7.1 speaker placement might be wrong

[guitarist155]

I am currently an audio engineering student in the final weeks of school, recently i finished classes on pre-post film work and have found something that is quite disturbing as i am working on building my HT. the spec for 7.1 is not really a spec at all and does not give guidelines on speaker placement for mixing or HT use. i know alot of people on here have 7.1 setups and use the common center, FL, FR, mid left, mid right, rear left, rear right. but as I have learned this is not even how speakers are placed for mixing or how mics are setup for recording 7.1 the current placement in the industry has the 2 extra speakers as rear center and high front center ( a few feet above the center) this is also the configuration for imax. a 7.1 mic can be seen here http://www.holophone.com/products.html note that it shows the other channels as es-ex rear center and top front center imax.

this really makes me wonder as not having speakers in the right spot could really mess with where sound is coming from like when the dialog starts coming from your right mid, the origins of the mid left and right come from matrixing the rears so it made sense to have them as mid surrounds but now that we have discrete 7.1 where is the audio truly going to come from?

looks like i will be running conduit to a few more locations

[Yeha-Noha]

I placed all my speakers on 3.5 - 4.0 stands except the center an Energy CLCR on a 30 in speaker stand between the L/R fronts Energy C200s on 3.5 ft stands. They are 8 ft apart with the center in the exact middle. The 47 in. LCD HDTV is just above the center speaker. The surround L/R are Energy C200s on 4.0 ft speaker stands. They are about a foot off the side walls and 2/3 the back to the back wall. The Surround back L/R (Tannoy 6o9s) are on 4.0 ft speaker stands about 18 in off the back wall and 6 feet apart. All 7 speakers are toed in so that a line perpendicular to each front baffle intersects in the geometric center of room. That spot is about 2 ft in front of the spot where we sit. From that location or spot, the distance to each speaker (except the subwoofer which is 12 ft) is the same distance or about 8 ft. I set the calibration microphone supplied by the yamaha AVR for YPAO calibration on a camera tripod that placed the top of the microphone about ear level from where we sit. One of the problems I had with an earlier setups where the microphone was placed at the actual setting positionm is that YPAO always set the back surrounds (the Tannoys) too low. That was with the flat calibration setting. Natural set them too high. Now with everything setup and calibrated the way I just described usint the flat calibration curve, the sound is excellent at least to my ears.

[kefrank]

Originally Posted by guitarist155

i know alot of people on here have 7.1 setups and use the common center, FL, FR, mid left, mid right, rear left, rear right.

Despite what happens during recording and mixing for theatrical presentation, I'm fairly certain that the discrete 7.1 mixes on Blu-ray discs are mixed specifically for the above speaker configuration.

[guitarist155]

Originally Posted by kefrank

Despite what happens during recording and mixing for theatrical presentation, I'm fairly certain that the discrete 7.1 mixes on Blu-ray discs are mixed specifically for the above speaker configuration.

i figure most are but it has me wondering about this as i can't find any info on 7.1 speaker placement for mixing and has me wondering if it it is true discrete or if it is simply being matrixed at the studio instead of in the receiver.

[srrndhound]

Originally Posted by kefrank

Despite what happens during recording and mixing for theatrical presentation, I'm fairly certain that the discrete 7.1 mixes on Blu-ray discs are mixed specifically for the above speaker configuration.

I don't believe any BD 7.1 titles use mid-left, mid-right--do you have some example titles in mind? Most (if not all) of them use 3 fronts (L, C, R) and 4 surrounds (Ls, Lb, Rb, Rs). You can see the typical 7.1 layout for homes (and as used by MiCasa, for example) at http://www.dolby.com/consumer/home_e...omlayout2.html , click on the 7.1 layout.

Blu-ray does support multiple 7.1 configurations. All of them use the normal 5.1 as a start, then add one of the following pairs:
1) Lc/Rc (as you described with mids)
2) Lb/Rb (as I mentioned)
3) Lw/Rw (wide placed fronts)
4) Lh/Rh (height speakers above L/R)
5) Ch/Ts (height above C, and a top surround overhead)

MiCasa experimented with mixing heights, but in the end decided that to reach the majority of existing 7.1 home systems, they needed to mix with a more conventional arrangement.

[guitarist155]

that is the same setup that i was talking about just different terms, the surrounds are sometimes referred to as mids since they are between the fronts and surround back

[guitarist155]

ok just looked at my surround panner for logic 7.1 and it gives me the option of using the 2 other speakers as mid left and right (surround left and right ) or using them as center left and center right for more fronts. but this now makes me ask the question: why would i buy a 7.1 mic for 5grand if the mics were not even in the right place. it really is looking like there is major confusion in this industry

[srrndhound]

Originally Posted by guitarist155

that is the same setup that i was talking about just different terms, the surrounds are sometimes referred to as mids since they are between the fronts and surround back

Ahh, thanks for clarifying. I'd not heard them called "mids" before. Sides, surrounds, yes...

Originally Posted by guitarist155

ok just looked at my surround panner for logic 7.1 and it gives me the option of using the 2 other speakers as mid left and right (surround left and right ) or using them as center left and center right for more fronts. but this now makes me ask the question: why would i buy a 7.1 mic for 5grand if the mics were not even in the right place. it really is looking like there is major confusion in this industry

The Holophone mic is a "space capture" tool. It's outputs can then be used in various ways in post-production, as may be desired. It does not have to necessarily map each output directly to a speaker. Ambisonics have also been capturing height for many years.

