Comment by mattdotc | Hacker News Reader

Comment by mattdotc | Hacker News Reader

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>surround sound for headphones (defined as: HRTF implementations) don't work

I'm not trying to be an ass, but do you have any hard evidence or citations for that claim?

I have been a skeptic of the technology as well, but just 2 weeks ago I tried a demo [1] that was _very_ convincing. In short, I wore ~$30USD headphones while a device with some positional sensors was moved around my head and music played. The only sound emitted was from the drivers in the headphones, but I do not exaggerate one bit when I say that my brain was tricked into believing the sound originated from the mystery box moving around my head.

Perhaps you have some scientific reason for why in theory (or fact) it doesn't 'work' in the physical sense, but my anecdotal evidence supports that there is a way to do a 'good enough' job where the brain is successfully tricked.

I admit to feeling there's still a bit of a snake-oil salesmen aspect to this technology, but the guys at Visisonics spun off their company from research at University of Maryland. They're not just another ragtag shop implementing your last decades' positional audio algorithms. They really seem to be pushing the space forward.

[1] http://visisonics.com/

Hard evidence for what? I've tried them all, I tried to like them, and it just butchered the directional cues for me, and also made the sound come out really oddly (some added excessive reverb, others just fucked the EQ all to hell).

Scientific theory doesn't mean shit if the resulting product doesn't work.

And I've heard working audio cues on natural audio, but as I said, they've all been binaural recordings done with dummy heads, so you can't claim its just something defective with my hearing.

I want headphone downmixing of 5.1 surround to work, but I've yet to find one that works without butchering the audio.

>Scientific theory doesn't mean shit if the resulting product doesn't work.

That's the thing, I'm claiming that the implementation I tried DID work. Now, questionable YouTube videos, however, haven't worked for me before. Nor do the settings in the software for my discrete sound card. But I have experienced it with one particular company's implementation.

What was explained to me is that they have a generic HRTF that works for ~90% of the population, but there's a minority of the population for which a customized HRTF must be determined. They claimed that certain differences in the spatial characteristics result in their generic HRTF not being a good fit; perhaps you are part of that unlucky 10% who would need to be measured in a lab.

This was actually the topic of one of the questions I asked of the presenters, and their answer was to concede that unfortunately those 10% would be out of luck unless they got their personal HRTF derived. Who knows if the numbers are real or not.

Sorry you're getting downvoted for having a dissenting opinion/experience.

Dummy head binaural recording is the physical equivalent of that generic HRTF math. It, too, would work for 90% of the population, but not the other 10%.

Dummy head binaural recordings work perfectly for me. I can hear forwards, backwards, up, and down perfectly.

The only 5.1 -> headphone HRTF implementations I've heard that properly give directional cues mangle the sound so bad that it isn't worth it.

>5.1 -> headphone HRTF implementations

The technology I tried is intended to be used for real-time games. Individual game objects' audio samples and their positions are run through their filter, accounting for position and the material properties of nearby reflective surfaces (hard vs soft, solid vs semi-solid).

Is this fundamentally different to the implementations you've tried? It seems to me you're referring to '3D' implementations that take an already-mixed 4 channel source and try to jam that into a spatial 2 channel mix. That's the kind of technology that I think is pretty lame/useless as well...

If you have a chance to try out Visisonics tech, I think it'd be worth giving it a go if games are your thing. Seems like you definitely know a lot about the subject.

Real-time games are "okay" if the game has the tech built in to the sound engine and does audio processing in a way that takes into account the position of your speakers (on head, surround, etc).

Problem is, I rarely meet a game that does (I think maybe I own one or two, but I can't remember which ones, which tells you what sort of impact those games made on me).

Being able to already have positional queues on a per sound basis is much different than downmixing 5.1. The technology isn't useless when all I want to do is watch a movie and be able to enjoy it with headphones without garbled audio.

Like I said above, you can downmix left, center, and right, and throw in a little sub, and get a stereo/headphone mix, but positional cues provided by surrounds are gone, and you can't just mix those in normally, the mix gets too confused.

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