[insyte]

I have wanted to try how will USB compare to a Coax out from my PC to the DAC.

So I was finally able to get out of work and purchase a 3 pin adaptor from a guy in another local forum

I located the 3 pin spdif out and checked which was pin 1 from the manual. I attached it with no problems, closed the box and attached my digital RCA cable.

Unfortunately, even with numerous experimentations with alsamixer settings, I couldn't get it to work.

But I was more than determined to make my PC coax capable.

Fortunately, I looked at one of my old PCs and it had an old soundcard with an spdif out

After dusting it and shooing away the baby spiders on it (yes its in storage already). I attached it to my pc. Yes I was that desperate.

And then.......................

Made the card default, and changed the alsamixer settings...

And finally it worked!!!!!!!!!!!!!!!!

---------

Im too tired to actually compare which input is better. But I did discover a problem. I tried to watch a video with mp3 audio and I got static. I tried playing an mp3 file and also got static. No problems with FLAC and videos with AAC audio. I wonder why this is so.

So was it worth the trouble???? , I don't know but the process was fun

 

[linuxworks]

8738 is a FINE chipset, very well understood and mature, by now.

it should work out fine.

 

[insyte]

Im still wondering why Im getting static when playing mp3s, but no problems with FLAC. Do you think its a driver problem?

 

[satshanti]

For a card with this Cmedia chipset, you migth want to try out these bit-perfect drivers. They might be able to improve the sound. I've used them for quite a while now.

 

[insyte]

Well Im using ubuntu, so I don't think I can use them in linux

 

[linuxworks]

linux has no notion of 'non bit perfect' drivers. no evil influence forcing an artifical 48k anything on anyone, here

if a sound card, at the hw level, reports it can natively support 44.1 and some material is at 44.1, only an EVIL empire would force a resample.

linux wont. you'd have to go out of your way to do a conversion when none was needed!

that google-code driver for the windows side is great, btw; I used it a lot when I was still windows bound.

 

[condor]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif linux has no notion of 'non bit perfect' drivers. no evil influence forcing an artifical 48k anything on anyone, here if a sound card, at the hw level, reports it can natively support 44.1 and some material is at 44.1, only an EVIL empire would force a resample. linux wont. you'd have to go out of your way to do a conversion when none was needed! that google-code driver for the windows side is great, btw; I used it a lot when I was still windows bound.

Alsa user Mailinglist consencus was:

Standard setting is 48khz, if you really want 44.1khz you need to force your soundcard to this, in most cases with dmix. This brings the problem, that 48khz won't work anymore, it'll need downsampling to 44.1khz.
This of course is only the case with multiple streams (flash / mp3 / video / system sound....)

This works
- force soundcard to 44.1khz,
defaults.pcm.rate_converter "samplerate"
defaults.pcm.rate_converter "lavcrate"
defaults.pcm.dmix.rate 44100
- use dmix to downsample 48khz (videos....) to 44.1khz
this requires some pcm slaves where you need to attach the 48khz players to...

Of course this only is a problem when mixing streams, if you have a deticated music box it's not a problem...
--------

If it works easier, please share it!

 

[linuxworks]

I'm not sure this is correct.

as I understand it, the sound arch queries the card for its 'abilities'. it can return things such as 'I speak 44.1 and 48 and 32'. then the sound system knows if a SRC is needed or not.

its only needed if a 'native' SR is not in the device list.

that's my understanding.

all sound cards I've played with (with spdif) have all had 44.1 and 48 and some even had native 32. for me, that covers it

if I had to downsample 48 to 44, its not the worst thing in the world. 48k means movies, usually, and there's nothing high end about them! (lol!!)

 

[condor]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif I'm not sure this is correct. as I understand it, the sound arch queries the card for its 'abilities'. it can return things such as 'I speak 44.1 and 48 and 32'. then the sound system knows if a SRC is needed or not. its only needed if a 'native' SR is not in the device list. that's my understanding. all sound cards I've played with (with spdif) have all had 44.1 and 48 and some even had native 32. for me, that covers it if I had to downsample 48 to 44, its not the worst thing in the world. 48k means movies, usually, and there's nothing high end about them! (lol!!)

That was exactly my problem... I was then told, that if the card provides a hardware mixer, it's not a problem (those onboard Realtek HD ones ICHx don't have that.)
If they don't have one, you need softwaremixing (makes sense, that only one kind of output is possible), which requires either 44.1->48 (standard) or 48->44.1 (define that in .asoundrc).

That's what I did, but I faced the problem that movies got async with downsampling (pc hardware isn't a performance bottleneck on my system).

See:

Dmix - ALSA wiki
and
Dmix Kde - arts, ESD and SDL quick and dirty HOWTO - ALSA wiki

 

[insyte]

Quote:

Originally Posted by condor /img/forum/go_quote.gif defaults.pcm.rate_converter "samplerate" defaults.pcm.rate_converter "lavcrate" defaults.pcm.dmix.rate 44100

Do I need to put this into .asoundrc?

 

[condor]

Quote:

Originally Posted by insyte /img/forum/go_quote.gif Do I need to put this into .asoundrc?

Yes, but this forces your software mixer to 44.1khz, so you get the mixing problem...
Actually I'm not using it anymore - I couldn't hear a difference and this reconfiguration for every app which doesn't attach properly to the right plug and the issues with async audio weren't worth it for me.

 

[insyte]

I guess I can always switch my DAC to usb input when I want to watch movies