Sound Science with Anthem dives into the engineering, innovation, and technology behind high-performance audio. From deep dives on amplifier design and speaker behavior to practical tips for getting the most from your system, we break down complex concepts into clear, engaging insights for enthusiasts and professionals alike.Does Passive Bi-Amping Waste Amplifier Power? Debunking the Myth
Bi-amping is a popular topic among audiophiles, but it’s often surrounded by confusion and misconceptions. One question we hear frequently is:
Does passive bi-amping waste amplifier power, since each channel still receives a full-range signal instead of just highs or lows?
The short answer: No. Not even close.
Table of Contents
Understanding Passive Bi-Amping
When you remove the jumpers on a bi-amp capable speaker, each section of the crossover no longer presents the usual 4 or 8 ohms across all frequencies. Instead, frequencies outside a section’s passband see very high impedance—sometimes hundreds of ohms or more.
Why does this matter? Because higher impedance draws less current. No meaningful current means no wasted power. Your amplifier isn’t straining to “push” signals that the speaker’s crossover is filtering out—it’s efficiently focused on the frequencies each driver is designed to handle.
The Active Crossover Myth
A common audio myth claims that bi-amping only makes sense with an active crossover, which splits the audio signal before it reaches the amplifier. The theory: each amp channel has less work to do.
While active crossovers have their place in professional PA systems, high-performance home loudspeakers rely on their passive crossovers, which are far more than simple frequency splitters.
A carefully designed speaker crossover:
• Corrects frequency response irregularities of individual drivers
• Maintains phase coherence between drivers
• Optimizes off-axis response
• Balances levels between drivers
• Manages impedance
• Protects woofers by rolling off frequencies that could cause distortion or misbehavior
Replacing this finely tuned network with a generic active crossover almost guarantees a change in frequency response. And just because the sound is different, doesn’t mean it’s better.
For most home audio setups, using the speaker’s passive crossover is the correct way to bi-amp.
What Is Bi-Amping?
Bi-amping uses separate amplifier channels for different sections of a speaker:
• Mid/High drivers – driven by one amp channel
• Low-frequency drivers – driven by another amp channel
Important: your speaker must have separate input terminals for highs and lows. Always remove the metal jumpers between terminals when bi-amping to avoid damaging your amplifier.
Why Bi-Amp?
One of the key benefits is headroom management. If the amp driving the woofer starts running out of power, the amp handling the mids and highs can continue to deliver clean sound. This reduces distortion in the frequency range your ears are most sensitive to—a real win for audio fidelity.
This same principle underlies bass management in home theater systems and the use of powered subwoofers.
Example:
Home Theater Systems with the Anthem MRX 1140
Scenario: Your home theater features a large 7.1.4 Dolby Atmos setup.
Benefit: Using the MRX 1140 to bi-amp your front left and right speakers separates the mid/high and low-frequency drivers. The woofer receives dedicated power while the mid/highs stay clean and precise.
Result: Explosive movie scenes have controlled, punchy bass without muddying dialogue or cinematic effects.
The Bottom Line
Passive bi-amping does not waste amplifier power. Your speaker’s passive crossover is intelligently designed to handle the frequency split internally, protecting your amp and optimizing sound quality. Active crossovers can be useful in professional setups, but in high-end home audio, sticking with the speaker’s built-in crossover is the smartest move.
Bi-amping isn’t about creating more work for your amps—it’s about distributing it efficiently for cleaner, more dynamic sound.
Experience the Power of Bi-Amping
Unlock the full potential of your loudspeakers with bi-amping. By separating the high- and low-frequency drivers onto dedicated amplifier channels, you get cleaner, more dynamic sound with improved control and detail. Anthem’s P Series and MCA Series amplifiers are engineered to deliver the precision and power your system deserves, letting every note come alive.
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