BACCH-dSP, anyone tried it on ML's?

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JonFo

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I use something similar for headphones, the Smyth Realiser A16, and there is now a 2ch speaker variant of it that does the same thing as the BACCH-SP, which is to render an immersive soundfield using a custom HRTF of the listener.
Here is a thread on the A16 SE: Smyth Research Realiser A16 Speaker Edition

My own experience with the A16 proves these mathematical convolutions are very effective at rendering a truly immersive soundfield, and that the Smyth's room/speaker impulse response metrics also work well at re-creating the 'feel' of the system.
Here is a picture of the A16 in my theater when I created my own Personalized Room Impulse Response (PRIR) using mics inserted in my ear canals and playing back special tones through each channel of the 5.1.4 setup. I also added a measurement of some phantom side channels by swiveling and using the rear Sequels as the 'sides', then created a custom 7.1.4 'room' for my A16.
BTW- I removed the row of usual seating and used an office swivel chair to have unobstructed audio paths to the speakers and be able to swivel for the various look-angles they require during the mapping.

IMG_0174.jpg

My A16 lives in the Media Room setup (a 5.4.2 in a small converted bedroom) so I can listen to full Atmos music and video over headphones, and the 'room' sounds like my HT with the ML ESL speakers; however, even an Electrostatic headphone fails to map the true sound of the ESLs totally. But it is pretty darn good.
The sense of listening to speakers is so realistic that after 20 minutes, I forget I'm wearing a headset and bang my hand on it, trying to scratch my head. The PRIR is absolutely critical to achieving immersion.

So not surprised the BACCH-SP is using convolution processing to simulate a truer 3D soundfield using just 2 speakers. But I bet it works a lot better using monopole speakers with constant directivity; guessing a KEF LS50M would be the perfect speaker for this, with its coincident driver.
The effect would likely collapse when attempted using a large dipole like a MartinLogan that sprays out-of-phase sound all over the place.
 

JonFo

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BTW- For those that want to experience the effect of a custom HRTF rendering 2ch or immersive (Atmos) audio / video, and you own an iPhone X or newer, and Airpod Pro or AirPod Max (preferred), you can now scan your own head using a feature in iOS 16 (beta for now).
More info: Apple iOS 16 allows users to personalise spatial audio for AirPods using the iPhone’s camera

Pre-custom HRTF, I rate the Atmos rendering of the AppleTV + AirPod Max pairing to be roughly 80% as good as my A16 rig which is a fully personalized HRTF, plus the room map of my HT.
I have yet to dare to put iOS 16 beta on my primary device (iPhone 11 Pro Max), I did put it on my iPad Pro (which has a truedepth face ID system, but only iPhones with trudepth cameras are allowed to do it for now.
I'm going to guess that will get the Max to a 90% match to the A16, which for most, will be quite satisfactory. The wireless nature is a big win here. My A16 requires a wired head-tracker mounted to the wired cans, so lots of cables are involved there.

PS- I absolutely love my AirPod Max; they have displaced the dynamic and Electrostatic headsets. It's the only headphone I've used in the last six months. The combination of good quality audio (best low-end I've experienced, very neutral, but DEEP) and really astounding noise cancelation, along with totally wireless convenience, means they become the go-to headset.
 

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Do you have to be tech savvy to use it? Do they have a plug and play system? I assume you have to have the camera on at all times, is it very noticeable (WAF)? Will only the person it is calibrated for be able to experience it?
 

JonFo

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Do you have to be tech savvy to use it?
Considering the setup requires an in-ear measurement sequence to capture the individual HRTF, then yes, to some degree. But it seems they tried to make it relatively easy.
The A16 is bloody hard to use, even for me, so the whole genre is still in its infancy.
Only Apple has mastered the touchless, simple HRTF process.

I assume you have to have the camera on at all times, is it very noticeable (WAF)?
Correct, it must be on and in a location where it can 'see' the listener's head to ensure the head-tracking works. See the pics in their brochure. It is small but noticeable. There might be ways to disguise it while preserving functionality.

Will only the person it is calibrated for be able to experience it?
It loads an individual HRTF, so that individual will get the most out of it, and they must be in the 'sweet spot'. Others listening concurrently will hear some of the effect, but not the full benefit.
So yes, it's pretty much for one.

Do they have a plug and play system?
Not really, as it requires an individualized calibration process. It also needs to be integrated into the system, so a lot depends on how one is currently set up. Also, there are three different models, one of which is a full-on Preamp, and the simplest is a simple processor only.

Again, based on my experience with the A16, none of this is straightforward, just degrees of complexity. This one seems a bit simpler than the A16, though.

And since we are on the ML forum, this is strictly for monopole speakers, the more cohesive the directivity, the better. An ESL would never work.
 

jimbill

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I contacted the company that makes the system (see below). Turns out, ML works "particularly well" with the BACCH. Now I just need to save my pennies...




Yes. While BACCH works with all types of speakers, it works particularly well with electrostatic speakers such as the ML (due to their high directivity, which decreases the importance of room reflections) . We use a similar speaker (Sanders M10) in both of our show/listening rooms (New York and Princeton).



Please do not hesitate to ask any other questions you might think of.



Regards,



Theoretica Sales & Tech Support
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