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Old 9th November 2013, 08:54 AM   #2181
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Location: D
I brought DLNA/UPNP up because

a. I wanted to test how to configure the Raspberry Pi as UPNP renderer
(To checkout if there is an alternative to squeezelite. I won't go for MPD!!)
b. I do have an UPNP server (Serviio) running for Video, Audio and Images
anyhow
c. there are network audio renderers supporting UPNP only
We're just checking out the giant killer (NAD D7050), a network based
Full Digital Amplifier, which runs UPNP only.
d. all my phones and tablets can also act as UPNP renderer

There are several reasons for having a closer look at UPNP.

I did realize now that Android UPNP control apps can't compete with SqueezeUniverse controllers like iPeng or OrangeSqueeze.
From that persepective UPNP would be a significant step back.

My main priority and decision criteria for a system is the quality of availble control apps. That's where e.g. MPD failed.

Cheers
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Old 10th November 2013, 07:14 PM   #2182
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It's a huge tread. Just to say hello happy linux users

I am an old linux user, begining with Suse on a 386, and now on gentoo ~amd84 for production and debian for testing. I also begun with rt-kernel at the time when no audio distribution was born. It was the only possibility to get jack to work in realtime as a normal user at that time. Now, I back with a "normal" kernel and the cgroups to get rt, that on gentoo. Unfortunately, they succeded to make the kernel cgroups fully unusable on Debian, so no rt on that box, and I don't want to install a rt kernel anymore if a vanilla one can provide me the same functionalities..
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Old 10th November 2013, 07:42 PM   #2183
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Hey, finally another gentoo user!

Do you care to share your kernel build options regarding real time functionality?

Rüdiger
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Old 26th November 2013, 11:22 AM   #2184
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I was not online for 14 days.
I thought I'll give a short feedback anyhow.


Quote:
Originally Posted by Onvinyl View Post
Hey, finally another gentoo user!
Poor you.


Quote:
Originally Posted by Onvinyl View Post
Do you care to share your kernel build options regarding real time functionality?

Rüdiger
* Processor Type and features
1. Preemption Model ( Fully Preemtible Kernel)
2. Timer Frequency (1000Hz)


These two options should do. Only these btw are also changed on the Ubuntu Low Latency Kernel (which I run on my Ubuntu Desktop system).
Full Preemption is obviously not avialable on the Ubuntu LL kernel.

My headless servers run newest 3.12.1-rt4

You might also want to checkout the Graysky patch, which explicitely lets you select your processor architecture from "make menuconfig". But that's maybe covered by your Gentoo installation.

Beside that remove all stuff form the kernel you don't need. And that's a lot. Probably 90% of default kernel options are activated, though useless for most machines.
And do not use "make localmodconfig". That option is supposed to select kernel options applicable to your HW only. It never really worked in my case. Usually I ran into hang-ups during boot. I do it manually nowadays (Usally I unselect a lot of driver related stuff, because that's the easiest part).

Once done with the kernel, make sure that your "user" is allowed to apply rt priorities and your app is supporting it. Otherwise the whole exercise is of no use.

Good luck.

Cheers

Last edited by soundcheck; 26th November 2013 at 11:37 AM.
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Old 29th November 2013, 10:51 AM   #2185
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The rt-kernel also here:
https://www.kernel.org/pub/linux/kernel/projects/rt/

And one toy named mxcd2cue which can conv mxcd file to cuesheet:
http://leonbernieniv.googlecode.com/files/xmcd2cue
It's binary for amd64 only, and still availability for the past many years.

Cheers
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Old 2nd December 2013, 06:26 AM   #2186
Gobble is offline Gobble  India
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Quote:
Originally Posted by soundcheck View Post

* Processor Type and features
1. Preemption Model ( Fully Preemtible Kernel)
2. Timer Frequency (1000Hz)


These two options should do. Only these btw are also changed on the Ubuntu Low Latency Kernel (which I run on my Ubuntu Desktop system).
Full Preemption is obviously not avialable on the Ubuntu LL kernel.
Good luck.

Cheers
Greetings
Have you compared the audio from a stock LL kernel with one rebuilt with full pre-emptible option and the RT patch?

I use the stock lowlatency kernel with linux mint and I notice a distinct improvement when jackd runs in RT mode (rtprio 99) versus stock priority of 20.

Without jack in RT mode (on LL), the sound is discernible as being somewhat thicker and sticky of a quality akin to congealed blood. Its a non-tactile version of that effect of course.

Since my audio PC is of low horsepower, I would like to save on the effort of compiling a kernel on that pc if possible. Or simply anticipate what kind of improvement a 4 to 6 hours compiling effort will bring to the table.

PS: These are the settings with stock LL

$ cat config-3.8.0-32-lowlatency | grep PREEMPT
CONFIG_TREE_PREEMPT_RCU=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT_NOTIFIERS=y
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
# CONFIG_DEBUG_PREEMPT is not set
# CONFIG_PREEMPT_TRACER is not set


--G0bble

Last edited by Gobble; 2nd December 2013 at 06:42 AM.
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Old 2nd December 2013, 04:36 PM   #2187
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Havn't been comparing LL to FullPreempt 1:1 for years.
Just using them as I always did.

I played around with the compiler options and revisions (4.8) not long ago.

You should get the compilation time down to a third at least, if you strip down your kernel options. Or let the computer compile over night.

Cheers
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Old 4th December 2013, 09:31 PM   #2188
UnixMan is offline UnixMan  Europe
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Or you can build the kernel on a different (and more powerful) machine...

Inviato dal mio GT-I9100 utilizzando Tapatalk
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Old 17th December 2013, 08:08 AM   #2189
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Hi folks.

Idea:

I'm thinking of "activateing" a two-way speaker system.

I neither want to run MiniDSP stuff, nor I want to use
a multichannel audio interface and additional amps.
I want to keep things simple.

I'd prefer a PC->Full Digital USB amplifier setup.

Since November Hifimediy sells a very interesting FullDigitalAmp (80$/60€) with asynchronous USB interface.

Basically it's based on the same PCM/PWM technology as used in the DDX320 amp, which I'm using ( a tweaked version of it) for quite some time on my main system.
The idea with the new project would be to use one USB-FD-amp per speaker.
And let the PC (new Cubox-I or similar ) do the DSP work.

Now. I know from earlier (some years back) discussions, that it has been a kind of serious issue to keep two USB DACs in sync.
With above device I'd even have to keep two "asynchronous" USB DACs in sync, which could be worse then adpative mode.

I'm wondering if it is still the case that I can't keep the async USB DACs in sync with Linux/Alsa!?!?

How much would those DACs run out of sync??
Would it depend on the buffer the interface chip uses??

Does Jack help ??

I did read somewhere that a company managed through its propriatary ASIO driver to keep their own DACs in sync on a Windows system. It should be possible somehow.

And there are also speaker which e.g interconnect wireless - Avantgarde Zero 1. Not sure how they manage to keep both sides properly in sync!?!?

Any hints are welcome.

THX
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Old 22nd December 2013, 11:32 AM   #2190
peufeu is offline peufeu  France
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> With above device I'd even have to keep two "asynchronous"
> USB DACs in sync, which could be worse then adpative mode.

Using only USB, only adaptive mode can do this, in this case the PC is the master clock, then You Got Another Problem.

Other solution is to transport a master clock (wordclock, etc) between devices, but you'll need to reconstruct it cleanly in each device...
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