After reading through the WEALTH of information I found in David Griesinger's papers at
[Link: world.std.com] escpecially the ones
... how many loundspeakers ...October AES conference &
Surround: The Current Technological Situation wherein he mentions discussions with Mr. THX (10 or eleven speakers is it - hint on Dolby "X"?)
I was wondering about the logic of the following:
Centre rear is the (for now) the matrixed difference between the left & the right rear. (same idea as the Dynaco/Haffler circuit!-difference technologies) Would not the logic for a right & left side mid channel (between the front & rear be then the difference between the front & rear left channel for the left side speaker & the difference between the front & rear right for the right side speaker! This could only be “matrixed” for now but would add an effect the same as the DPLI 4.1 did for R&L rear except it would be stereo not mono.
[I lost the thread on something Larry does & runs through an "old" prologic decoder for 2 speakers - for rear?] (speaking of Larry anyone seen him around here lately? - I'm going to need his input on this one)
If my above logic is correct how would I extract the information - as in what equipment would I need to use & how would it need to be hooked up?
Dougofthenorth

I think get your current system running and then mess around... ; )

Matt; I was asking because I got a source on some speakers & equip that my friend who owns an A/V store is getting rid of as his franchise is switching lines (brands)& he is going to be doing a reno to build more sound rooms, & well there's going to be all this equipment hanging (sur)'round in his store so I was thinking maybe......
Dougofthenorth (ears bigger than his current system state)

Well, if that's the case, get me a Lexicon MC-12 (or any DC model) they will blow your mind!

"There's no need to fear, Underdog is here!"

Doug, there is a difference between a rear-center extraction and a side-channel fill-in.

When adding a rear-center speaker, the 'original' rears should be moved to the sides (where some people prefer the surrounds anyway, or have to be if your seating is against the back wall).

The rear signal is encoded as a difference (L - R) signal, as in the aforementioned Dynaco/Hafler 'ambiance' extraction, but it's not necessarily meant to play whatever is 'different' between the two. In fact, a ProLogic decoder will send whatever is IN phase and at nearly equal level (L + R) to the center output. This is what my setup produces in the rears, and differences are steered to the sides.

For sides that are in additional to the stereo rears, they should be reproducing what is common (L + R) to the front-left and rear-left channels, to avoid the 'hole' effect from there being no speaker directly to the side; that's why the surrounds should be to the sides when adding a rear-center.

In other words, 6.1/7.1 surround is NOT the same thing as 7-channel logic (as provided by Lexicon, et al). 6.1/7.1 adds a rear-center (or two) to the existing surrounds, while 7-channel logic adds sides to the existing surrounds. See the difference?

Larry
www.fineelectricco.com

Yeah, so where's my MC-12?? ; )

Matt; see your Email from me.

Larry; Thanks again bro.
re: "For sides that are in additional to the stereo rears, they should be reproducing what is common (L + R) to the front-left and rear-left channels, to avoid the 'hole' effect from there being no speaker directly to the side; that's why *4)the surrounds should be to the sides when adding a rear-center."
Am I right in understanding:
1a)for the left side mid speaker = what is common to the Front left & Rear left AND
1b)for the right side mid speaker = what is common to the Front right and Rear right.
2)If so how is that extracted & with what equipment?
3)I wonder what the Yam front effect (+2) speakers extract?
re:"...centre speaker.. surrounds to the rear sides"
*4)I have put the centre 5' behind the rear the rear L&R I put to the back OUTSIDE of the listening area
pointed in at a 45 degree angle (essentially the same as my front L&C&R speakers. I think except for (+2)'s all 6 of my seakers are direct radiating ? Dipolar?
(still haven't got the mono/di/bi/tri polar figured out & the direct radiating & what ever else there is)
The Kenwood's are "front imaging" but were not for rear side surrounds - they were matched with another model.
Dougofthenorth

This message was edited by Dougofthenorth on 12/24/01 17:27.58.

