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Bi-Amping speakers

Ben23

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#1
what are the downsides of bi-amping speakers with a single multiple channel amp (4 or more channels) ? Is it worth it or are 2 separate amplifiers really that much better?
 

Wes

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#2
it is a good theoretical design as each driver gets its own amp to control it - this allows for cost savings if nothing else

bi-amping speakers designed for conv. amping costs money but is otherwise non-deleterious and may help if you avoid the low cost and crummy SQ cross-over in the speaker box, assuming it is crummy
 

sergeauckland

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#3
what are the downsides of bi-amping speakers with a single multiple channel amp (4 or more channels) ? Is it worth it or are 2 separate amplifiers really that much better?
No downsides, but absolutely zero benefit. You need to remove the passive crossover and go active to derive any benefit from biamping.

S
 

dfuller

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#4
My opinion, biamping (and especially using active crossovers) is always the better solution vs using a single amp with passive crossover. A single power supply (i.e. a multichannel amp) is not a big deal at all.
 

DSJR

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#5
No downsides, but absolutely zero benefit. You need to remove the passive crossover and go active to derive any benefit from biamping.

S
Maybe on the amps I tried it with, bi-amping merely gave each amp a simpler load, but if going active wasn't possible, I sold the odd bi-amped set as it usually sounded more powerful - more 'authority' but happy to accept it was less capable domestic amps having an easier time of it.

By the way, modern drivers may be ok, but going active in the past could put it all on the drivers if they're not so good, where a passive crossover can smother these things a bit ;)
 

sergeauckland

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#6
Maybe on the amps I tried it with, bi-amping merely gave each amp a simpler load, but if going active wasn't possible, I sold the odd bi-amped set as it usually sounded more powerful - more 'authority' but happy to accept it was less capable domestic amps having an easier time of it.

By the way, modern drivers may be ok, but going active in the past could put it all on the drivers if they're not so good, where a passive crossover can smother these things a bit ;)
it may be counter-intuitive, but passive bi-amping does not give the amps an easier load. For why, look up the Superposition Principle.

As to the quality of drivers, again active gives them an easier time as the DSP of the crossover usually includes equalisation and filtering, together with much sharper cutoffs that makes it easier to achieve a flatter result. It can't do much about in band distortion, but then nor does a passive crossover, and active at least takes better care if the out of band rubbish.

S
 

Berwhale

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#7
what are the downsides of bi-amping speakers with a single multiple channel amp (4 or more channels) ? Is it worth it or are 2 separate amplifiers really that much better?
I think you could waste your money on worse 'upgrades'. It cost me under £20 to bi-amp my Rega Jura front speakers to my Onkyo AVR. I used this cable... Fisual S-Flex Studio Grade White Speaker Cable 4 x: Amazon.co.uk: Electronics

I can't tell the difference, but hey, it used up an hour of my time and it looks more impressive.
 

DSJR

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#8
You didn't ever sell Linn and Naim passive/active speakers, did you Serge? That awful mesh covered ceramic dome tweeter and the Scansqueak spitter :D

I'll get me coat :D

Rega RECOMMENDED Bi-amping the Jura and that was one speaker I did it to with great success - at least with the mk1 Jura. Arcam Alpha 9 with matching power amp and the clamshell Rega Mira and Maia pairing.
 

bigguyca

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#9
No downsides, but absolutely zero benefit. You need to remove the passive crossover and go active to derive any benefit from biamping.

S
Do you have any idea of the amount of work required to do this correctly? For moderately price speakers, unless it's done as a hobby project, it would be a waste of time. Some of the work involved:

o Measure the T/S parameters of each driver

o Measure the response of the passive crossover

o Measure the overall response of the loudspeaker in quite a bit of detail

Of course you have no idea of the parameters used to design the speaker. You have no idea how far the drivers are from spec. You have no idea how far the crossover is from spec. You have no idea how the entire loudspeaker would have performed if built to spec. You have no idea how the characteristics of the drivers was used as effectively part of the passive crossover.

You need to decide if you will just duplicate the speaker as built, determine how it would have worked had it been built to spec., if you can determine what that spec is, or just change the whole design.

You can next determine why you a spending so much time messing with $5 to $10 drivers and perhaps a nice monkey coffin, to attempt to improve on a $1k MSRP loudspeaker that had a manufacturing cost of perhaps $100 in the PRC.
 

sergeauckland

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#10
You didn't ever sell Linn and Naim passive/active speakers, did you Serge? That awful mesh covered ceramic dome tweeter and the Scansqueak spitter :D

I'll get me coat :D

Rega RECOMMENDED Bi-amping the Jura and that was one speaker I did it to with great success - at least with the mk1 Jura. Arcam Alpha 9 with matching power amp and the clamshell Rega Mira and Maia pairing.
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
 

sergeauckland

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#11
Do you have any idea of the amount of work required to do this correctly? For moderately price speakers, unless it's done as a hobby project, it would be a waste of time. Some of the work involved:

o Measure the T/S parameters of each driver

o Measure the response of the passive crossover

o Measure the overall response of the loudspeaker in quite a bit of detail

Of course you have no idea of the parameters used to design the speaker. You have no idea how far the drivers are from spec. You have no idea how far the crossover is from spec. You have no idea how the entire loudspeaker would have performed if built to spec. You have no idea how the characteristics of the drivers was used as effectively part of the passive crossover.

