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Bi-Amping speakers

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#41
No downsides, but absolutely zero benefit. You need to remove the passive crossover and go active to derive any benefit from biamping.

S
That is comple nonsense

You can get a very decent improvement when Bi-Amping without resorting to active crossovers if you are building your own crossovers and speaker system

When using Dynaudio drivers with phase accurate 6db Butterworth crossovers, simply try the hybrid crossover approach to your design

Two way systems generally are easier to design and have fewer problems than 3 way designs, but when building a 3 way system, I used a low level passive high pass section with a high level passive low pass section

The tweeter is driven by a separate channel in a stereo amp with the low level high pass crossover "BEFORE" the amplification (between pre-amp and amp)
The crossover does not have active components and solves a lot of problems with 3 way systems

High frequencies have much better transient detail than when using high level passive crossovers

Normally, most people B-Amp for the bass section, but you will not gain as much in sound quality as when you Bi-Amp for the tweeter

It sounds counter intuitive to many, but it does work quite well

Bass and midrange use a 2-way high level passive crossover + a low pass inductor on the midrange at the tweeters crossover point

I have been using hybrid passive crossovers in Bi-Amped omnidirectional speakers now for about 40 years with great results

Only a phase accurate full digital crossover could compete with this and my next system will likely be digital
 

Putter

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#42
That is comple nonsense

You can get a very decent improvement when Bi-Amping without resorting to active crossovers if you are building your own crossovers and speaker system

When using Dynaudio drivers with phase accurate 6db Butterworth crossovers, simply try the hybrid crossover approach to your design

Two way systems generally are easier to design and have fewer problems than 3 way designs, but when building a 3 way system, I used a low level passive high pass section with a high level passive low pass section

The tweeter is driven by a separate channel in a stereo amp with the low level high pass crossover "BEFORE" the amplification (between pre-amp and amp)
The crossover does not have active components and solves a lot of problems with 3 way systems

High frequencies have much better transient detail than when using high level passive crossovers

Normally, most people B-Amp for the bass section, but you will not gain as much in sound quality as when you Bi-Amp for the tweeter

It sounds counter intuitive to many, but it does work quite well

Bass and midrange use a 2-way high level passive crossover + a low pass inductor on the midrange at the tweeters crossover point

I have been using hybrid passive crossovers in Bi-Amped omnidirectional speakers now for about 40 years with great results

Only a phase accurate full digital crossover could compete with this and my next system will likely be digital
Let me see if I've got it straight. If you're building a speaker system from scratch, you MAY see a benefit with bi amping. If I understood the OP's question, it involved a conventional speaker system. My understanding was that there was little or no benefit due to the superposition principle and confirmed by blind tests.
 

gene_stl

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#43
I wonder how many people who have piped up on this thread have actually used real bi or tri amping.
It never would have occured to me to do the biwire biamping thing that people do now but I think it probably is still better than one amp. Even though the amp is operating full range the impedance rises quickly outside the speakers range and removing the link probably improves the damping factor a little and you probably get a few db of extra head room.
An low level passive crossover can be built using RC and LC networks after the pre amp and before the power amp. I used to build these for my friends who frequently had extra power amps lying around and maybe some JBL horn speaker systems. They were great. An active crossover is the way to go though and they are inexpensive now.
 
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voodooless

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#44
What if it’s simply to gain more power? For example let’s say you have an 86db 4ohm speaker and a Purifi stereo amp 227 watts at 8ohms. You just want a little more juice for the speakers. What would it cost to get a 300-400 watt amp or comparable perform to that module? Adding a second would be about as good as one could do I would think for a very reasonable price.

bad logic?
If you add a second Purifi, see that you have the option to bridge them. That will actually get you more power. Bi-amping will not really get you any more power. As already mentioned, the voltage needed will not change on the amps, so voltage wise, you will not gain anything, if it clips, it clips, no matter what speaker is connected (or even none). Then current wise, most of the current goes into the lower part of the response. There is probably up to a factor of 5 to 10 of difference in power on low vs high-frequency drivers with real music. So on the high side, we don't need to look. On the low side, that means that you might gain 10 to 20% of additional current capacity? In reality, it will probably be less than that, because driving low frequencies is harder on the amp already. If you translate that to dB, it's almost nothing. So no, don't bi-amp if you want more power! if you want power, buy a bigger amp (and make sure your new amp will have at least double the power, or you will not really notice anyway), or make sure you have a setup that lets you bridge them.