Doug, you're really giving me a test here, but that's okay, I enjoy it. Okay, let's get into it:

1a&b) Yes, that's what I meant. I'm not claiming that I know that to be what Lexicon, et al, and their engineers had in mind with the Logic-7 decoding, just that it seems 'logical' to me. I do remember reading it somewhere, though.

By the way, in any case, when I mention side-positioned speakers, I'm referring to a position directly to the sides, not to the rear even a little bit.

If I were keeping my surrounds to the rear, I'd want a side speaker to fill in the 'gap', the way a center fills in for a pair of fronts to reinforce the 'sweet spot' for anybody off-center. In the exact center seating position, there is, theoretically, no difference between having and not having a center speaker (caveat: assuming proper recording, mixing, maintaining relative phase, high-quality and proper setup of the playback system, etc.)

Side note: When stereo began, there were THREE speakers, not two; the usual full-range two- or three-way unit, and a pair of satellites. (I'm not sure how the sound was steered, whether discrete or encoded, etc.) You should be able to understand the need for maintaining phase relationships, even though you can't form a 'phantom center' using one ear.

2) I don't know, you'd have to ask Lexicon. However, properly mixed and encoded surround sound should be able to approximate it. This is another reason I'd rather place the surrounds to the sides, even if there is no separate rear speaker. Plus, if you have a room that is wider than it is deep, the side position is a perfectly legitimate place for the surrounds.

3) My guess would be a 'spatializer' circuit of some sort. What these do is exaggerate the steering of the stereo difference, so sounds panned or located left sound farther left, etc. You could certainly try placing these front-effects speaker to the side.

4) Again, with any speakers to the rear of the main seating position, the sides should be directly to the side, not the back corners (not the best place for a speaker, anyway; too many early reflections). Also, all of my speakers, while not 'direct-radiating, are bi-polar, not di-polar, so they are closer to directional than not. The difference between the two is merely electrical, not physical; it depends on whether the drivers are wired + to + and - to - , or + to - and - to + .

For an explanation of the various speaker types, see: [Link: remotecentral.com]

About 'tri-polar': I haven't read anything about it, but I would guess it refers to a speaker with drivers on three sides. Still, as in the di-vs-bi wiring, the two (or two sets of) outer drivers could be wired bi-polar (in phase) or di-polar (out of phase).

However, the third, center-mounted driver must be wired in one direction or the other, and since there is no 'third phase', there really is no such thing as a 'tri-polar' speaker. Either all three faces are in phase (direct, bi-polar, or 'mono' all apply), the two outer in (bi-polar) and the center out (di-polar), or one face and the center in phase and the other out (di-polar).

Larry
www.fineelectricco.com

Larry;
I'll try to see if this is what I gathered about speaker positioning
---------- *FLE/\-----------------/\*FRE
---------FL\-------------|C--------------/FR


--------MS<---------------------------->MS

---------------------- ---X------------------------------------------------------------------------------------------ -----RSL<---------------------------->RSR
---------------------------------------------------------------------------------------------------------------------------------RL/----------|RC-------\RR---------------
MS= mid side, RS = Rear Side, FEL&R are 3 directional
radiating -used to be rear side Surrounds,
X =sitting position
The \ / < etc show direction of speaker "radiation"
RL&C&R are up on the back wall away from the corners
down sloped. RL&R are on swivel brackets in facing.

Am I interpreting I should add the RSL&R's as I only have RL & RR? If so "Y" connect off the RL & RR?

RE:"Doug, you're really giving me a test here, but that's okay, I enjoy it." Enjoy it! I bet that you like I, thrive on solving what we can! & require ALL the data on what we can't! - N'est pas mon ami?
Dougdunord (Français maintenant?)



This message was edited by Dougofthenorth on 12/25/01 16:33.15.

Doug, that's quite a diagram. I assume you meant for the X to be between the RSL and RSR.

