Why passive bi amplifying exists???

[highfigh]

I don't know. People seem to think that passive bi amping from amplifiers being sourced by the same power supply does make a difference. I think its BS. Also, I was responding to Kingnoob so I dont know why your showing me an angry face.

That face isn't for you, it's for the question and continuing debate.

 

[3db]

That face isn't for you, it's for the question and continuing debate.

Ahh. All good then

 

[Kingnoob]

Ahh. All good then

Found another new thread keeping this myth alive.

Bridging and Bi Amping. Aiyima A07 Aiyima

If you have high power floor speakers. And you have dual posts for High and Low. You can add another Amp to separately amplify the High and Low and balance the two. Treble often gets overpowered by Bass. Bridging and Bi Amping allows you to control the power between two Amps to bring those Highs...

www.avsforum.com

 

[Verdinut]

Found another new thread keeping this myth alive.

Bridging and Bi Amping. Aiyima A07 Aiyima

If you have high power floor speakers. And you have dual posts for High and Low. You can add another Amp to separately amplify the High and Low and balance the two. Treble often gets overpowered by Bass. Bridging and Bi Amping allows you to control the power between two Amps to bring those Highs...

www.avsforum.com

That AVS thread is Bullshit! High frequencies don't require much power and there's no need to use a second amp to amplify them. All is needed might be a better more powerful amp.

 

[m. zillch]

Passive bi-amping is a complete waste of electricity, wiring, amplifiers, and time because there is no increase in power and no audible difference (unless you, say, botch the polarity of one of the connections, twice as likely to happen, I might add, because you've needlessly made your setup twice as complicated with double the number of connections where you might accidentally botch polarity.

 

[m. zillch]

Interestingly the way most people apply passive bi-amping, say on an AVR where the extra channel of amplification they are using comes the the same receiver running the same singular power supply for all its channels, the power is actually decreased. This is because the fewer channels you run on a multi-channel amp the more power each has. Basically that one master power supply gets divvied up into fewer pieces of pie so everyone (every channel) gets more pie!

Who wants the biggest piece of pie? ME. Nom nom nom

 

[highfigh]

If you run a crossover before the amps, and bypass the onboard speaker crossovers, there is additional flexibility to be gained - and the ability to more accurately tune the speaker to the room, also if you are running out of steam on the bass, as the bass and treble are seperate amps, distortion generated in the bass amp (harmonics of which would extend into the high frequencies), won't extend to the highs.

Yes there are potential gains to be had - but many of the gains, are benefits that are generated due to the amp(s) being undersized/specced for the speakers.

In my case, there were only marginal gains to be had with the AVR onboard power and biamping, or with similar power external amps... fitting a much higher powered (high current) external amp, provided the same benefits, with a simpler configuration (and ended up cheaper than running a pair of smaller amps!).

How does passive bi-amping make crossovers more accurate? Your example of using separate amplifiers isn't what the OP was asking about and if you do it with passive crossovers, it's wasting power because of the insertion loss in ALL passive crossovers. Then, there's the issue of matching the HP and LP levels, which can't be adjusted on all separate power amps.

This, in addition to the fact that a system that runs out of steam was designed badly- no system should lack power.

 

[highfigh]

I don't know. People seem to think that passive bi amping from amplifiers being sourced by the same power supply does make a difference. I think its BS. Also, I was responding to Kingnoob so I dont know why your showing me an angry face.

You didn't make me angry, it's the fact that this is still being debated.

 

[TLS Guy]

Sure - but a power supply rated for 8ohm all channels driven, may well run out of puff driving 2ohm all channels driven.

I would like to see amps rated at 8 /4 / 2 ohm (with 1 ohm being optional)...

And there are valid reasons for saying that "all channels driven" may not be representative of actual use...

After all, in 99% of HT situations the load on channels other than L / C / R is lower than the load on LCR - so a more economical power supply could be fitted on the assumption that power requirements would be lower on the rest of the channels.... (or an asymetric design, with lower power amplifiers mixed with higher power ones, like Anthem do in some of their AVR's)

But yes it would be very desirable to get proper specifications from the manufacturers.

