Monoblocks, passive bi-amped or passive tri-amped?

I have been doing lots of research, but to no avail. Some writers & speaker builders say you will get sonic benefits from passive bi or tri amping, some say you get nothing. Some say running 2 identical amps will give a 50% increase in power to the speaker…some say zero. IMO it seems logical that an amp pushing 1 driver, as opposed to many, would have an easier load, and thus more headroom, control, speed, detail, etc.

The options I’m considering:
250W D monoblocks
220W D bi-amped
140W A/B tri-amped

I can’t active amp…so need technical info on which of these would sound best, and why. Thanks!
You have the message: There is a lot of bias and misinformation out there. It should tell you that there is NO consensus and, therefore, you are on your own, especially if you ask around here.

Just get a good amp and listen to music. (Is my bias showing?)

It would probably be much easier if you list a certain speaker you want to power.
You'll get detailed responses from members who've already tried it.
Good advice...on both accounts. :-)

I have Mirage OMD-28s. Absolutely love them, and now I need amps that will make them sing. Manufacturer recommends tri-amping, but as you have concensus. Just trying to be better informed for my decision.

Most reviews of the OMD-28 seem to be happy with a single amplifier in the 150wpc range. No one made any suggestion of wishing for more or for more complex arrangements.

What's wrong with your amp?
It would be helpful if you could spell out what you mean by "220W D Biamped". I think you mean either two 220 Watt per channel Stereo amplifiers or possible one amplifier Biwired. Are you really suggesting 3 stereo 140 Watt per channel class AB amplifers saying "triamped"??? Anything is possible.
I do agree that using multiple amplifiers on one speaker -of reasonably high caliber- that more power will be delivered.
I also think that for a recommendation you should find the amplifier that you find most pleasing of suitable power and use that one or that one pair of monoblocks.
I have been doing lots of research, but to no avail.

Kal's first response pretty much answers this. If you really want the answer though, you'll have to experiment to know for sure.
Isn't most of the power demanded by the woofer? So, adding a second amp for the mids and high doesn't really take much load away from the woofer amp.(assuming a three way design) I agree that adding a second identical amp does not really double the usable power available to the speaker. The tweeter amp mostly goes to waste.

What does "passive" mean? To me, passive indicates something that is not powered. Do you mean you are not using an active x-over and letting the amps get all the signal?
I understand there will be no consensus...just looking for any technical info to help in my decision. The reviews I've read, along with people here on audiogon that own them, all say 200 watts per channel minimum, as the dual 8" bass drivers really need power to shine. My current amp (Marantz SR7001) is only 110w per channel (bi-amped). It works fine, and sounds good...but its a receiver, and I want to really setup a nice system with separate processor, and amps.

I'm considering the following (each setup costs around $2,400):
1. 2 class d monoblocks from seymour av, or wyred4sound
2. The bi-amped would likely be a class d wyred4sound 7 channel amp, with fronts bi-amped, and the rest for a 5.1
3. The tri-amped would be 2 of the new Marantz MM7055s. 10 total discrete channels, 6 for the fronts, 1 each for center and surrounds.

I'm just torn as there is so much conflicting information, and I don't want to upgrade this stuff for a long time. Anyways, all info is much appreciated. Even that which I don't want to hear. :-)
Passive bi/tri amp means the amp is NOT getting only the frequencies the speaker driver needs. So each amp is amplifying all the frequencies aand the speaker has to throw away the energy that spaker does not actuall use, by heating up the parts of the crossover, OR, the speaker gets to use all those frequencies it can respond to, even if that messes up the overall frequency responses of the combined drivers.
I cannot personally understand the desire to bi amp or tri amp with the actual difficulties involved. The only way biamping makes sense is to use an active crossover to separate the frequencies before the amp.
@6650c: Yes, passive bi-amped...not active x-over. They get the entire signal, but only have to power part of the drivers, instead of all of them.

