Bi-amping speakers

[sleddogg]

I am pondering the idea of bi-amping my BW 683 fronts off of my Rotel 1095 amp and using 1 or 2 older RB850 amps (yes I currently own 2) to run my BW685 surrounds. They run 50w channel in stereo or can be run mono at 150w each. What can I expect to gain if anything by running such a setup? Is bi-amping something any speaker can benefit from or is it typically something one would do to larger bass driver models? Processor is RSP985 (may upgrade into 15 series). Also I don't know much at all about the finer points and purposes of bi-amping other than that the mid and highs can benefit from a less strained amplification giving LF it's own power. Or am I better off utilizing the 2 older amps in another fassion (other zone listening) Thanks, I'm new to all this and once basement is complete I'm sure some good ol' experimentation will reveal most of my answers.

[Kal Rubinson]

Experimentation is a good choice but so is Googling as this is a very commonly asked question all over the audio Internet. You will find a diversity of opinions and, no doubt, some will follow mine but here goes:

There is no advantage to bi-amping as commonly employed with the crossover remaining in the speaker box IF the single amp is sufficiently powerful.

Kal

[bleeding ears]

Kal, that was the most straight forward and logical answer I have heard about bi amping. Thanks for keeping it simple so I and other novices can understand easily.

How do you know when you have enough power though ? and since I and probably Sleddog also will be wondering, how about bi wiring ? anything in that ?

Pete

[Legairre]

As Kal said some will say passive bi-amping makes a difference and some will say it doesn't. I have my system bi-amped using an RMB-1095 and send 400w to each of my fronts(200w highs and 200 lows) and it makes a difference. We could debate it all day but neither side will change their minds.

As for bi-wiring you're sending the same wattage to the speaker just using more wire. No advantage at all to bi-wiring except if you're a wire manufacturer.

[jalyra]

I have an old onkyo receiver (TX-DS777) connected to a Rotel RMB-1075 that feed a pair of KEF Q11. I decided to run the surrounds using the recevier amps and bi-amp the Q11 with the Rotel and I definitevely like the bi-amp better. There is a noticeable difference but only when playing at higher levels.

I guess Kal is right, and when my speakers needed that extra punch, bi-amping helped a little, but in your case, the 1095 has plenty of power.

JALyra

[Legairre]

While the 1095 does have plenty of power there is still a noticable difference when bi-amping.

[bnieman]

Regardless of the debate your extra amps are far different in output power. I would be scared of overdriving the 50w per channel amp when the 1095 has so much headroom.

If you had 2 1095s it might be worth exploring but in your current situation I would stick with the 1095 and use the other amps in another zone.

To test biamping yourself try it with your identical smaller amps. I would try bi-amping and running the amps in bridged mono.

Let us know your findings!

[Legairre]

Regardless of the debate your extra amps are far different in output power. I would be scared of overdriving the 50w per channel amp when the 1095 has so much headroom. If you had 2 1095s it might be worth exploring but in your current situation I would stick with the 1095 and use the other amps in another zone. To test biamping yourself try it with your identical smaller amps. I would try bi-amping and running the amps in bridged mono. Let us know your findings!

I don't thing you understand my system because you are talking about equipment and configurations I don't even have. I don't have any bridgable 50w amps. I have two 70w RB 1050's driving the surrounds and backs and RB1050s are not bridgable.

The 2 RB1050s in testing have been shown to put out close to 100w per channel and have plenty of headroom for the level I listen at and have never ever had the clipping lights come on.

Using the 1095 for bi-amping is using identical amps. It seems that you think I'm mixing the 1095 and 1050 for bi-amping. The 1095 is used for bi-amping my fronts. I use 4 channels to bi-amp the fronts and the 5th channel is used for the center. The 1050s are for surround and back use only.

[Kal Rubinson]

How do you know when you have enough power though ?

Lots of variables here including speaker, room and personal choices of source material and listening levels. There is no general answer. OTOH, you cannot have too much (as long as you are not irresponsible).

and since I and probably Sleddog also will be wondering, how about bi wiring ? anything in that ?

Pete

Not in my experience.

Kal

[bleeding ears]

Well, Kal's word is good enough for me !


I wont go down that path. LOL

Pete

[Nuthed]

I for one am a fan of bi-amping for one reason and one reason only. It's not for any audible improvement either, because there really isn't one. The reason I do it is to possibly save a tweeter. How is that possible you may ask? By powering your speaker's high and low pass sections separately, you will reduce the risk of sending a clipped signal to your high pass section when and if a low pass amp clips. Since a speaker's low pass section uses the majority of an amp's power, driving the sections independently could save a tweeter. Bear in mind though this is only really a possibility when driving speakers full range. Also, as Kal and others have said, using a sufficiently large amp in the first place eliminates or reduces that possibility.

There are actually 3 things that convinced me it's a good idea.

1) Extra amps or unused channels in bi-amp capable receivers.

2) Speaker wire is cheap.

3) The above mentioned rationale.

For a little reading on this subject, check out this link from Anthem

[Kal Rubinson]

For a little reading on this subject, check out this link from Anthem

Note that it does not address the issue of whether there is any audible advantage to bi-amping.

Kal

[planitismetal]

For a little reading on this subject, check out this link from Anthem

This is very helpfull for me... Thank you Nuthed

[Nuthed]

Note that it does not address the issue of whether there is any audible advantage to bi-amping.

Kal

Agreed.

[imbeaujp]

Best way is tri-amping with an electronic cross-over.

[Kal Rubinson]

Best way is tri-amping with an electronic cross-over.

If you can design a crossover specifically suited to the vagueries of the particular speaker system so that the inbuilt one is simulated and replaced.

