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Discussion Starter · #1 ·
I am setting up a multi-zone speaker system for a home with 6 Zones. Each zone has two ceiling speakers hooked up to impedance control volume knobs, and they are all wired to a location near my home receiver. I currently have two receivers, an Onkyo TX-SR606 for controlling the surround sound of the main room, and the Sony receiver it is replacing. My budget is very limited, and I can't afford a multi-hundred $$ Multi-zone amplified switch. I do already own an impedance-balancing selector switch (passive, no amplification), but the sound was too soft from the speakers when all was set up.


So, my questions are:


1) How much power is required to run ~12 speakers when they are all hooked up to an impedance-balanced selector switch? Does it need 100W per channel (1200W), or is 100W just a peak value?


2) I'm fairly sure that the Zone 2 on my Onkyo receiver is incapable of providing enough power to all the speakers from the single Zone 2 connection. Is there some sort of single-channel amplifier I can use from the Zone 2 signal of my receiver to the switch that would satisfy the load? Maybe just a 1 channel 1000W amplifier.


3) I have no use for my old receiver (Surround Sound 5.1). If I hook up the Zone 2 signal from my new receiver to the input of my old receiver, can I wire up the 6 speakers from the old receiver (wired in parallel) to the single input on the selector box? It would be as if I were using the old receiver as an amp. My thoughts are that the weak Zone 2 signal from the new amp will be processed and amplified to a roughly 1000W signal into the selector switch, which I can then send to the speakers. Does this make sense?


Since I have volume control knobs in each room already, I wouldn't need any volume control from the receiver.


This has been driving me crazy thinking about, and I'm not completely sure how the impedance is affected by using the selector switch. Will the receiver just see 8 Ohms, or will it be less? Any help would be greatly appreciated.
 

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You need a VOM to really be able to see what is going on here.

12 speakers from one stereo AVR amp section does seem a bit much though.


Hard to make suggestions, without the complete picture, but I think you are going to have to purchase some more equipment here.
 

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First, you need to read the manual for the impedance matching box. Ideally, it would provide an 8 ohm load no matter what, but I can't say for sure. Read the manual and/or ask the company.


You would need very little power for background music. A few watts per speaker. A receiver might be able to power up 12 speakers for background music if there's no impedance issues.


If you want to go loud, you may need a separate amplifier.


p.s. If your receiver goes into protection mode by shutting off, you know you have issues
 

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Impedance matching switcher can work but don't use it with impedance matching volume controls. I'm not sure what type your volume controls are? Use the switcher with the old receiver's front 2 channels driving it.


If the receiver is pushed too hard it will either go into protect mode and shut off, overheat possibly causing a fire, or your sound will become distorted. Not all receivers have protect modes or good ones! Most will go into protect mode if shorted but not all do so if overdriven. We had a client that ran multiple pair of speakers off of a coincendentally a Sony receiver and caught fire and torched that wall and caused significant smoke damage to that room. Luckily the fire dept stopped it before he lost the whole house!


If your switch is rated at 100W per channel that is the max your amplifier can feed into it. Not 100W per speaker. I wouldn't parallel your speakers into the receiver, that will definitely overload the receiver causing it to go into protect mode or overheat and burn up.


Bob
 

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Discussion Starter · #5 ·
So after thinking about this problem a lot last week, I finally headed over to my parents' house this weekend and got everything set up. I did get a setup that I was very satisfied with, but it is different than the one I intended, so I will relay my experience for anyone who may be having a similar problem.


First Try

First, here's what I intended to do: All of my 7 'zones' have an independent volume control knob in each room. I wanted to find out if I could set up all 5 speaker channels on the old receiver to Mono sound and output 3 of them directly to a zone, and then pair up the other two channels with 2 zones in series each. I measured the impedance of each zone to be 5.5 ohms (lower than the 8 ohm recommendation, but not so low it put the system into PROTECT mode. For the ones in series, it would only be ~11 ohms to the system. There were a few reasons why this setup didn't work.
  1. For the channels lined up in series, something about the configuration didn't permit the volume control knobs to work properly. I knew how to properly line the speakers up [Receiver +]->[Speaker 1 +], [Speaker 1 -]->[Speaker 2+], [Speaker 2 -] ->[Receiver -]. I even tried every combination of speaker + to - and always had the same problem. When the knob was off, the speaker was off. But, instead of getting louder as the knob was turned up, it would either start loud and get quieter, or increase to some level then get quieter. It was not acceptable. So I think this setup would have worked if there were two speakers in series with one volume control knob, two knobs didn't work.
  2. It took a long time to figure out how to get the receiver set to Stereo mode instead of one of the Surround Sound settings. Even after getting the setting correct, the speakers on the back channel wouldn't output the same as the frond - only sound effects, but not the dialog of the show. So, somehow the receiver was able to convert the Stereo input into a surround sound mode. In addition, the speakers connected to the front right and front left channels sometimes played differently (depending on the input). These problems weren't as significant in Radio mode, but were very apparent when playing any video input.


So all this troubleshooting took a few hours and was quite annoying to figure out. I tried several more setups, but there were always compromises (And I can get kind of obsessive about problems I can't figure out). Finally, I did find a solution the worked very well.

The Solution

Since I still had the 6-zone speaker selector box, I was able to use it in the setup. Since each zone is connected to only one volume control knob, stereo sound wasn't going to work because I could only get Left OR Right side sound in each room, not both. After playing around with the setting on the receiver, I was able to connect the CENTER output from the receiver to the Left side of the selector box only (I left the right side empty). I then connected each of the 6 zones to the corresponding Left channel for one of the zone outputs on the box (again, leaving the right side empty). I was able to leave off one channel, since it likely wouldn't be used anyway. So each of the 6 zones were connected to the CENTER signal on the receiver through the impedance-balanced selector box.


I highly recommend that anyone attempting this makes sure they use an impudence-balanced zone selector (~$50) and NOT a regular speaker switch. Also, make sure the protection button on the selector switch is always on to avid harming the receiver.


To my surprise, the single channel was able to drive all the speakers with pretty loud volume - loud enough that with all of them turned on simultaneously, I only set the receiver volume to 55 (MAX is 75), and I didn't need to turn the individual knobs all the way up either. Since the volume was connected to the Center channel, I didn't have to worry about only hearing the Left or the Right side, since I'm pretty sure the Center channel or a Stereo input must be a blend of both. When trying a CD, the quality was very good, and the volume was high. Adding and removing speakers (either by turning of a zone, or disconnecting the wires to a zone) had no effect on the volume output to the other speakers.


So my final setup used two receivers: the new living room surround sound receiver, and an older 5X100W surround sound receiver. The living room receiver sends out a signal (un-powered) to the AUX input of the old receiver. The old receiver is setup to output to all 5 speakers, but most importantly, the Center speaker. The Center speaker is output to the 6-zone Impedance-balanced speaker selector box on one channel. Each of the zones are hooked up to the corresponding zone channel. All the zones are set to ON (since the speakers can be turned off individually at the volume control knob). The old receiver is set to an appropriate level, and the individual volume control knobs can adjust the volume in each room. The volume and quality of the sound to each room was quite good, even though 12 speakers are basically being run off of a single 100W channel. Please PM me if you have any questions about a similar setup you are working on, and have some questions about what I've written here. Good Luck.
 
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