Originally Posted by Bill Fitzmaurice
It's called bi-wiring. It doesn't actually do anything, but enough people think that it does so that some manufacturers use bi-wire terminals to placate them, rather than lose sales. Connect the top to bottom with jumpers, use one wire to the receiver.
Originally Posted by flyng_fool
It does do something Bill. It looks cool!
Originally Posted by cel4145
And don't forget. It helps high end audio shops sell more expensive speaker cables
This is all true enough as far as it goes, but there are some constructive options here as well. None are easy, but the blanket rejection of any positive use of these two pairs of inputs is incomplete. Normally, these speaker terminals would have been connected at the factory by use of a strapping bar: red to red and black to black, and you'd simply attach a singe dual strand speaker wire and be done. The straps must be missing here. Were these used?
On a pair of speakers like the Studio L Series L880, there are at least two ways to use the two pairs of inputs with significant effect. Whether this significant effect is good or bad depends on the preference of the listener, but it's easily perceived. On some smaller bookshelf speakers and tiny monitors that have two pairs of inputs, even the following options are of negligible value, but for a (nearly) full range floorstanding loudspeaker like the L880, there is difference to be heard.
Option One: Some listeners prefer the power and damping control of a solid state amp for low frequencies and the sound of a tube amp for the mid and high frequencies. By connecting a SS amp to the LF inputs and a tube amp to the HF inputs, they feel they gain tight, powerful bass and more euphonious warmth in the mids and highs. This requires a little extra in the way of set up and balancing the gain on the outputs to each amp, but it's worth it to some people.
Option Two: Some listeners will buy an external crossover to connect between their preamp (or the pre outs on their receiver) to separate the LF and HF signals before they reach the amp. These separated signals are then fed to separate channels in the amp and connected to the LF and HF speaker inputs. So there'd be at least a four channel amp needed to do this. This allows the bass drivers to deal only with the LF signal and the MF and HF drivers to handle the rest. (The speaker's built-in passive crossovers are still doing the work of distributing signals to the mid range driver and tweeter.)
Option Three is a combination of both Options One and Two: An external crossover separating LF and HF feeding a SS amp for LF and a tube amp for HF.
Again, I didn't say these options are either easy or cheap, but it's fair to say that on a speaker like the L880, they are options that it would be useful to explore if one were so inclined. OTOH, the L880s will sound quite good in a typical, single wire set up, and I'd guess 97%+ are set up just that way.