Am i doing this wrong? Kef Reference 5 Bi-Amping

[HarmonicTHD]

There is more here, in case you haven’t seen it yet.

Bi-amping 101

This article provides a quick look at how bi-amplification works. The conventional scheme is to split the signal into two frequency bands before the power amplifiers that drive the speakers. The bass (LF) amp sees only LF signals and drives only the LF driver (woofer). The treble (HF) amp sees...

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If you bi-amp. Although the amps are of the same make cross check that they indeed (still) have matching gains. Would be a pity to detune those wonderful speakers.

 

[fpitas]

Is the next level. I ran a tri-amp active system for years but not with DSP.

You used an analog crossover?

 

[NiagaraPete]

You used an analog crossover?

Yes the Linn amps had a "aktiv module" that crossed over bass, middle, treble.

 

[raindance]

Then you could do it either way. But I would not bother.

Either way will work exactly the same and is unlikely to change the sound quality in any way.

 

[exm]

I recently bought a pair of Ref 5s also for a great deal. Love all the original owners upgrading to the Metas! One thing about these speakers is that they really love power. I know there’s a debate how much power is necessary but the more, the better for these.

I am not a big fan of bi-amp/wiring but since you have the equipment anyway…

What exactly is your question? How to set it up?

 

[id.ray]

That's what I'M SAYING he shouldn't do for the exact reason you're mentioning. I'm not saying do it that way, I'm saying it makes no sense.

wouldnt i have double the power available to each speaker?

 

[HarmonicTHD]

wouldnt i have double the power available to each speaker?

Theoretically yes, but practically not really. Simply speaking the woofers take the most power while the equally powerful amps for the tweeters are getting bored as the tweeters hardly consume any power in comparison.

 

[DVDdoug]

Normally, bi-amped & tri-amped setups use active line-level crossovers instead of speaker-level passive crossovers. You can add an active crossover (digital or analog) but can't bypass the crossovers built-into your speakers unless you disassemble and modify them. (It can be "dangerous" to bypass the tweeter crossover because if you foul-up and send bass to the tweeter you can fry it.)

Most home theaters use an active subwoofer so that's bi-amplification. The active crossover is normally built-into the AVR, although the sub may also havea low-pass filter..

Most active studio monitors are bi or tri-amped with an active crossover. But since it's all done internally you don't have to worry about it. A lot of "big" PA systems use bi & tri-amped systems. An active crossover is a common "pro" item and from what I've seen most are analog,

Bi-amped car stereos are also pretty common. I have a tri-amped system in my van (separate tweeters, mids, and woofers with no passive crossover). Currently, I'm using this 5 channel amplifier which has a built-in adjustable (analog) active crossover. Previously, I had 3 separate amplifiers and a separate {analog) active crossover and it was complicated and not very reliable.

 

[NiagaraPete]

I stream Tidal connect to a Bluesound node 2i, SE out to the Yamaha C-60 pre amp, from there SE out to matching Yamaha M-60 Power amp

Putting the bi-amping aside. You could probably streamline your system by removing the pre-amp from the stream. Go directly from the Node2 SE to the power amp.

 

[killdozzer]

wouldnt i have double the power available to each speaker?

Hey! Look, I'm not trying to rain on your (or anyone's parade). Enjoy and have a blast (just not a literal one)!

But, if I read this correctly:

I would like to hook up both Stereo “non bridgeable” power amps, one to each speaker.

My thought was From Each channel of the pre amp, Y-split to both cannels of the power amp. Remove the link of the KEFS and run “left channel” to the highs and “right channel” to the lows and do the same for the other speaker, effectively Bi-amping.

And if it's without some active x-over between preamp and amps, then you would feed one half of the stereo image to one driver. But that's not really how this is done. You don't feed one channel to one binding post. You feed highs to high binding posts (if jumper removed) and you feed lows to low binding posts.

The way you described it, you would have:
each channel receiving a full stereo image and then half of that image would be sent to low drivers and half to high drivers. Because if you leave each amp with full stereo image, then left and right channel are not the same. You would get some sort of 2 x stereo.

That's why I posted this image:

You see:

You don't have "one amp to each speaker" as you asked in your first post.

You have each amp feeding both L & R speakers. Watch the schematics closely. Highs to highs, lows to lows.



P.S. My thoughts on this: you don't need it. I doubt any sonic improvement. I fully understand the possible visual and aesthetic improvement with having symmetry as in one amp on each side of your listening room with those 80' peak meters.


I have faith that if I said anything wrong, we'll stand corrected in no time.

ANSWER to your question: your speakers would have at their disposal double the power which they would never use and idle power doesn't affect sound quality.

