CentOS has great stability and Ardour is a fantastic audio editor. Let's put two good things together.
[Note: Ardour3 can be added to a base Fedora 21 Workstation install via a simple "sudo yum install ardour3" and then performing steps 8) + 9) below...so you should really just do that instead. This article is being left up for posterity.]
1) In a terminal, update your CentOS 7 base system:
sudo yum update
2) Add some software/repos that we'll need to compile Ardour:
sudo yum group install "Development Tools"
sudo yum install epel-release
sudo rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm
sudo yum install git jack-audio-connection-kit-devel libsndfile-devel liblo-devel aubio-devel cppunit-devel cwiid-devel liblrdf-devel libsamplerate-devel lv2-devel serd-devel sord-devel sratom-devel lilv-devel flac-devel gtkmm24-devel libgnomecanvas-devel libgnomecanvasmm26-devel suil-devel libcurl libcurl-devel uuid uuid-devel libuuid libuuid-devel fftw3 fftw3-devel liboggz liboggz-devel boost-devel alsa-lib-devel taglib-devel rubberband-devel vamp-plugin-sdk-devel libxml2-devel liblrdf-devel
3) Make a place to build Ardour:
4) Retrieve the latest Ardour 3 code (at the time of this writing, version 3.5.3698):
cd ~/ardour git clone git://git.ardour.org/ardour/ardour.git ./
5) Configure the Ardour build:
6) Build Ardour:
7) Install Ardour:
sudo ./waf install
8) Give the "audio" group realtime permissions, and add yourself to that group:
sudo tee -a /etc/security/limits.conf <<EOF @audio - rtprio 99 @audio - memlock unlimited EOF
sudo usermod -a -G audio `whoami`
9) Reboot to apply your new group permissions.
Now, you can open a terminal and run "ardour3" to use the software. Happy recording!