Vertical bi-amping. Impedance issues at all?


Bronze Member
Username: Varney

BirminghamEngland, UK

Post Number: 15
Registered: Sep-04
Would impedance change significantly with vertical bi-amping?

I'd like to try vertical bi-amping, using two NAD stereo integrated amps. Nad, unlike many other amps I know, always include a switch for mono operation. In this setup, each terminal pair (left and right when set as 'stereo') of the (now set to mono) amp would be connected to a driver (or driver network) of it's own. I think the crossover arrangement in my speakers has both midrange and bass together, while the tweeters appear to sound on their own when bi-wired. Of course, I have the bridges removed that originally strapped the speaker terminals together for this.

So - using what used to be a left channel would be driving the bass/mid speakers and the right channel driving the tweeters.

Audio interconnects from source would be split across those amps, simply by putting the right channel into the right amp and the same for the other side. Then set both amps to 'mono', sending the signal across both channels of each.

I've read somewhere that the input signal should be split using Y adaptors - but it's the simple reason that the amps can be set to mono, that I haven't bothered thinking about these.

Would it be better to leave them set to 'stereo' and actually buy a pair of Y splitters for this?

No control amp will be present. Both volume knobs will act instead of any balance control and I guess the balance controls of each amp will then be balancing treble and bass, rather than left/right.

My main concern, however - is a question of impedance - and therefore, safety.

Both amps can be set to 4ohms and I have 4ohm speakers, so on the surface of things, looks fine but this might be a statement of impedance for the speaker system as a whole. How would this change when I start running different cones into seperate channels?

The question isn't really meant to address possible sound quality - my ears will tell me if it's right or not. The question is more whether impedance wise, it's safe to do this.

Any ideas?

Thanks in anticipation,



Silver Member
Username: Fryguy

Nova Scotia Canada

Post Number: 241
Registered: Jun-04
Your questions have simple answers. You have supplyed lots of information, thank you as many dont say naything detailed and leave me guessing.
so its No, No, not much because of the crossovers on diffrent drovers that split the load at different frequencies and final answer yes your more then safe to do that with your amps.

Silver Member
Username: Fryguy

Nova Scotia Canada

Post Number: 258
Registered: Jun-04
My article and many more topics can be found at this waii answer the resistance and impedance question you have.
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