OT: Surround Sound?

[Dave Liquorice]

Works for binaural recordings and headphones but not for conventional stereo with two spaced speakers at some distance from the listener.

[Dave Plowman (News)]

Lot more to it than that. The head constantly moves slightly and the brain computes positioning etc by looking at phase differences. Clamp the head solid, and this function disappears.

A pair of microphones and speakers doesn't allow for this to be reproduced.

[Dave Plowman (News)]

Not on the demos I've been at. Only about 50% will hear the sounds come from behind.

[Man at B&Q]

I remember my father had some binaural recordings that were *very* good at giving an impression of 3D sound, but you really had to listem to them on headphones for the full effect.

MBQ

[Robin]

+1

(If anyone wants to try binaural recordings there are plenty of legally free samples online. And as a demo/test I quite like the rustling paper at

.)

[John Rumm]

Its certainly an interesting approach, if the original recording is made with a simulated head / ear combination then you should be able to capture some of the extra acoustic information the brain uses to spatially position sounds. Playback would have to be on headphones really, since the moment you move to speakers you start to introduce new acoustic clues that will conflict with the recorded ones.

Its obviously far more difficult from an authoring point of view though, since movie soundtracks are built up in layers over a period of time during post production. So there is no single audio performance that could actually be recorded with a binaural setup. Multi channel makes the process far simpler and predictable. (also easier in the cinema - bad enough people shuffling past to go to the loo without them kicking your headphone lead!)

[Dave Plowman (News)]

Quite. Basic stereo recordings made to be listened to on speakers commonly use a coincident microphone pair. Dummy head recordings use a pair of mics separated by a barrier.

Cinema sound tracks are almost entirely created in a dubbing theatre. A recording of a classical work in a decent hall needs no such thing - it can be issued to the public exactly as recorded.

The only true surround sound I've heard which really is convincing is Ambisonics. This is recorded using a quad coincident capsule microphone, and reproduced with 8 loudspeakers. Within the sound field of the speakers, it really does sound like being in a concert hall. But is extremely difficult to synthesise, so of limited use for manufactured sound tracks.

[The Other Mike]

I remember crouching down and shielding my chest behind a seat to try and avoid extreme low frequency torture during a concert in the 1980's.

[John Rumm]

You can also use infrasonic notes to trigger various responses in the nervous system - like inducing a sense of fear or unease.

[The Natural Philosopher]

Or alternatively just watch rolling 24 hour news.

[Dave Liquorice]

Or alternatively live near a wind farm.

[John Rumm]

Given the distance low frequency vibrations can travel, "near" probably covers several square miles!

[meow2222]

yes and no. Once the audio streams have reached the ear canal, then yes

No real world system is perfect, its a matter of picking your imperfections. I'd much rather start with something that sounds good.

NT

[meow2222]

If you're not moving you head, stereo channels capture all data one can exp= erience. If you move your head about when listening, that's where the diffe= rence happens. I typically dont move much when watching tv.

Its as good as the ears are, when youre not moving about, but not when you = are.

I didn't say that, I pointed out that nearly all home users use mass produc= ed domestic equipment, which is invariably compromised in sound quality. Th= is is not a stereotype, just a fact that most sound system sales are such e= quipment.

most people can now

That's missing the point really.

Its how such info is provided when using 2 channels. As eg the firework goe= s over and behind you, hf content drops. It provides our 2 ears with the ex= act same data they receive via 5 channels _if_ one isnt moving about at the= time.

1mm^2 per conductor, but fair enough.

Whatever system you use to deliver sound to ears, its what reaches the ear = canal that counts. And in the end there are only 2 of them. Stereo recordin= gs can be a lot less careful in the production stage at reproducing the efe= cts of up/down and front/rear, since such issues have routinely been ignore= d.

Some do, some don't.

Those that design sound systems or parts of them have a much better underst= anding off the issues _on average_ than those who don't. Its not condescend= ing at all, its just reality.

In the end we're talking about compromised systems, primarily due to price = limits. Most people won't spend on top notch speakers for home tv sound, so= its a question of picking your compromises. You can have your 5 channels, = I prefer better speakers.

NT

[tony sayer]

Yes I'd go with that:)...

[John Rumm]

As has been covered elsewhere in this thread, the only way you can make an attempt at capturing all the information that you hear during a live performance, is with binaural recording techniques. While these will work for live recordings, they are of no use for movie soundtracks. Also they require playback through headphones to work properly. So are not well suited to the task.

So in theory your point stands - it is possible for ordinary stereo channels to capture the required information. In reality however they don't and I am not aware of any significant number of movie soundtracks created using this system.

End result is multichannel is the only viable option.

For most (in fact in practical terms, one might say "all") commercial recordings this is not the case.

If you are looking for the highest quality audio playback for music, then I would agree that spending all your budget on the fewest number of required channels is the way to go.

Its my opinion though that for TV/film enjoyment the priorities change since surround will give you a level of engagement with what you are watching that 2 channel can't irrespective of the absolute quality.

Great, so get a first rate 2 channel setup for nothing, then use all your budget for a surround setup to add to it and you now have the best of both worlds.

(choose a decent active sub designed for use with music reproduction as well as for 5.1 use, and you will be able to derive a new level of realism out of your stereo playback as well)

No really it does not. If you want the full experience of a film, you need the extra channels. Personally I do. However I also care about my stereo reproduction quality, which is why I designed my system so that having one, does not compromise the other.

The head moving bit is a red herring - its a way we can aid our brain to get a better lock on location of a sound (any typically repeating short duration impulse sounds - e.g. a dog barking in the distance), but not the way we get the basic direction information in the first place.

Its also far deeper than simply "HF content" (it has polyphase and multipath elements as well). Full HF into the ultrasonic will still not capture much of the full 360 degrees of spherical information while using normal stereo mics, and certainly not when mixing down from a multichannel master.

Have been ignored, and by necessity will continue to do so. What you can make work for a single point binaural recording of a live event, can't be used for most recordings assembled from multiple mics, and multiple dubs etc.

IME most do, some don't.

Remember you are the one who claimed:

And yet no one has been promoting monster cables or any other marketing guff. We have explained to you why a multichannel system is required for fully immersive sound reproduction on *movie* playback. You will find electronics experts will say the same. Flip your DVD over and look at the back - you will probably find dolby pro logic, 5.1 or DTS, but I have never seen one that claims binaural yet.

Well in my case I built by music system many years before my surround system. Hence it was optimised to perform to my requirements on music. Adding surround capability to it did not in any way diminish it. On the rare occasion (classical/acoustic recordings mostly), bringing the sub into play can make the stereo performance even better.

[Grimly Curmudgeon]

Two tin cans and a bit of string is good enough for that.

[Grimly Curmudgeon]

There's something wrong with your hearing.

[Grimly Curmudgeon]

And buy boosters to get back to where they were in perceived loudness (which is likely higher in reality, due to hearing loss).

[alan]

multichannel surround sound, huge cables and other marketing guff. And expect lots of objections from people with no knowledge, qualification or design skills in electronics.

While I agree with the general message in your post surround sound can add to the listening experience.

On SD TV transmissions the quality of audio transmission is not to good in the first place and adding a couple of sub £10 speakers can possibly improve the sound quality from an average flat panel TV to around 95% of what you will get from a "Russ Andrews" system.

5.1 encoding on HD TV or on DVD makes surround sound worth an investment (IMO)

Surround sound speakers don't need to be expensive and definitely don't need connecting wire costing more than 10/20p metre