Surround sound activation for Mplayer, Ubuntu

Mplayer has enough configuration arguments to initiate surround sound from stereo audio. One of my earlier posts was on how to activate the subwoofer channel. Now here is the full configuration

$ gmplayer -ao alsa -af surround=10,sub=75:5,center=4 -channels 5

Here
surround=10 : specifies the delay in surround channels (here it is 10)

center=4 : Which channel to redirect center channel audio derived from the front channels.

Mplayer will then derive the rest of the channels from the front channels and we have 5.1 music.

A Website for Under the hood info on cars

I stumbled upon a site on the internet while searching for detailed information on car suspension and wheel alignment. Very lucidly presented information on cars and its maintenance is available on this site.

http://www.carbibles.com/

Activate subwoofer channel

Even if any music player like mplayer is used to activate the subwoofer channel, It won't get activated until 6 channel mode is activated in the volume control dialog.

To do this first double click the volume control icon on the top panel.

On the volume control dialog check if an "options" tab is available.

If not then click the "preferences" button and tick the "options" check box to activate it.

Now in the "options" tab change "Channel Mode" to 6 channel.

My sound driver & Mixer is ALSA for nVidia.

Installing HP Printer in Ubuntu

There is an easy way to install a HP printer in any Linux installation including Ubuntu. Thanks
to HP for providing an installer that does all the job on its own.

My printer is an HP Deskjet D2360. First goto the site -

http://hplipopensource.com/hplip-web/install_wizard/index.html

Then select Distribution, Version, Printer type and Model

Proceed to download the installer and move it into a folder. ( A separate folder)

The downloaded file will be something like hp[version].run. Start a terminal window and
access this folder then run the installer by typing

$sh hp[version].run

If you don't put the installer in a separate folder the default directory will be flooded with
installation files.

The installer itself will recommend you to run the installation as default user. Provide the
administrator/root user password when you are asked to.

Select automatic installation(Recommended by default). Proceed to answer some simple
questions and the installer will automatically download and install any dependancies if
required.

Then it will ask you to replug the printer and the installation is done. You can print a test page
if needed.

The HP download page also contains detailed instructions to run the installer.

CUPS Server not running

To install a printer in ubuntu, the installer program demanded that the CUPS - Common Unix Printing System had to be be operational. But my system showed that CUPS was not active.

Then I verified System>Administration>Boot-up Manager and I couldn't restart CUPS

Typying cupsd at the terminal to evoke the daemon, I got the message -

"Child exited with status 1!"

A bit of googling told me to check /var/log/cups/error_log and it gave -

"/etc/cups/ssl/server.crt" is a bad symlink - No such file or directory

I found the solution later on as -

sudo apt-get install --reistall ssl-cert

It worked and CUPS was running again.

Making subwoofer work for mp3 playback in Ubuntu

The only thing I felt missing whenever I played MP3s on Ubuntu was the rich punch of bass from my subwoofer speakers. There is no option of a mixer to reroute sub base frequencies to the subwoofer channel.

My Subwoofer is a home brewn one and has no external hardware to downmix and filter out the frequencies from the front stereo channels as found in 2.1 speaker systems. The ac3 filter or the ffdshow audio decoder I normally use in windows has this option but not in linux.

So I tried many media player applications in ubuntu. Amarok, Xine..etc...and ended up clueless

Then I installed mplayer from the repositories using

$ sudo apt-get install mplayer

MPlayer is a command line media player for KDE. The GUI version is GMplayer.

This one has got tons of command line options with it. The one I like particularly is the -af (Audio filter) option.

The man pages of mplayer are too large to scroll through, better make it into a file to be read by some thing like gedit.

it has the option sub=cutoff:channel

which it says will filter frequencies from the left and right channels using butterworth filter below the cutoff value and reroute it to the channel specified.

Here is what i have used

$ mplayer -ao oss -af sub=75:5 -channels 5

-ao : specifies the audio output driver, Here oss is given

-af : audio filter options without which the sub option won't work

sub=75:5 : the cutoff frequency and the sub channel

-channels : specifies the number of channels to be used.

Here mplayer recognises channel 5 as the sub channel.

if you want to invoke all these options when double clicking an MP3 file,

feed all these options with the "open with" menu's extra options. Add an "&" at

the end to make it work in the background.

Enjoy the thump of music!!!!

To configure the mixer for 6 channel mode in Ubuntu..see this post...

http://electrowonder.blogspot.com/2009/07/activate-subwoofer-channel.html

Solve APIC problem in Linux

My AMD Athlon system used to freeze at boot time stating an APIC problem. We can temporarily skip the issue by adding noapic at the end of the boot command line.

But the problem keeps on nagging at each startup.

To solve the issue permanently edit the GRUB bootloader configuration file - menu.lst

$ sudo gedit /boot/grub/menu.lst

Scroll down to find some text similar to the ones we see at the bootup options. Here is one

title Ubuntu 8.10, kernel 2.6.27-9-generic
uuid d727a8ef-4fbe-457d-987c-6959924f76b6

kernel /boot/vmlinuz-2.6.27-9-generic root=UUID=d727a8ef-4fbe-457d-987c-6959924f76b6 ro quiet splash vga=792

initrd /boot/initrd.img-2.6.27-9-generic
quiet

Like wise we'll see many options below this one. Now we have to just add the word 'noapic'
at the end of the line "kernel".

Save the file & restart the system.