A 1 ohm rating is ridiculous! A speaker with a dip to one ohm, is a lousy awful speaker for a start, and one likely in the 2 to 3 ohm range also. That is because those sort of impedances are likely below the DC resistance of the connected driver. When that occurs that is absolute evidence that the crossover is in resonance. That is prima fasciae evidence of a totally incompetent design. The fact that this occurs, and not occasionally, just illustrates that there on not only poor designs, but totally incompetent ones out there.

 

[TLS Guy]

And this is EXACTLY why this BS continues- business that should be dealing with facts are too chicken shyte to be honest. 40+ years after it began and it wasn't even about passive bi-amping at that time, it was because people presented the path length for bass and treble frequencies being different enough that it was audible in home installations. Then, Munster Cables came into existence and life has sucked since that time.

That crap is even troweled out to professional installers at places like CEDIA, where the clown who presented the 'Audio Setup and Calibration' class I went to said all speaker wires should be the same length. Really? In a large home with some speakers being a short distance from the amplifiers/AVR? Should the excess be hidden in the walls? What if the walls are filled with insulation, ductwork, solid, exterior, etc? That's ridiculous! He spent more time telling us how cool he and his company were than offering factual info.

Marketing BS- if I ever finish building my time machine, this is one thing I want to change.

What is really ridiculous about passive bi-amping means that in a two way, one amp is only supplying the tweeter, which only needs two or three watts. Even on three ways the upper terminals are only connected to the tweeter high pass crossover as a rule. This is all done by pig dribble ignorant marketers.

 

[m. zillch]

Passive bi-amping (called simply "bi-amping" by consumer's owners manuals) is not legit. Active bi-amping, real bi-amping, (also referred to as simply "bi-amping", but by the pro world) is legit.*
But I challenge anyone here to show me a section of any consumer speaker's owners manual which explains the distinction and doesn't instead just use the term "bi-amping" when what they are discussing is their unit's passive bi-amping capability.

Think about why they'd do this: If a consumer is curious and asks a pro, "Does Bi-amping work?" the pro will respond along the lines of: "Of course. We use it all the time" But what they mean is the legit kind, active.

*[But the improvement in output is rather modest and nowhere near what one would achieve simply by doubling the power of one's existing, single amp: +3dB. The sensible approach.] The main reason we do real bi-amping is more that it provides greater control and adjustability of sound.

 

[Verdinut]

Passive bi-amping (called simply "bi-amping" by consumer's owners manuals) is not legit. Active bi-amping, real bi-amping, (also referred to as simply "bi-amping", but by the pro world) is legit.*
But I challenge anyone here to show me a section of any consumer speaker's owners manual which explains the distinction and doesn't instead just use the term "bi-amping" when what they are discussing is their unit's passive bi-amping capability.

Think about why they'd do this: If a consumer is curious and asks a pro, "Does Bi-amping work?" the pro will respond along the lines of: "Of course. We use it all the time" But what they mean is the legit kind, active.

*[But the improvement in output is rather modest and nowhere near what one would achieve simply by doubling the power of one's existing, single amp: +3dB. The sensible approach.] The main reason we do real bi-amping is more that it provides greater control and adjustability of sound.

Another reason for active bi-amping is where the design needs a crossover frequency lower than 400 Hz. These low frequency filters require larger inductors. Popular iron core inductors which are often used in expensive speakers don't operate linearly.

For real linearity, air core inductors are most often used but they are huge, heavy and expensive. So one of the solutions is to use an electronic crossover to divide the frequencies between two power amps. The amp for driving the higher frequencies doesn't need to be as powerful as the one driving the woofer or sub.

 

[TLS Guy]

Another reason for active bi-amping is where the design needs a crossover frequency lower than 400 Hz. These low frequency filters require larger inductors. Popular iron core inductors which are often used in expensive speakers don't operate linearly.

For real linearity, air core inductors are most often used but they are huge, heavy and expensive. So one of the solutions is to use an electronic crossover to divide the frequencies between two power amps. The amp for driving the higher frequencies doesn't need to be as powerful as the one driving the woofer or sub.

You are correct, 400 Hz is the absolute lower limit of a passive crossover of any quality. Of course the industry make speakers with crossovers lower than that. Another example of extreme stupidity.

This is another big plus for active speakers. You can make better crossovers, far better in fact and at any FR you want.