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Topic: ASIO4ALL and bitmatched output (Read 4017 times) previous topic - next topic
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ASIO4ALL and bitmatched output

I am trying to get bit matched output from my optical output. I used to be able to do this directly with my Auzentech card whichg has failed. I just rebuilt my HTPC and it has onboard Realtek which I dont want to use as I have a great outboard DAC. I installed ASIO4ALL but all is not right. For instance on CD playback I can change the bit rate to any of the settings the card supports. For instance I can go from 48K to 44.1 so how can this be bit matched. The volume control also works, it shouldnt because in bit matched mode I should just be passing the PCM straight out to the outboard. I am using Foobar2000 which is setup for ASIO4ALL. Am I missing something?

This kinds of leads me to my next question -can anyone recommend a sound card that does support true bit matched output.

Re: ASIO4ALL and bitmatched output

Reply #1 –
Quote from: exponent on
I just rebuilt my HTPC and it has onboard Realtek which I dont want to use as I have a great outboard DAC.
So I guess you are using this outboard DAC now? Over USB?

Quote from: exponent on
For instance on CD playback I can change the bit rate to any of the settings the card supports.
Bit rate? Do you mean sampling rate? What do you mean with changing it, where do you change it?

Quote from: exponent on
The volume control also works, it shouldnt because in bit matched mode I should just be passing the PCM straight out to the outboard.
No, volume control can work just fine.
ASIO4ALL is just a wrapper of the Windows audio driver that exposes the audio interface through the ASIO recording API (programming interface).
An audio interface may still have a volume control... because the volume control may not even have anything to do with the DAC.


Quote from: exponent on
I am using Foobar2000 which is setup for ASIO4ALL. Am I missing something?
I don't even know what is wrong. Need more information.
Have you even configured ASIO? The channel mapping? Checked the ASIO4ALL control panel during playback?

Quote from: exponent on
This kinds of leads me to my next question -can anyone recommend a sound card that does support true bit matched output.
Even the onboard one probably does.
"I hear it when I see it."

Re: ASIO4ALL and bitmatched output

Reply #2 –
Did you install native drivers for Realtek or just the ones W10 offers?
Have you tried with VB-Audio's Voicemeeter Banana (WDM/WASAPI/ASIO API's there)?

Re: ASIO4ALL and bitmatched output

Reply #3 –
I don't use foobar2000 (don't tell anyone here!  ;)  ) but I found something about Bypassing The Windows Mixer.    It doesn't say how to find that option, and it doesn't exactly say that you'll get "bit perfect" data to your DAC, but that might be what you're looking for.


Re: ASIO4ALL and bitmatched output

Reply #4 –
Quote from: xnor on
Quote from: exponent on
I just rebuilt my HTPC and it has onboard Realtek which I dont want to use as I have a great outboard DAC.
So I guess you are using this outboard DAC now? Over USB?

Yes. I have an outboard DAC from Bryston.

Quote from: exponent on
For instance on CD playback I can change the bit rate to any of the settings the card supports.
Bit rate? Do you mean sampling rate? What do you mean with changing it, where do you change it?
 Play a CD at 44.1 KHz and I get 48 KHz. Play a flac at 88.2 KHz and I get 48 Khz. Play anything at any bit rate and it is always 48 KHz clock input displayed on my DAC.


Quote from: exponent on
The volume control also works, it shouldnt because in bit matched mode I should just be passing the PCM straight out to the outboard.
No, volume control can work just fine.
ASIO4ALL is just a wrapper of the Windows audio driver that exposes the audio interface through the ASIO recording API (programming interface).
An audio interface may still have a volume control... because the volume control may not even have anything to do with the DAC.

If you think about it - in bit matched mode the output should be the same output that is coming from the CD. With my old Auzentech the volume control in windows did not work and this was why. What I want is the bitstream from the source sent out the optical port untouched. I had this working fun under my old HTPC bit it appears that this realtek driver does not have the bit matched output option.



Quote from: exponent on
I am using Foobar2000 which is setup for ASIO4ALL. Am I missing something?
I don't even know what is wrong. Need more information.
Have you even configured ASIO? The channel mapping? Checked the ASIO4ALL control panel during playback?
Its strange because when I try to play a test tone in channel mapping I see ASIO pop up in the mixer as a source for a few seconds and then it goes away but no sound comes out.



Quote from: exponent on
This kinds of leads me to my next question -can anyone recommend a sound card that does support true bit matched output.
Even the onboard one probably does.

I wished it did but I have played around with drivers and ASIO and no matter what I cant get bit matched output.

Re: ASIO4ALL and bitmatched output

Reply #5 –
If the DAC has USB try Foobar > WASAPI > USB
This has bit perfect transmission as you bypass the windoes mixer
You might try the same over SPDIF/Toslink
TheWellTemperedComputer.com

Re: ASIO4ALL and bitmatched output

Reply #6 –
It seems that you only judge bit-perfectness by looking at information like sample rate, bit-depth, volume control and so on. The fact is that even if these parameters are changable, if you do not intentionally change them they will not affect bit-perfectness.

On the other hand, a device without abilities to change these parameters can still result in non bit-perfectness, it can silently change things without telling you.

The only reliable method to verify bit-perfectness is to record the SPDIF output of the suspected device and do a null test.
 

Re: ASIO4ALL and bitmatched output

Reply #7 –
Quote from: exponent on
Play a CD at 44.1 KHz and I get 48 KHz. Play a flac at 88.2 KHz and I get 48 Khz. Play anything at any bit rate and it is always 48 KHz clock input displayed on my DAC.
Then you are not using ASIO or your driver is completely broken.
What sampling rate range does your DAC support as reported by the ASIO control panel?


Quote from: exponent on
If you think about it - in bit matched mode the output should be the same output that is coming from the CD.
No, as I've explained. Bit perfect only refers to what the DAC receives. A volume control may be implemented after the DAC. In fact that's the preferred way to implement a volume control.

If a sound card or audio interface still has a usable volume control with ASIO then this is not a bug, it is a very useful feature. I wouldn't want an audio interface without it.


Quote from: exponent on
Its strange because when I try to play a test tone in channel mapping I see ASIO pop up in the mixer as a source for a few seconds and then it goes away but no sound comes out.
Yeah, that just confirms that you are not even using ASIO for playback. You are probably using DirectSound.

I will ask once more: have you even configured the device in the ASIO control panel, the channel mapping ... ?
"I hear it when I see it."