Question about Active Bi-amping

Curious about Active Bi-Amping.

My understanding is that to setup an actual active Bi-Amp (with compatible speakers), you would need either 2 mono block amps per speaker or 2 stereo amps and a External Crossover?

Would the Crossover in the Speaker need to be bypassed or removed?


If you were to do Passive Bi-Amping, you would connect each amp directly to the speaker terminals but how would you connect the Amp Signal connections back to a pre-amp or Integrated since most are only have a a simple left and right output?




                                        ---amp one---to tweeter/midrange

preamp---to crossover                          

                                        ---amp two---to bass 

Hey OP.

Your count of amplifier channels is correct.  You would need 1 channel per driver.

In an ideal situation, the speaker crossover is entirely removed.  However this is complicated for a number of reasons.  Crossovers are more than just frequency filters.  They also provide level matching and equalization.  DSP crossovers are supremely convenient for this as they can do all that plus delays.

I suggest before you experiment on anything fancy consider a simple test rig to learn more about this.  Get a pair of inexpensive 2-ways or kits, a miniDSP and a pair of cheap amps. 




"If you were to do Passive Bi-Amping, you would connect each amp directly to the speaker terminals but how would you connect the Amp Signal connections back to a pre-amp or Integrated since most are only have a a simple left and right output?"

You would need 2 Y-Adapters! 


 As @erik_squires noted, with most speakers the stock/internal crossover is not simply a set of filters that divides the entire input signal into two separate frequency bands, one for the woofer the other for the tweeter (or tweeter/midrange driver). The internal crossover in most loudspeakers also includes components (resistors, capacitors, etc.) that tailor the response of the drivers. External analog crossovers provide only "textbook" filters (1st/2nd/3rd/4th-order, which creates a 6, 12, 18, or 24 dB roll-off at the top or bottom of a driver's response). A textbook crossover can NOT provide driver compensation networks. It couldn't, as all loudspeakers have different ones for their specific drivers used in the way the speaker designer employs the drivers.

However, there ARE some loudspeakers which have internal crossover which do not include driver compensation networks. Magnepan, for instance. In Magnepan's pre-.7 iterations of their loudspeakers, the drivers were run in parallel, so they could be separated from one another for bi-amping. When Magnepan introduced the .7 version of each model (1.7, 3.7, 20.7) they went to a series configuration, which means the drivers can not be separated for bi-amping (at least not without doing "surgery").

Thanks everyone for your feedback, I will review the info that you have provided.

@ditusa , right now I am just contemplating and researching the topic.

I have Martin Logan Motion 40's and wouldn't mind getting more performance out of them.

@jay73 Wrote:

@ditusa , right now I am just contemplating and researching the topic.

I get it. See the article below last page bi-amplification.


@jasonbourne52 , Thanks for the feedback.

What speakers would you suggest?

Here is some of the equipment that I am working with currently:

- Sugden A21SE Integrated
- Vincent SV-500 Integrated

Going back and forth on the Integrated's to see which one I like

- Mofi Studio Deck with Hana SL

- Sim Audion Moon 110 LP V2 Phono Stage and Jolida JD9 MK II

Once again, using both back and forth

- Questyle CMA400i DAC

- Technics SLG-700 SACD

Let's say a budget of $5000

But wondering, if I were to consider other speakers, would I need to really make a huge jump to witness a difference?



In the case of ATC (which I import to the US), there is no driver compensation, just filtering. One would completely remove the driver connection to the [passive] crossover and install a new connection straight to an amplifier, with an active crossover determining level, slope and frequency. This is not an easy thing to know and is usually beyond most of us to "self calibrate" the speaker without measurement equipment and a lot of the technical data on what the final curve should look like.

I can recalibrate ATC’s in my shop when drivers are replaced or upgraded, but I have a $12K measurement system with an Audio Precision device (a computer basically designed for measurement) and special acoustical software and a "calibrated to the computer" mic for the measurements. I know no one could do that at home, even if they had the gear, because knowing what the original curve was or should be is critical to avoid changing the way the speaker sounds dramatically. Experimenting, one could easily ruin the sound of a system and not know how to get it back without sending it back to the factory.


@jay73 Wrote:

What speakers would you suggest?

Let’s say a budget of $5000

Look for a nice used pair of JBL 4429’s and you can passively bi-amp them. 😎




With the two integrated amps you mention you can only do passive bi-amping with speakers that are designed to be bi-amped. I believe you should be able to connect  all of your sources to one amp then use the preamp outs from that amp and connect those to one of the inputs of the second amp. You can then connect the speaker outs of the first amp to either the low or high inputs of the speakers and the second amp to the other speakers inputs.

You would need a different preamp/amp set-up in order to use an active crossover and unless you wanted to add subs to your system, it's probably not worth doing.


I hate to be the heavy, but I would not even bother trying to bi-amp in the way you are considering. In short, you won't be getting any better sound from your system.

Believe me, it has been tried many times, and as you can see very few amps allow you do this without going through hoops.

Unless you just have to try it out, I would put my money and efforts into getting the best equipment for the speaker that you love.


@gdnrbob , Hey no worries. That's why I posed the question, to see if it's even really worth it.

The Logan's sound good, I was just curious to see if I could squeeze out a little more from them.

@jay73 --

Active bi-amping, for the term to make sense at least, requires bypassing the passive cross-over and moving instead this part to function prior to amplification on signal level as a DSP or electronic XO for direct amp-driver control. As has been pointed to already, I too would suggest getting your bearings with this approach via a second setup, unless you’re the industrious and courageous type that jumps head first into these affairs with your main rig.

With similar stereo amps and 2-way main speakers you could further experiment with vertical vs. horizontal bi-amping. Or, using different amps to their respective driver segments in a horizontal configuration and see how that fares for you, like tube amps for the MF/HF section and solid state ditto for the lower frequencies; class A lower wattage SS for the highs and high power class D for the lows, etc. Try challenging any accepted thoughts here and turn things on their head, if nothing else to be the wiser with first-hand knowledge according to your own ears. Sometimes things turn out differently than one would’ve expected or has been told.


New speakers are a great idea for the next upgrade. Speakers really impact the sound of your system, so are worth really investigating. You should audition them. You want speakers that really connect with you. I would recommend listening to: Sonus Faber, B&W, Magneplanar, (lots of warm power required to drive these), a higher level Martin Logan, Dynaudiio. If you can spring for something in the $5K ballpark you are going to have speaker of tremendously greater potential.

If I were to consider new speakers or additional speakers, Pearl Acoustics Sibelius or Omega Speakers have caught my attention.

The Omega line of Speakers seem more affordable also and look like quality Speakers. I think either brand would match up well with the Sugden Integrated that I have.