Turn a lot of floorstanders and some bookshelf speakers around and you find not one pair of binding posts but two — four terminals, usually joined top-to-bottom by a pair of little metal bridges called jumpers. That layout is an open invitation to a question that has fuelled hi-fi forum arguments for decades: should you bi-wire, bi-amp, or just leave it alone?
This guide explains what those terminals actually connect to, the three ways to wire them, and — being honest about the evidence — how much difference each one really makes.
Why there are two pairs of terminals
Inside a passive speaker sits a crossover — a network of components that splits the incoming full-range signal and sends the highs to the tweeter and the lows to the woofer. In a speaker with dual terminals, that crossover is built in two separate sections — a low-frequency section and a high-frequency section — and each section is wired to its own pair of posts. The metal jumpers simply reconnect the two so a single amplifier feeds both, exactly as if there were one pair of terminals.
So the terminals aren't a feature you must use — they're an option the designer left open. With the jumpers in place and one cable, the speaker works exactly as intended. The debate is only about what happens if you remove the jumpers and wire the two sections separately. (The internal crossover is the same one covered in Cabinet, ports and crossovers.)
Single-wiring: the default, and it's fine
One amplifier, one pair of speaker cables, jumpers in place. This is how the large majority of systems are connected and there is nothing second-rate about it. If you take one thing from this guide, it's that single-wiring with a good cable and clean, tight connections is a perfectly high-end way to run a speaker. Everything below is about small, optional refinements — not about fixing a problem.
One small tip that costs nothing: the stock jumpers on cheaper speakers are often thin stamped metal, and replacing them with short lengths of decent cable, or good aftermarket jumpers, is a more reliable improvement than any of the fancier schemes below.
Bi-wiring: one amplifier, two cables
Bi-wiring removes the jumpers and runs two separate cable pairs from the same amplifier terminals — one to the low-frequency posts, one to the high-frequency posts. There's still only one amplifier; the split happens in the cabling.
The theory offered is that keeping the large, distorted return current drawn by the woofer out of the tweeter's cable stops it from contaminating the treble. It sounds plausible, and it's the argument you'll see repeated everywhere.
The honest verdict: because both cable pairs still meet at the same amplifier output, any measured difference from bi-wiring is extremely small, and controlled listening tests generally don't support an audible improvement. If you already own two runs of cable it's harmless and cheap to try; it is not worth buying a second set of expensive cable for, and it is not the upgrade the internet sometimes makes it out to be.
Bi-amping: two amplifiers, and here it splits in two
Bi-amping uses a separate amplifier channel for the low and high sections. This is where a real difference can appear — but only in one of its two forms, and the distinction matters enormously.
Passive bi-amping. You remove the jumpers and drive the LF and HF terminals from two amplifier channels, but the speaker's internal passive crossover is still in place, doing the filtering as before. Each amplifier now handles only part of the load, which frees up headroom and keeps the woofer's heavy current demands off the amp channel feeding the tweeter. The benefit is real but modest, and it comes with a catch: the two amplifiers must have the same gain, or the tonal balance shifts — mixing two different models, or an amp with tone controls, can make things worse, not better.
Active bi-amping. Here the signal is split by an electronic crossover at line level, before the amplifiers, and the speaker's passive crossover is bypassed or removed entirely. Each amplifier is then connected directly to its driver with nothing lossy in between. This is a genuinely different and better arrangement: no power is burned in passive crossover components, each amp sees a simpler load, and the crossover can be implemented with far more precision (often in DSP). It's also much more involved — you need an active crossover or DSP unit correctly set to the speaker's design, and getting it wrong sounds worse than leaving the speaker alone.
The twist: an active speaker already does this
Active bi-amping done properly — an electronic crossover ahead of a dedicated amplifier per driver — is exactly what an active speaker is. The manufacturer designs the crossover, the amplifiers and the drivers as one system, matches their gains perfectly, and tunes the whole thing in the factory. You get every benefit of active bi-amping with none of the guesswork, because the person who designed the speaker also designed the amplification.
You can see it throughout this catalog. The studio monitors from Genelec, KRK, Adam Audio and HEDD Audio are internally bi-amped — two amp channels and an active crossover per cabinet — and the hi-fi active speakers from Dutch & Dutch, Kii Audio and Dynaudio take the same idea further with DSP. If active bi-amping appeals to you, buying an active speaker is the finished, guaranteed version of the experiment. The full case is in Active vs passive speakers.
Practical rules if you try it
- Always remove the jumpers before bi-wiring or bi-amping. Leaving them in shorts the two sections back together and undoes the whole point — a common and quietly damaging mistake.
- Match the amplifiers for passive bi-amping. Same gain, ideally the same model or two channels of one stereo amp. Mismatched gain tilts the tonal balance.
- Never do active bi-amping without removing the passive crossover — feeding a driver full-range from an amp with no filter in front of it can destroy a tweeter instantly.
- Spend on the room and the speaker first. Placement, the speaker itself and the amplifier's basic quality all outrank any wiring scheme by a wide margin.
The bottom line
Ranked by how much they actually change the sound: single-wiring is the honest baseline and all most systems ever need. Bi-wiring is cheap and harmless but, on the evidence, close to inaudible — don't pay extra for it. Passive bi-amping offers a small, real headroom benefit if you already have a second matched amplifier. Active bi-amping is the only version that transforms things — and the surest way to get it is to buy a speaker that was designed active from the start.
To see which speakers on TrueScale give you these choices, the spec sheets note active versus passive designs — read Active vs passive speakers next, or Amplifiers explained for how the amp end of this actually works.