Crosstalk Cancellation/Ambiophonics: Updated CTXMatrix Lite with standalone processor & 60° speaker angle support.

Significant changes in the UI from the previous CTXMatrixBeta release.

I want to remind 2-channel "immersive sound" lovers about the potential for using stereo crosstalk cancellation (XTC) / ambiophonics playback to enhance the 3D soundstage. You might have already heard of uBACCH in the audio magazines and on forums - why not try a similar effect for free (or through a small coffee donation)?!

You might recall, last year STC contributed a post on CTXMatrixBeta DSP for Windows. Well, it's great to see that he has continued to develop the software with updated user interface and abilities, this latest edition renamed CTXMatrix Lite, currently at version 1.3. It now includes a standalone processor which I'll spend some time discussing in this post, along with the 64-bit VST3 plugin as shown above that can be used in JRiver, Audirvāna and DAW software like Reaper.

Furthermore, there is now a VST3 plugin for Linux. Since I primarily use Windows for my music listening and processing, I'll stick with the Windows variant here with the hopes that some of this will be applicable. In my discussions with STC, he's aware of interest from Mac OSX users.

Perhaps the most important update in the last few months is that there is now improved support for standard ~60° stereo speaker angle (typically, the recommendation is 20-30° in ambiophonics). As a result, one should have a much better experience with the effect on most set-ups. In particular, hopefully more desktop computer music lovers will give this a listen without needed to move the speaker position and explore what you might be missing in your existing music library.

[If you run a miniPC streamer in the sound room like I do, CTXMatrix can easily be used like with HAF X-talk Shaper DSP discussed a couple years ago.]

Stereo Crosstalk Cancellation (XTC) / Ambiophonics: Introducing CTXMatrixBeta, a Free VST3 Plugin with XTC Calibration. [Guest post, STC.]

Greetings audiophiles!

As you may recall, Archimago and I (STC) wrote the previous article from October 2023 on stereo crosstalk cancellation (XTC). If you're not familiar with the topic, I recommend a look at that to familiarize yourself with the principles behind the technique.

I now want to introduce CTXMatrixBeta, a free 64-bit VST3 plugin that brings Ralph Glasgal's vision with freely accessible Ambiophonics for all to try. (In the near future, I'm planning to work on adding support with surround channels for the "Domestic Concert Hall" [DCH]. The ideas and logic are ready to implement.)

Regarding CTXMatrixBeta, by harnessing intuitive ear-based calibration, this plugin aims to deliver precise XTC, empowering enthusiasts to experience the immersive, lifelike sound of their 2-channel recordings with unmatched clarity.

Home Audio Fidelity's (HAF) X-talk Shaper DSP. And is crosstalk correction/cancellation (XTC) just an "effect"?

See video and plug-in info at Home Audio Fidelity site.

Let's spend some time talking about X-talk Shaper in this post, a new DSP plug-in that will allow speaker system listeners enjoy crosstalk cancellation.

For those who have not read much about this, perhaps review the post from last year written with STC on crosstalk cancellation (XTC) and Ambiophonics. There's also the reposted article written by Ralph Glasgal that discusses some of the rationale for Ambiophonics you might find interesting and I hope provides good background for the 'hows' and 'whys' of this technique.

A Psychoacoustic Rationale for the Subjective Evaluation of Stereophonic Sound Systems by Reviewers and Audiophiles (Ralph Glasgal)

With the discussion of ambiophonics ("ambio") and crosstalk cancellation (XTC) last time, I came across a number of fascinating writings from Ralph Glasgal in the Ambiophonics Facebook group. The one below is one of them I think worth considering that I had not seen before, explicitly written as copyright-free. I've made some mild formatting edits and wording substitutions/additions for clarity as well as emphasis in areas I felt of importance. I trust this mildly edited version retains the full meaning and intent of the original found at the group above. A copy of this has been sent to Mr. Glasgal but I'm not sure if he's reviewing his E-mails or active in audio discussions these days in his 90s.

A Psychoacoustic Rationale for the Subjective Evaluation of Stereophonic Sound Systems by Reviewers and Audiophiles

By Ralph Glasgal, BEP, MSEE, AES, IEEE

glasgal@ambiophonics.org

(original text posted on Facebook - October 15, 2015)

The oft repeated assertion that high end components of stereo systems can only be truly evaluated by listening rather than by measurement or blind A/B testing by listening panels has been argued for decades now. The following text will, I believe, provide a psychoacoustic explanation of why this position is largely correct and not a question of practicing voodoo audio.

Very few audiophiles will want to read what follows since it is rather long, too technical, and not what they are used to reading in Stereophile or The Absolute Sound. But this article is for the record, for discussion forums, and to have it available for future debates. Anybody is free to use or forward this text. It is not copyrighted. Supporting technical references by a variety of authors are available at ambiophonics.org (mirrored).

Stereo Crosstalk Cancellation (XTC): A review by STC. And trying out uBACCH, ambeo.one, and AmbiophonicDSP VST plus Foobar foo_dsp_ambio plugins.

Hey everyone, it has been very busy as expected through September here at the Archimago household. As a result, I haven't been able to spend as much time on the audio hardware hobby (still very much enjoying the music of course!).

Over the years, you might have come across the term "crosstalk cancellation" (XTC) for speaker playback, words like "ambiophonics" or acronyms like "BACCH" may have passed by in your readings (for example great discussion on Reddit). For this blog post, let me ask an outspoken advocate of XTC to join for some guest content to discuss the reasons and techniques, and later on, we'll talk about a few DSPs one could try at home to experiment...

Take it away STC for Part I, I'll be back with STC for Part II, then I'll talk about trying some of the DSP options in Part III:

Part I: An introduction to XTC (by STC)

Crosstalk cancellation is an attempt to deliver stereo sound as it was meant to be played without the interaural crosstalk errors with loudspeakers (see Keele, 1986 for a technical exposition). Many listeners may not realize how much realism their high-end stereo hi-fi system is lacking until they hear a system with crosstalk-cancelled (or XTC for short) playback. It is like comparing a photo of a window with a view to an actual window looking out at the scenery. Or like watching Avatar in 2D versus 3D.