Bridge Mono or Vertical Bi-Amp?

[dpohlman]

I just purchased a new pair of Revel Salon 2 speakers.  I currently own two XPA-2 Gen 2s, so I am focused on deciding what approach to take in powering these hungry beasts. 

The manual suggests these speaker can reach a load of 3.7 Ohms, so using the mono function on these amps seems risky given the fact that the amps are fairly clearly rated specifically for 8 Ohms when using the mono function.  As a result, I am considering setting them up in a vertical bi-amp configuration (one amp per speaker - one channel for the lows, and one channel for the mids / highs).

I have balanced Y adapters and I have two sets of high quality 3ft speaker cables for each speaker.  These speakers are set up to be bi-amped with the terminal bridge straps removed. 

Running these amps in mono scares me, given that extreme clipping could cause damage to both the amps and these $21,000 speakers.   My question is related to what other people having experienced with a vertical bi-amp arrangement with speakers that have a difficult load profile?  And I would be interested to see if others feel I am thinking about this correctly?

Thank you for your thoughts in advance!

   
www.soundstage.com/synergize/pics/031998vbiamp.jpg

[repeetavx]

As you can see by my signature I vertical passive bi-amp with XPA-2s. I found that it improved bass definition. What I didn't expect is that it removed "glare" from the tweeters.

The XPA-2 would probably work ok with the amp bridged. Emotiva rates their stuff conservatively. But there is no way of knowing how much stress it would cause to the amp. Vertical bi-amping would remove all doubt of stress and, from my experience, improve the performance.

[guest2]

Passive bi-amping is a good way to improve the sound stage, tighter bass, better imaging. I've did it with two different speakers, a pair of vandersteen 2ce's and a pair of tannoy studio monitors, made a believer out me big time. What about horizontal bi-amping, that's what tannoy always recommends.

[frenchyfranky]

With vertical bi-amp you have the best of both worlds (mono power supply for each channel and separated amp for high and low freq.)

And in prime you'll have one LED meter for the bass and the other for the high on each of your XPA-2...

BTW if you decide to try both setup, it should be very interesting to share with us your find.

[AudioHTIT]

I'm also a fan of vertical bi-amping and have done it with both Beveridge Model 3's and my current Maggies (though I'm currently 'just' using monoblocks). You can place them close to the speakers like monoblocks, each amp's supply is shared between highs and lows, and you don't have to worry about the low impedance bridging issue. You have the equipment, no reason not to try it. I would be reluctant to try bridging with that load.

[mgbpuff]

I have the Revels but I do not bi-amp as I have 500W monoblocks. I am not a fan of strapped amps, you would be better served by vertical bi-amping.

[guest2]

What the pro' and con's between vert, vs horiz, bi-amping?

[repeetavx]

Apr 26, 2014 15:30:18 GMT -5 guest2 said:

What the pro' and con's between vert, vs horiz, bi-amping?

By using the same amp and its power supply for both stereo channels, there is a good chance that the power supply could rob power from the other channel (especially with the bass amp) and lessen the stereo separation.

When you vertical biamp, each amp channel in the amp amplifies a different frequency range, and any power lulls are limited to the one side of the soundstage.

[frenchyfranky]

Apr 26, 2014 15:30:18 GMT -5 guest2 said:

What the pro' and con's between vert, vs horiz, bi-amping?

Vertical bi-amp is comparable to mono plus the advantage of seperated amp for low and high freq.

[ocezam]

1. There is no need to worry about stressing the XPA-2's when bridged into your speakers. 6 ohms nominal, 3.7 minimum will hardly stress ANY Emotiva amp, bridged or not. That's not a hard load by any means. Further, if it were, all it would do is send the amp into protect mode. Big deal! unhook it and go into your bi-amp mode...

2. If you bi-amp. don't waste your time with passive bi-amping. What an incredible waste of power... Get an active x-over and do it right. It's not hard. Biggest problem is the avalanche of misinformation on the web from people who've never done it correctly. Active bi-amping will get you to a totally new level.

But again, it's simpler, cheaper, and easier, to simply bridge the amp. The XPA-2 is an incredible amp that outperforms it's cost ratio many times over. If you're simply in need of the headroom, forget the bi-amping. Your XPA-2's should be fine running bridged into that load.

Peace

P.S.
Killer speakers!

Enjoy!

[Gary Cook]

My suggestion is to try all three methods and see which one you, yourself, personally prefer. Each has advantages and disadvantages, ultimately it will come down to what your ears prefer, using your speakers, in your room.

