Some experience - r/w remount problem, usb audio, octave shifted, latency

[gkita]

Some experience:

-sometimes I cant remounted r/w the file system (when I modified files on sd card, with an other pc) : mount -o remount,rw / mount -> can't find / in /etc/fstab

solution:

mount /dev/mmcblk0p1 /boot mount -o remount,rw /dev/mmcblk0p2 /

• I use usb audio, but not working.

Solution:

touch /etc/asound.conf and write into 2 lines:

defaults.pcm.card 1 defaults.ctl.card 1

(and into samplerbox.py: AUDIO_DEVICE_ID = 2)

• when I played with piano preset, the octave was shifted. Solution (SamplerBox.py):

def MidiCallback..:

midinote = note + 12

• I experimented with buffer (to lower latency) It seems to lower:

in the open audio section (try-except): blocksize=0 (instead of 512, 128, 32 etc)

But there is still a lot of latency. I think 20-30 ms. Especially when I played piano preset. It has fast attack, and I feel the latency, and it disturb me a bit. Whit the slow attack preset (like slow string, chello etc) it isn't annoying.

Have someone ever try any real-time kernel, or very small and easy raspbian image for faster system? If you have any idea, please write. Thanks.