looking for NYD summing box schematic with LCR panning

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outoftune

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Jul 14, 2007
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ive seen refernce made to this schematic in other threads, some even have a link to the groupdiy image site, but either i cant find it or its not there. does anyone have a copy they could send to me?
 
LCR panning is a MAJOR project. You really have a choise of custom-build, multi-gang precision potentiometers, OR seriously convolved electronics.

You will not find it here. I have the SSL LCR schematic, and it is a majorly complicated undertaking, with several op-amps, a pair of SSM2402-type electronic switches, and STILL with a custom-build 3-gang pot.

...and in order to get divergence control, you need even MORE pots and active electronics.

The Amek does it differently, and nowhere NEAR as well. That uses switvched ladders for several take-them-or-leave-them divergence settings, but it is NOT clever enough to do hard-center panning.

You seem to be dead set on passive summing; -why, I have no idea- yet you also seem to be very keen on "L-C-R panning" though you haven't clearly defined your divergence requirements... that too will be crucial.

Hell, PLAIN STEREO panning with a passive summing network is super-lossy and VERY prone to bleed-back and crosstalk.... mixing that with LCR panning is going to be:

1) ULTRA lossy

2) VERY prone to crosstalk

3) SUPER-interactive

4) a VERY bad idea.

Even the active solutions are sufficiently complicated to be moderately daunting in terms of cost to most manufacturers, so I suggest you build a 3-channel summing system with perhaps 6 hard-asignment positions:

1) left only (hard left)
2) right only (hard right)
3) Left-and-right only (fully diverged center)
4) center only (hard center)
5) left-and-center only (halfway-left)
6) Right-and center only (halfway-right)

Your options would realistically be to build something like the above, or to just buy a real LCR panning mixer...

-Seriously.

Anything else is really Fred Flintstone, very hand-to-mouth in that it may work, but isn't actually a good solution.

Keith
 
LCR panning IMO has more utility for some fixed install applications where The majority of the audience in not in a sweet spot and your speakers may be set up with a center cluster, L, and R.

Music playback is typically a stereo (2ch) or perhaps surround (5? ch) experience.

So basically what SSL said, and be sure you actually want what you're asking for. How do you plan to use a discrete center channel output? Surround typically has a mono center channel but surround is more than LCR. More like LF, C, RF, RR, LR.

JR
 
The guy's talking about a stereo mixing network with Left, Center and Right assignment switching on each input--"center" meaning assigned to both outputs.

I'll see if I can dig it up.
 
[quote author="NewYorkDave"]The guy's talking about a stereo mixing network with Left, Center and Right assignment switching on each input--"center" meaning assigned to both outputs.

I'll see if I can dig it up.[/quote]
hey dave, that would be amazing.

yes i meant left center right assignment switching, so it can deal with mono or stereo signals...

sorry for the confusion!!
 
[quote author="outoftune"]did anyone happen to stumble across this schematic or something similar?[/quote]

Buss.JPG


That's one channel, just duplicate as many times as needed. LCR stepping is done with rotory switch.
Hope I was able to help.

analag
 
I saw this thread again after analag bumped it.

I believe this is may be the particular schematic you've been looking for; it's a balanced, passive mixing network with optional level, mute and assign controls. Sorry it took so long for me to find it.

http://www.twin-x.com/groupdiy/albums/userpics/balancedmixnetwork.pdf

PS: Don't sweat the exact value of Rx. 220 ohms is close enough for any practical number of inputs.
 
anyone have recommendations for quality 4p3t switches and where to get them?

thanks again dave for the schem!!
 
[quote author="JohnRoberts"]Isn't that called mono?

JR[/quote]

Sound from one speaker box/array is mono. I don't really consider the same sound coming from multiple speaker positions to be a mono listening experience due to the speaker interaction. So center = mono; no. I'll take one speaker box for mono over two at any time. My 2 cents.
 
[quote author="emrr"][quote author="JohnRoberts"]Isn't that called mono?

JR[/quote]

Sound from one speaker box/array is mono. I don't really consider the same sound coming from multiple speaker positions to be a mono listening experience due to the speaker interaction. So center = mono; no. I'll take one speaker box for mono over two at any time. My 2 cents.[/quote]

I'm not sure that is a useful distinction. I don't care if there's a hundred speakers playing back a mono source IMO it's mono.

Stereo (or more) playback, presents two (or more) discrete sources that in combination create the illusion of spatial positioning for instruments across a space between the speakers, not directly from them. Dual, or multiple mono appears to come from a single spatial source, either at the speaker or shifted when multiple speakers are playing but still a roughly concise sound source. If the speakers vary in frequency response there may be some perception of localization if specific instruments play louder in one speaker than another.

YMMV



JR
 
emrr and JR,you are both right.
However,in a studio environment,when it comes to checking mono compatibility,it is best to listen to a single speaker.
Room reflections from two sources will make a non true sound reproduction.
This because of comb filtering.


Kåre
 
Well, in fact one is 'hard mono' and one is 'phantom mono'. -This is the precise distinction between LCR and LR panning as I read it with my first post.

Kåre, I think you've READ that somewhere and decided that it sounds sensible, rather than determined it to be true by personal experience... Path-difference comb filtering is an absolute NON-ISSUE if you're equidistant, and -anyway- even a single speaker under anything other than anechoic conditions gets both room reflections and comb-filtering.

To say that one is 'true sound reproduction' and the other is not is colossal over-simplification... likewise to suggest that one is more prone to room reflections is also inaccurate.

L-C-R (with a hard center) is used in movie theaters because of the precedence effect and the resultant 'tugging' effect which it has on dialog when listeneners sit to one side of a movie theater or the other.

If phantom mono (left and right at equal volumes) is bad, then the music we've been listening to for the last 35 years is bad. -the kick, snare, vocals and a lot of other stuff is almost invariably equal level in both speakers, and it has the capacity to sound pretty good to me! :wink:

Keith
 
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