BACCH and other XTC

[chjan]

SOUNDPIMP XTC

To anyone interested in XTC type of software: I am the developer of Soundpimp.com which is compliant to Windows, Linux and Mac OS at a modest price level, compared to some alternatives, at least. Available as a standalone product, or as VST in all versions (VST only on Windows at the moment, but a MAC version may be back during 2024). SoundPimp was the first ever xtc software on the market some +ten years ago. A revised version is currently on the test bench. We have demos on the website.

 

[Keith_W]

SOUNDPIMP XTC

To anyone interested in XTC type of software: I am the developer of Soundpimp.com which is compliant to Windows, Linux and Mac OS at a modest price level, compared to some alternatives, at least. Available as a standalone product, or as VST in all versions (VST only on Windows at the moment, but a MAC version may be back during 2024). SoundPimp was the first ever xtc software on the market some +ten years ago. A revised version is currently on the test bench. We have demos on the website.

Great. I tried out the VST version some time ago (I think we chatted on email a bit). Keep us updated on the new version please.

 

[chjan]

I will announce the new version here, but we are not quite there yet, except that a 64bit vst version (vst2 or vst3) has become available lately, but so far only per email request to us (sales @ hdsoundlab.com)

 

[Keith_W]

Thanks Carl. I tried the 32 bit VST version of Soundpimp, which forced me to use a 32 bit version of JRiver to host it. I did not like losing the 64 bit volume control so I stopped using the Soundpimp VST.

 

[chjan]

Thanks Carl. I tried the 32 bit VST version of Soundpimp, which forced me to use a 32 bit version of JRiver to host it. I did not like losing the 64 bit volume control so I stopped using the Soundpimp VST.

send me an email if you like to test the 64bit version.

 

[maty]

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

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

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

PLUGINS

Digital room correction plugins

www.homeaudiofidelity.com

 

[STC]

Hoping someone can compare HAF, Soundpimp and BACCH.

 

[doorofnight]

Speakers - DALI Epicon 6 (slightly toed in)
Distance - between speakers 227 CM, Distance L-Speaker/R-Speaker to MLP: 245CM
RT - 0.343s*
XTC - uBacch for MAC

The effect of uBacch is clearly audible in almost all music.

*even though my room has a lot of acoustic treatments, 0.343 is still quiet "lively"

 

[jhenderson0107]

I have recently experimented with Xtalk shaper using my living room rig. This week, I installed MacroDeck onto the PC which runs Hang Loose Host and the Xtalk VST. Macrodeck is similar to Elgato StreamDeck, but uses of a phone/tablet instead of dedicated hardware to initiate custom actions. Below is a screenshot showing the custom actions I've created to support sound-field experimentation:

Pressing the 2.0 button activates simple 2.0 stereo via the VST flow below.

Pressing the 4.0 Atmos button activates Atmos 4.0 ambiphonic via this VST flow:

Finally, pressing the 2.0 Xtalk button activates 2 channel stereo, but with the Xtalk Shaper plug-in activated:

These configurations were tested using some chamber and instrumental music with which I'm familiar:
Xavier Diaz-Latorre playing De Visee on Theorbo
Nigel North, Les Voix humaines
Thibault Cauvin plays Leo Brouwer: 30 Estudios Sencillos

The Diaz-Latorre recording is extremely wet, with lots of ambience/reverb baked-in, whereas the Cauvin guitar set is dry, incorporating minimal ambience. The North set is nicely-recorded, not overly wet and exploits nice instrument spacing and depth.
I was surprised at how vastly different each of albums sound using the three surround presets. Unexpectedly, Xtalk Shaper creates the widest and deepest sound field - surpassing even the Atmos 4.0 configuration!

Now, it's all too easy to over-do any form of spatial enhancement; I typically dial back the volume of the rear surrounds or the effects knob of XTalk Shaper so that the effect is subtle, but noticeable. Anything more becomes fatiguing during extended listening.

In my opinion, crosstalk cancellation is an effect which reduces accuracy. But, the ability to dynamically change spatial rendering attributes on-the-fly can improve immersion and enjoyment. With most recordings, it seems to widen and deepen the sound field, but slightly diffuses the sound, reducing imaging clarity.

However, it's a lot of fun and given it's modest cost, I recommend experimenting with Xtalk Shaper.

 

[STC]

In my opinion, crosstalk cancellation is an effect which reduces accuracy. But, the ability to dynamically change spatial rendering attributes on-the-fly can improve immersion and enjoyment. With most recordings, it seems to widen and deepen the sound field, but slightly diffuses the sound, reducing imaging clarity.

I have not used the Xtalk shaper so I cannot comment about the accuracy and clarity because XTC supposed to enhanced them. IIRC, Xtalk is using IR for cancellation and that could affect clarity. BACCH is also using IR so basically when you add IR to a track it adds ambiance. I am speculating here because it is hard to come to a conclusion without knowing the actual setup.

XTC only deals with 2.0 stereo and if you have Quadrophonics recordings of 4.0 then the front and read XTc can give 360 degree sound. Any other format requires great attention to not mix the ambiance info into XTC. I hope you can resolve the clarity and accuracy part.

