP 9632 [RME Hammerfall HDSP 9632] Subdevices: 0/1 Subdevice #0: subdevice #0 $ aplay -L default:CARD=DSP Hammerfall DSP, RME Hammerfall HDSP 9632 Default Audio Device null Discard all samples (playback) or generate zero samples (capture) This 'null' is rather strange... What have I missed? Where to dig in? Andrew