The tweeter likely doesn't need it's own amp...probably would be wasted. Good point. It only needs a few watts. The Bass definitely needs the power, and now that you mention it...taking the mid/tweeter away wouldn't do a ton. So the lower powered Marantz is likely out. I am still wondering then on the bi-amped for mid/tweet and bass. I would think that not having to split the power between 3 driver sections would benefit them.

@Elizabeth: I'm gonna make a big assumption don't hurt me. :-) I'm assuming that Mirage built them this way, and recommends multi-amping, as a means to better sound from the speaker. I've read the same of B&W speakers. Maybe it is a bad assumption...I just want to get the best sound out of them.

I look at it like a multi-processor PC...a PC with multiple processors, in general, runs better than a single processing PC. Just an analogy...not trying to get into that debate. Or a 12 cylinder engine as opposed to a 4...12 will perform magnificently comparatively. Does that make sense? Sometime I don't explain well. :-D
Bi-amping, whether you advocate it or not, is one of the largest wastes of Internet bandwidth. It is argued and discussed incessantly and each side of the argument never convinces the other. Even active bi-amping is disputable these days.

In this case, if the OP really believes his speakers are underpowered, I would advise him to buy a good 200wpc amp with the emphasis on good.
Yes the speakers mentioned by the OP (you) do have that option. Some posting is part for the OP and part for the years of searching and reading going to go on long after the OP forgets about the topic.
So I do tend to write a bit more than is needed.
(and i do tend to disparage multi amping. Folks CAN use it well, the trouble is folks who do not know much, wanting to do it. It is NOT easy to do well, and most people are better off just buying a bigger two channel amp straight up. Instead of buying a second amp, finding out it does not work out well, then pissed because they bought TWO amps and are still not happy.
Buy one better amp straight off will usually be much better, unless you are very lucky, or get professional help, or wait until you really know a LOT about it, (and then you would not need to ask a question about it here!)
So IMO you (and most folks) are far better off forgetting about biamping or triamping.
(and I am not disparaging people who do it, just so many ask about it who are in over thier heads about it, when usually it is not very practical. Like you need at least two sets of speaker wires, two or three sets of pre to amp interconnects, and the proper way to handle those if your pre does not have multiple outputs.)
Just trying to be helpful.
Mano -- "I'm assuming that Mirage built them this way". That is unlikely: they would have supplied the crossovers separately had that been the case.

In my passive days, I invariably found that "single amping" with the (sonically) better amp invariably outperformed multi-amping with mediocre amps.

All things considered, you're probably best off using a good quality amplifier spec'd at, or above 100W / 8ohms.

If you opt for a multichannel amp, choose "quality" over higher power output specification... and drive the woofs separately.

IF you opt for a super multichannel amp, with discrete PS for each channel and you have channels to spare after hooking up whatever, you might as well drive the mids separately too.
I'll throw my 2 cents in. I currently have a pair of Mirage OM-9 that I am running in a passive horizontal bi-amp setup and they sound absolutely fantastic this way. I tried an normal stereo setup with them and they sounded ok, but nothing special. I went to the the bi-amp setup and it was like I went out and bought new speakers, the OM-9s just came to life. IMO Mirage designed their crossovers for exactly this type of setup. The amps I was using initally were NAD 2100 now I'm using a NAD 2100 for tweeters and a NAD 216 for the drivers.

I would suggest if you have or maybe can borrow and extra amp, give the bi-amp or tri-amp a try and see what you think. If you run the amps horizontally then they dont all have to be the same amp and will give you an idea if its worth spending the extra on more amps. If you are using different brand/model amps you will have to pay attention to phase as the amps may be out of phase with each other, but that is just a simple matter of flipping the wires around till you get the best sounding combination.
What amp do you have and what speaker, and the speaker configuration and sensitivity, and room size. Typically, the less amplifiers, the more simple the better...but there are exceptions...jallen

What's the dispute with active bi-amping?
Other than simplest signal path arguments, I'd think that the merits of active bi-amping (particularly for those who don't object to crossing in the digital domain) are pretty much unassailable. No?