Cheers!

 

[jhenderson0107]

I have used only conventional stereo recordings throughout my tests. In fact, I own only a tiny number of true, multichannel recordings; The vast majority of music I play is Redbook CD standard.

The 4.0 preset I documented above uses the Penteo16+ upmixer to produce ambisonic signals for the rear surround speakers, driving the fronts with unmodified stereo signal. The other two presets utilize only the front speakers.

 

[STC]

I have used only conventional stereo recordings throughout my tests. In fact, I own only a tiny number of true, multichannel recordings; The vast majority of music I play is Redbook CD standard.

The 4.0 preset I documented above uses the Penteo16+ upmixer to produce ambisonic signals for the rear surround speakers, driving the fronts with unmodified stereo signal. The other two presets utilize only the front speakers.

I didn’t know that you can convert stereo format to 4.0 Ambisonics. Such upsamples probably extract the ambiance and render to the side or rear speakers. I thought you need a Ambisonics format to do just that. As far as I know, the developer of Ambisonics mentioned of incorporating Ambiophonics in the playback for the stereo component only in the playback.

Maybe, you can just use XTc for the front stereo speakers only to see if it makes a difference to the accuracy.

 

[AudioJester]

I am also using xtalk shaper with HL host/convolver. My setup is an active 3-way stereo system.
Completely agree it increases soundstage, "spaciousness" by "moving" certain instruments/sounds furher apart horizontally and vertically.

I posted in another thread about a waves plugin - PAZ stereo anlyser. It has a horizontal stereo position display where you can see the effects of xtc. Some of the effect seems to be phase related - maybe why you perceive a loss of detail?

 

[Tell]

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

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

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

View attachment 354018

PLUGINS

Digital room correction plugins

www.homeaudiofidelity.com

I tried this one the other day but couldn't hear a slightest bit of a difference

 

[Keith_W]

I tried this one the other day but couldn't hear a slightest bit of a difference

All XTC is speaker and room dependent. It is better to use narrow directivity speakers and place the speakers to avoid side wall reflections - i.e. the opposite to the usual recommendation of wide smooth directivity with side wall reflections. If you are getting a lot of early reflections, the crosstalk cancellation won't work properly.

 

[Tell]

All XTC is speaker and room dependent. It is better to use narrow directivity speakers and place the speakers to avoid side wall reflections - i.e. the opposite to the usual recommendation of wide smooth directivity with side wall reflections. If you are getting a lot of early reflections, the crosstalk cancellation won't work properly.

I'm not sure exactly of the directivity of my speakers but I guess they are pretty average, and I have absorption for the first reflection behind the speaker, and just a bit of early sidewall reflections, so generally average for a livingroom I guess?
But I'm going to have a go on my computer speakers later on, they're way more direct so might work better there

 

[jhenderson0107]

In my limited experience, the XTC effect seems highly-dependent on the ambience which has been baked into the recording. The recordings I listed above contain widely-varying amounts of ambience. The XTC effect is obvious on the wet Diaz-Latorre recording, but subtle on the dry Cauvin recording.

 

[boxerfan88]

Trying to understand what bacch does… i asked chatgpt..

The "Ubacch" system, often referred to as "UBAC2," is a signal processing technique used in stereo systems to enhance spatial imaging and soundstage. Here's a breakdown of what it typically does to the left (L) and right (R) channels:

1. **Ubacch Processing (UBAC2):**
- **Addition to Left (L) Channel:** The Ubacch system typically adds a delayed and phase-shifted version of the right (R) channel to the left (L) channel. This addition is carefully adjusted to enhance the perception of spaciousness and stereo separation.

- **Addition to Right (R) Channel:** Similarly, a delayed and phase-shifted version of the left (L) channel is added to the right (R) channel. This process helps in creating a wider and more immersive soundstage.

2. **Effects:**
- **Enhanced Stereo Imaging:** By adding processed signals from the opposite channel, Ubacch can widen the perceived soundstage. It creates a sense of spatial separation between the left and right channels, making the sound appear more three-dimensional and enveloping.

- **Depth and Localization:** The delayed and phase-shifted signals contribute to better localization of instruments and vocals within the stereo field, improving the clarity and positioning of sound sources.

3. **Application:**
- Ubacch processing is often used in high-end stereo systems and professional audio setups to achieve a more natural and immersive listening experience. It aims to reproduce a more realistic portrayal of the original sound recording by simulating the natural reflections and spatial cues present in a live performance or recording space.

In summary, the Ubacch system adds delayed and phase-shifted components of the opposite channel to each stereo channel (L and R). This technique enhances stereo imaging, widens the soundstage, and improves the overall spatial perception of the audio signal.

Is the above broadly how it works?

 

[LIΟN]

Trying to understand what bacch does… i asked chatgpt..



Is the above broadly how it works?

Nope.

It's basically what we look like when we hear it.
Assuming that the L has sound, the left ear will be heard first and after a slight delay (220us based on 30 degrees stereo), the right ear will be heard.
And at this point, half of our faces are kind of gripped by shadows, and it's what Bacchor XTC does to cancel this.

