WDM Drivers and ASIO..whats the difference. Aren't they both WDM

On mine I never did get the AISO drivers to work very well. The WDM drivers worked fine. I'm using Sonar 2.2 XL with the Audiophile 2496 card. Sonar 2.2 just seems to like WDM drivers.

ORIGINAL: Axel

HI,

I read alot of threads talking about the pros and cons of using the WDM Vs Asio drivers. I get problems with both so so far its just dialect.

Now the Delta 1010 has produced WDM drivers version .36.

In the audio/advanced tab of Sonar one selects ASIO to use these WDM drivers, yes? So when one selects the WDM drivers, are we selecting a Microsoft generic WDM? And is there an updated WDM Microsoft driver (I haven't found one and I've looked)?

Cheers, Axel

Here it is Axel-when you select WDM/KS you are selecting the WDM drivers. When you choose ASIO you are using the ASIO drivers. When you leave it at default you are using the Microsoft drivers. I would go with the WDM/KS and work on your sysyem till it works. Sonar was supposedly designed to work best with these. I went through the same issue with my MOTU and there are a couple of threads. If you choose the WDM/KS drivers, go to your aud. ini and change to KsUseInputEvent=1 -this will make latency sloiders (that's Brooklyn for sliders) respond correctly.

Take care.

I think that it all depends on the quality of the sound card driver. For example the WDM driver of my Pulsar it's comparable to a piece of ****, so I use ASIO that work very fine

The difference between various driver models boils down to how the driver's kernel-mode component talks to its user-mode component.

Quick aside: User-mode is where applications like SONAR, IE, Word, etc. live. Kernel-mode is the lowest level area in the OS, where OS features such as memory protection, thread scheduling, etc. are implemented. As in most modern OS's, you cannot directly access hardware in user-mode; you must be in kernel-mode. A "device driver" is the code whose job it is to live in kernel-mode and talk directly to the hardware.

Win32 Driver Model (WDM) is very thoroughly designed and documented framework that defines how kernel-mode drivers talk to hardware. Microsoft provides documentation, driver qualification, etc, for WDM drivers. Furthermore, for audio drivers, WDM provides a way for user-mode applications to talk directly to the kernel-mode drivers. This is the Kernel Streaming (KS) interface.

Thanks to this design, SONAR can implement it's lower edge (the part that talks to the driver) using the KS interface, knowing that any WDM compliant driver will behave in the expected ways.

By comparison, ASIO is pretty different beast. ASIO defines how an audio application can talk to an audio driver, but doesn't specify *anything* about how the driver is to be implemented. So a host can implement a lower edge that talks ASIO, and can usually get consistent behavior just like KS. But there are some subtle and important differences.

First, I said with ASIO you can "usually" get consistent behavior. The issue here is that ASIO doesn't have nearly the degree of documentation and support that WDM/KS has. Let's face it, Microsoft is an orders of magnitude bigger company than Steinberg. The documentation team for KS is probably bigger than Steinberg's entire development team.

For ASIO, the end result is that many driver vendors test ASIO under Cubase, and then declare victory. Because the ASIO specification is unclear in some places, different hosts behave differently, and without a qualification system there's no easy way to ensure consistent behavior.

The other subtle difference between ASIO and WDM/KS is that ASIO doesn't specify how the kernel-mode piece gets written. A vendor is pretty much left on their own to figure out how to write their .SYS driver.

Ironically, if an audio hardware vendor wants to write an ASIO driver, they'll probably grab the Windows driver development kit (DDK), and look up the chapter on writing kernel-mode audio drivers. This chapter is all about writing WDM/KS drivers!

So in many cases, an ASIO driver has a WDM/KS kernel-mode piece at its core. This means that SONAR can automatically talk to the driver through the KS interface. This point is crystallized in the "ASIO4ALL" driver, which takes the low-level KS interface and wraps it in an ASIO interface.

