6yrs into CAS, the best sounding OS finally is close ...

[DM]

Tonight, my friend (an IT Director in one of the biggest banks in the world) and I finally hear some of the best sound from the CAS, this OS took us 6 months to optimise:

 

Trying different config

 

Booting

 

The Player interface (what interface?)

 

How good it is? The whole OS(kernel)+ Player only take up 4MB of RAM.

 

Compare to a "minimum" Windows/Mac system, the OS(kernel) + Player will take up 40-50MB of RAM, the normal Windows/Mac system usually take up 100-200MB of RAM when running.

 

The music background is so dark and quite, the music notes just jump out to you like watching a 3D movie, it is scary really ...

 

But sadly the player interface is back to the old DOS style ...

 

[fmak]

''Compare to a "minimum" Windows/Mac system, the OS(kernel) + Player will take up 40-50MB of RAM, the normal Windows/Mac system usually take up 100-200MB of RAM when running''

 

 

My small footprint XP uses 45 MB ram when playing hirez files. Fully functional interface. It has 8 uS latency on spdif and 15 using Async USB.

 

With memory play, it uses 775MB ram

 

[DM]

fmak, thanks for the info.

 

Are you using the normal WinLogon, or MinLogon?

 

[Audio_ELF]

But what configuration are you running? Details, details, details...

 

Eloise

 

[fmak]

But according to MS,this doean't make much difference to the footprint if Windows Explorer Shell is used.

 

 

 

[Krisbee]

Fascinating annoucement, but I'm with Eloise. Do we get to know what kernel patches you've used and and see your kernel configuration file? Or, after 6 months experimentation, are you just going to keep this wonder system to yourself?

 

As voyage is on your grub boot menu, is it fair to guess that their kernel config was your starting point?

 

Is it much different to what can be found here?

 

http://www.symphonic-net.com/kubotayo/articles/voyagempd.html

 

And then there's the whole debate as to whether a real-time kernel is of any benefit for audio playback, or is it just the manipulation of irq threads you were interested in. Any tweaks made to scheduling, compared to a generic kernel, will need careful explanation.

 

I'm all ears ...

 

[Julf]

And how much of it is kernel tweaking vs. minimizing other things going on in userspace?

 

[EuroChamp]

Hi DM!

 

Very interesting, we want to know everything! :-)

 

[DM]

We are still in the process of optimise it, so here is the framework that we started with:

 

Linux Distro : Voyage MPD Linux

http://linux.voyage.hk/voyage-mpd

 

-ck Kernel patch Con Kolivas

http://users.on.net/~ckolivas/kernel/

 

-rt RT Kernel

https://rt.wiki.kernel.org/

 

MPD Yan patch - Voyage MPD —-Linux Music Environment For The Best Audio Performance—

http://www.symphonic-net.com/kubotayo/articles/voyagempd.html

 

Jack

http://jackaudio.org/

 

Tips for Setting Up your Real-Time/Audio/Midi System yourself.

http://wiki.linuxmusicians.com/doku.php?id=system_configuration

 

ALSA Low-lantency HOWTO

http://www.alsa-project.org/main/index.php/Low_latency_howto

 

IRQ Priorities How-To

http://subversion.ffado.org/wiki/IrqPriorities

 

Will post more later when we have settled a bit more.

 

[Jud]

Jumping on to the list of those who will follow this with interest. Thanks for the citations so far.

 

[DM]

On cheap Dell

- Ubuntu LInux : Kernel 3.2 with -rt real time patch v.s. -ck patch. *Extremely* optimised for audio playback. You can hear the BEST technology Linux can offer!

 

- OSS vs ALSA (on headphone only - unfortunatively OSS not support USB2.0 audio thus doesn't work with the AMR DP-777.)

 

On decent HP i5 laptop

- MPD Voyage 0.8 on USB thumb drive, Kernel 3.2 with -rt real time patch v.s. -ck patch. No harddrive required. Medium optimisation.

 

[phofman]

Why jack on a playback machine?

 

[Krisbee]

So after 6 months you are still "optimizing" ... Your list of web pages is well known to many of us, and tells us nothing about what might be different, new or special about your OS config that you claim to be the best. May be if you post the config for your "*Extremely* optimised" kernel we can start to make a judgement.

 

Are your really running jackd on this? If not, why bother to site a reference.

 

It's old news that OSS4 on Linux doesn't do USB audio class 2, it doesn't even do USB audio class 1 very well.

 

While you are still testing try this one, it's the best "all memory audio Linux player" (ha,ha)

 

Install Lubuntu 11.10 in VirtualBox. Install a low-latency kernel for here https://launchpad.net/~abogani/+archive/ppa, along with rtirq-init. Install MPD and ncmpcpp. Remove unwanted software, including the deskstop if you wish. Remaster the iso with remastersys. Copy the iso out of your virtual machine guest to the host with scp. Burn the new iso and then boot the new live CD on your laptop using the "toram" boot option. Now you'll have the entire OS and apps running in memory. The more memory your laptop has the better, because copying audio files from the local disk to the home directory of the booted liveCD means you'll be playing these files from memory. There'll be no disk access at all. Check with iotop.

 

 

Compare this with your "if took six months to optimize OS". I wonder if there will be a big difference in sound.