Biamping IS active. Unless you're running full range signals to both amps and still using passive crossovers, in which case you've thrown away any advantage of biamping as opposed to just using a bigger single amp.
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Help with biwiring logic
- Thread starter garbulky
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fpitas
Master Contributor
That's what I was talking about. There's very little reason to biamp otherwise.
fpitas
Master Contributor
Time for this again:
sound-au.com
BiAmp (Bi-Amplification - Not Quite Magic, But Close) - Part 1
ESP - The Audio Pages. How to biamp or triamp your hi-hi speaker system for greatly improved sound, and higher sound levels with less distortion.
restorer-john
Grand Contributor
There's a lot of ill-thought out, blanket statements about monoblocks and bi-amping in this thread. It's not so black and white.
Ken Tajalli
Major Contributor
We were talking different scenarios then.
What you are describing is reffered to as Active speaker operation, which incidentally Meridian has been promoting for decades.
The biamping I was reffering to, was the other method.
Using an extra stereo poweramp and power each speaker (not drive) separately.
As I had explained before, this method is a simple, cheap upgrade add on method, by just buying one extra poweramp.
Ofcourse if you already have a capable, powerful amp, there is no point. But with mid-budget equipment, there is some benefit, not a lot, but there is.
My first post stated, that I thought those extra posts on the speakers were for that purpose, which made some sense, against biwiring which made none.
Perhaps you guys can just scroll back.
Google search on biamping:
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What you're referring to is passive bi-amping, more a marketing invention than anything useful. Cheap is buying an extra power amp instead of a simply sufficient one in the first place?
Ken Tajalli
Major Contributor
The term Active was used, back in late 70s (to my knowledge ) to separate the mode of operation from Passive crossover. An Active xover circuitry was employed instead of Passive.
Whether it had to be biamped, tripleamped etc, was just a necessary step, so those term, at least in UK, wasn't used to mean Active mode, as it would have been confusing.
Linn Isobariks of 70s could have been driven with an Active analog xover and then necessarily tripple amped.
To use the term "biamping" reffering to all Active speakers would have been nonsensical.
The biamping I was reffering to, was not a solution (I am repeating myself again), but it was an optional afterthought, should one wanted to upgrade without dismantling his system.
Again, if you already had a good powerful amp, there would have been no point. But many would start up with a simple playback system. then a year down the line, without parting with their equipment, could add on a second poweramp for this purpose. A few UK brands, offered poweramp duplicates of their existing popular integrated amps, for this very purpose.
It worked with mid-budget lower power setups.
All you had to do wad buy the amp for a couple of hundred pounds, and hey presto, you had doubled your power output. (I know, only 3dB
)we are talking, afterthought , cost effective, optional addon here. Not something that one should start off with.
Some speaker manufacturers, offered extra posts, again for this purpose .
Then some questionable cable manufacturers, used the opportunity to promote biwiring!
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Passive bi-amping used to mean a passive (RLC) line-level crossover instead of an active (transistor or tube) line-level crossover. AVRs and speaker manufacturers introduced the concept of "passive" bi-amping which they (re)defined to mean sending the exact same signal to two different amplifiers (often in the same box) and depending upon the high-level crossovers built into the speakers. Thus there is no voltage headroom gained in the amplifiers since both amplifiers must be able to handle the full frequency and voltage range of the signal as if one single amplifier was used. Power is not "doubled" in this scenario though the power delivered (and current, but not voltage) is determined by the signal sent to each crossover. The HF amp may be required to produce less power than the bass section, but even that is not guaranteed since the HF band is frequently much wider than the bass band.
The only practical benefit of so-called passive bi-amping is if the single amplifier is current-limited or of such poor performance and/or high output impedance that separating the HF and LF loads (speaker sections) reduces distortion caused by output modulation of the amplifier (again due to current limiting; the voltage demands are exactly the same for both amplifiers).
There is a theoretical benefit for some extreme cases, which of course leads to manufacturers' marketing feeding into audiophiles' psychoses' to sell more amps.
You could, of course, insert a line-level crossover before the amplifiers and drive into the LF and HF terminals of speakers retaining their internal crossovers. But you'd have to ensure the line- and speaker-level crossovers interact productively or you'll have squirrelly (bad) frequency response.
The only practical benefit of so-called passive bi-amping is if the single amplifier is current-limited or of such poor performance and/or high output impedance that separating the HF and LF loads (speaker sections) reduces distortion caused by output modulation of the amplifier (again due to current limiting; the voltage demands are exactly the same for both amplifiers).
There is a theoretical benefit for some extreme cases, which of course leads to manufacturers' marketing feeding into audiophiles' psychoses' to sell more amps.
You could, of course, insert a line-level crossover before the amplifiers and drive into the LF and HF terminals of speakers retaining their internal crossovers. But you'd have to ensure the line- and speaker-level crossovers interact productively or you'll have squirrelly (bad) frequency response.