This is the right speaker sending the reverse phase signal at the right time, which will cancel it first.
But it leaves another mark in the opposite ear.

And it repeats the inverse phase with a certain level of gain attenuation, and only the negative effects of Crosstalk will be heard after the trace has been erased as much as it is not audible.

I don't think this directly improves the sense of space.
However, the width of the speaker we perceive is always set when we listen to the speaker at a certain distance from the opposite ear and half of my face, and if we get rid of it (expressing it as erasing the speaker), we may perceive it as "wider."
However, it is not broadened in terms of spatial perception.

Dr. Edgar Choueiri explains BACCH

How does BACCH enhance the spatial realism in the reproduction of acoustical recordings made in real acoustical environments? Crosstalk cancellation (XTC) techniques, such as BACCH, suppress the sound recorded on the left (right) channel of a stereo recording at the right (left) ear of the...

www.audiosciencereview.com

If you look at this thread and several XTCs and BACCH threads, you can learn more.

 

[STC]

Trying to understand what bacch does… i asked chatgpt..



Is the above broadly how it works?

The concept is correct but the reasoning is wrong. Anyway, ChatGPT source is Audiophilestyle, WhatsHIFI and other usual audiophiles sites.

here is what it said about Ambiophonics.

Both **BACCH** and **Ambiophonics** offer intriguing approaches to enhancing audio reproduction, but they differ in their goals and implementation:

1. **BACCH (Band-Assembled Crosstalk Cancellation Hierarchy)**:
- **Purpose**: BACCH aims to create a more authentic stereo listening experience by canceling interaural crosstalk (XTC).
- **How It Works**: BACCH derives crosstalk cancellation filters using a mathematical method. These filters allow for vivid, natural soundstage imaging.
- **Advantages**: BACCH can enhance existing stereo content without remixing or remastering.
- **Limitations**: Some debate exists regarding its impact on accuracy¹.

2. **Ambiophonics**:
- **Purpose**: Ambiophonics focuses on recreating the room or venue where the recording was made.
- **Experience**: With Ambiophonics, you can move around (forward, backward, sideways) without compromising the wide soundstage.
- **Implementation**: Any pair of stereo speakers can be operated Ambiophonically.
- **Note**: Ambiophonics is in the public domain and can be used in various setups, including clock radios and home theater systems¹².

In summary, both have their merits, and the choice depends on your preferences and listening environment. Feel free to explore and find what resonates with you!

Source: Conversation with Copilot, 7/21/2024
(1) BACCH, Ambiophonics, etc - General Forum - Audiophile Style. https://audiophilestyle.com/forums/topic/32987-bacch-ambiophonics-etc/.
(2) BACCH SP vs Ambiophonics - Immersive Audio - Audiophile Style. https://audiophilestyle.com/forums/topic/69384-bacch-sp-vs-ambiophonics/.
(3) BACCH filter vs. R.A.C.E | diyAudio. https://www.diyaudio.com/community/threads/bacch-filter-vs-r-a-c-e.194897/.
(4) undefined. http://www.ambiophonics.org/.
(5) undefined. http://stchelvam.wixsite.com/mysite.
(6) undefined. https://www.princeton.edu/3D3A/PureStereo/Pure_Stereo.html.
(7) undefined. http://www.whatsbestforum.com/showthread.php?17284-BACCH-SP-The-future-of-high-end-audio-Yes.
(8) undefined. https://www.nativedsd.com/homepage/binaural_dsd_music.

1. BACCH (Band-Assembled Crosstalk Cancellation Hierarchy):
   • Purpose: BACCH aims to create a more authentic stereo listening experience by canceling interaural crosstalk (XTC).
   • How It Works: BACCH derives crosstalk cancellation filters using a mathematical method. These filters allow for vivid, natural soundstage imaging.
   • Advantages: BACCH can enhance existing stereo content without remixing or remastering.
   • Limitations: Some debate exists regarding its impact on accuracy1.
2. Ambiophonics:
   • Purpose: Ambiophonics focuses on recreating the room or venue where the recording was made.
   • Experience: With Ambiophonics, you can move around (forward, backward, sideways) without compromising the wide soundstage.
   • Implementation: Any pair of stereo speakers can be operated Ambiophonically.

And when I corrected it about DCH. This is the new answer.

1. Ambiophonics:
   • Ambiophonics indeed encompasses more than just crosstalk cancellation.
   • It introduces concepts like the Domestic Concert Hall or Virtual Concert Hall, aiming to recreate the acoustic environment of a concert venue.
   • The core Ambiophonics algorithm focuses on precise sound localization and minimizing crosstalk.
2. BACCH and Adaptation:
   • BACCH, developed by Dr. Edgar Choueiri, builds upon the principles of Ambiophonics.
   • While Ambiophonics is in the public domain, BACCH refines the approach and commercializes it.
   • BACCH’s Band-Assembled Crosstalk Cancellation Hierarchy enhances stereo imaging by canceling crosstalk.