 

[voodooless]

ANSWER to your question: your speakers would have at their disposal double the power which they would never use and idle power doesn't affect sound quality.

No they won’t. Most power goes into bass. You have exactly the same amount of power available there. Nothing changes.

 

[Vincent Kars]

You feed highs to high binding posts (if jumper removed) and you feed lows to low binding posts.

There a 2 ways to bi-amp.
One is horizontal, 1 amp driving the woofers L/R and another the tweeters L/R

The other one is vertical: one amp driving the L speaker, the other the R.
The rationale is that in general the woofers are the ones that are power hungry so feeding 1 woofer and 1 tweeter is easier on the amp (PSU) than feeding 2 power hungry drivers.
Of course your line-in has to split but this applies to horizontal as well.

 

[killdozzer]

There a 2 ways to bi-amp.
One is horizontal, 1 amp driving the woofers L/R and another the tweeters L/R

The other one is vertical: one amp driving the L speaker, the other the R.
The rationale is that in general the woofers are the ones that are power hungry so feeding 1 woofer and 1 tweeter is easier on the amp (PSU) than feeding 2 power hungry drivers.
Of course your line-in has to split but this applies to horizontal as well.

This is STILL NOT what he described. If he said it like this, I wouldn't raise any concern. I know of vertical and horizontal. You'll notice that in your pic you feed only one channel per amp. He said he would leave them stereo and feed the entire signal to both. In which case you should do it as in my pic. Your pic implies running single channel per amp.

 

[killdozzer]

No they won’t. Most power goes into bass. You have exactly the same amount of power available there. Nothing changes.

As I said, I stand corrected although on an issue I regard less important. I was hoping you'd say something about ways to hook it up.

@id.ray we're slowly but surely narrowing it down to just "the looks" and no "benefit" at all.

Still, if you asked me, I'd do either what @Vincent Kars proposes or what was shown in my image. I wouldn't vertically hook up an amp that carries a full stereo image.

 

[NiagaraPete]

There a 2 ways to bi-amp.
One is horizontal, 1 amp driving the woofers L/R and another the tweeters L/R

The other one is vertical: one amp driving the L speaker, the other the R.
The rationale is that in general the woofers are the ones that are power hungry so feeding 1 woofer and 1 tweeter is easier on the amp (PSU) than feeding 2 power hungry drivers.
Of course your line-in has to split but this applies to horizontal as well.

The real issue here is. If you stack the amps one side is all bass so you’ll be doubling the heat. Generally you put the bass amp on to top for best cooling.

 

[Vacceo]

Theoretically yes, but practically not really. Simply speaking the woofers take the most power while the equally powerful amps for the tweeters are getting bored as the tweeters hardly consume any power in comparison.

This leads me to a question: why manufacturera such as KEF add ab class amps for the tweeters and class d for the woofers?

The class D makes sense due to the enclosed nature of the system (less heat in a harder to vent space) but the class AB? Sure, consumption will still be low due to tweeter requirements, but why not going class d for everything? Could it be cost?

 

[killdozzer]

This leads me to a question: why manufacturera such as KEF add ab class amps for the tweeters and class d for the woofers?

The class D makes sense due to the enclosed nature of the system (less heat in a harder to vent space) but the class AB? Sure, consumption will still be low due to tweeter requirements, but why not going class d for everything? Could it be cost?

My guess is they still don't build in something like Purifi or Hypex or similar because of the price. And older models still have some distortions in highs.

 

[HarmonicTHD]

This leads me to a question: why manufacturera such as KEF add ab class amps for the tweeters and class d for the woofers?

The class D makes sense due to the enclosed nature of the system (less heat in a harder to vent space) but the class AB? Sure, consumption will still be low due to tweeter requirements, but why not going class d for everything? Could it be cost?

I guess only Kef can answer that question. One can only speculate. But yes maybe class D is cheaper in terms of bang for the buck and off cause cooler. But why AB for tweeter? Maybe leftover amp modules?

 

[voodooless]

But why AB for tweeter? Maybe leftover amp modules?

Probably because the cheaper Class D modules still have relatively high THD at high frequency, and also many designs (especially the cheap ones) are still pre-filter feedback, making them impedance dependent as well as higher THD again. A cheaper AB chipamp can often do better and may be more economical.

 

[levimax]

This leads me to a question: why manufacturera such as KEF add ab class amps for the tweeters and class d for the woofers?

I believe it is because it is easier and cheaper to build a quiet low power class AB amp (chip based) than a quiet low power class D amp. For high power there is no doubt class D is easier and cheaper especially if low HF noise is not a requirement such as for a woofer in an active speaker.