Bi-amping question, thoughts needed.

**Moonfly** · **08-03-08, 09:16 AM**

I currently have an Onkyo 875 and I'm running with a pair of Monitor Audio R270's up front. Later this year I want to upgrade the front 2, switch the MA's to the rear and get a proper pair of floorstanders for the front. My aim is to maximize music performance as I'm a 50/50 music HT person. I'm going to check out the SVS MTS towers when they become available to demo (I'm in the UK BTW).

Now these speakers are Bi amp-able and so is the matching center so I have a couple of questions. The 875 cant bi-amp 6 Ohm speakers, and cant do the center. If i'm going to bi-amp then I want the front three the same.

I'm thinking I can get the best musically by getting a separate amp for the front 2/3, would this be worth it. Can I get a separate power amp that is capable of powering the front 3 in bi-amp mode and would I notice the improvements. How about adding a power amp for the front 3 thats not bi-amped and would I need to match the amp to my Onkyo or would any amp do.

Theres is one other option for me. I can bridge the 875 to deliver more power to the towers and just stick with running of the 875. Obviously this means I cant do the same with the center so I'm not sure thats the way forward. Would anyone here consider running by bridging the towers but not the center, how do you think that would affect movie performance.

Cheers for all your thoughts.

**nova** · **08-03-08, 11:28 AM**

Personally, I'm not a big fan of bi-amping using a receivers "extra" amps

I did it with my Denon and RBH 1266-SE, it was entertaining for a bit, I could not hear any difference from the "bi-amp", bit I could boost the gain on the 12" woofers, kinda a fun for a while. I see no benefit to bi-amping in this manner. Now if you want to bi-amp with active crossovers and separate amps,... that may be another story. I have no experience with that but I'm sure others have and will soon jump in.

I'd just suggest good, quality amps and some good speakers. Skip the bi-amp unless you are going to go all out.

**tonyvdb** · **08-03-08, 04:18 PM**

Bi-amping speakers is not necessary as it yields little to no difference in sound quality unless you get into the really expensive speakers over $5000 and involves allot of equipment to do it right.
You need external amps and crossovers along with some EQ's to really hear a difference. Its just not worth it in my opinion.
I have bi-amp able speakers on both my two channel system and my theater system and have tried it and I could not hear any difference.
Your best option is to get an external amp to run your mains using it.

**JCD** · **08-04-08, 04:16 PM**

I think there is plenty of evidence and anecdotes that state bi-amping a speaker does not increase the performance of the speaker.

All of that changes if you tell me you're also going to go with an active crossover.

JCD

**Moonfly** · **08-05-08, 06:25 AM**

Well at this point I would have to ask you to explain an active crossover to me

**DougMac** · **08-05-08, 09:04 AM**

Quote:

Moonfly wrote:

Well at this point I would have to ask you to explain an active crossover to me

Here you go: http://en.wikipedia.org/wiki/Audio_crossover

That's a pretty good explanation. Basically, there is no crossover circuitry in the speaker, the connections go directly to each speaker component. There is a separate amplifier for each driver. The signal supplied to the amplifier comes from an active crossover unit, which provides signals in the optimal frequency range for the driver. Digital crossovers not only allow you to choose the crossover frequency and slope, they also allow you to adjust delay and phase.

Purchasing the needed crossovers, amplifiers and either building or purchasing speakers which can be bi-amped can get expensive for just 2 channel. Setting up a 7.1 system could take a significant invsestment. In order to fully exploit the advantages of a bi-amped system I think you'd need to also consider room treatment and making sure the audio chain consisted of TOTL components.

Considering the quality of my ears and the size of my wallet, the law of diminishing returns kicks in very early for me! FWIW, my mains (Ascend 340's) allow for bi-wiring, hooking different amps to each side of the internal crossover. My amp allows me to dedicate the extra two amps normally used for remote listening to be used for bi-wire mains. The only advantage would come from driving the mains with four amps instead of two, giving a little more headroom. I think I can hear a slight improvement, but I imagine it's mostly placebo effect.
Doug

**Moonfly** · **08-05-08, 10:39 AM**

Cheers. My case is more that the speakers I am looking at as part of an upgrade are bi-wirable. Taking all factors into account, including running extra wire all over my partners living room,I think I'm going to be best just adding a 2 channel amp so music is as good as it can be (although ive seen it said that even this isnt worth it with the Onkyo 875 as its analogue stage isnt that good) and leaving everything else to the Onkyo.

