The Difference Between Bi-amping and Bi-wiring

[AcuDefTechGuy]

How is adjusting sub level supposed to affect frequencies from 200Hz to 20kHz?

I set my XO @ 120Hz.

What I meant was that the main speakers do not get equalized; only the bass gets equalized and adjusted.

I use Audyssey Bypass L/R, which bypasses EQ to the main channels, but still EQ the subwoofers.

 

[katzkid]

What happens in a passive bi-amp setup when I leave the jumpers on?

 

[RichB]

What happens in a passive bi-amp setup when I leave the jumpers on?

Best case, you trip the amps protection circuits.
Likely case, your amp requires service.
Worst case, your amp is destroyed.

In other words, DON'T.

- Rich

 

[haraldo]

What happens in a passive bi-amp setup when I leave the jumpers on?

There will be lots of smoke
And burned up transistors

 

[PENG]

There will be lots of smoke
And burned up transistors

It could be a survivable experience if identical amps are used and wired in phase.

 

[haraldo]

It could be a survivable experience if identical amps are used and wired in phase.

I wouldn't count on it

 

[AcuDefTechGuy]

It could be a survivable experience if identical amps are used and wired in phase.

You think it would blow a fuse (Amps w/ fuses) or trip the circuit breakers (fuse-less ATI amps)?

Not that anyone would experiment.

I would think amp companies (like ATI's fuse-less Amps) could make an almost "fool-proof" amp that could prevent disaster.

No?

 

[TLS Guy]

This pretty much always causes instant disaster.

 

[Andrew08]

There should be a fine print written on the manual against doing this.

 

[lovinthehd]

What happens in a passive bi-amp setup when I leave the jumpers on?

Just goes to show ya that passive bi-amping is not only a waste of time and wire, but is dangerous, too.

 

[PENG]

You think it would blow a fuse (Amps w/ fuses) or trip the circuit breakers (fuse-less ATI amps)?

Not that anyone would experiment.

I would think amp companies (like ATI's fuse-less Amps) could make an almost "fool-proof" amp that could prevent disaster.

No?

YES!! That's if the protective system is well designed, and even then there is still the risk of serious damage however low the risk is, depending on the nature and severity of the fault. I agree one should not count on the protection system intentionally. They are there for you in case you make a mistake. It's a little like ABS system, if you drive properly according to the road conditions, it should not need to activate. When it does activate, you may still get into trouble depending on the situation.

 

[Barnabas Puskas]

Hi Guys,

Regarding bi-amping, I have an idea, and I wonder of your opinion. I have a Monitor Audio Bronze 6 speaker with integrated passive filter (crossover frequency is 2.5k). I think the main advantage of bi-amping is not to amplify the whole spectrum reducing the intermodulate distorsion with this method. But for this advantage you need an active filter before the amps to split the spectrum otherwise both amplifier will amplify the whole spectrum eliminating this advantage.
On the other side I do not want to remove the passive filters from the speakers, because they were to expensive to destroy them. And I also do not know the exact characteristic of the passive filters to be able to reproduce them on active way.
So my idea: Leave the filters (with 2.5k crossover frequency) in the speakers and use active filters too with the following characteristics:
- LF: Low pass filter with break point frequency at about 4kHz
- HF: High pass filter with break point frequency at about 1kHz
With this method the characteristic of the passive filter will prevail, but the spectrum on both amplifiers will reduce significantly reducing the intermodulate distorsion.

What do you think about this?

 

[lovinthehd]

Hi Guys,

Regarding bi-amping, I have an idea, and I wonder of your opinion. I have a Monitor Audio Bronze 6 speaker with integrated passive filter (crossover frequency is 2.5k). I think the main advantage of bi-amping is not to amplify the whole spectrum reducing the intermodulate distorsion with this method. But for this advantage you need an active filter before the amps to split the spectrum otherwise both amplifier will amplify the whole spectrum eliminating this advantage.
On the other side I do not want to remove the passive filters from the speakers, because they were to expensive to destroy them. And I also do not know the exact characteristic of the passive filters to be able to reproduce them on active way.
So my idea: Leave the filters (with 2.5k crossover frequency) in the speakers and use active filters too with the following characteristics:
- LF: Low pass filter with break point frequency at about 4kHz
- HF: High pass filter with break point frequency at about 1kHz
With this method the characteristic of the passive filter will prevail, but the spectrum on both amplifiers will reduce significantly reducing the intermodulate distorsion.

