Am I wasting money on the theory of Bi-amping?

Some refer to active configuration simply as "bi-amping," or tri-, quad- etc. ditto, as it requires running multiple amp channels to feed each their driver section. As such it’s an inherent necessity of active and its true asset compared to just bi-amping passively. Multiple-amping as an approach should at least have its specific implementation clearly outlined to avoid confusion, i.e.: whether it’s passively or actively configured, but no doubt the latter option holds the real advantage here.

@mikelavigne wrote:

bi-amping, in my experience, is best with 4 identical channels of amplification and a speaker allowing separate low octave and upper octave inputs. the reason is my priority is always coherency first and foremost. and if the amps for upper and lower octaves are different, unless the speaker is designed with those particular amps in mind, you will always fight for optimal coherency.

I fully agree. It’s a tempting route to try and tailor amps to their respective driver sections, which I’ve tried in my 3-way active setup, and while I’m not saying it can’t be done with a careful approach (or luck) the effect of hearing what similar amps can do by comparison, to me at least, has been the most convincing and rewarding. It requires of one the seek out the amp that "has it all," or certainly has a balanced presentation that ticks off the boxes to one’s preference over the entire frequency range, in regards to resolution, tonality, power capacity, etc. Once there I’ve not since looked back; it just makes the presentation fall into place more effectively.

@wolf_garcia wrote:

Ask yourself why almost nobody, including people who could easily afford it and wouldn’t mind the extra hassle, ever bi-amps home audio systems. Almost nobody

You mean actively? If so, then ask yourself how many have actually tried configuring their speakers actively. Not that many are aware of the fact that ’active’ isn’t defined preemptively as a bundled, all-in-one package, and as an outboard active solution intimidation creeps in with the thought of not least setting filter values by oneself. I can understand that, truly, but for someone who doesn’t mind the extra hassle and perhaps has a secondary system to experiment with, it’s just go ahead and do it.

No, by and large it’s not experience with actual intel to go by that keep audiophiles from venturing into outboard active bi-, tri- or whatever-amping, but rather the opposite and a bunch of conjecture. Conservatism as well, even dogma. Economy may be a factor to some, but it doesn't have to be expensive as such to go active. Use the same money on 2 or 3 cheaper, less powerful amps for an active approach. Many would be surprised to hear those cheaper, actively configured amps would likely, and rather easily hold on to the more expensive amp running the speakers passively. 

@panzrwagn --

Lot of interesting info, some of which I agree with, other that I don’t.

... the advantages proper bi-amping are clear: improved LF performance and dynamic range, but are most apparent only in high output (loud) applications. If your home listening never gets above 90dB or so, bi-amping is doubtfully a cost effective add-on . If you have a big system in a big room, it’s the only way to go.

I believe that’s shortchanging active a bit in its breadth and diversity of use. Yes, improved LF performance and dynamic range, but it goes beyond that to my ears with improved resolution, less smear, and an overall more uninhibited and tonally "accurate" presentation - at all volumes. Perhaps it’s the added "bonus" of active at elevated SPL’s with its better composure and precision here that to some makes for the more impressive take-away, which I cherish as well, but I find there’s much more to it than that.

@invalid wrote: 

what about passive line level crossovers?

I have no experience with them, but it seems the article provided by @ditusa has some bearing on their usefulness. 

that's just one person's opinion.

What specifically are you referring to here?

@asctim wrote:

... It was interesting to me that even though the digital crossover had to do A/D D/A conversion steps, people still noticed no obvious degradation in signal. It may have to do with the people chosen for the test. Over and over I get the impression that audiophiles are particularly sensitive to things that most people don’t notice, but also peculiarly unsensitive, or at least unconcerned with things that most people can easily hear as problems. Audiophiles have learned not just to listen, but to curate particular tastes.

This. 

@kraftwerkturbo wrote:

I now assume that horizontal/vertical deals with the option of using 2 stereo amp for the 2x2 'feeds'. Either one stereo amp for each SPEAKER or one stereo amp for the woofers and one stereo amp for the mid/high. If that is the case, what is considered 'vertical'?

'Vertical' bi-amping is one stereo amp driving one speaker, its two channels divided over the two pairs of terminals on that speaker. 

I read a few posts claiming BENEFITS of passive crossovers (vs active), but none mentions issues like phase shift from those passive components. 

And can't those mentioned 'beneftis' of passive crossovers not 'simulated' or realized in active crossovers as well? 

Active can do what passive does, and more - while not least getting out of the way between the amp and speakers. 

@asctim wrote:

With horn loading the problem is amp hiss gets highly amplified.

Indeed, but using a 16 ohm driver - if available - will help knock down hiss noticeably as well.

@btbluesky wrote:

Amp hiss, is not a normal thing. It’s a product of "too much gain in chain" + "not so good amp". I can crank up to over-concert level, and theres no distortion.

It doesn’t fall back on a "not normal thing" or a "not so good amp." High sensitivity, as has been stated just above, simply amplifies noise. If you removed the passive crossover from your JBL 4367’s and connected your amps directly to the compression drivers, I can assure you hiss would be audible to some degree - and yet your amps are the same; they didn’t suddenly get bad in the absence of passive crossovers (in fact they’d get better).

It’s great though you’ve found a good pairing amp-wise with the JBL’s.

@russbutton --

+1

Another major benefit is that you can use much, much lower powered amps when you use active crossovers. A lot of power is wasted having to push through a passive crossover. You really don’t need to push many watts into a tweeter or mid-range driver to get a lot of level out. You could even run a single ended tube amp on your tweeter, and a mid-level tube power amp on your mid-range driver, and a solid state amp for the bass driver. You have a lot of options.

Options are plentiful, yes. To me though the lesser power needed over the entire frequency range actively would be better served by spreading it out evenly, so to ideally use the same amps top to bottom, or certainly the same amp series/topology with a differentiated power approach for better coherency. To me coherency always comes first, and using similar amps is vital for this to come true in the best way.