An low level passive crossover can be built using RC and LC networks after the pre amp and before the power amp. I used to built these for my friends who frequently had extra power amps lying around and maybe some JBL horn speaker systems. They were great. An active crossover is the way to go though and they are inexpensive now.
Adding additional crossover components will alter the response. Surely it will sound differently, and in case of crappy design possible better, but without equipment to measure what you have done, it's not really a good idea.
 

DSJR

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#45
Amplifier manufacturers (and dealers) love passive biamping as it sells twice as many power amps and 'speaker cable. That's all it does.

No, I didn't sell Linn or Naim. I couldn't sell Linn as I majored on CD and sold Pink Triangle, and couldn't sell Naim as I didn't sell Linn. Horrible times. Sold a lot of Quad, Meridian and Musical Fidelity, but not enough to stay in business.

S
I just want to add I never ever worked on personal commission in my times. KJ in its 70's heyday used to give each store a top-up commission which was split equally with the staff and this gave us the final 10 to 20% of our final salary. Some staff like me worked a lot in the basement setting up turntables, making up speaker cables and so on and some others weren't so good at this but were high flyers in sales, so I felt it was good we were treated equally to make for a whole team effort.

A few years back, I'd have argued till blue in the face how much 'better' bi-amping could be if a speaker had 'buy-wire' terminals on the back, but now I can't, as slight level differences tell all. Not in a position to do it all again under controlled conditions though sadly and feel a bit of a has-been in these times. I certainly don't think bi-amping does any harm at all, so on the used market for example, if an exact matching power amp is available, or an old AV amp can be configured to use two channels for left and two for right for instance, I'd suggest giving it a go, *as long as no harm is done* of course... :)
 
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gene_stl

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#46
The low level passive crossovers were just "the gateway drug". Most of them went on to get real crossovers. You need an RTA (I have had one since the late nineties). Before that I had (and have ) an HP audio oscillator and a gadget from Technics that had a flat microphone a meter and a warble oscillator. I also had a Pink Noise oscillator that was based on a digital chip. Its pattern repeated about every 20 second or so. It was pink pseudo noise.
All the friends I built those for were pretty badly addicted and none of them went back to full range , except when they got old and down sized.:( or croaked.:oops: Unfortunately I have inherited some equipment that way. I would prefer to have the friends back.
 

Wes

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#47
I wonder how many people who have piped up on this thread have actually used real bi or tri amping.
It never would have occured to me to do the biwire biamping thing that people do now but I think it probably is still better than one amp. Even though the amp is operating full range the impedance rises quickly outside the speakers range and removing the link probably improves the damping factor a little and you probably get a few db of extra head room.
An low level passive crossover can be built using RC and LC networks after the pre amp and before the power amp. I used to build these for my friends who frequently had extra power amps lying around and maybe some JBL horn speaker systems. They were great. An active crossover is the way to go though and they are inexpensive now.
I used to biamp my old Maggies using a Sunfire 5 channel amp. It enabled you to avoid the crummy crossover, or so 'they' said. I did no real tests but don't recall any differences in casual listening.

My understanding is that there was little or no benefit despite people not understanding the superposition principle or its applicability.
 
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#48
If you add a second Purifi, see that you have the option to bridge them. That will actually get you more power. Bi-amping will not really get you any more power. As already mentioned, the voltage needed will not change on the amps, so voltage wise, you will not gain anything, if it clips, it clips, no matter what speaker is connected (or even none). Then current wise, most of the current goes into the lower part of the response. There is probably up to a factor of 5 to 10 of difference in power on low vs high-frequency drivers with real music. So on the high side, we don't need to look. On the low side, that means that you might gain 10 to 20% of additional current capacity? In reality, it will probably be less than that, because driving low frequencies is harder on the amp already. If you translate that to dB, it's almost nothing. So no, don't bi-amp if you want more power! if you want power, buy a bigger amp (and make sure your new amp will have at least double the power, or you will not really notice anyway), or make sure you have a setup that lets you bridge them.




Adding additional crossover components will alter the response. Surely it will sound differently, and in case of crappy design possible better, but without equipment to measure what you have done, it's not really a good idea.
bridging with a 4ohm load wouldn’t work though right?

I still don’t see how having two amps wouldn’t up the power reserve the same as an amp with twice the wattage
 

bigguyca

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#49
Let me see if I've got it straight. If you're building a speaker system from scratch, you MAY see a benefit with bi amping. If I understood the OP's question, it involved a conventional speaker system. My understanding was that there was little or no benefit due to the superposition principle and confirmed by blind tests.

