cmASIO and DAW issue?

[JJ4SDR]

I exchanged messages with Bryan - W4WMT - several months ago, asking him about use of cmASIO and Digital Audio Workstation (DAW) when processing audio. He is, I would imagine, part of the group having written some of the code, I don't know. Bryan, I hope you don't mind me bringing up your name. Below, one of the potential issues that he brought up.

"Low latency is the main design goal of cmASIO. But if you have a DAW in line, it will probably dominate your latency performance because it shares the same thread with cmASIO and eats up a lot of compute cycles or adds layers of buffering."

Now, "latency" is a little vague unless you define it exactly in terms of milli-seconds and if you don't monitor yourself in real-time (I don't) additional latency may not be a problem.

I have held off on installing any Thetis software that has cmASIO as a feature due to potentially really long latency (some of the VST plug-ins I use, themselves, are very CPU intensive) rearing up its not-so-pretty head. So, it could be that any REAL latency is strictly due to my use of DAW rather than using a Thetis version that has cmASIO in it. Naturally, if I keep on using a rather old Thetis version I will be missing out on some really awesome features altogether.

Would anyone using a DAW for audio processing care to chime in, to advise whether I am making a mountain out of a mole-hill (again)?

Juha
NI2M

[Trucker]

cmASIO isn't something you cannot avoid if you use any of the latest versions of Thetis. You can use VAC as always and route your audio wherever you want in Windows. ( same thing with cmASIO)
cmASIO is a very low latency way to handle transmit and receive audio with an external USB sound card . Plus, it doesn't have problems with buffers like VAC can. I would suggest using the latest version of Thetis to get the benefits of all of the improvements that have been made.
James
WD5GWY

[JJ4SDR]

James,
I appreciate your feedback!
Juha
NI2M

[w-u-2-o]

My audio setup is quite complex.

Thetis (cmASIO)
|
Voicemeeter Banana <--> Presonus Interface
|
Reaper DAW

The entire chain uses ASIO drivers exclusively. Even with a setup of this complexity, latency is minimal.

Bryan is indeed responsible for the cmASIO code, and a lot of VAC code, as well (thank you, Bryan!). However, luckily he was overly pessimistic about DAW interactions with cmASIO. He was also originally concerned that cmASIO would not work with Voicemeeter, but that is also happily not a problem.

Anyone who wants the best audio latency performance should be using cmASIO with a high quality ASIO sound interface. This is even faster than the CODEC hardware path built into the ANAN hardware.

[JJ4SDR]

Scott,

I sure value your comments.

My 2 main audio chains are as follows:

1. Thetis->
External Analog Mic-pre/EQ ->
Digital Mixer/Audio Interface (Soundcraft which comes with native VST plug-ins, too) ->
Live Professor 2 (DAW)

2. This is the same as above except, I have taken the DAW out and use audio processing that the Digital Mixer/Audio Interface provides + some Thetis processing.

Now, in terms of settings inside Thetis, how do I deal with VAC settings? I guess I will find out when I install a newer version of Thetis. Any recommendations on which one, that is stable?

In the past, when upgrading to more recent Thetis version, I have completely uninstalled Thetis from the PC, leaving the AppsData Folder intact. Is this way alright?

Thanks!
Juha
NI2M

[w-u-2-o]

You should be using the latest version of Thetis, as just posted to the Thetis sub-forum here.

To clarify, I use the DAW only for additional audio routing and mixing. I do not use any effects or processing in the DAW. I could do what I want with Voicemeeter alone, but I like the ergonomics of the DAW. So Voicemeeter is used only as a simple patch panel.

I've also thought about replacing Voicemeeter with VB-Audio Matrix, as it is intentionally designed as a patch panel.

The problem with most ASIO devices and software is that they all only allow a single ASIO connection at a time. Supposedly this is part of the "standard". Thankfully, Vincent Burel ignored that and build tools that allow multiple ASIO connections at the same time. If you use Voicemeeter or VB-Audio Matrix to connect all your devices and app's, then it's unlikely you will need to use VAC at all.

