I’m in the process of setting up a home theater system in my living room, but with a slightly different twist. On the west wall is my existing entertainment system, with a 32" TV and all the electronic gadgets. On the east side I have hung a screen, and we have an LCD projector so we can watch big screen movies.
Now here comes the problem. I have a 6.1 Dolby receiver, with 3 speakers on each end of the room, but sometimes the speakers on the west side need to be the front speakers with the rear speakers on the east, and sometimes the opposite.
In my old computer stuff I have a 25 pin switch box which I have figured out how to wire up to do the switching back and forth. On the common connector I will have pins 1-12 connect to the speaker outputs on the receiver, and pins 14-25 connect to the various speakers. On the A and B connectors I have wired up connectors with the appropriate pins jumpered together to match the speakers with the outputs. So far so good.
Here’s the rub. To connect to the common connector I took a 25 pin male-male cable and cut one end off, thinking I would splice the wires to the receiver and speakers onto this cable. However, the individual wires in the cable are only 28 AWG. Is this going to cause problems either with not giving enough power to the speakers, or with the wires overheating? The length of this cable is about 2 feet from the switchbox to the splicing in of the other wires. The receiver output is 100 watts/channel. The remainder of the wiring is either 18 or 20 AWG.
I can’t cite all the equations (I’m surprised Q.E.D. hasn’t stopped by yet), but I don’t think this is a good idea. I’m not one of those people who claims he can hear the difference between ordinary zip cord and monster cables, but I think 28 ga. is just a little too thin for speakers. I think damage to your amp could result, as well as some loss of frequency response.
Maybe with my bump someone with a stronger technical background will look in and provide some supporting details.
I’m sure if you give this a day or so (and maybe a bump here and there) someone will have an answer for you (probably no). Either way this would be a good question to ask over at the AVS Forum (I would ask it in any of the topics you see under “Audio Area” I belive it’s called). I can pretty much assure you they’ll say it’s a bad idea as 90% of them are audiophiles, BUT they may have a good workaround for you.
The main problem here is one of currenty-carrying capacity. 28 AWG wire carrying 100 watts can get damn hot, maybe even hot enough to melt the insulation and pose a fire risk. That’s far too thin a wire for the application. You need to use at least 20 AWG, and even that’s cutting it close, athough on shorter runs, it’s fine. If you’re going over, say, 50 feet, you’ll want to go down to 18 AWG.
Have you opened up the switchbox and looked inside? The internal wires between the box’s connectors and the switch are probably pretty thin, too. But, if you remove the box’s connectors, you may be able to pass the speaker wires through the holes and solder them directly to the switch.
Alternately, you could get a big ganged rotary switch (twelve-pole, double throw, right?), and build your own box with parts from Radio Shack. Probably about $20 or $30, unless you want to put some fancy multipin connectors on it. If you really need connectors, you may want to consider some form of pigtails with individual connectors for each line, instead of a flush-mounted multi-pin connector. A little messier, perhaps, but simpler to wire, less likely to fail, and maybe cheaper. And if you do the male-female connectors right, you can set it up so it will work without the box.
Let us know how it works out.
BTW, it sounds like for your viewing area you need to find a couple of those old style railroad coach seats that could be switched from forward facing to backward by swinging the seatback from back to front. How cool would that be?
You also want to be careful about switch quality. Lousy switches and dirty contacts can create all kinds of pops and other problems that could damage your speakers and/or amp.