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Will it work?

  • Yes - it should work fine

    Votes: 0 0.0%
  • No - you are an idiot

    Votes: 0 0.0%
  • Possibly - but could cause other problems - not worth it

    Votes: 0 0.0%
  • Maybe - but I have a better solution

    Votes: 0 0.0%

Changing surround channel orientation between 2 screens?

6853 Views 26 Replies 5 Participants Last post by  Speedskater
Need your opinion on whether this setup will work or if you can think of a better solution. First some information on my setup to help you better understand where I'm coming from.


I have a projector set up on my deck/screen porch with 2 screens hanging on perpendicular walls. I pivot my projector 90 degrees to change from one screen to the other. I know it's a little strange using two screens but both have their purpose (mainly due to ambient light issue). I've got a 7.1 receiver inside that feeds all the speakers, sub and a separate amp for two buttkickers. The problem I have is changing the orientation of the surround sound when switching screens.


I have all the speakers oriented toward (we'll call it) screen #1. When I change to screen #2....everything still sounds like it's happening around #2 (obviously). I was able to rig up a cheap switch I that allows me to change center channel from Screen #1 to left surround speaker (on #1 but now obviously center channel on #2) So that got me thinking could I use a speaker selector switch box like this one (okay it won't let me post the link but it is an 8 way selector switch box that has a & b inputs) where I split the speaker wire coming out of receiver so that the "a input" corresponds with surround sound on screen #1 and then switch it to "b input" for surround sound on screen #2. Would also allow me to control volume from the screen porch which I cannot do at present.


Think it will work? (see poll at above) Any better solutions?
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Okay, I cast the first vote. Just realized, "hey" I need a separate input for each channel. I'd need something like 8X16 box or something like that. Only one's I've seen so far are over $1,000....so me thinks me like it as it is.......That is unless someone has a better solution.
you could do something with relays. cheaper by far.
Not sure I'm savvy enough for the relays unless they come pre-wired in a box to which I simply attach the speaker wire.
Use several 4PDT switches such http://www.allelectronics.com/make-a...WITCH/-/1.html or http://www.allelectronics.com/make-a...WITCH/-/1.html in a box. Each will switch two speakers. Then you just have to throw a few switches for the changeover.
The second link looks very similar to what I have hooked up now. That's a lot of splitting and joining for just one channel BUTTTTT.....may be my best option. Only other thing I've thought of is to get an inline volume controller (with 7 in and 7 out...doesn't necessarily have to have volume control for each channel. One master would be fine). And if there is such a thing as a power outlet toggle, I could connect two of the volume controllers, one wired for screen 1 and the other wired for screen two. Connect those to a toggled power source (to hopefully prevent kids from powering both on at the same time). Still thinking......
Okay what about thoughts on this.... split all seven channels (leave the subs out of the equation) and then put rca adapters on the speaker wire. Connect to a component video switch box with analog audio inputs also. I could connect (up to 5 channels) surround sound for screen #1 as input #1, then sound arrangement like I want it for screen #2 as input #2. (add second box to pick up remaining two channels). Just not really sure about the speaker wire to rca adapter or if the component ins and outs would pose a problem.
I think that running speaker-level voltages (wattage, too) into a component video matrix would not be kind to those circuits.... and should definitely void any warranty.
Not worried if I fry a cheap switch box. That's half the fun. Still I figured the component video ports could handle the audio. The analog audio ports are speaker level.

Quote:
Originally Posted by Keen1 /forum/post/16843053


Okay what about thoughts on this.... split all seven channels (leave the subs out of the equation) and then put rca adapters on the speaker wire. Connect to a component video switch box with analog audio inputs also. I could connect (up to 5 channels) surround sound for screen #1 as input #1, then sound arrangement like I want it for screen #2 as input #2. (add second box to pick up remaining two channels). Just not really sure about the speaker wire to rca adapter or if the component ins and outs would pose a problem.

The problem is frying the amp. The component switch will only work if your amp outputs have a common ground (most have a bridge output and can't share a ground) since a component switch likely has a common connection for all the outer shield connections. If you try to connect two amp outputs to the same ground you may kill the amp. Don't think you want that.

Quote:
Originally Posted by crutschow /forum/post/16843898


The problem is frying the amp. The component switch will only work if your amp outputs have a common ground (most have a bridge output and can't share a ground) since a component switch likely has a common connection for all the outer shield connections. If you try to connect two amp outputs to the same ground you may kill the amp. Don't think you want that.

Even if the second amp (subwoofer amp) is NOT connected to the switch box? I wouldn't need to change the orientation of the subs. I would leave it alone running simply from sub-out directly to the amp (for buttkickers) and a powered sub.
It has nothing to do with the subwoofer connection. I'm referring to connecting more than one speaker amplifier output to the same common point, as would occur if they were connected to a video matrix switch with common grounds. That will likely fry the amps. Each speaker output has to have two isolated connections to make the switch.
Ok....I'm with you now. Never did I think this would be such a big deal. I think I'm down to building a box with 7 toggle switches and A LOT of wires. Definitely going to need every color electrical tape ever made to keep it all straight.


Thanks for all the feedback....in the meantime...I'm STILL open to better ideas.
Obviously I'm no wiring expert so before I fry something I have another question. Using the 4PDT switch on-off-on. Assume all switches are in the up position feeding the 7 channel surround to screen one. Do I need to move all switches to the off position before flipping them "down" to change to the screen two orientation? Concern is, for example, I flip the switch feeding the center channel, if I go all the way down with it, it would be sending the center channel output and the right surround output at the same time to what I was using as the right surround. If it's just going to cause noise from two signals until I flip the next switch, that's fine because it will be done quickly. Just don't want ruin the speakers sending two different signals at the same time.
The switches can be the ON-ON type. You don't need the ON-OFF-ON type. Don't quite understand your concern about switching since there's no way that two speakers can be connected together at the same time.


Perhaps you misunderstand the wiring. To clarify, the amp out goes to the center switch (wiper) terminal. One speaker goes to one of the switched contacts and the other speaker goes to the other switched contact. See schematic Attachment 148211


You might want to wire the switches to banana jacks mounted on the box. Since the wires would be short, you could use 20AWG wire (only 10 milliohms/ft), which is easier to work with. And a Dymo label maker would help to identify all the jacks.


The 12-circuit knife switch would work, but, of course, you would need two since they are SPST.
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Very good chance I am confused. Also, just to clarify, I'm not worried about two speakers being connected, I'm concerned about two inputs feeding into the same speaker at the same time. Using the schematic you linked. Assume input is the center channel. Speaker A is the center channel for screen one, Speaker B is the Right Surround for Screen #1 (and center for Screen #2), So when I switch the center channel input from speaker A to Speaker B, Speaker B would be getting input from the center channel AND the Right Surround (until I switched that channel also)
Wish I could show you my attempt at a schematic. Guess I mistakenly thought the switch would have 8 terminals instead of six. But I see now that I've overcomplicated things.
Question from my ignorance here. Why a 4PDT instead of a DPDT?
I see the problem now. I was confused, I didn't read your post carefully enough. I thought you had two sets of speakers, but you are switching the same speaker from one channel to another, so now I understand your concern, which is valid.


In that case it would be better to have a center OFF switch, or two separate switches such as the knife switch you posted. Two switches are probably better since it is less likely that you would accidentally cross connect the speakers. To be extra safe you should do the switching with the amp turned off, so even if you accidentally cross-connect it won't do any damage. If you always turned the amp off during switching then you could use a ON-ON switch with no center OFF.


To be absolutely safe you would need to do an interlock type switch but that would require a more complex circuit, such as relays controlled by a single switch.
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