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ASIO, WASAPI, Direct Sound... is there any difference in sound quality?

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#22
How do you see what Driver your DAC uses by default in Win 10? I looked in Device Manager, and i dont see any mention of ASIO or WASAPI.
 
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#23
How do you see what Driver your DAC uses by default in Win 10? I looked in Device Manager, and i dont see any mention of ASIO or WASAPI.
There are several places in Windows 10 to find audio settings. If you right click on the volume control and choose "open sound settings" you will see a drop down where you can choose your device. If your device uses USB only, it will probably only have your existing device. If your motherboard has a Realtek audio chip, as most do, you may also have "Realtek Digital Output (optical)" and perhaps a "Realtek Digital Output" for coaxial or hdmi output. These do not represent your DAC but you may select them if you wish to use optical/coaxial/hdmi outputs on your motherboard to your dac.

If you click Device properties and then Additional device properties another window will open where you can choose if you want the dac to be capable of being used in exclusive mode. The advanced tab allows you to select the bit depth and sample rate. Generally, you should choose the highest bit depth available (24 or 32). The bit rate or frequency is what Windows 10 is going to resample all your normal audio, such as youtube, to. This is a decision only you can decide upon, depending on whether or not you want everything resampled to a higher frequency or not. Most people choose 44.1khz because that is probably the most used bit rate and would require no resampling if the original is file is 44.1khz. This is actually the DS windows driver.

When you install a music player, such as MusicBee, you will have more advanced options for the playback of high quality files. When you open those software programs you will be able to find settings that will include any ASIO and WASAPI selections your hardware allows. I generally use WASAPI exclusive mode as it is technically as good as it gets for sound. ASIO may equal the sound of WASAPI, if your dac has such a driver and may even be lower latency (important for recording studios). DS is the base Windows driver and is the one you will hear when using the internet but is generally not bit perfect.

You may find that if you have Youtube open and you try to start a file in your music player, it may not start, or alternately you may find that if you are playing a music file with WASAPI exclusive mode, you will get errors when you open a youtube video. That is normal to some extent, but manageable.
 

majingotan

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#24
You may find that if you have Youtube open and you try to start a file in your music player, it may not start, or alternately you may find that if you are playing a music file with WASAPI exclusive mode, you will get errors when you open a youtube video. That is normal to some extent, but manageable.
You can avoid that error by outputting YouTube to a different DAC while you have your music played on your main DAC through WASAPI
 

Pluto

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#25
It's probably worth mentioning a potential weakness when using ASIO in a domestic environment (i.e. outside the studio where the computer is totally dedicated to, and set up as, an audio workstation). ASIO does not offer the exclusive mode available to WASAPI. Let's dig a little deeper. If you look at the Sound section within Control Panel, select the playback device in question and look at its Properties, Advanced, you'll see two check-box options relating to exclusive access. Let's assume they are selected. Also, note the sample rate set in the upper area of the same box.

Control.jpg

When some audio playback software is using this device via the WASAPI, that device is effectively locked out and unavailable for any other purpose until released by the software using it.

ASIO, being designed for maximum flexibility and multi-track audio (and possibly, more than one audio application contributing to the mayhem), does not offer that facility. You can prove this by playing some audio from any application set to use ASIO. If the default format is set to the same sampling rate as the audio being played by your software, pressing the Test button will cause the test sound to be mixed with the audio you are playing i.e. you will hear both. Ergo, not exclusive! If you try the same experiment with the application set to use WASAPI, pressing the Test button will illicit a distinct message to the effect that the audio hardware is away on business.

So, if you are paranoid about avoiding the risk of anything polluting your precious audio, WASAPI is the choice for you :p
 

crtesta1

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#26
Lots of great information here from many erudite minds, thank you all. If I may add, I've been using the excellent streaming service Qobuz and was trying to discover the reason why my DAC was not displaying 88KHZ sample rate when I was playing an album allegedly in that quality from the Qobuz app on Windows 10. Turns out I could not get the high res output to go through by either wasapi or asio (using the qobuz app output selector) but was able to when I switched the app output to the dedicated driver for the DAC I am using (Denafrips Ares II by Vinshine audio).
 

Vincent Kars

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#28
So, if you are paranoid about avoiding the risk of anything polluting your precious audio, WASAPI is the choice for you
That is why I use WASAPI in exclusive mode, I don't like email notifications or other system sounds in full blast over the stereo :)
 

Pluto

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#29
If, for whatever reason, you really do want to use ASIO with its inherent lack of exclusivity, a simple workaround is to set the system default audio device to be something that, typically, goes nowhere (such as one of the computer's internal digital outputs). Provided your serious audio software (and nothing else) is set to drive your DAC – via whatever API – nothing from the system will interfere with playback.
 

bennetng

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#30
It's probably worth mentioning a potential weakness when using ASIO in a domestic environment (i.e. outside the studio where the computer is totally dedicated to, and set up as, an audio workstation). ASIO does not offer the exclusive mode available to WASAPI. Let's dig a little deeper. If you look at the Sound section within Control Panel, select the playback device in question and look at its Properties, Advanced, you'll see two check-box options relating to exclusive access. Let's assume they are selected. Also, note the sample rate set in the upper area of the same box.

View attachment 57408

When some audio playback software is using this device via the WASAPI, that device is effectively locked out and unavailable for any other purpose until released by the software using it.

