Just like the title says: Can multiple speakers share a common ground? Is there some reason this would be a Bad Idea(TM)? With my very basic understanding of electrical theory, I see no problem with it.
I want to put a single custom-made 'plug' on my wall behind the entertainment center, which would connect to behind-the-walls wires leading to each of my 5 speakers (not worried about the subwoofer). If there are no contraindications to using a common ground, I need only use a 6-conducter plug at the wall. Otherwise (obviously) I need to move up to a 10-conducter connection.
I don't see a reason why a common ground would be an issue, but I'm not exactly an audiophile, and my electrical theory is pretty light.
What say the experts?
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Why don't you just use a normal terminal block? They have nice wall-mount units that will give you 3 or 4 pairs (+ and -) of binding posts in a single-gang box size. Put in a double-gang and two of these plates and you've got your hookups. |
That's what I was afraid of, oh well. -- View image here: http://episteme.arstechnica.com/groupee_common/emoticons/icon_frown.gif -- I was hoping to integrate a custom-built connection into my existing plate (keystone with coax and a pair of cat5 connections) and keep things to a single-gang hole. Thanks for the input before I bought something that wouldn't work. |
it can be, if the amplifier is single-ended. I think most home amplifiers are, assuming it's not bridgeable.
it's quite possible that they do actually do this inside the box.
a single-ended output put the signal out on the + terminal and leaves the (-) terminal as the reference ("ground," if you like.) A differential/BTL amp like in most car radios outputs signal on both terminals; the signal on (+) and its inverse on (-).
right, but you can do that just fine with one signal lead and one return/ground. It works for AC mains power, after all -- View image here: http://episteme.arstechnica.com/groupee_common/emoticons/icon_smile.gif -- |
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jz: I see... Zeus, I defer to others here because as I said, I don't know much more than basic/practical experience in this stuff. |
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If it absolutely, positively has to fit in a single-gang box, have you considered a bulk wall plate? |
Use your multimeter to check. |
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One thing I just thought of: even if they can share a common negative lead, you need to size that lead appropriately for the wattage your amps are pushing to the speakers. I've been using 12GA all around for my speakers and each one gets its own pair of copper. This is probably overkill with the cruddy JVC receiver I have, but it is something to keep in mind. If you're trying to run every channel with a shared negative and the wire gauge is too high you could limit your sound output. |
Amps don't 'push' power to the speakers, speakers draw current from the amp. |
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As someone mentioned above, speakers do not use a ground at all. All they are is a positive and negative voltage. The positive voltage makes the magnet go one way, and the negative the other. It may look similar to other home wiring, but it's direct current. You can't just wire all the negative wires together - the speakers won't work properly. |
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I'm going to be nicer than stud would.
They very well can, it depends on the amplifier design.
right. but the amp can tie (-) to "ground" and the audio signal on (+) is then referenced to it.
No way. direct current will make the speaker move one way and stay there. The output of the amplifier is AC, with the "live" (+) and "neutral" (-). Just like mains power. |
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Well, as you see, whether or not (-) is common or "live" depends entirely on the amplifier. Some are single-ended, some are bridged. I'll posit for the sake of argument that *most* 5.1 HT amplifiers are single ended. But that doesn't mean all are, or will be. I have seen high-power high-end stereo amps that are bridged. And you don't know what you (or the next guy) is going to hook up to this thing in the future. |
Ah, but sometimes you have a positive live and a negative live. (And half the time, the "positive live" is actually negative with respect to the "negative live.") Just like certain types of mains power. |
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