vertical bi-amping - worth it?

I'm am looking to upgrade the amplification on my front floor standing speakers. Currently they are being driven by a HK3490 receiver, 120Wx2.

I've read about the benefits of vertical bi-amping, having two seperate amplifiers, one for each speaker, and I'm wondering if this would be worth trying.

For instance if I went with a single 2-channel amp, the Emotiva XPA-2 for $700, that would give me 250W into each speaker. OTOH if I went with two UPA-2's, which are 125Wx2, and vertically bi-amped them, I would still get 250Wx2 per speaker but the amplification would be separated and for $200 less than the XPA-2.

Is there any drawback to this I am missing? It seems with vertical bi-amping you would get me better quality amplification for cheaper.

1) To use a two-channel amp, with both channels, on a single channel out is called "bridging". It is not usually a 2x change in power (on good amps it's more, because the resistance is lower). From what I read, you are essentially discussing turning two stereo amps into two mono amps through bridging and powering one speaker off each.

2) The UPA 2 does not support bridging that I can tell. This will not work.

3) The difference between 125W and 250W is 3db. I doubt it will make a difference for you.

4) BiAmping a passive-crossover speaker is generally futile. It doesn't sound like you are discussing biamping (using separate amps for separate drivers on a single speaker). but I thought I would mention it.

Are you having sound quality problems? If so, what problems are you having?

Drawback is that it is more complicated.

I doubt that this kind of setup can make an audible difference.

Go to your dealer and ask him if he can set this up for you for an audition. If you can't hear it...

JerryLove said:

4) BiAmping a passive-crossover speaker is generally futile. It doesn't sound like you are discussing biamping (using separate amps for separate drivers on a single speaker). but I thought I would mention it.

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I think that's what they're referring to with 'vertical bi-amping'. If the passive crossovers are removed and active filters that do exactly what is needed, it would add headroom and output because the insertion losses would be eliminated. The trick is to get the filtering right.

JerryLove said:

1) To use a two-channel amp, with both channels, on a single channel out is called "bridging". It is not usually a 2x change in power (on good amps it's more, because the resistance is lower). From what I read, you are essentially discussing turning two stereo amps into two mono amps through bridging and powering one speaker off each.

2) The UPA 2 does not support bridging that I can tell. This will not work.

3) The difference between 125W and 250W is 3db. I doubt it will make a difference for you.

4) BiAmping a passive-crossover speaker is generally futile. It doesn't sound like you are discussing biamping (using separate amps for separate drivers on a single speaker). but I thought I would mention it.

Are you having sound quality problems? If so, what problems are you having?

Click to expand...

1), 2) My speakers are bi-ampable, in that there are two sets of binding posts, one to the mids and one to the highs. If I were to run one stereo amp to one speaker it wouldn't be bridged, the left channel would go to the mids and the right channel would go to the highs.

3) you're probably right. I'm just wondering if having more headroom like that would bring a noticeable increase in clarity and/or dynamics.

4)my speaker manufacturer (Energy) recommends vertical bi-amping, one amp per speaker, as opposed to horizontal bi-amping, one amp per driver. that way the internal passive crossovers still do their job but the power is better distributed between the drivers, at least according to them.

I'm not having any sound quality issues per se, just looking to try and squeeze the most out of my speakers I can. I've tackled room treatment & EQ... now I'm about to incorporate an active crossover for the subs (DCX2496) and will be adding additional amplification for the fronts, so it just boils down to if one big amp or two small would be better.

highfigh said:

I think that's what they're referring to with 'vertical bi-amping'. If the passive crossovers are removed and active filters that do exactly what is needed, it would add headroom and output because the insertion losses would be eliminated. The trick is to get the filtering right.

Click to expand...

He hasn't mentioned what his speakers are: but the speakers which allow bypassing of the passive crossover without surgery are certainly the minority.

Imagining for a moment we are discussing a single speaker, two-way, and the difference between a passive XPA-2@250w and active UPA-2@125w x2: I would say that the higher load LF is being denied a lot of headroom, and the lower load HF is being over-powered (more power than necessary), assuming it's not both being over powered.

To the OP: What speakers are you using?

Energy RC-70

here is what the manual says about bi-amping as one of the wiring options:

BI-AMPLIFICATION METHOD
This connection system involves the use of two separate two channel amplifiers to power one set of speakers. The idea is to have one stereo amplifier connected to one speaker, and another identical amplifier powering the second speaker. This is often referred to as “Vertical” Bi-amplification. It is the only method ENERGY® recommends.

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the other wiring options listed are traditional and bi-wiring, which I am doing now but with no noticeable improvement in SQ that I can tell

The RC-70 uses a pair of passive crossovers. I don't believe bi-amping will offer you any useful benefit. In fact you will loose headroom as you are using an amp 1/2 the power (125w vs 250w). Hooking two 125w channels is not equivalent to a single 250W, and even if it were: the HF and LF portions of the speaker do not offer equivalent loads.

Finally: your speakers have a 93db sensitivity. That's 93db @ 1w @ 1m.
100W = 113db, before we talk about room effects (which will make it louder still). You should be able to permanently deafen yourself with just your AVR.

Personally: I'd consider bi-amping these speakers at best, a waste of time and money. If you want 250w, and price is your issue: try a Yamaha P2500S (just remember to get the XLR adapters)

BTW: Nice speaker choice. I do love Energy's Reference line.

Thanks, that's what I was thinking. In theory the only real benefit would be each amp/speaker being powered by an individual power supply, as opposed to sharing a power supply, therefore crosstalk. In practice however it appears it would be negligible. The only reason I was asking is because the manufacturer specifically mentioned it in their literature.

That Yammy looks like a nice amp for the price. I was considering getting the 5000S as well for sub duty so those would go good together.

The Yamaha pro amps are very well regarded. I've recently bought four.