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Bit Perfect Audio from Linux - Page 13

post #181 of 295
What I think they where trying yo do is give you a bare bones install with only what is needed to run the audio system and usb interface . So if you have a old ass computer around you could just make it do audio where if some of the other stuff was running you might get hiccups while trying to decode or output the 24/96 stream. Linux is modular like this so that you can install specifically what you need. I would not be surprised if you used this install on an old ass machine it would work good. In reality on high end hardware it is overkill
post #182 of 295
Quote:
Originally Posted by julian67 View Post


Question: if you already have bit perfect audio then how do the bits get more perfect?

Some think that there is more to it than just bit-perfect:

http://www.audioasylum.com/forums/pcaudio/messages/12/126159.html
post #183 of 295
From my understanding, 1011111000001110101001 is all digital is. Now from what they where talking about I could agree that the timing of the packet going from host to slave if there was not enough buffer Hiccup in stream cpu cycle on some ither process might affect the decoding and introduce something that should not be there. These are my humble observation.
post #184 of 295
If a computer has an audio chip that supports 24/96 then it isn't likely to struggle converting audio. Decoding audio files and passing off to a DAC is not exactly going to put any load even on very modest hardware. No special "audiophile" distro required. If someone somehow has a very modest system that includes a decent sound card then the obvious thing to do would be to run it headless with no X server or graphical environment. It's very easy to set up mpd and then control it from a client i.e. another PC, a tablet , a phone and so on. By the reasoning of the ap-linux crew this would be even more "audiophile" than their offering biggrin.gif

The audioasylum article is about ground noise. I'd love to know how a board with ground noise problems has its problems solved by the choice of a real time kernel or by disabling a daemon or by choosing a particular window manager or desktop environment. You could waste some time trying out the magic software and the mysterious process or you could send the audio elsewhere via spdif and stop worrying about it.

btw Deac0n you mentioned you will be trying this in a VM. This is pointless if you're trying to discover some change in sound quality. You would need to actually install it to hard disk and run it on real hardware, otherwise your "audiophile" OS just inherits all the alleged deficiencies of your current environment.
post #185 of 295
I was only using virtual box to look at it. And check out the install. Which 10 years ago would have needed a lot of expert friend help. This if you like to tinker is great. Another way to move people from windows.
post #186 of 295
Did anyone ever do any testing between oss4 alsa and jack?

I hear talk that each one of them is better tongue.gif
Has there been any real tests with figures graphs etc ? Or is it all hear say
post #187 of 295
Quote:
Originally Posted by undersys View Post

Did anyone ever do any testing between oss4 alsa and jack?

I hear talk that each one of them is better tongue.gif
Has there been any real tests with figures graphs etc ? Or is it all hear say

These are not all interchangeable and directly comparable so "testing between" them would be in large part futile.

JACK is a sound server daemon which can use OSS or ALSA (or several others) as a backend.

ALSA is a sound framework that includes kernel drivers and an API.

OSS is similar to ALSA in conception and implementation being a set of kernel drivers and an API.

You could make a fresh comparison of OSS and ALSA, or you could join in a pre-existing religious war and enjoy the same happy experience and reactions.

If you want to compare JACK to something that would probably be Pulse Audio. Again, have fun but that mud slinging contest started a long time ago.

Anyway this thread is "Bit Perfect Audio from Linux" and in that context it doesn't matter if you use ALSA or OSS as long as your sound card has a working driver. If the hardware is capable but the driver doesn't allow you to enjoy bit perfect audio then you have to consider it isn't yet a working driver.
post #188 of 295

Ok sure, thanks for the reply.

I use jack now on my desktop for audio recording.

 

I am aware of what alsa/oss is, but from what your saying as long as the driver can interface directly; IE no mixer or crap in between in theory it should not matter as both will be bit perfect. (the real goal)

 

I agree, but has any one tested it ?

I am likely to go with ALSA for my new setup with MPD but was interested in testing checking etc... a bit more scientific rather then holy-wars :) 

If they are exactly bit perfect then there should no measurable difference between OSS and ALSA. 

post #189 of 295
Quote:
Originally Posted by undersys View Post

I agree, but has any one tested it ?

You can easily check for yourself on your own hardware by outputting via spdif to external dac or digital recorder and checking the result is the same in turn with alsa and oss.
post #190 of 295
Quote:
Originally Posted by julian67 View Post


You can easily check for yourself on your own hardware by outputting via spdif to external dac or digital recorder and checking the result is the same in turn with alsa and oss.

 

That was my plan :)

I don't have the H/W yet for the new audio setup.

Hence they question. 

post #191 of 295
I would use mplayer (command line, not GUI front end). Then it's easy to send decoded audio direct to hardware, specifying driver, bypassing system mixer and sound daemons, and taking exclusive control of the hardware. Run it in verbose mode to see exactly what it's doing.
post #192 of 295

thanks for that. I love the CLI anyway :) (Gentoo user)

I'll worry about that when the kit gets hear, thanks for you reply.

post #193 of 295

Has anyone had experience with the Cubieboards? They would seem to offer everything that's needed: S/PDIF, a SATA port, and Fedora or Ubuntu. The version 3 board has Toslink, the previous version coax with some TTL level changing from its IO headers. 

post #194 of 295
No experience except a lot of reading and having used the pi as a bit perfect music player.

But from what I can tell the cuboxi is by far the superior product with none of the issues the pi had (many USB sync issues and dropouts) and make a fantastic little media device. All of alsa is present and accounted for in packages for the kernels being prepared, the very latest kernel actually.

Ive ordered one for my girlfriend for xbmc duties and one for me for programming duties. If you need more hardware don't forget to check out the utilite.
post #195 of 295

Could I ask, which model Cubie did you decide on getting? Their models' features / pricing are a bit confusing, with the CubieTruck seeming to be less expensive than the preceding models ?

 

Sounds like you haven't taken delivery yet, but I would really like to know what build of XBMC you find works the best, or also for that matter what OS you decide to run on it. Linux and XBMC are my current choice for the use I want to put the board to, a remotely controllable jukebox of as high quality as I can reasonably achieve.

 

I have in mind also one of these http://www.ebay.com/itm/Hi-Fi-24bit-192K-USB-DAC-Amp-CM6631A-CS4398-Coaxial-RCA-Out-Headphone-Amplifier-/190850934929?pt=LH_DefaultDomain_0&hash=item2c6f9a2891

 

as an audio output. Even if it doesn't get used for the main system, I figure I get a headphone amp. It should in theory be great though, and I can use my receiver as DAC, music collection on local SATA drive and Android tablet running Yatse to control it.

 

 

 

I agree btw, regarding you comments on the RasPi. It's been a wonderful step, no doubt introduced thousands of people to small computers, to programming and to hardware at a fairly low level, Truly a great product, but, as you say, their are factors that limit its use in 'mission critical, cannot tolerate error' situations like audio playback. The USB situation, given my plan of using a USB -> S/PDIF converter, is very important.

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