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


As a long time audiophile I'm finally able to bi-amp my setup. I'm using two identical amps in a vertical bi-amp configuration. 
 

Now me not fully understanding all of the ins/outs of internal speaker crossovers and what not. I've read quite a few people tell me that bi-amping like I'm doing whether it's vertical or horizontal bi-amping is a waste since there's really not a improvement because of how speaker manufacturers design the internal crossovers. 
 

Can anyone explain to a third grader how it's beneficial or if the naysayers are correct in the statement?

ibisghost

I have actively bi-amplified my Magnepan 3-series using an external active crossover (Marchand). You have to have a decent crossover or it’s a waste.

My take was that the active bi-amping was a complete sea change in sound. As it should be since you are using an entirely different crossover network and the crossover is before and not after the amplifier, so the amplifier is freed to fully power the drivers it’s connected to. Worked very well.

But that’s because Maggies have that biamp capability without surgery. You have to take out the internal crossover network in speakers to do this right. With most speakers I’d say it probably isn’t worth the risk or effort. The speaker designer had the crossover network in mind. Magnepan clearly had active biamping in mind.

So, in limited circumstances it can be a huge improvement. But, limited circumstances. Biamping without taking out the passive crossovers is just a bit more oomph in power but at the cost of a lack of consistency. I wouldn’t do that.

I biamp in one of my systems.  I use a pair of mono amps to handle the bass and a different pair of mono amps to handle the mids and highs. The mid/high have the bass rolled off using high quality caps at the amp inputs and there is an adjustable unit to balance the bass (which goes through untouched) with the mids/highs.

This is the system that Richard Vandersteen uses and it works very well with my big Vandersteens, although many would prefer to avoid the complexity of four mono amps with an external adjustable crossover for the bass.

Does it sound better done this way?  I was pleased to find that it does and the improvement warranted the extra system complexity.

Whether you would get the same gains depends entirely on your particular system.

Seems biamping in an ideal way would be using a tube amplifier for upper drivers, and solid state for bass. I believe it's widely accepted that tube amps for bass drivers presents lots of less than ideal issues.

To me using solid state across all drivers when biamping will have benefits but if you go to this trouble you might as well go all the way with tubes.

 

 

Panzrwagn

"2) "Passive Bi-amping" is BS. You’re still delivering a full range signal to both the LF and MF/HF passive crossovers, the unused half of the signal is just turned to heat."

This is not true. There is no signal flowing through a circuit at frequencies that are filtered out by a crossover network, subject to the slope of the filter. The crossover network doesn't create an offramp for the filtered frequencies to be converted to heat.

OK folks. Listen up. Here's WHY active crossovers are so very much better than passive. A single loudspeaker driver is an inductor, and provides a frequency dependent, reactive load to an amplifier. Looking at the image here, the blue line on the bottom is the frequency dependent impedance curve for an SB Acoustics SB29RDAC Ring Dome Tweeter, and it typical of any dynamic tweeter. As you can see, it is anything but flat, yet it is listed as having a 4 ohm impedance. It's 4 ohms at about 1200 hz, but at 600 hz, has an impedance of nearly 10 ohms.

Now if you put a passive crossover circuit in front of it, you add capacitors, resistors and inductors, which then give you a frequency dependent impedance curve which looks like a Coney Island roller coaster. And that's just for a tweeter high-pass circuit.

Now when you add in mid and bass drivers, with high and low pass filters there... It's a real mess. But we're not done there yet. Nope. Many of your extreme hi-end loudspeakers add in equalization to their crossover designs, which makes that impedance curve even worse. This is very hard for an amp to properly manage. That's why people drop many, many thousands of dollars on things like Krell, Threshhold, Bryston, or Rowland Research solid state power amps.

Now when you use an active crossover, an amp channel only has to manage a single driver. There's no passive, reactive component in between the amp and the loudspeaker driver. Then you don't need a megabuck amp to deal with it.

All of the Linkwitz loudspeaker designs use active crossovers. Earlier designs used analog crossovers, but his last designs were all digital crossovers. There are some digital crossovers that offer DSP EQ, which allows you to tailor the total system response for the room you are in. Then you're not just limited to whatever sound your speakers give you in the room you're stuck with.

The lowest cost active crossovers are typically pro grade, from manufacturers like Behringer, dbx, Rane or even Nady. There are many manufacturers. Some of the best known home audio digital crossovers are from miniDSP.

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.

So instead of dropping $7,000 on that Threshold Stasis 8.0 power amp. You could spend much less on an active crossover and the various much more modestly priced amps of your choice.