[JJ4SDR]

The Digital Mixer enables use of more than one ASIO instance which is one of the reasons that I bought one. So, I have no need whatsoever for Voicemeeter or VB anything and just love the way things sit.

Thanks!
Juha

[K1LSB]

In the past, when upgrading to more recent Thetis version, I have completely uninstalled Thetis from the PC, leaving the AppsData Folder intact. Is this way alright?

JJ,

In his v2.10.3.9 Release post Richie recommends that you uninstall Thetis using the Add or Remove Programs utility in Windows before installing the latest Thetis.

For my own part, I also recommend after installing Thetis that you delete the wdspWisdom00 file. Thetis will regenerate it, that'll take several minutes but will insure optimal function of the WDSP features in Thetis.

Mark

[JJ4SDR]

Mark,

Good to hear from you, but I am confused. Install Thetis that generates that file BUT I need to delete it...... Why would Thetis generate it IF that degrades the performance of Thetis?

JJ

[Trucker]

Mark, when you install the latest version of Thetis one of the first things it does is check how old your wisdom file is. If it's older then three months old, it will ask you to let it rebuild the wisdom file. If you decline rebuilding the wisdom file, it will remind you again in three months. And it will ask again every three months. That should help keep things optimized better.
James
WD5GWY

[w-u-2-o]

Starting with 2.10.3.9, you no longer have to worry about the "wisdom" file. When you run the installer it will offer to rebuild it for you if it is more than 3 months old.

Other than that, the standard upgrade procedure is:

1. Use the Thetis database manager to make a backup copy of your database.
2. Use the standard Windows "Apps & features" control panel to uninstall the existing version of Thetis.
3. Run the Thetis installer for the new version of Thetis.

Easy peasy!

[K1LSB]

I'm taking the liberty of sharing some comments from Warren regarding the wisdom file that Richie posted in his Discord server (see below). Take from it whatever you wish. For my own part I afford some weight to the sentence that says, "It is therefore wise to recreate wisdom every time an application is recompiled."

From Warren....

Unfortunately, the file cannot be included at installation. The "wisdom" algorithm creates a custom file for the particular computer it's running on. The contents of the file can change depending upon the CPU characteristics and well as the memory system. It does so by trying a number of different algorithms for each size of FFT and selecting the ones that are most efficient on the particular computer. This is important because FFTs are very frequently used and executed billions of times.

The FFTW Library authors advise that, for ultimate performance, the "wisdom" optimization should be run every time the code is recompiled as well. However, I have not found that to be necessary for our purposes (perhaps because I do some alignment when allocating memory). Their reasoning for that is that alignments may change with recompilation. Such authors have spent significant parts of their careers learning how to make FFTs computationally efficient.

Here's some supplementary info from an FFTW manual:

"Caveats in using wisdom
For in much wisdom is much grief, and he that increaseth knowledge increaseth sorrow. [Ecclesiastes 1:18]

There are pitfalls to using wisdom, in that it can negate FFTW's ability to adapt to changing hardware and other conditions. For example, it would be perfectly possible to export wisdom from a program running on one processor and import it into a program running on another processor. Doing so, however, would mean that the second program would use plans optimized for the first processor, instead of the one it is running on.

It should be safe to reuse wisdom as long as the hardware and program binaries remain unchanged. (Actually, the optimal plan may change even between runs of the same binary on identical hardware, due to differences in the virtual memory environment, etcetera. Users really interested in performance should worry about this problem, too.) It is likely that, if the same wisdom is used for two different program binaries, even running on the same machine, the plans may be sub-optimal because of differing code alignments. It is therefore wise to recreate wisdom every time an application is recompiled. The more the underlying hardware and software changes between the creation of wisdom and its use, the greater grows the risk of sub-optimal plans.

On an unrelated note, we should point out that the accumulation of wisdom is not thread-safe, although the utilization of wisdom is."

Mark

[JJ4SDR]

Very interesting and important points being made here. I, for one, had no idea that the wisdom file was PC specific! Well, I have no idea of a lot of things that make Thetis such a uniquely positioned platform in the world of ham-radio !

Juha