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restorer-john
Grand Contributor
This is correct. Active crossovers were pretty big in the 1970s for audiophiles with decent budgets. The major Japanese manufacturers has some wonderful active (line level for insertion into pre/power or tape loop) crossovers for use with multiple amplifiers (bi/tri amplified etc).
I don't think anyone would use the term that way.
Active loudspeakers are simply loudspeakers with built in amplifier/s. They may have active crossovers either in digital, analogue, or even in some cases, passive internal crossovers.
Bi-amplifying loudspeakers with internal passive crossovers is also quite valid.
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restorer-john
Grand Contributor
Bi-amping with passive crossovers intact (bi/tri wired at the terminals with the shorting bars removed) generally will mean each amplifier will see an easier load than it would driving the entire speaker system. Also by keeping the passive crossovers, mid/high drivers are protected against DC events and the attenuation provided by those networks reduces residual noise as opposed to active designs with the crossovers being done prior to amplification.
Not only that, amplifiers can be chosen for their strengths- say an ultra quiet (low residual noise) /medium power amplifier for mid/highs, particularly with horns and a powerful amplifier for the low/mids. Levels can also be more easily tweaked as well.
Bi-wiring on the other hand (simply paralleling speaker cables to the 'separate' speaker terminals) is just a complete waste of time.
Not only that, amplifiers can be chosen for their strengths- say an ultra quiet (low residual noise) /medium power amplifier for mid/highs, particularly with horns and a powerful amplifier for the low/mids. Levels can also be more easily tweaked as well.
Bi-wiring on the other hand (simply paralleling speaker cables to the 'separate' speaker terminals) is just a complete waste of time.
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Ken Tajalli
Major Contributor
"Powered speaker" term, is used for those with internal amps, but with passive crossovers.
First domestic Active speaker was Meridian M1, with active xover and dedicated triple amps in 1977!
@DonH56
You are correct.
If one stereo amp is used per side, the bass side would use the lion's share of the current available, since with music, the treble part is usually many many dB's quieter, regardless of bandwidth.
Again, this afterthought, was beneficial to mid-range equipment setups.
For what we think of as passive bi-amping, agreed. But for passive bi-amping the way these AVR manufacturers have defined it, the load part may be true, but you must have amps with the same power (or at least voltage) rating since the input signal to each amp is identical (full range of frequency and voltage). The "new" scheme confused the heck out of me (and got me into hot water in some forum debates) until I understood what they were doing. It is basically an easy way to make customers feel good by connecting the "unused" amplifier channels in a multichannel AVR to the speaker, even though the extra channels have the same voltage requirements as the original single channels.
The loading part is why I said power and current will be different from each amplifier, but not the voltage.
I miss the days when real crossovers were included in some preamps and integrated amps. Today they are found mostly just in high-end AVR/AVP units (my Harman Trinnov processor is one).
Of course, almost every AVR owner is using one active line-level crossover -- for their sub(s).
Ken Tajalli
Major Contributor
Correct on every point.
thanx
Yes, that's where there's an actual benefit. It's what I did for my NHT 3.3 mod, pulled a bunch of components out of the passive crossovers (all of them for the woofer), put in a time delay and EQ, and actually got deeper bass, higher SPL, and better integration between top and bottom.
Of course, the various active speakers around my house (Vanatoo T0, T1+, and Kali LP-6) all run separate amps for tweeter and woofer, so take advantage of the extra electronics.
restorer-john
Grand Contributor
Pretty sure the Philips MFBs (domestic and studio) beat them to the punch from the early 1970s:
Philips RH 545 Studio | Inner Magazines
The RH 545 Studio was Philips’ most advanced MFB loudspeakers monitoring its own playback through a feedback loop.
www.inner-magazines.com
Ken Tajalli
Major Contributor
Well . . . .Pretty sure the Philips MFBs (domestic and studio) beat them to the punch from the early 1970s:
Philips RH 545 Studio | Inner Magazines
The RH 545 Studio was Philips’ most advanced MFB loudspeakers monitoring its own playback through a feedback loop.www.inner-magazines.com
That's a servo speaker.
There is no xover circuit of any type.
Ken Tajalli
Major Contributor
restorer-john
Grand Contributor
Have a closer look...
Active crossover, two separate amplifiers (bi-amped), one with MFB, the other with a passive Xover for the mid/treble units. All inside one box.
I think you are mainly referring to power capability.
So if you have (say) a 100W amp that is capable of delivering 100W both channels continuous without clipping, then by purchasing another identical amp, you can gain some power by delivering one channel on each side to the tweeter.
But with a typical 3KHz crossover, there might be an 85%:15% split between woofer and tweeter. So you can now deliver 100W to the woofer and then maybe 18W to the tweeter.
So you have gained a total of 0.72dB of peak power, at a cost of one full 100W/channel amp.
I guess you might argue that each amp is also now having an easier life, but `i would say that is pretty meaningless if you are playing real music without clipping, since the actual average power is probably already only 10% or less of the amp continuous rating. Biamping only reduces that to 6%
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