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Best way to use 7 mono amps on my 5.1 system

post #1 of 11
3/20/12 at 4:19pm
Thread Starter 
I just purchased seven Marantz MA6100 mono block amps and should have them by next Tuesday. Each amp puts out 125watts at 8ohms, 160watts at 4 ohms, and two can be bridged for 360watts at 8 ohms (not sure what they can do at 4 ohms or if that is even safe with these). I'm excited about going with separates, but was curious on how to implement them to get the best sound out of my system.

I am using the following speakers -

Onix Rocket RS550 MKII mains
Onix Rocket RSC100 MKII center
Onix Rocket RSS300 surrounds
Emotiva xref-10, which is self-powered

I am currently driving the five Rockets with a Denon 3805 which claims 125watts per channel. It sounds pretty good, but I know that receiver amps are usually shy of their power ratings with all channels driven.

My question is, how should I set up the mono blocks?

A - Use a single amp to power each speaker and save the other two for a DYI sub in the future.

B - Bridge four amps to power the mains and use the remaining three to power the center and two surrounds.

C - Bridge four amps to power the mains, two for the center and let the receiver power the surrounds... leaving one amp left over as a pretty paper weight.

D - Some other combination.

Thanks for the input!
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post #2 of 11
3/20/12 at 6:39pm
Use them to actively biamp the front three channels and let the denon power the rears and any future surround additions. Without going through that quite substantial effort to mod your current system, I don't see how they will realistically add anything to your current setup other than perhaps a smidge of extra headroom if you bridge for the mains or front three.
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post #3 of 11
3/21/12 at 3:17pm
If 'twas me, I would hook 3 of the Marantz amplifers to the front and center channels, and let the receiver drive the RSS300 speakers. The speakers are rated as 6 ohm speakers and have good sensitivity, so it would be kind of silly to do any bridging; totally unnecessary. Those amplifiers apparently put out around 140 watts at 6 ohms, and that is certainly all you need.

Bridging the amplifiers would only increase the possibility that you might burn out the speakers by overheating them. Of course that is another upgrade path...new speakers!

The reason receivers typically may have problems driving all 5 at high power levels is not that the individual amplifiers have a problem putting out 125 watts, it is because the Power Supply does not have enough total power available for all of them to be driven hard at once. The power supply might have only 450 watts available for all 5 amplifiers, for example, and that is 90 watts for each channel (which isn't all that bad...).

Since the front 3 will be driven by the Marantz amplifiers and the sub is self-powered, the receiver will be loafing just driving those remaining channels. Everything should have loads of power that way; any more would be a waste of time.

That should give you tons of power for everything, and four amplifiers left over for doorstops or another project...lol. Maybe you can return 4 of them and get a better subwoofer.

Personally, I would have just bought 3 amplifiers and spent $1000 on a top-quality subwoofer like the Rythmic F12SE. That would have made a lot of sense.






Quote:
Originally Posted by austindub View Post

I just purchased seven Marantz MA6100 mono block amps and should have them by next Tuesday. Each amp puts out 125watts at 8ohms, 160watts at 4 ohms, and two can be bridged for 360watts at 8 ohms (not sure what they can do at 4 ohms or if that is even safe with these). I'm excited about going with separates, but was curious on how to implement them to get the best sound out of my system.

I am using the following speakers -

Onix Rocket RS550 MKII mains
Onix Rocket RSC100 MKII center
Onix Rocket RSS300 surrounds
Emotiva xref-10, which is self-powered

I am currently driving the five Rockets with a Denon 3805 which claims 125watts per channel. It sounds pretty good, but I know that receiver amps are usually shy of their power ratings with all channels driven.

My question is, how should I set up the mono blocks?

A - Use a single amp to power each speaker and save the other two for a DYI sub in the future.

B - Bridge four amps to power the mains and use the remaining three to power the center and two surrounds.

C - Bridge four amps to power the mains, two for the center and let the receiver power the surrounds... leaving one amp left over as a pretty paper weight.

D - Some other combination.

Thanks for the input!
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post #4 of 11
3/21/12 at 4:29pm
Quote:
Originally Posted by Bigus View Post

Use them to actively biamp the front three channels and let the denon power the rears and any future surround additions. Without going through that quite substantial effort to mod your current system, I don't see how they will realistically add anything to your current setup other than perhaps a smidge of extra headroom if you bridge for the mains or front three.

