orangerory

I've had a 6.1 Onkyo Home Theater System for about 2 years (HT-S680). I recently moved into a new home with 4 sets of ceiling speakers. Since the receiver has an A/B speaker set up, I hooked up the "B" input to the ceiling speakers and the surround speakers to the "A" input. The problem is that my receiver keeps shutting off whenever I try to use the ceiling speakers with my iPod. I've tried to use the "B" speakers without the "A" speakers - that doesn't work - still shorts out. And I've hooked up the iPod using the "A" speakers only and that works just fine. So, I think I've narrowed the problem down to the actual ceiling speakers.

I'm just not very technically saavy. I pulled out the old manual and it's not much help. It does say "you can use speakers with an impedance of 8 ohms or higher. If you use the amplifier at high volume levels for a long period of time, the built-in protection circuit may be activated."

Could it be the ceiling speakers are lower than 8 ohms? (I don't even know what that means...). And I also don't have the technical specs on the speakers - they were put in by the builder.

If I bought a separate bridge amplifier like this
http://www.amazon.com/AudioSource-AM...0283377&sr=1-5

and hooked up the "B" speakers to that, would that work?

Patman

Lower impedance (less than 8 ohms) draw more current from the amplifier, so if the amp is "asked" to drive the speakers at a high volume, it'll need more current, current that the amp can't provide "cleanly" and just shuts down the amp to protect it from further damage if you cranked it up more and more.

orangerory

Thanks for the clarification. So - should I just get a new amp to separately power the ceiling speakers? Is there a less-expensive option you know of or would that amazon one work I noted in my first post? I don't want to buy a whole new receiver/speaker set up if I can avoid it.

Spiky

If it shuts off instantly, you probably have a short somewhere. You need to sort that out first.

orangerory

It does play for a little while - it's not instant.

E Unit

May be a shot in the dark, but are you using the same gauge speaker wire for all your speakers? I didn't and it caused incorrect signal flow making it unbalanced, causing that to shut down the receiver. It was an easy fix though.

Spiky

You know, I'm not sure I read that first post correctly. What exactly is the setup right now? Meaning, which speakers to which connections on the receiver, etc? Also, what is your plan for all these speakers? Will they be part of surround, for music, etc?

I'll say this before waiting for your answers:
These kinds of receiver amps are only designed to have 1 speaker per channel, and right now you have 6 amp channels, which suggests no more than 6 speakers. I really don't like the A/B connections on receivers and avoid them. I used to use them, but eventually you will overload the amp and shorten its life.

Brian Shannon

How are these 4 pairs of "B" speakers connected? Please don't say that there are 4 pairs of cables stuck into each terminal.

Are you running "A" and "B" at the same time or seperately?

Spiky is right, sort out the wiring issue first, this has nothing to do with the Ipod. You must check each speaker cable at both ends and make sure they are tight and that no sray wires are touching.

Then I suggest a speaker selector box and try not to run more than two pair at the same time off that receiver.

orangerory

Right now - the set up is the surround speakers that came with the package are attached to the "A" set - as they are supposed to be. There were two sets of red/black connections in the wall for the ceiling speakers with the "twist knobs." When the the speaker subcontractor came to the house (I wasn't home) he installed those into the two "B" inputs on the receiver with basic stereo wire I believe.

I checked them and re-installed them - none were touching. I agree that I don't think it's the iPod since it runs just fine on the "A" speakers. It's only when I also play the "B" speakers - with the iPod or a DVD - that the whole receiver shuts down. So - it is "B" and "A" that is the problem. Although, I also just tried playing "B" without "A" and that also shut down the receiver. It will play for a bit though like I mentioned. And I can turn it back on and it will play again for a little while.

So - it sounds like I need a separate amp probably for the ceiling speakers... Or - a speaker selector. But I'm not sure how those work. Since my surround is for 6 speakers - and there are two more sets I'm adding - do I need an 8 speaker selector?

Spiky

Well, first, A & B are for the front speakers, not surround. It looks like the markings on the receiver are a little weird on this. So I don't know if that is just a semantics issue in your posts or if you have them hooked to the wrong speakers.

A & B use the same amp channels. A left and B left are the same channel, so are A right and B right. You really don't want to use 2 speakers on one channel. The A/B is really meant to be a switcher, not to run both at once. Running two speakers alters the ohms that the amp "sees". So an amp rated for 8ohm speakers sees 4 ohms when you plug in two 8 ohm speakers in a normal fashion. (it's called wiring in parallel) That's how the math works. And that receiver is not made for a constant 4 ohm or less load. Pretty much no sub-$2000 receiver is, although you can find inexpensive power amps that are.

Next, at one point you said you had 8 ceiling speakers. Are these all running through one pair of connections on the wall? (one connection = 1 red/1 black, so I think you mentioned 2 connections) Because if you are hooking in 5 speakers (the 2 from the Onkyo set and 4 each from the ceiling) to each of your front channels....well, that's why it's shutting off. You should NOT do that if you like your amp.

There is another way to wire speakers (called wiring in series), and that can allow more speakers to the same channel, sorta. But definitely you should think about another amp, and not just a 2 channel amp. A speaker switch could do something for you, but then you have to choose one group of speakers or the other.