I'm seeing alot more people saying its not really worth it to bi-amp than those saying it is.

**MatrixDweller** · **08-05-08, 10:52 AM**

I've tried bi-wiring and bi-amping my Klipsch RB81's and could not hear any difference what so ever. I wasn't using active cross overs or anything, but I'm sure if I was the effect would be minimal. The cost of the added equipment would be much better spent on better speakers or a better receiver to begin with.

**tonyvdb** · **08-05-08, 11:59 AM**

Quote:

Moonfly wrote:

the Onkyo 875 as its analogue stage isnt that good) and leaving everything else to the Onkyo.

This is simply not true, The Onkyo's analogue section is top notch. The only way your going to get better is going Tube amp or spending three times as much on a receiver or high end pre/pro setup.

**darrellh44** · **08-05-08, 02:00 PM**

Quote:

tonyvdb wrote:

This is simply not true, The Onkyo's analogue section is top notch. The only way your going to get better is going Tube amp or spending three times as much on a receiver or high end pre/pro setup.

He may mean the analog input stage. They are not as good as using the digital inputs for the new Onkyo/Integra AVRs/prepros.

-Darrell

**Moonfly** · **08-05-08, 04:31 PM**

Quote:

darrellh44 wrote:

He may mean the analog input stage. They are not as good as using the digital inputs for the new Onkyo/Integra AVRs/prepros.

-Darrell

The comment was in reference to using the Onkyo's pre-outs to control another power amp which would then be used to power either the front 2 or 3 speakers. Another forum I go on had a member that has tried using a separate amp with his 875. His comments where that he couldn't tell any difference although he wasn't using proper floor standers as I will. Apparently a comment was made by another member that the issue was that the analogue stage in the 875 wasn't good enough for a separate power amp to improve things that much.

I guess it could just be that the 875 is a really good amp.

**salvasol** · **08-05-08, 06:17 PM**

Quote:

Moonfly wrote:

... His comments where that he couldn't tell any difference although he wasn't using proper floor standers as I will. Apparently a comment was made by another member that the issue was that the analogue stage in the 875 wasn't good enough for a separate power amp to improve things that much.

I guess it could just be that the 875 is a really good amp.

I don't use a separate amp ... but I read that some amps require the use of this box to get the full power
(see post # 4 here http://www.hometheatershack.com/foru...ti-1000-a.html ) ... that could be the case on his 875 and external amp

**billybishop81** · **08-05-08, 10:17 PM**

Hey Guys

I have found that there is a number of ways to bi-amp through a AVR however you are limited to the near entry versions of it I have installed an RX-V3800 bi-amped on to a set of BSA Towers now BSA has a great cross over which is good cause bi-amping through a AVR usually does not have a selectable cross over but wiring these speakers this way I found I got better bottom end through a down ward firing 8 inch woofer and better highs though the twin kevlat 4 inch and 3/4 inch soft dome I also found that I could ultimatly beat the speakers more befor distortion would set its nasty little sound into the equasion but unlimalty it would be best to remove the cross over in the speakers and go to a power amping system with selectable cross over there will be a big difference in sound and as for the rest of the speakers how loud do you watch your movies and TV because unless you are cranking it in surround modeyou won't really benifit from bi-amping everything else remember in surround modes your rear speakers and front mains and only effect speakers so in a sence yes proporly bi-amp your front mains but only if you plan to listen to high quality 2 channel sound and leave the rest go as far as your buget will allow the onkyo has great amps in it but you might want to go to a power amp system in which case there pre out are not to strong when it comes to pushing a power amp jus keeping in mind that when I install a power amping system I always upgrade to a 20 amp plug for all that power requirment also keep in mind that that is north american power I know you guys use diferent stuff over there I hope this is a little helpful

Cory

**Moonfly** · **08-06-08, 05:53 AM**

Mains power supply here in the uk is 240 volt as opposed to 110 in the US. I dont know how exactly that will affect things though. I do listen to music as much as films and its 2 channel music playback I'm after getting the most out of (Ive been looking at an Arcam p7).
It looks as though if I want to go this route I'll probably need some sort of booster for the analogue pre-outs on the 875 which will increase clutter and I'm not sure I want to go that route. All this information has been very useful though.

Cheers guys

**thxgoon** · **08-06-08, 01:53 PM**

I think everything has pretty much been said. I'll just add that if you do decide to bridge your Onkyo for the front channels it would be seeing a 3 ohm load requiring more current from the amp. I'm not sure if the amp would be limited by the power supply at that point or not but may be worth a try?? I'm assuming that by bridging the amp you are using the surround back channels?

