This short guide will tell you how you can get WineASIO to work with Reaper and Guitar Rig.
So one of the first things we need is wine.
sudo pacman -S wine
Should do the trick. Then we also need the jack server and a frontend for it, the most popular is qjackctl.
sudo pacman -S qjackctl jack
Now run qjackctl to select your audio interface in the Setup screen. I have this dedicated guitar interface: http://www.behringer.com/EN/Products/UCG102.aspx
It's not the best, but it's cheap and works on Linux.
Be sure to set the sample rate and the buffer size correctly. I can get it down to 256 samples and to a latency of around 10 msec (on Windows it does go under that).
Add your user to the audio group with
sudo usermod -a -G audio yourusername
And now you should be able to start the jack server from qjackctl
Next up we need wineasio, this has to be installed from AUR wineasio or wineasio-git.
For some reason, this didn't really work for me, so I compiled my own. You still need steinberg-asio though.
sudo packer -S steinberg-asio
This will install asio.h into /usr/include/steinberg-asio/asio.h
(Normally you would get this from the Steinberg SDK, which you would get by signing up for a Steinberg Developer account)
Now if the AUR package didn't work for you, then you can download wineasio from here:
http://sourceforge.net/projects/wineasio/
And copy asio.h from the above location to the source tree. After which, as the README file says:
Do the following to build for 64bit Wine.
# ./prepare_64bit_asio
# make clean
# make -f Makefile64
Now that should result in wineasio.dll.so being built. Check the architecture with the following command:
[balazsbela@archlinux wineasio]$ objdump -f wineasio.dll.so |grep arch
architecture: i386:x86-64, flags 0x00000150:
All good, now copy it into /usr/lib64/wine/ (Assuming you use the 64 bit version).
Now we need to register it, so REAPER sees it.
wine64 regsvr32 wineasioa
This should result in the message: Successfully registered DLL wineasio.dll
Now run winecfg and check that the drive in the Audio tab is winealsa.drv and only that.
WineAsio is now installed!
So lets get Reaper from: http://www.reaper.fm/download.php
The instalation is straightforward, next next finish.
Now you can get the free version of Guitar Rig from here:
http://www.native-instruments.com/en/products/komplete/guitar/guitar-rig-5-player/download/
So download and install that, set the VST plugin folder in Reaper (start it with wine reaper.exe, it usually lives in ~/.wine/drive_c/Program\ Files/REAPER\ (x64)/)
Now Guitar Rig should appear when you add effects to a track and you should be able to use it.
This approach is not perfect, I still get some buffer underruns with my USB interface, there is also a way to use a realtime kernel, that would probably make it a lot better, but it works and it's good enough for now.
In case I may have forgotten something:
http://lkubuntu.wordpress.com/2014/01/09/how-to-set-up-wineasio/
http://forum.cockos.com/showthread.php?t=16786
It does show how wine has come such a long way, maybe now with the open-sourcing of .NET it will get even better.