Getting the best sound quality out of your HTPC
or why my HTPC sounds worse than the CD Player even though both are connected over SPDIF?
See eg:
https://forum.team-mediaportal.com/showthread.php?t=7025
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.
or why my HTPC sounds worse than the CD Player even though both are connected over SPDIF?
See eg:
https://forum.team-mediaportal.com/showthread.php?t=7025
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.