What do you think about this?

I don't understand why you think this has some benefits. I wouldn't bother.

 

[RichB]

Just listen to a single speaker and decide for yourself. Better yet, get a friend help you setup a SBT.
Switching can take seconds using stacking banana plugs

Separating the crossovers avoids interaction between the two and presents a different load to both amplifiers.

- Rich

 

[Barnabas Puskas]

I don't understand why you think this has some benefits. I wouldn't bother.

The answer is simply coming from a basic rule. In case of an amplifier less bandwidth produce less harmonics. If you split the whole bandwidth in two parts and amplify separately the generated harmonics will be less. (the same benefit than the basic active bi-amping method). In my case the only different is that there would be overlapping between the bands. So this benefit would be a little bit less than in normal case.

 

[Swerd]

Regarding bi-amping, I have an idea, and I wonder of your opinion. I have a Monitor Audio Bronze 6 speaker with integrated passive filter (crossover frequency is 2.5k). I think the main advantage of bi-amping is not to amplify the whole spectrum reducing the intermodulate distorsion with this method. But for this advantage you need an active filter before the amps to split the spectrum otherwise both amplifier will amplify the whole spectrum eliminating this advantage.

The idea that bi-amping lowers IM distortion (intermodulation), or improves sound by separating a woofer's back EMF from the tweeter, is old and has been debunked.

On the other side I do not want to remove the passive filters from the speakers, because they were to expensive to destroy them. And I also do not know the exact characteristic of the passive filters to be able to reproduce them on active way.

Removing or disconnecting your speakers' crossover networks will also void the warranty.

So my idea: Leave the filters (with 2.5k crossover frequency) in the speakers and use active filters too with the following characteristics:
- LF: Low pass filter with break point frequency at about 4kHz
- HF: High pass filter with break point frequency at about 1kHz
With this method the characteristic of the passive filter will prevail, but the spectrum on both amplifiers will reduce significantly reducing the intermodulate distorsion.

Depending on how these additional filters are designed, this, at best, will accomplish nothing. At worst, these additional filters will have a negative impact on the function of the speakers' crossover filters. This is a solution for a non-existent problem.

 

[TLS Guy]

Hi Guys,

Regarding bi-amping, I have an idea, and I wonder of your opinion. I have a Monitor Audio Bronze 6 speaker with integrated passive filter (crossover frequency is 2.5k). I think the main advantage of bi-amping is not to amplify the whole spectrum reducing the intermodulate distorsion with this method. But for this advantage you need an active filter before the amps to split the spectrum otherwise both amplifier will amplify the whole spectrum eliminating this advantage.
On the other side I do not want to remove the passive filters from the speakers, because they were to expensive to destroy them. And I also do not know the exact characteristic of the passive filters to be able to reproduce them on active way.
So my idea: Leave the filters (with 2.5k crossover frequency) in the speakers and use active filters too with the following characteristics:
- LF: Low pass filter with break point frequency at about 4kHz
- HF: High pass filter with break point frequency at about 1kHz
With this method the characteristic of the passive filter will prevail, but the spectrum on both amplifiers will reduce significantly reducing the intermodulate distorsion.

What do you think about this?

That is a terrible idea. You will have cascaded filters, and the order of the filters sum

The other point is that the power above 2.5 KHz is minimal. You are wrong even with passive biamping the amps do not amplify the whole spectrum only the frequency range delivered.

Passive biamping is a waste of time. Active biamping on the other hand eliminates the the power losses of the passive crossover, which are significant, and other associated problems.

The real benefits of active biamping come when the crossover region progressively drops below 500 Hz, when the problems caused by passive crossovers rapidly escalate. In addition then you do get power sharing, as the power divide is at 400 Hz or close.

 

[Barnabas Puskas]

That is a terrible idea. You will have cascaded filters, and the order of the filters sum

The other point is that the power above 2.5 KHz is minimal. You are wrong even with passive biamping the amps do not amplify the whole spectrum only the frequency range delivered.

Passive biamping is a waste of time. Active biamping on the other hand eliminates the the power losses of the passive crossover, which are significant, and other associated problems.