Ron, any time you want to come to Japan let me know. I have a room for you in my house. (and lots of room in my studio. <G>

Axel,

Glad you brought up this topic! I've been struggeling with this issue for some time. Ron made a good case in pointing out that in all likelyhood WDM will provide a more uniform level of stabilization between various manufacturers because the protocol specifies the handling requirements down to the kernal level. However my problem is this:

Both my UAD-1 DSP card and my melodyne state that I must use ASIO drivers in order for their products to work properply. In the case of the UAD-1 the statement is to use ASIO as opposed to MME, and their is no mention of WDM as part of the equation. The melodyne is specific about ASIO, period. I currently run with the WDM/KS drivers in Sonar 3.1. I have tried to use ASIO to at least see if I could detect any differences but I have not been able to make ASIO work. If I select ASIO, my ASIO panel button is disabled, the latency slider is gray, and all of I/O dissappear. I am using a MOTU 2408 /w the 324PCI card. In 2.2XL I could use the ASIO drivers without a problem. Any thoughts? Should I worry about the ASIO drivers? If so any suggestions on how to get them to work in 3.1?

Tom H

ORIGINAL: Ron Kuper [Cakewalk]

On the same hardware, either driver should sound the same. A driver doesn't color or affect the sound of a signal. It simply moves the sample bits out to the digital to analog converters. In other words, changing the kind of driver doesn't change the kind of hardware, therefore there is no sonic difference.

Doesn't that depend on the phase of the moon? <G>

Win32 Driver Model (WDM) is very thoroughly designed and documented framework that defines how kernel-mode drivers talk to hardware. Microsoft provides documentation, driver qualification, etc, for WDM drivers. Furthermore, for audio drivers, WDM provides a way for user-mode applications to talk directly to the kernel-mode drivers. This is the Kernel Streaming (KS) interface.

Ron,

Unlike ASIO, doesn't WDM rely on a successful dynamic analysis of the soundcard? There are many cases I can recall, where - if you don't change the detected parameters or make a tweak to your AUD.INI file - you won't get the best performance from WDM. In the case of the MOTU 828mkII, for example, I have to set KsUseInputEvent=1, else the WDM latency is about twice of ASIO (tip from Noel). Once set, everything is fine. ASIO doesn't seem to require this potentially problematic step.

Eric

Even though you are only seeing the left channels, in fact SONAR is accessing all of them as a stereo pair. In other words, if you ASIO driver has channels named:
MyASIO (1)
MyASIO (2)
MyASIO (3)
MyASIO (4)

SONAR will present them as MyASIO (1) and MyASIO (3). However, (1) will be a stereo pair consisting of 1 and 2, and 3 will consist of 3 and 4.

I hope this helps.

ORIGINAL: Ron Kuper [Cakewalk]

Even though you are only seeing the left channels, in fact SONAR is accessing all of them as a stereo pair. In other words, if you ASIO driver has channels named:
MyASIO (1)
MyASIO (2)
MyASIO (3)
MyASIO (4)

SONAR will present them as MyASIO (1) and MyASIO (3). However, (1) will be a stereo pair consisting of 1 and 2, and 3 will consist of 3 and 4.

I hope this helps.

Yeah - that's the story I got originally too. In terms of Creamware's 16-bit ASIO drivers, this is all true. However, with their 24/32 bit ASIO drivers, there is still a problem. Sonar shows only odd numbered channels but ASIO channel 3 in Sonar actually ends up in ASIO channel 2 in Pulsar. Whatever. Seems illogical to me personally but the main thing is that I can get audio in and out. That's what counts. The numbering schema is just an annoyance as far as I'm concerned.

Puffer,

Thanks for that info. I don't mean to steal Axel's topic, but I have installed the 2.1 update for the Melodyne and it doesn't show up as a DXi plug anywhere on my menu. I think I will try reinstalling again. Anything special about the install?

Tom H