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 of course 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.

 

[highfigh]

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.

Consumers don't know and they don't care, it's MORE.

 

[dlaloum]

Consumers don't know and they don't care, it's MORE.

Sometimes it's not about the Watts but about stability into the reactive load.

The Quad 606's aren't super powerful - but they ARE super stable - and with the Gallo CDT tweeters showing 1.6ohm capacitive load... that becomes essential.

So you could allocate a 606 to the tweeter and use AVR onboard amps for the woofer (as an example)

You might want an "ordinary" amp capable of handling the relatively "ordinary" load of the woofer with loads of Watts.... but then something like the 606 for that reactive tweeter load....

Active speaker designers are making these sort of decisions all the time nowadays.... and having asymmetrically powered speakers is becoming the norm. (with the details of that asymmetry varying based on the requirements of the speaker/drivers, etc...)

 

[Verdinut]

Sometimes it's not about the Watts but about stability into the reactive load.

The Quad 606's aren't super powerful - but they ARE super stable - and with the Gallo CDT tweeters showing 1.6ohm capacitive load... that becomes essential.

So you could allocate a 606 to the tweeter and use AVR onboard amps for the woofer (as an example)

You might want an "ordinary" amp capable of handling the relatively "ordinary" load of the woofer with loads of Watts.... but then something like the 606 for that reactive tweeter load....

Active speaker designers are making these sort of decisions all the time nowadays.... and having asymmetrically powered speakers is becoming the norm. (with the details of that asymmetry varying based on the requirements of the speaker/drivers, etc...)

Why would you use the more powerful Quad 606 for the tweeter which only needs a couple of watts, while a woofer needs a lot more power? By the way, the 606 has a higher power rating than any of an AVR amps, and surely is more stable as well. If only 2-3 watts of power are needed, an AVR amp should be able to handle a low impedance tweeter. Otherwise, a 4 ohm 10 watt resistor could be added in series with the tweeter.

 

[TLS Guy]

Sometimes it's not about the Watts but about stability into the reactive load.

The Quad 606's aren't super powerful - but they ARE super stable - and with the Gallo CDT tweeters showing 1.6ohm capacitive load... that becomes essential.

So you could allocate a 606 to the tweeter and use AVR onboard amps for the woofer (as an example)

You might want an "ordinary" amp capable of handling the relatively "ordinary" load of the woofer with loads of Watts.... but then something like the 606 for that reactive tweeter load....

Active speaker designers are making these sort of decisions all the time nowadays.... and having asymmetrically powered speakers is becoming the norm. (with the details of that asymmetry varying based on the requirements of the speaker/drivers, etc...)

What utter nonsense, absolute bilge from start to finish. What an absolute waste to have a Quad 606 powering a tweeter! The 606 and 909 series Quad amps are among the finest power amps that have ever been produced. If you have one, just use it to power the whole speaker.

 

[highfigh]

Sometimes it's not about the Watts but about stability into the reactive load.

The Quad 606's aren't super powerful - but they ARE super stable - and with the Gallo CDT tweeters showing 1.6ohm capacitive load... that becomes essential.

So you could allocate a 606 to the tweeter and use AVR onboard amps for the woofer (as an example)

You might want an "ordinary" amp capable of handling the relatively "ordinary" load of the woofer with loads of Watts.... but then something like the 606 for that reactive tweeter load....

Active speaker designers are making these sort of decisions all the time nowadays.... and having asymmetrically powered speakers is becoming the norm. (with the details of that asymmetry varying based on the requirements of the speaker/drivers, etc...)

Uneducated consumers- marketing departments absolutely depend on them. If they don't buy because of marketing claims, they buy because of the confusion that comes from reading or hearing something that seems plausible. They weren't particularly good in Science classes, don't understand the concepts that we harp on when someone presents BS as fact and they have the money to spend. When Sansui was harping on their amplifiers having higher Slew Rate during the late-'70s/early-'80s, Consumer reports and a few other magazines repeated it, confusing many people who would go to the local stereo stores and have another spec to throw at us, so they could act likee 'experts'. Many brought their own experts, too. They would ask about slew rate, we would answer and it proved that they were interested in hearing that tehy wanted specs that showed more, not better. Reliability was a huge thing for us at that store and we saw all kinds of failures in various brands because we had service techs repairing the equipment that was supposedly better, but not reliable.

Why would you use a 606 on a tweeter that won't present a difficult load to it? SHow the Gallo tweeter and explain why it should be used if it actually presents a 1.6 Ohm load. While you're at it, I would like to know why Gallo can't be bothered to design their CDT tweeter to have a voice coil that doesn't present a difficult load.

BTW- the passive crossover on a tweeter should be able to remove the frequenies that cause the difficult load and when did woofer loads become "relatively ordinary"? Of course, the standard response will be "Because passive crossovers cause phase shift and takes away the best parts of the sound....."- good, reliable speaker design should include components that won't cause amplifiers to puke, not force the users to search high & low for an amplifier that will survive being connected to them.

 

[TLS Guy]

Uneducated consumers- marketing departments absolutely depend on them. If they don't buy because of marketing claims, they buy because of the confusion that comes from reading or hearing something that seems plausible. They weren't particularly good in Science classes, don't understand the concepts that we harp on when someone presents BS as fact and they have the money to spend. When Sansui was harping on their amplifiers having higher Slew Rate during the late-'70s/early-'80s, Consumer reports and a few other magazines repeated it, confusing many people who would go to the local stereo stores and have another spec to throw at us, so they could act likee 'experts'. Many brought their own experts, too. They would ask about slew rate, we would answer and it proved that they were interested in hearing that tehy wanted specs that showed more, not better. Reliability was a huge thing for us at that store and we saw all kinds of failures in various brands because we had service techs repairing the equipment that was supposedly better, but not reliable.

Why would you use a 606 on a tweeter that won't present a difficult load to it? SHow the Gallo tweeter and explain why it should be used if it actually presents a 1.6 Ohm load. While you're at it, I would like to know why Gallo can't be bothered to design their CDT tweeter to have a voice coil that doesn't present a difficult load.

BTW- the passive crossover on a tweeter should be able to remove the frequenies that cause the difficult load and when did woofer loads become "relatively ordinary"? Of course, the standard response will be "Because passive crossovers cause phase shift and takes away the best parts of the sound....."- good, reliable speaker design should include components that won't cause amplifiers to puke, not force the users to search high & low for an amplifier that will survive being connected to them.

You are correct. The issue is appalling speaker design and not bad amps. I have never designed a speaker that would put an amp at risk, and that should apply to commercial designers as well. If a speaker needs a monster amp, it is a bad incompetently designed speaker and you should avoid it.

 

[m. zillch]

Consumers don't know and they don't care, it's MORE.

Yes. The math is easy for them. The increase is not just "more": it's a substantial "2X," or "double". Who wouldn't want "double" the power of their existing amp? Them:"100w+100w=200w, right?" LOL

The math is also easy for the dealers pushing the myth but in this case their math is actually quite correct: Bi-amping/wiring = Bi-profitability.