ASIO, being designed for maximum flexibility and multi-track audio (and possibly, more than one audio application contributing to the mayhem), does not offer that facility. You can prove this by playing some audio from any application set to use ASIO. If the default format is set to the same sampling rate as the audio being played by your software, pressing the Test button will cause the test sound to be mixed with the audio you are playing i.e. you will hear both. Ergo, not exclusive! If you try the same experiment with the application set to use WASAPI, pressing the Test button will illicit a distinct message to the effect that the audio hardware is away on business.

So, if you are paranoid about avoiding the risk of anything polluting your precious audio, WASAPI is the choice for you :p
Something is exclusive does not mean something is bit-perfect. If one only uses Windows' built-in driver (class compliant), then things are more or less expected (i.e. bit-perfect).

On the other hand, if you have installed a third party driver, even if you are using WASAPI exclusive mode, and blocking other audio streams, resampling (and potentially other modifications) can still occur.
wasapi.png


In my soundcard if I use ASIO, the Creative control panel's sample rate always match the audio stream's rate, if I play a file at another sample rate, the soundcard will briefly mute and switch to that sample rate, and the control panel will then show that sample rate, in WASAPI exclusive mode, albeit working exclusively and blocking other sounds, the card's master sample rate won't change, and that means resampling. It doesn't matter if it is a Creative soundcard or some other brands or products, it proves WASAPI behaviour can be overridden by installing a third party driver.

So, unless you don't have any third party driver installed, WASAPI exclusive mode does not guarantee bit-perfectness. That means you may need to uninstall the driver, and potentially losing some important features. In my case, uninstalling the Creative driver indeed enables auto sample rate switching in WASAPI exclusive mode, but the headphone output no longer works.

Also, before bashing Creative, read something from RME:
https://www.forum.rme-audio.de/viewtopic.php?id=26980
 

Pluto

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#31
What you describe about the behaviour of the Creative driver seems unusual, but that company does seem rather determined to do things their way ("it's what our users want").

The basis of the Thesycon driver (a good example because their drivers are well-written and many decent DACs employ their interface devices and accompanying drivers) is that when an application is using WASAPI, other applications are well & truly locked out of the audio system. I have tested this many, many times and have no doubt that this is the case.
 

Vincent Kars

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#32
WASAPI exclusive mode does not guarantee bit-perfectness.
Good points.
My take is that WASAPI has nothing to do with "bit perfect".
It is a protocol and this protocol does nothing except transporting faithfully the audio from source (media player) to audio endpoint (the buffer of the audio device).
It doesn't alter a single bit nor does it alter the sample rate.

As it is a protocol it is not in control of what happens up- or downstream.
If the source applays DSP e.g. volume control, the audio send to the audio device is of course not bit perfect.
Likewise, even if the source is configured to bit perfect, the moment it is send to the Win mixer, it will always be dithered (but with a 24 bit audio path not a problem) and resampled if needed.
The driver of the audio endpoint might resample.
Likewise if it enters a DAC, this DAC might run internally ASRC,etc.

Bit perfect is not about the protocol but about the routing starting with the media player and ending with the audio endpoint.
Involving the OS audio (mixer etc), you know for sure it isn't bit perfect.
Eliminating the OS audio stack does not guarantee the result is bit perfect.
 

bennetng

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#34
What you describe about the behaviour of the Creative driver seems unusual, but that company does seem rather determined to do things their way ("it's what our users want").
Not only Creative. Read the RME link I posted above.
 

Pluto

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#35
No it doesn't. Discrete soundcards most of the time don't cope well with WASAPI.
Which rather suggests that soundcard drivers are operating outside the "rules". The WASAPI documentation appears reasonably unambiguous (as much as any Windows documentation can be) that if an endpoint has its 'exclusive' boxes checked, an application (typically, a media player) can lock that endpoint for its exclusive use, at its pleasure.
 

Pluto

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#36
Reading the tale on the RME forum supports my view that ASIO, of necessity, offers a great deal of flexibility in exchange for the ability to shoot oneself in the foot. It is up to the more sophisticated user (for whom ASIO will typically be the mode of choice) to ensure that it works correctly.

For most users, most of the time, WASAPI is the preferable choice.
 

q3cpma

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#37
On GNU/Linux or *BSD, people use the generic USB audio driver without any problem, any reason people don't on Windows? Because that tinkering looks a bit useless from afar; unless you can really hear the resampling at work, which seems a bit dubious.
 

Pluto

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#38
...unless you can really hear the resampling at work
Given that [few would dispute] the optimum way of playing digital audio these days is a DAC fed via asynchronous USB, the resampling could be considered an inconvenience even if it is not a sonic disaster. Why convert when to do so is unnecessary?
 

q3cpma

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#39
Given that [few would dispute] the optimum way of playing digital audio these days is a DAC fed via asynchronous USB, the resampling could be considered an inconvenience even if it is not a sonic disaster. Why convert when to do so is unnecessary?
Well, because it seems a lot of people (at least when reading amirm's reviews) have numerous problems with ASIO drivers.
 

bennetng

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#40
On GNU/Linux or *BSD, people use the generic USB audio driver without any problem, any reason people don't on Windows? Because that tinkering looks a bit useless from afar; unless you can really hear the resampling at work, which seems a bit dubious.
When some features you need require installation of a third party driver, so it is not limited to SRC quality or bit-perfectness.
Some devices (especially pro audio interfaces) have additional onboard DSP and FPGA and they also require drivers to work, the drivers can override WASAPI behaviour as well.
If there is no loss of useful features, I would recommend using a generic driver as well.
 
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