Hi,
After much research, I managed to install Vortexbox 2.4 (Fedora 23 based) with Lynx Card (uses OSS sound driver). OSS and ALSA generally conflict each other.
Vortexbox by default uses Squeezelite/LMS as player - this works fine. I installed MPD player and managed to make it work using Gnome Music Player (Windows) client. However, I have to run the foll commands to get MPD working:
1. Reassign the specific Lynx device to /dev/dsp
# ln -sf /dev/oss/lynxtwo0/pcm4 /dev/dsp

2. Stop Squeezelite service which I suspect uses ALSA-OSS emulation which i had to install to get LMS player working.
# systemctl stop squeezelite0.service

Questions I have
- Is there anyway to automate the above commands by default when booting my machine.
- If I want to go back to LMS, I have to manually restart the Squeezelite service (not practical) - possible to avoid this.
- Can I streamline overall? I currently hear 3 pops and click in my DAC when booting highlighting the Lynx card is called 3 times through the Fedora boot process

I think systemd would be the simplest. Just open a systemd rule in an editor and change it to what you need. Then save it to a different name.

Thanks heaps.
I edited a rule for mpd.service to stop Squeezelite. Now, i can start MPD player without the need to get onto command line mode.
When I need squeezelite, i just resubmit Vortexbox device device assignment and I can play via LMS.

However, I have one last puzzle to solve. Once I start using Squeezelite, I can't play via MPD again (since Squeeezelite uses ALSA which locks in the sound device and disallowing MPD to use the same device). How can I get this resolved?

Cant think I can resolve via the systemd as the issue seems to be event based and don't know how to identify that MPD player is used again (i.e if MPD is called, disable squeezelite, else leave it enabled)

are you saying you cannot play more than 1 sound sources together under alsa?
mpd is using alsa?
if so, you might need alsa's dmix plugin - something that's been enabled by default in archlinux for ages, so i don't really know how to activate it manually, but maybe this can help: https://wiki.archlinux.org/index.php/Alsa#Dmix

dmix tends to be enabled by default and the soundcard should allow "sharing". With anything recent anyway (< 5 years).

About the only time I have trouble with sharing, is with pulseaudio and using multiple users. At which point networking needs enabled in pulse and a $HOME/.config/pulse/client.conf needs to exist with the contents of "default-server = 127.0.0.1". When using a user other than the one who started pulse on the same machine. Probably not your issue though. You might be running something else like jack over alsa which is locking the card. At which point you need to tell the player to use jack and not alsa when outputting sound. Or other trickery like snd-aloop and routing things through the Loopback device.

Thanks for the replies. I tried using alsa for both mpd and squeezelite players. This still caused mpd to not find the player (sort of locking the sound card).
It seems squeezelite and mpd services are mutually incompatible. If i stop squeezelite service, mpd can play.
Is there anyway i can detect the event of either player being used so thar i can start or stop particular services?