What does superposition have to do with bi-amping? Since you are claiming that as a fact, please explain.
 

DonH56

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#50
bridging with a 4ohm load wouldn’t work though right?

I still don’t see how having two amps wouldn’t up the power reserve the same as an amp with twice the wattage
Take a 100 W amplifier driving the high and low sections of a speaker. The most any section can see is 100 W. Now bi-amp using two, 100 W amplifiers, one each driving the high and low sections. Again the most either section can see is 100 W. If you need 200 W, you must buy a 200 W amplifier.

The reasons for bi-amping are usually so you can use a smaller amplifier on the treble section, not to "double the power" -- it does not work that way. Connecting the amplifiers directly to the drivers allows you to bypass the passive crossover, providing less loss, higher effective damping (lower driving impedance), and better control over frequency response using DSP or whatever before the amplifiers.
 

dreite

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#51
Well, in a perfect world bi-amping could achieve "double the power" with a second, identical amp.
But, you'd need to satisfy numerous conditions to yield that advantage.

"Passive bi-amping," as most seem to be referring to here, will not come close. At best, you're splitting the current load between two amplifiers rather than a single one. So, assuming all other things being equal, there would be some amount of extra current reserve in that configuration.

This still remains one of the most misunderstood topics by audiophiles.

Rod Elliot's two-part article on bi-amping is still the best comprehensive reference on this topic on the net. Suggested reading for all.
https://www.sound-au.com/bi-amp.htm

Dave.
 

pjug

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#52
The tweeter is driven by a separate channel in a stereo amp with the low level high pass crossover "BEFORE" the amplification (between pre-amp and amp)
The crossover does not have active components and solves a lot of problems with 3 way systems
You have an amplifier buffering between the the filter and load so this is active, no?
 

DonH56

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#53
Well, in a perfect world bi-amping could achieve "double the power" with a second, identical amp.
But, you'd need to satisfy numerous conditions to yield that advantage.


"Passive bi-amping," as most seem to be referring to here, will not come close. At best, you're splitting the current load between two amplifiers rather than a single one. So, assuming all other things being equal, there would be some amount of extra current reserve in that configuration.

This still remains one of the most misunderstood topics by audiophiles.

Rod Elliot's two-part article on bi-amping is still the best comprehensive reference on this topic on the net. Suggested reading for all.
https://www.sound-au.com/bi-amp.htm

Dave.
Could you explain the conditions?
 

DonH56

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#55
That's why I pointed to Rod Elliot's webpages. :)
He gives a "perfect world" example and describes the conditions of the various configurations in detail.

Dave.
I am familiar with the discussion. He does not ever say you get twice the power AFAIK, but does explain the potential "effective" increase within the range of the amplifiers, or words to that effect, through frequency division (splitting). IOW, a driver might get the full 100 W in one band (e.g. bass), unencumbered by any signal in the other (e.g. treble) band, but will not see 200 W. That is the thing many fail to grasp; two 100 W amps do not allow you to drive either band to 200 W, it is not the same thing as doubling the amplifier's power. The real-life advantage possible depends greatly upon the speaker design, crossover frequency, and source frequency (spectral) content, natch.

Alas, even that potential is lost with so-called "passive" biamping as implemented by most AVPs/AVRs. In those cases you can argue current headroom is gained, though it may be minor, but essentially no practical increase in voltage headroom, thus essentially no real-world benefit assuming decently low amplifier output impedance and cable resistance.
 

Putter

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#56
What does superposition have to do with bi-amping? Since you are claiming that as a fact, please explain.
I didn't actually claim it as a fact, but rather my limited understanding as a non technical reader and supported by most of the posters and what I've read from more knowledgeable people than myself. My real point was the first paragraph. Ignore the last sentence if you like.
 

blueone

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#57
Not that I'm trying to defend passive bi-amping, but isn't there a possible (but unlikely) case where the amplifier driving the low frequency section of the crossover clips, but since the high frequency section is almost certainly not demanding similar power the speaker sounds better overall?

Personally, I think in 99%+ of the real world cases, the reason owners want to passively bi-amp is because they think the layout of a bi-amped speaker looks cool and sounds cool when they're describing it. I think if passive bi-amping were invisible almost no one would do it. Speaker manufacturers that configure their crossovers with two sets of binding posts are the root cause of the problem.
 

