Real-time kernel without debug hasn't helped so far. Must be a Jack/Pulse/Alsa/FluidSynth/position of the moon/ audio recording problem. I'll start a new thread if I can't get it working.
How crazy, I had to make all these changes for better Linux audio. Get "hg clone https://realtimeconfigquickscan.googlecode.com/hg/
realtimeconfigquickscan" and run "perl QuickScan.pl" to see what changes you need to make. LinuxMusicians website really helped out!
I recompiled Fedora 14 Updates-Testing kernel 188.8.131.52-39.fc14.i686 with seperate debuginfo, and real-time kernel support set to 1000.
Also added these lines to /etc/security/limits.conf
@audio - rtprio 99
@audio - memlock unlimited
And added new 40-rtc-permissions.rules file in /lib/udev/rules.d with
Changed settings in /etc/security/limits.d/99-jack.conf to
@jackuser - rtprio 99
@jackuser - memlock unlimited
@pulse-rt - rtprio 99
@pulse-rt - nice 0
Added new 40-hpet-permissions.rules file in /etc/udev/rules.d/ with
Added this to /etc/rc.d/rc.local
echo 2048 >/sys/class/rtc/rtc0/max_user_freq
echo 2048 >/proc/sys/dev/hpet/max-user-freq
sysctl -w vm.swappiness=10
sysctl -w fs.inotify.max_user_watches=524288
I enabled ACPI 2.0 support on my motherboard.
I didn't change to GOVERNOR=performance in /etc/sysconfig/cpuspeed, since my computer is old, and my motherboard settings are conservative.
I changed the default Capture device in alsamixer to only PCM for recording internal audio, otherwise I got loud static.
I changed the default connections from System into my recording app, to Qsynth into my recording app for MIDI recording into audio.