The real benefits of active biamping come when the crossover region progressively drops below 500 Hz, when the problems caused by passive crossovers rapidly escalate. In addition then you do get power sharing, as the power divide is at 400 Hz or close.

Thanks for your useful answer. Yes, the other thing why I begun to think about biamping is the power sharing. At this moment I use a pure class A amplifier (a John Linsley Hood one) to drive this speakers, but it has quite a low output power (8-10W RMS max.) So I have two ways now:
- use biamping with 2 JLH amp / channel or one A/B class for LF and one pure class A for HF
- build a bigger amplifier: here the problem is that it is not easy to build high power class A amp because of the cooling and high power consumption problem
Note: I prefer class A only based on my good experience.

 

[Swerd]

The answer is simply coming from a basic rule. In case of an amplifier less bandwidth produce less harmonics. If you split the whole bandwidth in two parts and amplify separately the generated harmonics will be less.

Even this concept isn't true. Analog audio signals are alternating current (AC) not direct current (DC). The idea that amplifiers are upstream from the speakers doesn't apply.

A single amplifier channel, attached by a single speaker cable, to a 2-way speaker, with an internal crossover, can be compared garden hose. You can turn off the flow of water (analogous to electrical current) with the valve between the house and the hose. Or, you can turn off the flow to either the woofer or the tweeter by sending it through the speaker's crossover. The low-pass filter leaves flow to the woofer, but shuts off flow to the tweeter, and the high-pass filter leaves flow to the tweeter, but shuts off flow to the tweeter. In the garden hose analogy, this is like using a hose nozzle with a built-in trigger shut off, at the far end of the hose. It doesn't matter whether you shut off water flow at one end of the hose or the other, it's still shut off.

The amplifier essentially sees the woofer only for sound below the crossover point. Any signal above the crossover point is essentially shut off to the woofer. The crossover produces so much impedance to signals above the crossover point that the amplifier produces zero current. In electricity, zero current equals zero work, or no amplifier work. The same is true for the tweeter but above the crossover point.

The idea that the woofer and tweeter benefit if two separate amp channels drive them is not true.

Similarly the idea that there is an audible difference depending on where the crossover filters are placed in the network is also untrue. There is a measurable electronic difference with upstream crossovers, but what is measurable electronically does not always translate into differences that can be heard by listeners.

 

[Barnabas Puskas]

Even this concept isn't true. Analog audio signals are alternating current (AC) not direct current (DC). The idea that amplifiers are upstream from the speakers doesn't apply.

A single amplifier channel, attached by a single speaker cable, to a 2-way speaker, with an internal crossover, can be compared garden hose. You can turn off the flow of water (analogous to electrical current) with the valve between the house and the hose. Or, you can turn off the flow to either the woofer or the tweeter by sending it through the speaker's crossover. The low-pass filter leaves flow to the woofer, but shuts off flow to the tweeter, and the high-pass filter leaves flow to the tweeter, but shuts off flow to the tweeter. In the garden hose analogy, this is like using a hose nozzle with a built-in trigger shut off, at the far end of the hose. It doesn't matter whether you shut off water flow at one end of the hose or the other, it's still shut off.

The amplifier essentially sees the woofer only for sound below the crossover point. Any signal above the crossover point is essentially shut off to the woofer. The crossover produces so much impedance to signals above the crossover point that the amplifier produces zero current. In electricity, zero current equals zero work, or no amplifier work. The same is true for the tweeter but above the crossover point.

The idea that the woofer and tweeter benefit if two separate amp channels drive them is not true.

Similarly the idea that there is an audible difference depending on where the crossover filters are placed in the network is also untrue. There is a measurable electronic difference with upstream crossovers, but what is measurable electronically does not translate into differences that can be heard by listeners.

Nice analogy and it is true if we speak about power. Of course the amplifier cannot push any power on the high impedance part of the load (that frequency range which is out of the woofer / tweeter range). But a question? What about the voltage limit of the amp? E.g.: there is -+20V PSU. If you have an 50Hz sine wave with the maximum output amplitude (20Vpp) and you want to add a 10kHz 2Vpp signal on it, the 10kHz signal will be cut and limited because of the supply voltage limit. If you filter out the high amplitude 50Hz before the amp, you will not have this problem on high frequencies. So in this case it makes sense to use the filter before the amp. What do you think?
Note: I use an own built class A amp with limited power.