What is your plan for all these speakers? Is it all part of the surround sound setup? Or are you planning for ambient, "whole house" music?

You should look up what ohm rating your in-ceiling speakers are. And find out how they are wired.

BTW, if you want some indirect proof of A/B hookups being a bad idea, look carefully at any receiver lineup. Somewhere around $500 as you climb through the models, the B speaker connections magically vanish. Wonder why they don't put them on the higher-end models, eh?

orangerory

Thanks, Spiky, for all your help. I admit I'm totally ignorant in all of this which is why I come here to the experts. Here's what the manual says about speaker set B and speaker set A:
I was hoping I could just turn Speaker Set B on (turn A off) and play the iPod through the ceiling speakers to get ambient music in different rooms. I didn't really think it would work as a "surround sound system." There are 2 speakers in the living room ceiling, 2 in the kitchen, 2 outside, and 2 in the master bathroom - but there are only 2 sets of speaker connections coming out of the wall. So, I'm assuming 4 speakers are on one and 4 are on the other. Each set has a separate volume control in the wall though.

Do you have a suggestion on an inexpensive amp to use to run the ceiling speakers? I only need it for that.

I need to contact the subcontractor to see the ohm rating of the speakers and find out how they are wired. I have no idea.

Spiky

Yeah, definitely find out the installation details before purchasing anything else. And, I'd see about getting them to fix what is apparently wrong.

Amps seem to come in 1, 2, 5, 6, 7 channels mostly. The 5, 6, and 7 are mostly surround receivers, but they can be used as stereo-only. Most have a mode called All-Channel Stereo, which simply does stereo output from all speakers. Or you might just want it in Mono mode since the ceiling speakers probably aren't going to give good stereo separation, anyway.

So, a few options:

1) You could look for a 6.1 surround receiver to power the indoor speakers all at once. I'm not sure what you mean by inexpensive, but for the low volumes I presume you would want for ambient music, almost any receiver should do. They start new around $200 for 5.1 models, you might be able to find a 5.1 or 6.1 below $150 used or on clearance. That would cover the indoor speakers, and you could use a switch or A/B hookups (wired correctly!) for the outdoor. I'm guessing the outdoors would be the least likely to need to be on at the same time.

2) A midrange 6 channel power amp designed for custom installation (CI) of whole house audio is probably going to start around $800 new. Or a few 2 channel power amps. CI would be ideal of course, but that's a different price range. If you feel like spending something, check out Adcom for an amp. Very nice sound.

3) That amp you linked in post #1 is a nice price, but you'd either need a switch to run one room at a time (with a speaker switcher) or get a couple of them to run all your rooms. Still, $92 x1 (or even x4) plus some other accessories is pretty good price range for power amps and whole house audio. AudioSource is a low-end CI company, not bad I believe. Surely better than most low-end surround receivers.

SpeaksUp

It is possible to use more than one speaker on an amplifier channel, but you must be careful when doing so because if not set up properly you can damage your amplifier and/or your speakers. This has to do with resistance measured in Ohms. An amplifier will have documentation describing the power output of the unit at varying levels of resistance or Ohms. The Ohm rating of the speakers and the method of wiring determine the resistance in the channel. There are two different methods for wiring multiple speakers to one channel.

SERIAL: This is when you connect a wire from the positive lead on the amplifier to the positive lead on speaker 1. Then you connect a wire from the negative lead from speaker 1 to the positive lead on speaker 2. Finally, you connect a wire from the negative lead on speaker 2 back to the negative lead on the amplifier. The whole thing forms a loop. With this method the resistance increases with each speaker you add. Two 4 Ohm speakers wired this way create 8 Ohms of resistance. The result is basically as follows. If you have a 50 watt channel on the amplifier, the power is divided between the speakers, 25 watts to each. Keep in mind that there is a limit to the level of resistance an amp can handle. In most cases you don't want to exceed 8 Ohms on a channel so generally no more than 2 speakers on one channel.

PARALLEL: This is when you wire the positive and negative leads from each speaker directly back to the positive and negative leads of the same channel on the amplifier. Interestingly, this has the opposite effect and actually decreases resistance in the channel. Two 4 Ohm speakers wired this way will lower the resistance in the channel to 2 Ohms. The result is basically as follows. If you have a 50 watt channel, each speaker receives 50 watts, essentially doubling the power output. Again, keep in mind that not all amplifiers are built to successfully do this, so read the documentation for your amplifier. Adding too many speakers to a channel can lower the resistance to a dangerous level that could damage your speakers and/or your amplifier.

When wiring speakers in parallel you can see the benefit of starting out with speakers of higher resistance (such as 8 Ohm speakers over 4 Ohm speakers) so that you don't lower the resistance in the channel too much by adding speakers. On the other hand, if you only want to use four 8 Ohm speakers in your system, you may be better off to wire them in parallel to only 2 channels of your amp, rather than one speaker on each of 4 channels.

Superman07

Talk about a bump. OP did you figure this out? What happens if you hook the wall plate (ceiling speakers) into the A set and have nothing in B?