Can I rig a home theater amp to run in wall speakers?

My friend has an older rotel 5 channel power amp that he used to use with a rotel home theater preamp for a home theater.  Now he has a modern marantz home theater receiver that handles the home theater.  His new house has 8 in wall speakers distributed throughout the house.  He has a sonance speaker distribution box.  I advised him to use the rotel power amp to drive the speakers in the sonance box, using the pre-outs from the Marantz.  The current set up can only make use of 2 channels, due to the 2 pre-outs from the marantz, and thus, 3 of the channels in the Rotel power amp are going unused.  I'd prefer to put one pair of in walls at least on its own channels in the rotel, and minimize the quantity of speakers in the sonance box.

any thoughts?
If the Sonance "speaker box" you refer to is their 260 x 3 amp, don't sell it short.  It will do fine with in-walls.

Regarding the 3 unused channels, you may have to use some 1-into-2 rca splitter cables on the Marantz pre-outs.

I currently have the pre-out on my Marantz going to the Sonance to power 3 pairs of in-walls.  Kitchen, patio, and garage.
The sonance box in question is a speaker distribution box, not an amp.  

Do do the RCA splitters have any major negative effect?

" His new house has 8 in wall speakers distributed throughout the house."

8 mono speakers, 4 pair stereo. or 8 pair stereo? 

"using the pre-outs from the Marantz"

Stereo or A/V, and if A/V, main preout or zone 2 preout?

Any way to control volume of individual rooms?

"Do the RCA splitters have any major negative effect?"

I would be more concerned about the speaker distribution box. Some have as much as a 50% power loss. Do you know the model number of this box?

tls49,  thanks for the help!

he has 1 pair of outdoor speakers, 1 pair in living room, 1 pair in family room, a single speaker in kitchen, and a single speaker in a hallway (which is a low priority).

On the Marantz HT Receiver, he is using the main speaker outputs for his home theater, and then the stereo pre-outs to the Rotel amp.  Is there a better way to feed the Rotel here?  What is the A/V out?

no way to control volume in each zone

At this point, we are shooting for a minimally functional system!  I advised him that a great way to do this properly would be to purchase a Sonos Connect Amp to each pair of speakers for excellent control, but that is an expense he does not want to incur at the moment.  So, to use what he has will have to do for now.  Is there a way to disable the speakers on the Marantz HT Receiver while the pre-outs send signal to the other speakers? 
Hi Mark,

Happy to try and help. Retired now but worked in the A/V industry many years with experience in HT and distributed audio. I have some ideas but need more info to see if there is a way to use what he has and make it function correctly, safely, and be user friendly.

Do you know if the single speakers are what is called a summing speaker, plays both channels with L&R connection on the single speaker? One way to find out is look at the selector box to see if that position has both channels connected, assuming a 6-way selector box. If it's a 4-way box then he may have L speaker in one location and the R speaker in the other. Model number of the selector box would be great or does it have knobs and switches or just switches and how many, 4 or 6?

Can you get me the model number of the Marantz? Should be close to the name on front, in small print.

I know I'm asking for detailed info, but without it is like shooting at a target blindfolded. Get what you can and we will kept working toward a solution.

OK, with the SS6, I'll assume the single speakers are summing speakers as I described above, and he is using 5 of the push button switches, one for each location, 3 rooms, hallway, and outdoors. When playing multiple locations, which one could use a little more volume?

That is hard to say, though I would guess the outdoor speakers will need more amplifier juice, by nature of them being outside.  

Looks like they may not be summing speakers, he sent a photo and 3 pairs are connected as usual, but one line speaker only is connected to one channel. 

Thank you for the help!  

Outdoor speakers would be my guess as well. On the SS6, 3 positions are connected normal, L&R. Then 2 positions, hallway and kitchen, have only one channel connected. Correct?

I do have a couple of ideas, but really need to know the model number of the Marantz to know it's capabilities.

That Marantz has Zone 2 output, as long as you are using 5.1, not 7.1. You can use Zone 2 pre-outs to feed the Rotel to drive the whole house speakers. You can connect all the speakers to the SS-6 and the Rotel will probably have enough power to drive them, although I would check to see if it can handle the 5 ohm load from the SS-6. In-wall and outdoor speakers are usually pretty efficient so the Rotel should be OK if it has 100W output. You will probably need analog inputs to use Zone 2.  Also, check to see if the speakers are all 8 ohm. That many 4 ohm speakers would definitely be a problem

You can certainly use a simple RCA splitter to separate the signal in order to use 4 channels of the Rotel. There can be some minor impedance issues between the Marantz and the Rotel doing that, but the effect is pretty low and should not be an issue for whole house speakers.

The biggest problem will be volume control. You are almost certainty going to want to be able to change volume for different rooms. You could use impedance balanced speaker selector boxes like the Niles SSVC-6. Make sure such a box has impedance matching. For example, the Monoprice ones do not, I believe.

So, I would check the speaker impedances, the impedance the Rotel will handle and think about volume control.

Thanks Mark, and I have taken a look at the manual. Hopefully I can clarify some of the info provided by "dtc".

Zone 2 - When using Zone 2 speaker output, 7.1 is not an option for HT, however when only using Zone 2 pre-outs, you can do 7.1 HT. These Zone 2 pre-outs can drive 2 channels of the Rotel amp, but not directly. A passive VC will need to be inserted between the Zone 2 pre-outs and the Rotel amp. The manual implies that the Zone 2 pre-out is a fixed output, so depending on its level, it could overdrive the amp. It is true that Zone 2 will only play sources from analog inputs or the tuner. Any sources from HDMI or digital inputs are not available for Zone 2.

