PC's digital out not as good as DVD digital out

[sorcer]

Quote:

Originally Posted by 1UP /img/forum/go_quote.gif Have you got a digital HT decoder? Try feeding it a DTS stream to see if your laptop is emitting a bit-perfect signal. But then again, why bother, if it sounds crap, just get a USB-SPDIF dongle.

Sorry, not sure what you're referring to here. What's an HT decoder? Hyper-threaded?

Not quite sure about why you're mentioning DTS either (sorry again; I'm new at this, although I think I understand the basics pretty well

)

 

[sorcer]

Quote:

Originally Posted by 1UP /img/forum/go_quote.gif Hold up, this is confusing. These are the things you need to test: 1. the quality of the rip - is the distortion in the rip file itself? Listen to it using speakers/headphones 2. something to do with Foobar - are you using any DSP? Try no DSP or upsampling or try Winamp instead 3. your ASIO driver - use a different one 4. What's the receiver chip in your DAC?

1. I get the same distortion if I playback flac or directly from the CD - either one sends the signal out the laptop's spdif connection to my Zero DAC/HP amp, and then to my Sennheiser HD650s. Trying Winamp is a good idea.

2. I don't think I'm using any DSP stuff. foobar's Preferences->Playback->DSP Manager shows no Active DSPs.. I'm also not deliberately upsampling, but this may be occurring. foobar/asio config info:
asio4all's config screen shows my sigmatel audio codec with Available In, and Unavailable Out(?), both listed as "2x 48kHz, 24 bits". Also, when I edit the asio settings through foobar's Preferences->Playback->Output->ASIO Virtual Devices, I get the Virtual Device Editor window, with the Channel Map showing 2 Deveice Channels called "Not Connected 1" and "Not Connected 2" (?). Format is 32 bit and Mapping is Left and Right.

3. I guess I could try this, but asio4all seems popular; any suggestions?

4. not sure what the receiver in the Zero is, but it works well with the dvd output.

 

[infinitesymphony]

Quote:

Originally Posted by sorcer /img/forum/go_quote.gif asio4all's config screen shows my sigmatel audio codec with Available In, and Unavailable Out(?), both listed as "2x 48kHz, 24 bits".

The Sigmatel chipset likely follows the AC'97 specification, which means that it forces resampling to 48 kHz; your internal sound card is not capable of bit-perfect output.

 

[sorcer]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif The Sigmatel chipset likely follows the AC'97 specification, which means that it forces resampling to 48 kHz; your internal sound card is not capable of bit-perfect output.

So, it seems like I should get a PCI card that will play bit-perfect; PCI because it could be used in a variety of computers.

Any suggestions?

 

[infinitesymphony]

Quote:

Originally Posted by sorcer /img/forum/go_quote.gif So, it seems like I should get a PCI card that will play bit-perfect; PCI because it could be used in a variety of computers. Any suggestions?

You may want to double-check which SigmaTel chipset your laptop uses, because some of the more recent ones follow the HD Audio specification, which would mean that it is capable of bit-perfect transmission. That still doesn't address the possibility of jitter, which the Zero may or may not reduce on its own.

Since you have a laptop, the most elegant solution for you would be something like the Trends UD-10 USB. It's a little expensive for a pure digital transport, but you can be sure that it will provide a quality output for your DAC.

 

[maarek99]

You probably have some eq'ing going on in your soundcards drivers. Try lowering your master volume below 100%. If it works, the clipping is causing distortion.

 

[gregorio]

There are quite a few potential culprits for your problem. It is unlikely to be jitter as jitter doesn't cause distortion as such but other problems mainly based around phase issues. Most likely it is the filter in your different DACs. A filter will add gain to the signal. If your source material is normalised, say to -1dB and your filter adds 2dB, if there is no headroom built into your DAC you will hear clipping. Exactly where you hear clipping will depend on the individual DAC, that is why a good mastering engineer will try to peak the master mix to around -3dB or so, to take account of the filters in various different DACs. As I said, there could be other reasons for what you are experiencing by my money would be on the filters in your two DACs.

In other words, try Maarek99's suggestion, lower the gain by say 4dB and then play on both your systems. If you're still getting clipping, at least you have eliminated the filter clipping point as a possible cause.

 

[infinitesymphony]

gregorio, he only has one DAC, two transports.

 

[nick_charles]

Quote:

Originally Posted by sorcer /img/forum/go_quote.gif asio4all's config screen shows my sigmatel audio codec with Available In, and Unavailable Out(?), both listed as "2x 48kHz, 24 bits". Also, when I edit the asio settings through foobar's Preferences->Playback->Output->ASIO Virtual Devices, I get the Virtual Device Editor window, with the Channel Map showing 2 Deveice Channels called "Not Connected 1" and "Not Connected 2" (?). Format is 32 bit and Mapping is Left and Right.

The ASIO4ALL widget is a bit misleading, the better monitor is FooBar. If FooBar says Not Connected you are not using ASIO, go To Playback>Output what device is listed there ?

I also have a SigmaTel (HD) Chip in my Desktop Dell, and it is patchy with ASIO4ALL, if I run the TV card it fouls up ASIO in FooBar, but if FooBar is the only sound app running it loads up okay.

Personally I hear no difference between ASIO4ALL and DirectSound in my setup and no distortion as such into the Zero, but my chip may not be the same chip as yours.

As mentioned by Infinitesymphony can you find out which SigmaTel chip you have, there are some new drivers for their chips, but since they just produce the chip their support is minimal. What laptop do you have ?

Quote:

Originally Posted by sorcer /img/forum/go_quote.gif So, it seems like I should get a PCI card that will play bit-perfect; PCI because it could be used in a variety of computers. Any suggestions?

For a laptop you could use a PCMCIA card or a USB device. For my laptop system I use an Edirol UA-1EX USB device which supports ASIO and I use this just to get an optical output which I connect to my External DAC , in the US this is $80. It is a pain having to do this but there may be cheaper options.

Perhaps this one if it supports ASIO

Behringer UCA202 USB Interface from zZounds.com!

EDIT: It does have ASIO support.

DJ MIXERS, AUDIO TECHNOLOGY

This has a max sampling output of 48Khz, but I would not worry about that.

I cannot vouch for its quality.

Sadly USB brings its own potential problems, USB is prone to drop-puts if you have high priority CPU calls and it is tricky to debug if you have this problem, but it may be worth the risk for $30 ?

 

[sorcer]

Quote:

Originally Posted by maarek99 /img/forum/go_quote.gif You probably have some eq'ing going on in your soundcards drivers. Try lowering your master volume below 100%. If it works, the clipping is causing distortion.

Yay! That did it! I lowered the Volume on the Volume Control applet (contains Volume Control, Wave, SW Synth, and CD Player sliders), and I no longer hear distortion. I played around with it and it is 100% the cause of my distortion. Lucinda sounds clear as a bell

Thanks a bunch maarek99. This saves me a lot of trouble.

I never thought if I was sending digital output from the laptop that volume control would matter; I don't get why this "processing" is even done - can I bypass it?

Also, the "Wave" slider affects volume out of the Zero as well, but no distortion occurs even if it is turned up all the way..

 

[thomaspf]

bypassing means to get bit perfect playback.

You need to make sure you have no processing in th playback application. Use something like ASIO or direct kernel streaming and finally you need a sound card that does actually support passing through CD audio data at 16bit/44.1Khz unmodified.

Cheers

Thomas

 

[maarek99]

Glad to be of assistance. Some soundcard drivers are actually digitally raising the volume when set to 100% so that will cause clipping. An eq will also make music clip if it goes over 100%.

 

[1UP]

Yeah, nice one.