I agree with this. It probably isn't going to be much of an upgrade at all, but might be lots of fun to configure!

I wouldn't bother with bridging, won't do a whole lot for you. Also wouldn't worry about ACD specs either; doesn't mean a whole lot for you.
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post #5 of 11
3/21/12 at 5:51pm
Thread Starter 
Thanks for the advice Commsysman, that's the route I think I will go.

You are probably right when you said three amps are all I really needed, but at $75 a pop I just couldn't pass them up.

I also agree with the subwoofer comment, and am now thinking I will use the remaining 4 amps to power a couple of DIY subs, most likely 12's in ported sonotube enclosures tuned pretty low. I think the 360 watts going to each will be more than enough low end if I pick the right drivers and size/build the enclosures well. I'm also contemplating a dual voice coil 15 inch sub but have to do a bit more research on the topic of two moderately powered/priced 12's vs. one very well driven and higher quality 15 inch sub.
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post #6 of 11
3/21/12 at 5:54pm
Thread Starter 
Quote:
Originally Posted by walbert View Post

I agree with this. It probably isn't going to be much of an upgrade at all, but might be lots of fun to configure!

I wouldn't bother with bridging, won't do a whole lot for you. Also wouldn't worry about ACD specs either; doesn't mean a whole lot for you.

That is probably what I would have done, but the Rockets aren't set up for bi-amping, as they only have a single set of terminals.
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post #7 of 11
3/21/12 at 5:56pm
Quote:
Originally Posted by austindub View Post

That is probably what I would have done, but the Rockets aren't set up for bi-amping, as they only have a single set of terminals.

Oh no, the "bi-amping" feature that many speakers come with is not what was meant by "active bi-amping" - that's passive, and not worth wasting time on. What was meant was having frequency dividers between the pre-outs and the amplifiers, and then tying them into the speakers sans crossovers; it's a lot of work to do right.

Like I said, this whole setup won't do a lot for you.
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post #8 of 11
3/21/12 at 6:44pm
Thread Starter 
Quote:
Originally Posted by walbert View Post

Oh no, the "bi-amping" feature that many speakers come with is not what was meant by "active bi-amping" - that's passive, and not worth wasting time on. What was meant was having frequency dividers between the pre-outs and the amplifiers, and then tying them into the speakers sans crossovers; it's a lot of work to do right.

Like I said, this whole setup won't do a lot for you.

Hmmm, ya learn something new everyday! I hadn't heard of active bi-amping before, but to be perfectly honest, I'd prefer a little more simplicity in my system. Or do I? Haha, one thing is for sure - these little amps sure give me a lot of options
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post #9 of 11
3/21/12 at 7:44pm
^ Until I started reading audio forums like this, I had never heard of "passive" bi-amping...

By far the easiest thing is to use the amps one per speaker and save the leftovers, or as commsysman said use them on the front three and have more toys for future projects.
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post #10 of 11
3/22/12 at 10:51am
$75 each; where's the line form? ROFL

I see.... Sounds like fun.



Quote:
Originally Posted by austindub View Post

Thanks for the advice Commsysman, that's the route I think I will go.

You are probably right when you said three amps are all I really needed, but at $75 a pop I just couldn't pass them up.

I also agree with the subwoofer comment, and am now thinking I will use the remaining 4 amps to power a couple of DIY subs, most likely 12's in ported sonotube enclosures tuned pretty low. I think the 360 watts going to each will be more than enough low end if I pick the right drivers and size/build the enclosures well. I'm also contemplating a dual voice coil 15 inch sub but have to do a bit more research on the topic of two moderately powered/priced 12's vs. one very well driven and higher quality 15 inch sub.
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post #11 of 11
3/22/12 at 11:39am
$75 each? Not bad!

Use them for the front channels... or not. Won't matter. Would be more beneficial and fun to use them on some DIY sub projects, or to expand the number of channels maybe in the future. Or power additional zones or distributed whole house audio. Or if you really get bored one day and want to actually improve the sound quality of your current speakers, explore then active biamping option mentioned.
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