Why my HTPC sounds worse than the CD Player even though both are connected over SPDIF

[BugsBunny]

or why my HTPC sounds worse than the CD Player even though both are connected over SPDIF?

See eg:
Music quality discussion

Setup:
1) A CD player digitally connected to an amplifier (SPDIF) playing a track
2) A HTPC digitally connected to the same amplifier (SPDIF) playing the same track (eg ripped as WAV)
When doing an A/B comparison it would sound logical that there should be no difference (the same bits should go to the D/A converter
What is not taken into account here is sample rate conversion see:
http://en.wikipedia.org/wiki/Sample_rate_conversion

Most consumer soundcards put out a fixed sample rate of 48kHz.
I've got an external (AD) DA converter that indicates the sample rate of the signal:


I've tested some motherboards with onboard spdif and some consumer soundcards (soundblaster live!, soundblaster audigy2).
They always put out a signal with a sample rate of 48kHz on the SPDIF.
The digital audio CD (and MP3s made of CDs) uses a sample rate of 44,1kHz. So if you play back a CD/file with 44,1kHz the sound chip converts the sample rate to 48kHz. Often the conversion is done with bad quality so you will notice a difference in quality.

Some pro soundcards do put out the correct sample rate - so there is no audible difference when you do an A/B test in a setup described above.

Some pro soundcards (and my experience with them) that always put out the correct sample rate over SPDIF:

Many years I used the sekd Prodif 96 on my main PC, damaged the card and then switched to the DIGI96/8 PAD from RME (uses the same drivers as the sekd Prodif 96).

When I started with my HTPC project back in march, I thought that I would simply use the DIGI96/8 PAD in my HTPC. But I had issues (stuttering sound) with TV and radio using this card.

I then bought the M-Audio Audiophile 192 that caused different problems: incompatible with XP + VIA 133 chipset -> bought new MB. Then I found out that the driver (most probably) has a bug if you use the SPDIF out of the card - even got a new card - problem stayed - tested it with different PCs - problem stayed. If you play back a CD or files after some tracks the sound get's scrambled or muted. After a track change sound is OK again - weird!

In august I finally got an ESI Juli@ since then my HTPC works like a charm and puts out high end sound quality!

There are probably a few more pro soundcards that do not resample the audio signal.

[rtv]

There are probably a few more pro soundcards that do not resample the audio signal.

In fact some very cheap c-media based soundcards (like the Z-Cyber Nightingale Pro6 for 35 EUR) do not resample, too ;-)

http://au-ja.de/review-zcyberngp6-1.phtml <-- old german review

[sderuiter]

The Chaintech AV-710 doesn't resample. Unfortunately, you cannot buy this card in Europe, or so it seems. I had mine brought to Europe by a friend from the States. Can't go wrong for USD 25. :-)

[trosty]

Originally Posted by rtv

In fact some very cheap c-media based soundcards (like the Z-Cyber Nightingale Pro6 for 35 EUR) do not resample, too ;-)

Right, that is why I bought the "Typhoon Acoustic 6 Soundkarte" - it was only 22 Euros and it has the 44.1 kHz-option .

[knutinh]

Audiophiles will argue that:
*re-sampling can be detrimental to the sound
*even though a "bit is a bit", D/A-converters could have less than ideal jitter-suppression. If your soundcard/cable has a high level of jitter, this could lead to audible "frequency-modulation" of the D/A analog output if it does not contain proper PLL/rebuffering/reclocking.

Me, I use a m-audio audiophile 2496, and I think that people are talking about many differences that simply cannot be heard under ABX testing.

-k

[BugsBunny]

Thanks for all the addidions! If someone knows of other soundcards that do not resample the S/PDIF out signal please add them here in this thread.

@ knutinh:
Sure jitter can be quite a bad thing, but using a soundcard that does not resample can get you at least one step further to "audiophile sound".
I'm not a "high end" audio guy, but I do prefer getting the digital signal out clean and let some external converter/amplifier do the D/A conversion.

I've started this thread because most people think: use your digital out on your onboard soundcard, hook it to some external D/A converter/amplifier/receiver and everything is perfect. Few people know that this digital signal can be messed up, by some bad resampling. Some may notice a difference but don't know what is causing it.

[knutinh]

m-audio audiophile does no resampling, Idont think that any maudio cards do.

-k

[johanb]

The quite cheap M-Audio Revolution does not resample either.

I use it with winamp under mp along with the kernel streamer plugin (to bypass windows kernel mixer) to get 44.1 kHz with my mp3's.

See http://www.stevemonks.com/ksplugin.

// Johan

[reagan+carter]

Originally Posted by BugsBunny

If someone knows of other soundcards that do not resample the S/PDIF out signal please add them here in this thread.

Every motherboard using a nForce 2/3 audio chipset stamped 'soundstorm' (e.g. the ALC658).
Everything based on the old Cirrus Logic DSP chip (CS4630), i.e. Turtle Beach Santa Cruz.

[Henry Mac]

Originally Posted by johanb

The quite cheap M-Audio Revolution does not resample either.

I use it with winamp under mp along with the kernel streamer plugin (to bypass windows kernel mixer) to get 44.1 kHz with my mp3's.

See http://www.stevemonks.com/ksplugin.

// Johan

I use the m-audio revolution 5.1. Works good BUT when the htpc wakes after suspend the s/pdif connection is not restored. You would need to re-load the drivers and so (re-boot) the machine. Still a case open with m-audio support. I do not expect it to be solved as their support is supposed to be horrible...

M-Audio Revolution 5.1 standby.