First of all, I thought that the Front Effects speakers were meant to go outside of the mains, but that's a Yamaha question.

Also, you have three (!) pairs of speakers for sides, MS, RSL&R, and RL&RR. You have that many speakers OR amp channels???

What I had in mind was:


Left Center Right


Side Side


RearL RearR


Or:

Left Center Right


RearL RearR

Rear


Which depends on your speaker and amp budgets. Mine is the first one, physically, but the second electrically, as my rears are mono via a Y-cord. My Sides are directly to the sides, even though they're RearL & RearR.

Larry
www.fineelectricco.com

Wow, that's a ton of speakers, and I question it's ease of operation..lol

I would stick with what Larry is saying in the note above, first choice is 7.1 second is 6.1. I just don't see any advantage of using so many surround speakers. All the acoustical interaction in the room between the speakers will probably hinder its effectiveness anyway.

Gonna hook up my rear center today with my old Pro-Logic decoder. Should be interesting.

Larry; this is what I have now (actual)6.1(+2)

---------- *FLE/\-----------------/\*FRE
---------FL\-------------|C--------------/FR


_______________SEATING_____________


--------------RL/-------|RC---SUB---\RR---------------

All have their own individual amplified outs. I was trying to:
1) allow for the fact I do not have multi-directional speakers for the rear L&R's & since all the posts are mentioning rear SIDE L&R surrounds I was going to "Y" connect 2 extra's off the rear L&R feeds. I can't see putting the 2 I use at REAR L&R to the REAR sides. As they are not "Surrounds".

____RL-___________SEATING____________-RR_

___________________\RC/

2) Mid L&R sides were an experiment idea only - please disregard for now
(It is hard for me to input & process data when I am missing the aural component. Some quirk I have - being essentially MID brained as opposed to right or left hemisphere dominant)
Anyway, I'll keep plugging at it as long as your gratious patience will permit.
Thanks Larry I appreciate your input.
Matt, thanks, your 6.1 & 7.1 comment helped to enable me to mentally "key" in what Larry was saying, then I was able to understand.
Dougofthenorth

P.S. As an point of interest, re 6.1 as per
[Link: dolby.com] &
[Link: dolby.com]
Am I understanding that per the above links there
IS actually a 6.1 format on a FEW 3rd channel encoded
films extracted by the Dolby SA10 Surround Adapter.
However, the 6.1 dd-ex setting on my YAM is only a "matrixed" (faked) 6.1. Is this correct?





This message was edited by Dougofthenorth on 12/25/01 21:14.18.

Doug, when I refer to 'surrounds', I'm talking about speaker position, not speaker type. I still believe that direct radiating (mono-pole) speakers are preferable to the non-directional (di-pole) type once you have 5.1 or more.

Since the rear is stereo, you DO want to be able to tell where the sound is coming from, and the greater the number of sound sources (speakers), the better the dispersion (spread) of sound.

Mine are BI-polar (did you read my post I referred to above?) because they radiate sound more similarly to real sound sources, i.e., in all directions, but localize more like mono-poles.

In my opinion you should keep the setup you have now, with ONE change: Move the RL & RR speakers to the sides of your seating, directly to the side. The stereo separation in the rear channels will be more pronounced, but will still sound like 'surround sound', and any sound intended for the back of the room will be reproduced by the RC. Give it a try.

Larry
www.fineelectricco.com

Larry; Thanks once again. I think I will try & experiment with moving them to the sides. BUT I think the SWEET spot will be pretty small. If I don't like it I will get some BI-POLARs (as you have) to replace them up on the sides.
Now for your REAR: where I have 1 centre rear have you split the information into 2 rears (centres) & placed them apart in the rear. If so how do you use the extra prologic amp to split as in how do you do the hookups?
Dougofthenorth


This message was edited by Dougofthenorth on 12/25/01 23:38.46.