Mano, are you sure that Mirage "recommends" tri-amping? The manual states that biamping or triamping "CAN further enhance performance" (emphasis added). My instinct would be to interpret "can" as "might," not as "will." And it would seem very conceivable to me that the three sets of connections are provided simply to give the user flexibility in choosing the amplification configuration.

Regarding the question of how much of a power increase passive biamping (or triamping) may provide, in typical situations the power that can be delivered by a single amplifier is limited by voltage swing capability (i.e., by the onset of clipping), not by current capability. Since, as Elizabeth pointed out, passive biamping (or triamping) requires that all of the amplifiers output a voltage swing corresponding to the full range signal, it will not typically result in a significant increase in power capability, compared to the power that could be provided by a single amplifier of the same rating. There may be a small increase in power capability if the design of the amplifiers is such that the reduced current demands on each amplifier in the biamped or triamped configuration result in increased voltage swing capability.

Keep in mind also that if you use different amplifiers for the lows and the mid/hi's, you have to choose amps that have matching gains, or provide external attenuation to match their gains. And be aware that if the amp you choose for the lows is significantly more powerful than the amp you choose for the mid/hi's, much of the power capability of the higher powered amp will be wasted, because since both amps will have to handle the full range signal, the volume level you can achieve will be limited by the clipping point of the lower powered amp.

Certainly passive biamping can SOMETIMES result in improved sonics, if not a significant power increase. But as several others have suggested, my advice would be to buy a single high quality high powered amp, and avoid all of these complications.

-- Al
So thanks for all the great advice. This is what I was looking for. Some solid technical reasons for, or against, multi-amping. It seems like the benefits are minimal at best, and that good quality monoblocks are probably the best way to go to maximize sound quality, control, and output.

I know people have asked about this before, and I appreciate your patience. Thanks a ton!

Now to find the best monoblocks for these bad boys. Oh boy. :-D
I would still recommend you try a bi-amp setup before going out and buying something, technical reasons or otherwise, if your Mirages are anything like mine they loved the bi-amp setup. As I mentioned earlier if you set it up for horizontal bi-amp you don't need two matching amps, just beg, borrow, scrounge, etc to get a couple amps and give it a try.
I am absolutely going to try it. A friend has 4 class D monoblocks that I am gonna borrow to try in both single and bi-amped methods, to see if we can hear any difference. But even he believes that high quality monoblocks, bi-wired, are the better way for me to go. :-)
Please report back with your findings, I would be interested in what the results were.
No report back yet?

I thought I'd weigh in, since I'm vertically passively biamping a very bare-bones system right now. Like others, I lurk the forums looking for firsthand experiences, so I may as well share mine. It just so happened that a couple of two-channel amps and a preamp kind of showed up one day. I got some biampable speakers off of craigslist and started playing.

Anyway, for me, the difference between two-channel with the bridge and four-channel sans-bridge (biamped) was undeniable. I won't say one is better than the other, necessarily. The definition increased a lot, but one person's separation is another loss-of-connection, so . . . Anyway, I liked it so much that I didn't even switch back and forth for detailed testing. I may play around again one day, but I like it for now.

Nothing Special Sony Blu-Ray Player
Lexicon DC-1
Two Rotel RB-980BX ss power amps (2x120 each)
Sony SS M3 two-ways

I've pretty much just assumed that all the untapped power, especially at the tweeters, doesn't really hurt anything. Under-stressed gear often performs better, right? I was surprised to find the volume drop when I switched to a biamp config. I expected the opposite. Turning up the volume, however, I was immensely pleased. All those intangible platitudes came up: separation, forward, lively, etc. I plan to experiment as funds allow, which is to say, gradually. For the sake of this thread, though, I just wanted to add my two cents as someone who has a simple budget setup with just enough gear to try one way and then the other.
Hey thanks for the input @Poprhetor, I haven't had the chance to do much testing yet, as I am a snowbird and away from my main system for the winter. :-(

Before I left, I did try single amping and passive bi-amping from my Marantz. I felt there was a clear improvement when bi-amping. I know that is blasphemy on this forum...but it was a very clear improvement to me. I will definitely bi-amp whenever I have the opportunity.