You need to decide if you will just duplicate the speaker as built, determine how it would have worked had it been built to spec., if you can determine what that spec is, or just change the whole design.

You can next determine why you a spending so much time messing with $5 to $10 drivers and perhaps a nice monkey coffin, to attempt to improve on a $1k MSRP loudspeaker that had a manufacturing cost of perhaps $100 in the PRC.
Not only do I have some idea, I've done it with my 801s. Good fun.

S
 

dreite

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#12
it may be counter-intuitive, but passive bi-amping does not give the amps an easier load. For why, look up the Superposition Principle.
Yeah, it is counter-intuitive, because it's incorrect. :)
Passive bi-amping does indeed reduce the load on respective amplifier channels because the current load is decreased.....relative to a single amplifier. The effect may not be much, but it is there.

However, the resultant sound of the speaker system will probably be identical, or nearly so.
But it's not because of the Superposition Principle, strictly.

Dave.
 

sergeauckland

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#13
Yeah, it is counter-intuitive, because it's incorrect. :)
Passive bi-amping does indeed reduce the load on respective amplifier channels because the current load is decreased.....relative to a single amplifier. The effect may not be much, but it is there.

However, the resultant sound of the speaker system will probably be identical, or nearly so.
But it's not because of the Superposition Principle, strictly.

Dave.
As long as the amplifier remains linear, the Superposition Principle absolutely does hold, and there is no benefit whatsoever. Whether the load remains the same or reduces is also irrelevant if the amplifier remains linear, which any half-decent amplifier will. If the amplifier does not remain (or never was) linear, as some SET amps are, then all bets are off as the Superposition Principle no longer applies.

S
 

Wes

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#14
The Superposition Principle I learned as a physics major would not result in zero benefit as the drivers reproduce different frequencies.


Nonetheless, I am sure the correct answer to the OP is "Don't bother."
 

Berwhale

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#16
As long as the amplifier remains linear, the Superposition Principle absolutely does hold, and there is no benefit whatsoever. Whether the load remains the same or reduces is also irrelevant if the amplifier remains linear, which any half-decent amplifier will. If the amplifier does not remain (or never was) linear, as some SET amps are, then all bets are off as the Superposition Principle no longer applies.

S
My understanding is that the Superposition Principle applies to linear systems. Wouldn't the system in this case include both the amplifier and the transducer? If this is the case, then would the system be linear if it included a dynamic driver?
 

sergeauckland

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#17
The Superposition Principle I learned as a physics major would not result in zero benefit as the drivers reproduce different frequencies.


Nonetheless, I am sure the correct answer to the OP is "Don't bother."
This from Wikipedia

The superposition principle,[1] also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So that if input A produces response X and input B produces response Y then input (A + B) produces response (X + Y).

As long as the amplifier remains linear, and amplifiers are linear to a very high degree, then the above applies. It's because the loads respond to different frequencies that Superposition applies. I shows that the amplifier does not know or care what the load is, or how its distributed as long as the amp remains linear.

A highly distorting amplifier isn't linear so Superposition doesn't apply.

S
 

sergeauckland

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#18
My understanding is that the Superposition Principle applies to linear systems. Wouldn't the system in this case include both the amplifier and the transducer? If this is the case, then would the system be linear if it included a dynamic driver?
As the drivers are outside the amplifier (unless included in some sort of feedback), they have no effect on the amplifier, Back emf from the bass driver won't get through the crossover to affect the tweeter, and anyway, will be hugely attenuated by the amplifier's low output impedance, so there's no effect there.

As nothing is perfectly linear, nor is the amplifier's output impedance actually zero, there is always some residual effect of non linearity, but with any even half decent amplifier being 99.99% linear or even 99.999% linear, any non linearity can be safely ignored.

S
 

bigguyca

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#19
This from Wikipedia

The superposition principle,[1] also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So that if input A produces response X and input B produces response Y then input (A + B) produces response (X + Y).

As long as the amplifier remains linear, and amplifiers are linear to a very high degree, then the above applies. It's because the loads respond to different frequencies that Superposition applies. I shows that the amplifier does not know or care what the load is, or how its distributed as long as the amp remains linear.

A highly distorting amplifier isn't linear so Superposition doesn't apply.

S

What is your point here as relates to bi-amping? What does amplifier power have to do with the superposition principle?
 

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