Bi-Amping and The Law of Conservation of Ignorance

[bob p]

The Law of Conservation of Ignorance: A false conclusion once arrived at & widely accepted is not easily dislodged, & the less it is understood the more tenaciously it is held.

I ran into this phenomenon at one of the consumer audio forums dedicated to magnetic field amps. I made the mistake of asking what sort of active crossovers people were using to bi-amp their systems. As it turns out, I was the only person there who was familiar with the concept of active crossovers, and I was told that a bi-amped system that used active crossovers was "unnecessarily complex" and offered "no benefits." I was promptly run out for having spoken heresy, as everyone knows that "active crossovers are NOT needed for bi-amping." [sic]

Evidently, everyone there is happily running their systems using what some people call "passive bi-amping" or "Fool's Bi-Amping," in which no active crossover is used, and both amps are sent identical full range signals, and these signals are sent to speaker arrays containing passive crossovers. <sigh>

The funny thing is that I found the Law of Conservation of Ignorance referenced at the Klipsch Forums in a bi-amping thread. I thought it was pretty funny, so I thought I'd share it here.

[Tom Phillips]

Bob,
Interesting but not surprising experience you had. I don't even try to participate in any audiophile forums because I can't seem to have a rational exchange of information. However, they are often interesting to read. It is tempting to come up with a magic product to sell like the $450 wood volume knob that improves the performance on your amp. Imagine what those guys would do to me if I told them that I utilize D130Fs in my stereo system.
Regards,
Tom

PS: I haven't forgotten about that scan you requested of the old Dynaco catalog but times have been crazy busy for me.

[mashaffer]

Were none of them using PLL crossovers?

mike

[bob p]

Bob,
Interesting but not surprising experience you had. I don't even try to participate in any audiophile forums because I can't seem to have a rational exchange of information. However, they are often interesting to read.

Well, if you want to witness an episode of me being dumb enough to bang my head against the wall, read this. Its only a couple of pages:

http://www.carveraudio.com/phpBB2/vi...r=asc&start=15

What I find most entertaining about the whole conversation essentially boils down to a syntax issue. There are some people who say things like, "Language is fluid, and definitions change." Another person's viewpoint might be, "Definitions don't change. People who don't understand them just misapply language." I think the bi-amping thread is a classic example of that.

[bob p]

Wow. I didn't realize how widespread the misconceptions were about what it means to bi-amp. I googled for the phrase "fools biamping" and found this rather funny conversation. It essentially tells the exact same story that I ran into at the mag amp forum:

I think that there are many terms whos meanings change depending on the context in which you use them. Each field tends to develop it's own lingo and it just so happens that pro-audio and hi-fi have different definitions to the term "bi-amping". This doesn't make either of them right or wrong. To break it down bi means two and amp means amplifier so no matter if it's passive or active, if you use two amps you're bi-amping.

domestic audio stands alone in using 'bi-amping' as a catch-all phrase for the use of two amplifiers.

I think that your statement is possibly correct, BUT domestic audio has difference lexicon than the other two audio fields that you mention. Over time, in the world of domestic hi-fi, bi-amping has come to be accepted as meaning that two amps are used, either passively or actively. Language is constantly evolving and meanings sometimes change over time, or are adapted to specific usage. I'm sure that the term "Near-field listening" conjures up a different idea to somebody in the recording industry than it does to somebody in the home audio field. In the long run, I doubt that the terms really change the end listening experience anyway.

I don't agree that domestic audio has a different lexicon than car audio or pro audio. I think we have people who use technical language colloquially and incorrectly because they don't know the difference.

How funny!

The moral of this story is that I'm done looking for advice on the internet. I'm just going to buy a RANE active crossover and be done with it.

[Tom Phillips]

Holy oxygen free, gold plated hospital grade plug power cord. What fun.
I never considered bi-amping to be anything but with the crossover before the PA.
Now I think a need a bi-drink (A good stout beer and a shot of single malt) But I can't drink it in my listing room because the evaporation off the whiskey changes the density of the air around my chair and destroys the sound balance.

Anyway...I'm surprised they didn't get into a discussion of phase distortion.
Later,
Tom

[David Schwab]

Oh lordy be!

So, using their reasoning, a stereo (two channel) amp is a bi-amp?

That totally ignores the benefits of running two amps for highs and lows.

I had a nice GK-800RB bi-amped bass rig once.

http://en.wikipedia.org/wiki/Bi-amping

[Tom Phillips]

This looks like a good candidate for a Bi-Amped system.

[bob p]

Are those your JBL woofers in your home stereo, Tom?

[Tom Phillips]

Only the left channel

[bob p]

Oh lordy be!

So, using their reasoning, a stereo (two channel) amp is a bi-amp?

That totally ignores the benefits of running two amps for highs and lows.

Yes, they're not doing any separation of HF and LF at all. I was shocked when I read that, and I thought that this practice was contained within a close knit community. But when I looked around, I found that the same methods are actually quite widespread in the HiFi home audio community.

It would seem that a great many people don't want to be unnecessarily confused by the kinds of technical considerations that get used in pro audio, and the common response seems to be "that approach is unnecessarily complicated." To me, it looks like what this segment of the HiFi community calls "Biamping" or "Passive Biamping" is in reality nothing more than parallel amplification. Somebody coined the term "fools biamping" to describe it.

[bob p]

Only the left channel

Whew! I feel better now. I was worried that you were going to tell me that it was the center channel of your 7.1 surround system.

tom, I love that photo. where did you find it?

[Enzo]

Stereo would not be biamping because the two amplifiers serve different channels. Biamping refers to a single channel with individually powered drivers.

I must be old fashioned. To me biamping means separate amplifiers for the separate drivers. Period. WHile in pro audio we would never use full range amps and passive crossovers, we would always use an active Xover, but either method meets the test. personally I think the audiophole method is silly, but we don't lack for silliness in the world of guitars and pro audio.

Without reading all the arguments, I would guess the audiophiles would revile an active Xover as yet another thing in the signal path to add distortion or whatever it is that things in the signal path add. The passive Xover in the speaker they do not think of as an impediment to the signal path it seems.

If you want to get them: they don't want that active in there, yet they need to split the signal to both amps. We wouldn't want to have the front ends of the amps intyeracting in anay way, so there would need to be some sort of buffer stage there - another thing in the signal path. Oh dear...

[Tom Phillips]

tom, I love that photo. where did you find it?

Tripped across it surfing the net some time ago. Can't remember where but it was so cool that I saved it to my JBL folder
Tom

[Arthur B.]

Were none of them using PLL crossovers?

mike

What does a phase locked loop have to do with a crossover? Anyway, it seems that the crux of the problem is that they can't understand the concept of a passive crossover.