Kal

[AJ1560]

I have recently purchased the Rotel 1560 receiver. I also have the following B&W Speakers:

Mains: 683
Center: HTM62
Sub: ASW610
Surrounds: DS3

Since the 1560 has 7 channels and I only plan on using 5 I want redirect the 2 Center Back channels to the front and Bi-Amp the 683’s. I have made the change to redirect the CB>Front in the Default menu of the 1560 and did a factory re-set. No problem so far… However, when I bought the amp the dealer told me I should setup the Front Mains and Center Channel as “Large” and the 2 surrounds as “Small”. However, when I go into the Speaker setup menu and choose my speaker sizes and change the surrounds to “Small” it will not allow me to change the center backs to "Large2" (only Small1 & Small2 are available). Any suggestions on how to proceed, i.e do I have to set the surrounds to Large as well? If yes, will that cause a problem for the DS3s?

Also, what cross over settings would you recommend I used with the above setup? Right now they are all just set to the default 100 Hz.

Thanks for the advice.

AJ

[Kal Rubinson]

1. I wonder why the dealer told you to set the fronts/center as large. Generally, unless the speaker is extraordinary and acoustical situation is optimum, it is better to bass manage all channels.

2. The crossover settings, afaik, are for the crossover to the subwoofer and not for bi-amping. If you think that the Rotel is different from the usual in this aspect, you should confirm it with direct reference to the user's manual.

3. Seems like a lot of bother for little or no gain. (No pun intended.)

Kal

[Kevin D]

Agree on all points.

Ultimately, it sounds like your sales guy didn't fully understand how it works. Setting the fronts to large will set it for the normal front amps and the center-rear amps set to bi-amp. The large/small setting for the center rears will now only affect the pre-amp outputs.

I can say with 100% certainty that nothing in the 600 series needs to be set to large.

Kevin D.

[wettou]

Generally, unless the speaker is extraordinary and acoustical situation is optimum, it is better to bass manage all channels. Kal

Interesting so would you set the 802D as small?

[Kal Rubinson]

Interesting so would you set the 802D as small?

Yes for mch SACD but not stereo. The difference is small. (Not a pun.)

I would not hesitate with 683s.

Kal

[AJ1560]

Kal/Kevin.

Thanks for the advice. I will set everything to Small and see how it goes.

My primary reason for Bi-Amp'g the 683s is too feel like I am getting my money's worth by using all 7 channels in the 1560. A dumb reason I admit. My current floor plan does not allow for a 7.1 setup (5.1 is a stretch). However I wanted to "future proof" my purchase thus I went with the 1560 vs. 1550. At a later date when I get a better floor plan I figured I will be happy I spent the extra $$ and had the 7.1. option.

Thanks again.

[gp4Jesus]

go to this link. The writer answers many questions. All watching this thread may not agree with everything he says but... ...I agree w/ most

cheers tony

[gp4Jesus]

ooops! sorry

http://sound.westhost.com/bi-amp.htm

cheers

[sarsi]

I am too having 7 channels but in 5.1 setup, a RMB1095 (for C and Surr L/R) and a RB1092 (for L/R). Last week I finally decided to switch to bi-amp using the RMB1095 for the front L/R speakers, there are noticeable improvement over the RB1092 configuration (a little waste to use the RB1092 as a surr amp).

This is the not the first time I had done bi-amp on my B&W 703, in the past (few years back via two MF A3.2cr Power Amps), frankly my speakers has never sound so good before the MF. However, after a while I decided to decommissioned the setup as I still preferred an all Rotel setup for all the 5 speakers, as I quite frequently for the discrete multi-channel SACD playback and it is my main Home Theater setup.

Bi-amp is really quite subjective, my stereo HiFi setup which is Dynaudio Contour S5.4 do not come with any bi-amp option as the company do not believe in bi-amp or tri-amp, even their $100K+ Evidence series does not provide bi-amp option

[gp4Jesus]

...As for bi-wiring you're sending the same wattage to the speaker just using more wire. No advantage at all to bi-wiring except if you're a wire manufacturer.

Not true! You've cut your speaker wire resistance in half. Important w/a very reactive or low impedance load. W/out all the details, years ago I reduced my sub woofer (3 ohms!) wire resistance, formerly .02 ohms, to .005 ohms & had to reduce the LP output over 3dB to restore system balance.

[PewterTA]

Only from personal experience can I say that I've done both bi-amping (4 channels off a RB-1095 and 2x RB-1095 and 2x RB-1080). I can say with both of these configurations I did not notice any real difference (positively) to make it worth doing things this way. The one thing I noticed was the soundstage smeared between the lower and mid/highs. Almost as if anything crossing a certain plane actually moved in the soundstage (left or right, forward or backwards). It was a wierd sensation and just seemed to mess with what I was hearing. I ended up going back to the 1095 just with the normal 2 channels.

*side note* I HIGHLY believe at the 1095 is voiced for HT if you use any of the rear channels to amp your L/R speaker while using the L/R there's a definite notice of something not right.

Anyways, now I've gone with the RB-1090 amp (modified it some) and found that using both binding posts and biwiring, it has made the most positive change in the system. What changed is the lower end of the mid range. It cleared things up and made vocals more clear and higher in the overall range (ie. sounds more realistic to me). Now I read somewhere that it has something to do with the backwave off the lower bass drivers that can't effect the incoming signal to the mid/high drivers. Whether that's true or not... I can't say...but there was a difference that I've had a few people agree, it sounds different.

So in review... I think you need to make sure with bi-amping you use two of the same amps and bi-wiring can be effective.

[hurin]

I don't know if bi-amping will help or not. But in my opinion it is one of the last things to experiment with.

Spending 500$ on a wool rug or bass traps is a far better investment that using the money to buy cables.