Cheers
Gary

[Boomzilla]

Mr. Cook's advice is sterling. My experience, having tried the options you have, showed that vertical bi-amplification with long interconnects and short speaker wires sounded best.

Your rig may vary...

Boomzilla

[mgbpuff]

Do not active bi-amp these speakers. These are an expensive highly developed product. You will have to modify them by removing their crossovers; that will destroy their value. It takes some chutzpah to think that you will do a better job than the Harmon group which has perhaps the best speaker development facilities in the world. If you want to go the active route, get some cheapass speakers that you can actually improve upon and not ruin by active bi-amping. Having said that, it's your choice to do what you want with your own equipment. $21,000 MSRP may not be a significant investment to you!

[dpohlman]

I hooked the Salon 2s up this afternoon in the vertically bi-amped approach.  I am very impressed thus far.  It seems like the power is ample, and the imaging is absolutely incredible!  These speakers are very impressive!

I would not consider active bi-amping these with an external electronic crossover.  I understand the concept of electronic crossovers more effectively focusing the power because you are only amplifying the signal range you will hear; however, the crossovers in the Salon 2s are a major part of what makes them so good.

I still may consider trying the mono-block mode, but I am still a little concerned with the ability of these amps to handle a 3.7 Ohm load in mono-block mode.  I have received some mixed feedback on taking this approach.  More thoughts would be appreciated.  

The approach I may ultimately take is to sell my two XPA-2 Gen-2s, and then replace them with either two XPA-1 Gen-2 mono-blocks, or two XPR-1 mono-blocks.  I am curious as to what others think about my current vertical bi-amping vs. the possible move to true mono-block amps?

Again, thank you in advance for you feedback!

 

 

[Gary Cook]

If there is a problem with the XPA-2 handling the occasional drop to 3.7 ohms the XPA-2 will protect itself by shutting down. I can't think of an occasion where the speakers would be at any risk. My experience with Emotiva power amps (XPA2/3/5/100) is that they handle loads at low impedances quite well. The warning about using XPA-2's bridged with 4 ohm speakers is not due to the speakers normal 4 ohm rating, more their ability to regularly get below 2 ohms at some frequencies. I just don't see 3.7 ohms (at some frequencies) as being an issue. So personally I'd try it, just sneak up on the volume.

I'm with the learned boom on the "long interconnects & short speaker wires" also being my preference.


Cheers
Gary

[deltadube]

Good day Dpohlman.. I like you last idea... mono blocks.. see novisnick for details on membership into the mono block society!!!

lots more head room..

first thing some one told me hear you can never have too much power eh..

cheers

[mgbpuff]

The Revel Salon 2 speaker is 6 ohms nominal, 3.7 ohms minimum. This is clearly outside the range recommended by Emotiva for the XPA-2 in monoblock mode. The manual warns that the XPA-2 could suffer damage (these are Emotiva's words in the manual, who are we to second guess?). I would get a pair of the best Emotiva Amps, the XPR-1 and couple them with an XSP-1 preamp with all balanced cabling. This would be the absolute best you can do with Emotiva. Forget the Class A products, this speakers sensitivity is only 86%, you will never hear any difference due to Class A and these speakers are among the most dynamic made, so, go for the power!

[dpohlman]

Based on the feedback from both threads I had initiated (XPA section and XPR section), I am going to stick with my XPA-2 Gen-2 Amps driving the Revel Salon 2s in a passive vertical bi-amped arrangement. I am extremely impressed with the clarity and imaging this combination is able to deliver. At this point, especially given my dedicated listening room size (14 X 12 foot), I don't really have any need for the additional power that might come from a pair of XPA-1 or XPR-1 amps.

However, I tend to like to try various options, so I could still see a pair of mono-blocks in my future. I could ultimately use either the XPA-2 Gen-2s either vertically bi-amped or in mono-block mode or the XPA-1 or XPR-1 amps to drive the Dali Euphonia MS5 main speakers in our theater. These are currently powered by a Lexicon 7 channel amp today, and I really think the mains need more power and headroom than this 175 watts per channel amp can deliver.

I sincerely appreciated all of the help and wonderful insight everyone provided. Thank you! - David

[novisnick]

Hi all, I do best with diagrams and pictures.
Would someone be kind enough to help me out and post one or the other,,,,,or both.

I just want to make sure I've got it correct. Hate to see an amp or speaker go up in smoke.

Thanks

[Boomzilla]