Basically, it doesn't work, neither does mpg123, while mplayer and aplay work quite fine.

alsaequal is here

gstreamer log:
0:00:06.652308334 1395 0x1327080 DEBUG ringbuffer gstringbuffer.c:479:gst_ring_buffer_open_device:<a udiosinkringbuffer0> opening device
0:00:06.654541790 1395 0x1327080 WARN alsa pcm.c:2104:snd_pcm_open_conf: alsalib error: Cannot open shared library /usr/lib/alsa-lib/libasound_module_pcm_equal.so
0:00:06.654688452 1395 0x1327080 WARN alsa gstalsasink.c:697:gst_alsasink_open:<alsasink0> error: Could not open audio device for playback.
0:00:06.654704934 1395 0x1327080 WARN alsa gstalsasink.c:697:gst_alsasink_open:<alsasink0> error: Playback open error on device 'default': No such file or directory
0:00:06.654811648 1395 0x1327080 INFO GST_ERROR_SYSTEM gstelement.c:1677:gst_element_message_full:<alsasi nk0> posting message: Could not open audio device for playback.

yet, its file strace just before exit:
1002 access("/etc/asound.conf", R_OK) = -1 ENOENT (No such file or directory)
1002 access("/home/hell/.asoundrc", R_OK) = 0
1002 open("/home/hell/.asoundrc", O_RDONLY) = 5
1002 open("/usr/lib/alsa-lib/libasound_module_pcm_equal.so", O_RDONLY) = 5
1002 open("/usr/lib/gconv/gconv-modules.cache", O_RDONLY) = 5

which, AFAIU, means that it was opened successfully.

Debian sid/experimental, gstreamer0.10-alsa version 0.10.20-1, kernel 2.6.28, libasound2 1.0.16-2
All binaries and libraries are ELF 64-bit (x86-64).

Question: What I can check regarding this problem?
E.g., how can I find reason for 'alsa gstalsasink.c:697:gst_alsasink_open:<alsasink0> error: Could not open audio device for playback.' message?