Bi-amping and Tri-amping: why and how

Why: Because manufacturers know that audiophiles often use poly-amping (bi- and tri-amping), so by making their speakers bi-ampable (or look like they are bi-ampable), they make the speakers look like they are higher quality. But the vast majority of speakers with two sets of inputs are not truly polyampable. They are poly-widable. What’s the difference, it’s all about an important part inside almost all speakers called the crossover .

Understanding turnouts and the benefits of poly-amping

Most speakers have at least one passive crossover inside. That’s why, when you connect a single set of wires to your amplifier, the full-range signal comes out of all the drivers (cones) in your speaker: the high frequencies go to the tweeter, the bass goes to the woofer, and so on.

The passive excursion inside most speakers cannot be adjusted, and for good reason: the excursion points are matched to the transducers in the speaker. These passive turnouts inside the speaker convert up to 30% of the energy from the amplifier into heat, which is not exactly ideal for high sound quality. Each component in the turnout partially degrades the sound. By bypassing this internal turnout and amplifying each transducer in the speaker with a different amplifier via an external electronic turnout, only the appropriate frequency band is sent directly to the transducer.

Tri-amping allows us to tune the split frequencies to the specific shape, size and character of the reflective sound of our room. It also allows us to adjust the gain (volume) of each frequency band, lending us another tool to fine tune our stereo or HT to our room. But if the internal turnout inside the speaker is omitted, then none of these adjustments will improve the sound! In fact, the sound will be worse than ever because our outer and inner turnouts will be working on top of each other.

The difference between Tri-amping (amazing!) and Bi-wiring

When a speaker is Tri-amped, the internal passive turnout inside the speaker is omitted. Most speakers you find in the store-and even products sold in specialty stores and hifi studios-do not allow you to bypass the internal turnout, even though they appear to allow Tri-amping by having two or three sets of speaker terminals.

The manufacturers of these speakers (with more than one set of terminals, but no way to bypass the internal turnout) recommend bi-wiring speakers. Bi-wiring is when you run two sets of wires from one amplifier and into two sets of terminals on the back of the speaker. The truth is that bi-wiring does not provide any of the benefits of bi-amping, other than the appearance of a more technically advanced setup and higher quality speakers.

The whole reason we talk about tri-amping is because the sound is better and more complete. We’ve already talked about how to achieve fine-tuning of x-over frequencies and amplification of each frequency band, which helps customize the sound for your specific room. The benefits of this are immense and are reason enough for a Tri-amp.

Tune the x-over points and amplify the frequency band:

Every room is different, and contrary to what most sales people will usually admit – there can be a big difference in your room’s sound. Also, contrary to what you may have heard the speaker, no matter how “good” it is, it usually needs to be adjusted and balanced to compensate for the room shape, size and acoustic-reflex characteristics.

Tri-amping with an adjustable active electronic crossover goes a step beyond conventional equalization, allowing you to adjust the x-over points and gain for each transducer in your speakers.

To customize the sound of your room, start “wiggling” the mid/low x-over points until the sound is “just right”. Listen. Then adjust the mid/high x-over point. Listen. Next, adjust the gain of each band, listen and repeat. Finally, you will have the sound perfectly tuned for your listening room!

Have a wonderful musical experience.