**Moonfly** · **08-06-08, 02:54 PM**

Quote:

thxgoon wrote:

I think everything has pretty much been said. I'll just add that if you do decide to bridge your Onkyo for the front channels it would be seeing a 3 ohm load requiring more current from the amp. I'm not sure if the amp would be limited by the power supply at that point or not but may be worth a try?? I'm assuming that by bridging the amp you are using the surround back channels?

The 875 is limited to 8 ohm loads when bridging or bi-amping, which means this is out of the picture with the svs MTS speaker unless I add another amp. Hence the thread. It does bridge that way and thats how im running my current speakers, the radius 270's from Monitor Audio

**salvasol** · **08-06-08, 03:16 PM**

Quote:

Moonfly wrote:

The 875 is limited to 8 ohm loads when bridging or bi-amping, which means this is out of the picture with the svs MTS speaker unless I add another amp. Hence the thread. It does bridge that way and thats how im running my current speakers, the radius 270's from Monitor Audio

I have a Yamaha RXV2700 ... I remember reading the manual, and said that it can be used to bi-amp speakers (using the back surrounds internal amps); but it didn't mention that he AVR will bridge anything

... I suppose that if you're bi-amping your speakers that way (using the back surrounds amps), you're okay with the 8ohm loads

... but that's my opinion

**thxgoon** · **08-06-08, 04:00 PM**

Ya if you can bridge an 8 ohm load then it's implied that the amp is 4 ohms stable. I can't see why you couldn't bi-amp lower than 8 ohms though.

**Bill Fitzmaurice** · **08-06-08, 05:30 PM**

Quote:

MatrixDweller wrote:

I've tried bi-wiring and bi-amping my Klipsch RB81's and could not hear any difference what so ever.

You couldn't, because bi-wiring does nothing. To have any effect would violate the Superposition Principle; in simple terms, bi-wiring claims that 1+1 equals more than 2.

As for bi-amping, two good reasons to do so is that active crossovers work better than passive, while amplifiers work better when they don't have to cover the entire audio bandwidth. That's why subs use separate amps, and why bi-,tri- and even quad-amping are standard proceedure in pro-sound. But in home audio the level of sophistication, and cost of implementing it, may not be justified by the improvements gained.

**Moonfly** · **08-06-08, 05:59 PM**

Quote:

thxgoon wrote:

Ya if you can bridge an 8 ohm load then it's implied that the amp is 4 ohms stable. I can't see why you couldn't bi-amp lower than 8 ohms though.

The 875 is fine with 4 ohm loads, but lower ohms draw more current. Maybe its power supply isnt designed to feed that extra current in a bi-wire/amp or bridged config. It suggests it may cause an overload when pushed.

**thxgoon** · **08-06-08, 06:09 PM**

But this wouldn't be any different from running 4 ohm speakers both front and surround back. I wonder if they are compensating for a situation where the internal crossover of the speaker isn't totaly isolated and would cause the amps to couple

**Moonfly** · **08-06-08, 06:19 PM**

Given the heat this thing can throw out maybe it becomes a heat issue. The manual does warn that if your running 4 ohm loads at higher volumes for extended periods, that the protection circuits may cut in.

**09-19-08, 01:18 AM**

I have the ARCAM P1000 AMP and the AVP700 processor running my Monitor Audio GS60's and surrounds. I am currently bi-wired on the front but I'm soon to go bi-amp'd. I'll let you know the results.

**billybishop81** · **09-19-08, 01:00 PM**

I Hooked up an Audio Lab Integrated Amp to a set of Castle Richmond Series the result was ok highs and no bottom end. Now I have come to beleive that you english folk really like your warm sounds where as us Canadians are big into our highs and lows. While play around with the system I found that bi-Wiring the speaker brought them down to 4 ohms and the amp up from 60W per to 95W per. The results was huge with lots better highs and a noticable tight bottom end. let me know if this helps you out at all.

**salvasol** · **09-19-08, 01:45 PM**

Quote:

billybishop81 wrote:

I

...I found that bi-Wiring the speaker brought them down to 4 ohms and the amp up from 60W per to 95W per...

Not to debate what you're saying (I'm learning) ... but I don't think is possible to brought down an 8ohm speaker to 4 ohms just by bi-wiring them

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