Using the stereo (L&R) preout - I believe this is the current setup. It will be necessary to select stereo only on the SR5006, no surround. Then the main VC will affect the volume of all speakers. "Is there a way to disable the speakers on the Marantz HT Receiver while the pre-outs send signal to the other speakers?" Yes, assuming there are no speakers connected to the speaker B outputs. The "Speaker A/B" switch on the remote will toggle, (A) - (B) - (A+B), then back to A. Set this to "B", then the HT main speakers will not play. Since stereo only was selected on the receiver, center and surrounds will not be playing as well. Also, if stereo only is not selected, these preouts will only output the L&R of a 5.1 signal, and likely sound poor on the in-wall speakers .

Trying to use more than 2 channels of the Rotel amp - possible, but a few ways to do this. Rather than list all the scenarios, is it possible to get a little info on what sources are used for the distributed audio, analog, digital, or both? For example, 2 channels in addition to how things are currently setup could be driven from Zone 2 pre-outs as described above, but those speakers would only play an analog source. RCA splitters could also be used, but depending on the arrangement, additional devices may be necessary. 

If, in fact, one of the speakers is truly mono, then you might want to think about making everything mono.    Wall and ceiling speakers and outdoor speakers seldom benefit from being stereo and mono is often better since there is seldom a "sweet spot". You can do this with simple Y cables - not elegant and I would not do it for critical listening, but it is often a good option for whole house music.
Thanks guys.  The source is an Apple TV via HDMI to the Marantz.  The Apple TV serves up a large collection of music on hard drive.  My friend is not an audiophile, he just likes music.  He is not even a gear enthusiast, nor one to obsess over the quality.  Of course, he appreciates nice sound, but there you have it.

TLS49, I think we are on the right track with the stereo output, taking advantage of the HDMI input on the Marantz.  So, he chooses stereo mode, sets the speakers to speakers B only, and his in-wall system is doing its job.  Sounds great.  

This is a relatively temporary band aid situation.  I think a stack of Sonos Connect Amps (or similar) would serve him better, but this solution may remain for a while, so we'd like to get the most out of it.

I really like the idea of using all 5 amp channels on the Rotel.  It just makes sense to have a speaker than can get its own 100 watt channel to take advantage of that, as well as to reduce the load and loss on the sonance box.  I think the outdoor pair can get 2 Rotel channels, perhaps the kitchen gets one (in mono?) and the sonance box gets a pair, now with only 2 pairs of speakers, reducing the load!

What do you think of this product?

How do we get the kitchen in mono?  One of these?

Ah heck.  I just realized there is a flaw in that plan.  He'd need to be able to turn off the outdoor speakers.  Cant be jamming in the living room, not using the outside area, and pissing off the neighbors.

Ok, please advise.


dtc, I agree with the idea of a mono due to no "sweet spot", however, IMHO, I would not just use a simple "Y" cable on the L&R pre-outs of the SR5006, main or Zone 2. This just shorts the 2 channels together, and may cause adverse effects. It would be best to use some type of a stereo to mono converter, even something as simple as a "Y" with resistors inline on the signal connections.

Here is an option that is very simple to use 4 channels of the Rotel.

(Example only, quality should be same as interconnects used.) Use this type of Y adapter on each (L&R) of the SR5006’s main pre-outs.

This gives you 2 pair of stereo RCA outputs with a female connection. That way, you can use normal interconnects for everything. (The splitter box from the link in your post would work also, just using 2 of its 4 outputs.) Use one of the pairs for 2 channels on the Rotel to the SS6 like the current setup. Then connect the other pair to the input of a passive volume control,

cheap passive VC -

better passive VC - only one input would be used

with the passive VC output driving 2 more channels of the Rotel to the outdoor speakers. Indoor speakers will play as they do now, but outdoor speakers will be able to play louder due to the increase in available power not being connected to the SS6. The main volume on the SR5006 will still affect all speakers, but the passive VC on the outdoor speakers can be turned down or completely off allowing a desired volume inside. Keep in mind that the passive VC only attenuates, so maximum volume of outdoors will still be determined by the SR5006 volume control. No doubt the outdoor speakers will be able to play as loud or louder than they do now with a given indoor volume, but more important, this solves the problem to turn outdoor down or off.

Now to try and use that 5th channel on the Rotel gets a little more complex. You would need the splitter box from your link, 2 passive VC’s, and a stereo to mono converter like this,

I do not advise using a simple Y adapter to convert stereo to mono. See previous post.

I would definitely use 4 channels of the Rotel as this creates more flexibility between indoor and outdoor speakers, but not sure about trying to use that 5th channel. Is there a major problem with volumes between the indoor speakers? Something too loud, not loud enough? And if so, what?

TLS49, this looks like a very sound plan.  I will be happy to walk my friend through this!  Thank you both for the input.  I will be sure to tell what he ends up doing.
I was typing while you posted, but here is some additional input. Sounds like you have a solid direction in which to go.

My original post :

I agree that a resistive stereo to mono adapter is better than a y cable, although I find that in most situations the y cables are fine for this type of application. The one suggested should be fine.
And y cables can certainly be used to split out the signal into two signals.

I suggested using zone 2 because it can be independent of the main output. However, to use it you will need analog outs from the Apple TV, which I do not think it has. So, zone 2 is out if the source does not have analog outs.

So, that leaves the stereo pre-outs with volume controls(s) and Y cables and maybe a stereo mono converter. Several small parts, but it should work.

My guess is that the Rotel with handle a 4 ohm load (assuming that is what the SS-6 presents in Protect mode), but you need to check that first. Do you know the model?

If the Rotel handles 4 ohms, before going much further I would suggest hooking up the the Rotel to the 5006, and feeding that into the SS-6 with all the speakers connected. That will give you an idea of whether you have enough power to drive everything and whether you will need additional volume controls for different rooms and for outside.