Home Computer Audio Asylum

Music servers and other computer based digital audio technologies.

RE: Tuning Linux/MPD/Alsa for best sound on ALIX processor

============
Strangely I receive no error setting to 100. After issuing modprobe, I cycled MPD. Sounds like I should have power cycled the DAC??
============
I eaplained that in my previous post. The modprobe command loads the usb-audio module (i.e. the usb-audio driver). However, when the module is already loaded, it quits without any output. The module gets loaded automatically by udev upon attaching the USB soundcard/at boot respectively. In your case the module was already loaded, that is why modprobe did not complain. Nothing really happened, you could not hear any sound difference.

Either rmmod the module which may be a bit more complicated if some software is already accessing the sound device (rmmod snd-usb-audio), or reboot with the dac disconnected (better than powered-down, it could still be detected, I do not have your gear to test).

Upon rebooting, run the modprobe command with the nrpacks param. You can always remote it with rmmod. Play with the different values to identify the upper limit of 20 (I raised the limit to 1000 in my diy experiment but that requires rebuilding the kernel).

After the module is loaded with modprobe, attach you USB DAC. This time udev will not load the module as it is already present, with the parameters you specified.

This way ABX testing is simple, e.g. using my simple script at http://blog.ivitera.com/pavel/linux-audio/tool-for-ab-testing - just redefine CMD1 and CMD2 to rmmod the module, modprobe with another nrpacks value and play some file.


This post is made possible by the generous support of people like you and our sponsors:
  Signature Sound   [ Signature Sound Lounge ]


Follow Ups Full Thread
Follow Ups

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.