DonH56

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#58
Not that I'm trying to defend passive bi-amping, but isn't there a possible (but unlikely) case where the amplifier driving the low frequency section of the crossover clips, but since the high frequency section is almost certainly not demanding similar power the speaker sounds better overall?

Personally, I think in 99%+ of the real world cases, the reason owners want to passively bi-amp is because they think the layout of a bi-amped speaker looks cool and sounds cool when they're describing it. I think if passive bi-amping were invisible almost no one would do it. Speaker manufacturers that configure their crossovers with two sets of binding posts are the root cause of the problem.
The problem with "passive" bi-amping is that the amplifiers are limited by the voltage rails which are usually common to both amplifiers. Since the input signal applied to both amplifiers is the same, if one side clips due to limited voltage, the other will as well. An actively bi-amped system, with or without removing the speaker's crossover, limits the out-of-band energy to each amplifier so you could in fact see an advantage. A common example of that outside the pro audio world is your subwoofer. The AVR/AVP limits the HF energy applied to the sub's amp so it only has to deal with a narrow(er) frequency band.

I have read the passive bi-amping trend arose partly due to "extra", unused channels in multichannel AVRs coupled with extra binding posts on speakers so people could "bi-amp" using the unused amplifiers but without the benefit of an actual (internal, line-level) crossover. so maybe AVR and speaker manufacturers are in cahoots. Shocking. Marketing over engineering, again.
 

blueone

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#59
The problem with "passive" bi-amping is that the amplifiers are limited by the voltage rails which are usually common to both amplifiers. Since the input signal applied to both amplifiers is the same, if one side clips due to limited voltage, the other will as well. An actively bi-amped system, with or without removing the speaker's crossover, limits the out-of-band energy to each amplifier so you could in fact see an advantage. A common example of that outside the pro audio world is your subwoofer. The AVR/AVP limits the HF energy applied to the sub's amp so it only has to deal with a narrow(er) frequency band.
The high-frequency section of the crossover sees all of the same frequencies as the low frequency section, and vice-versa, but the current is different because the impedance is different across the range of frequencies for each crossover section.
 

gene_stl

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#60
I have reached the age where repeating ones self is a hazard.

Quote:
This is a nice dated piece from 1986 which I have been referring people to since I got onto the internet.

https://www.audiocontrol.com/downloads/tech-papers/tech-paper-102.pdf
https://www.audiocontrol.com/downloads/tech-papers/tech-paper-104.pdf

Also read the March 1969 issue of Radio Electronics which has an article by the Late Great Norman H Crowhurst and English audio engineer.
https://www.americanradiohistory.co...ronics/60s/1969/Radio-Electronics-1969-03.pdf
I feel that I became an audiophile exactly when I read the above mentioned article. It explains how active crossovers eliminate intermodulation.
starts on Page 32.
That was in March. In October he showed you how to build one:
https://www.americanradiohistory.co...ronics/60s/1969/Radio-Electronics-1969-10.pdf
Pages 42,43,44
Those two articles changed my life.

I was in the process of home building an electronic crossover using op amps based on info in Walt Jung and Don Lancaster books.
I had etched and was drilling a circuit board.

Then I ran into THIS:
https://pdfs.semanticscholar.org/f3...417.1160101081.1558408539-44099534.1558408539
The famous Linkwitz 1976 article on how to do it right.

The Pioneer Series 20 (Pioneer Elite) D-23 was I believe the first commercial product to incorporate the Linkwitz criterion for preventing shift in the radiation pattern at the crossover. When the Pioneer came out I threw my project away. I believe the Pioneer engineers may have come up with the "Linkwitz Riley function" independently because the D-23 had to have been in designe prior to Linkwitz's 1976 publication.

I don't have a mini DSP yet. But it is likely just a matter of time. The more time has gone by since the above the more ways there are to skin the cat. You can buy kit or assembled circuit boards from all over. mini DSP. mini DSP even lower priced clones from Dayton audio and China
Lots of folks make crossovers now.

In my opinion you should open the speaker box and wire straight to the drivers. You should include fuses and sometimes for tweeters series capacitors that don't affect the response in the drivers range. If you have more drivers than amplifiers (ie bi amping a three way) you need to leave part of the crossover in place. This may require careful examination of the speakers crossover network because engineers and manufacturers have gotten very sophisticated in that department. It really is better to remove the whole thing. In this day and age power amps and active crossovers are very inexpensive so if its a two way biamp it a three way tri amp and like I have done since 1977 quad amp a four way.

: End of Quote.
 

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