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Thread: Bluetooth

  1. Default Bluetooth

    Will a mind machine with Bluetooth for both the headphones and the Ganzframes ever be possible?
    Like others, I am not a big fan of cables, and I have the additional problem of a pet who loves cables, so I have to put him in another room when I use my mind machine, and I can hear his protest in the background.
    Maybe it is just not possible, but I was just wondering...
    Thank you.

  2. #2

    Default Re: Bluetooth

    I'm sure it will be possible someday, but the technology is not there yet. There is latency issues with the light and sound not being synchronized, and the slight, but possible catastrophic explosion of the battery blinding the user

  3. Default Re: Bluetooth

    I've looked into this quite extensively and can offer a few insights.

    As Joe mentioned above, if you connect LED glasses directly to an AVS device, but stream the audio to Bluetooth headphones or something similar, the audio latency is significant enough to throw the sound and the light out of phase; this is because of the inherent latency to streaming audio over Bluetooth.

    You could get around the latency issue, hypothetically, if you created a fully integrated unit that was like a Kasina or Limina, except it was all integrated into a single headset with glasses, headphones, and decoding/playback all happening on the same device. Playing back audio locally on such a device wouldn't have any issues obviously, and theoretically you could alternatively stream Bluetooth audio to such a device, and decode it on the device after the audio stream was received; similar to how the Kasina/Limina can decode a stream through either aux. input or USB audio input. I believe BrainTap has something like this.

    Of course, the issue with Bluetooth audio as it stands now is that there are many versions and standards for audio streaming, and they are pretty complex. They have a lot of strange compression algorithms, and sometimes adapt dynamically with bit rate, compression, and other settings based on the quality of the radio signal and transmission. This matters because AudioStrobe and SpectraStrobe encode the visual signals into the high frequency bands of an audio stream (around 19 KHz), and any compression or bit rate variation can dramatically alter, or even completely ruin the ability to decode the visuals from the audio. Add on top of this a huge variability of adoption and implementation within consumer Bluetooth streaming devices, and it's just a very messy and complicated solution for something like AudioStrobe and SpectraStrobe. Results will vary, but newer implementations like aptX HD might suffice.

    I think it would really come down to a single integrated device that you wear that could receive an incoming wireless audio stream, decode it locally, and send the signals to the headphones and glasses respectively. For streaming you'd want a constant bit rate (non-adaptive), lossless (or near lossless) compression algorithm for audio streaming.

    Personally, I'm waiting to see what happens with Ultra-wideband (UWB) technology. It's adoption and rollout to devices and smartphones is happening now, but is slow. It can operate like Bluetooth, but has dramatically improved bandwidth, and presumably latency as well. UWB can definitely send multichannel audio completely uncompressed, which is not true with Bluetooth. Likely, UWB will replace Bluetooth for many applications, especially audio streaming.

    In terms of safety and batteries blowing up next to your head... it's always a risk I suppose, but I think the current offering of Bluetooth headphones and VR headsets shows that the engineering can be done in such a way that is is acceptably safe and low-risk.

  4. #4

    Default Re: Bluetooth

    I'd love to see more research that looks at evoked EEG amplitude vs. the audio and visual stimulation phase relationship. We had some preliminary research that indicated that the visual flash could be delayed behind the audio pulse, probably because the propagation chain of neurons in the visual cortex is longer than those in the audio cortex. There is the possibility that the phase relationship is less important than the frequency, assuming the goal is to produce the largest EEG amplitude entrainment. However, other factors like how much brightness and loudness one selects are also significant (louder and brighter tend to produce stronger effects), so overall the phase relationship might be less important, and the bluetooth audio plus wired visual approach could be quite acceptable. Ideally, an "all in one" approach would simplify matters, though the "braintap" strikes me as not quite there... but that's purpose built for hypnotherapy as far as I know.

  5. Default Re: Bluetooth

    Thanks everyone for your insight and your research.

  6. Default Re: Bluetooth

    It does seem like the latency of the audio and visuals doesn't have to be perfect to still receive benefit. I'm curious too where that threshold is. I know that with Bluetooth audio typically you will see latency of around 40ms - 80ms. If you had an entrainment frequency of 10 Hz the waveform period is 100 ms, 20 Hz it is 50 ms, etc., so the higher the entrainment frequency the more pronounced the sync issue would become, but ultimately it may not matter - if it works for you, it works for you. Robert, I agree some EEG study would be very interesting to figure out if and where such a latency mismatch threshold might exist.

  7. #7
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    Default Re: Bluetooth

    Nothing stopping anyone from using a BT transmitter connected to a Kasina or Limina and some BT headphones to "try it out" and see whether the latency is bothersome...
    -Andy.

    Hey, if someone makes a good post, don't forget to click at the bottom of their post to add to their reputation!

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