[guitarist155]

i understand rerouting the channels but why place mics for things like imax and call it 7.1 it's starting to sound to me like it's a 5.1 mic with extra feature mics built in, always thought the .1 mic was funny though.

[mustang-gt-2002]

take a look at my HT gallery see if it looks ok or if you think something needs to be changed. thanks.

[jomari]

cant believe no one commented on the product linked by the op tho...

no, im not saying anything regarding his posting, but man, that surround sound microphone, for 6 grand is definitely too much for my taste. id rather have my trusty ol SPL meter instead for half a dime

[guitarist155]

it really is geared more for pro filming and surround audio recording for the stuff that ends up coming out of your speakers. so i suppose the price tag is warranted for that amount of accuracy

[srrndhound]

Originally Posted by guitarist155

i understand rerouting the channels but why place mics for things like imax and call it 7.1 it's starting to sound to me like it's a 5.1 mic with extra feature mics built in, always thought the .1 mic was funny though.

There is no "0.1 mic" per se. They electronically collect the bass from the other mics for production convenience.

[guitarist155]

Originally Posted by srrndhound

There is no "0.1 mic" per se. They electronically collect the bass from the other mics for production convenience.

it actually has a .1 capsule the .1 lfe mic is on the inside of the head in the middle and is designed to capture the resonance of the head itself strange concept but i would have to guess it works

the distribution of low end to the lfe electronically is usually handled by the bass management system on playback as you never know what size speakers someone will be using

[srrndhound]

Originally Posted by guitarist155

it actually has a .1 capsule the .1 lfe mic is on the inside of the head in the middle and is designed to capture the resonance of the head itself strange concept but i would have to guess it works

Thanks much for correcting my error. You're right!

[Blu_Ray_Fan]

Maybe what your suggesting is we need 9.1 or 11.1 or mabye even 11.2 or 11.11??? haha I CAN'T WAIT!

Truth of it is, most movies are only encoded in 5.1, thats what most of us have, and thats all thats really needed for home use.

[MatrixDweller]

Sorry for joining this a little late, but what is set up in a big theater as compared to the average home theater must be different.

In a big theater you have massive acoustically transparent screens that are 10's of meters wide and have speakers positioned behind them in a room that is the size of three houses. In a very good home theater you might have an 8 or 9 foot wide screen in a 12'x20' or bigger room, but on average it'll be a 60" LCD or Plasma or less in a much smaller space.

So with those differences you don't need these configurations:
1) Lc/Rc (as you described with mids)
3) Lw/Rw (wide placed fronts)
4) Lh/Rh (height speakers above L/R)
5) Ch/Ts (height above C, and a top surround overhead)

That leaves:
2) Lb/Rb (as I mentioned)
and is what the standard is and what all 7.1 Bluray and 6.1 DVDs are mixed as.

Yes it is less than adequate for those of us with larger home theaters. A high and low center would be great. A second set of side surrounds would also be great for theaters with 2 or more rows of seating.

Ideally from a mixing perspective, I think in the front there should be and array of channels up and down the sides of the screen. Then using stereo imaging a sound could be localized to a spot on the screen in a calibrated setup just as 2-channel music fans have a phantom center. Of course then the problem is if you move off axis or have less than stellar speakers you just won't get the proper imaging. It would get ridiculously expensive too on a very large screen because you would need a lot of speakers.

So compromise I guess is the game. One center to tie dialog to the center of the screen. Two front channels to bring localize sounds to the sides of the screen. Two side surround speakers to give surrounding off screen and panning type effects. And two rear speakers to produce effects of things behind you and continue the surrounding effects.

So what's missing? Maybe a speaker above the listener? One below? You can sort of fake those with good mixing in the surrounds. A high center in combination with a low would be the only speaker that would make a difference.

[guitarist155]

sadly though that's what i mean. the speaker config you are talking about is the standard for 7.1 however coming from a mixing background the standard is 6.1 plus the imax high center for 7.1 which really means things are not so standard as people think but rather could change. i also think that's why you don't see a whole lot of 7.1 movies out there, not many are setup for 7.1 mixing as it's not fully standardized yet

[Sir Terrence]

Originally Posted by guitarist155

sadly though that's what i mean. the speaker config you are talking about is the standard for 7.1 however coming from a mixing background the standard is 6.1 plus the imax high center for 7.1 which really means things are not so standard as people think but rather could change. i also think that's why you don't see a whole lot of 7.1 movies out there, not many are setup for 7.1 mixing as it's not fully standardized yet

I come from a film and audio mixing background, been at it for 23 years. The standard has never been 6.1 plus the god channel mimicking the IMAX setup. The 7.1 setup has always(at least since the idea of 7.1 from a mixing stand point) has always been L/C/R/LS/LR/RR/RS and LFE. The standard you mention is strictly a IMAX standard, and I have never seen it used for theatrical film purposes, or home mixing for that matter.

[guitarist155]

not arguing with you, I have always known it to be the way you describe, however i had a teacher tell me they always mixed the 7.1 with the imax setup and since all the 7.1 mics i have seen agree with the imax setup, I am just very confused as all documentation i have found never really mentions 7.1

and the one article on 7.1 mixing i found that does say the ''most common'' way of mixing is the standard we know however it says that as of yet 7.1 really has no standard and has been mixed many ways