Thought I might expound a little on the previous comment, as this is somewhat confusing the way Vienna has set this up.
Vienna has two seperate players for their soundfonts depending on which version you purchase. The Synchron libraries use the Synchron player, the Vienna Instruments libraries (commonly abbreviated around here as VI) use the Vienna Instruments player. The instruments player can be started the same way you start Synchron in Ensemble (right clicking in Ensemble and adding a VI instance).
The differences between the libraries:
The Vienna Instruments libraries are dry, no reverb in the original samples (you can add reverb through MIRx, MIR Pro, or another reverb engine of your choice), no pre-eqing (sort of, see the last paragraph), and their volume has not been tuned to match the rest of the orchestra (meaning, you have to do manual mixing to get the volumes right, or, purchase any of the MIRx / MIR plugins and use the natural sound option those plugins provide). This gives the flexibility to customize the reverb and eq to get the timbre of sound you are looking for, at the cost of having to do these things yourself. These dont sound "great" out of the box, they require some effort to get the sound you are looking for, but you have greater control and flexibility to get the sound you might be looking for.
The Synchron libraries are wet using the reverb from the Vienna recording stage, are pre-eqd to "sweeten" the original sound, and their volume has been tuned to match the rest of the orchestra. The result is that these instruments sound great out of the box, but because these effects are baked in, its harder / impossible to get the exact sound you might be looking for.
One quick note on the VI libraries, Vienna does provide a couple of ways to get the VI libraries to have pre-eqing similar to the Synchron libraries, and since you just bought the harpsichord, you might find this useful, as I found myself using the harpsichord library to record an authentic recording of minuet in G (searching high and low, no accurate recording of this exists until the version I created was made). The harpsichord has in the original samples, all of the mechanical noise. This is neat for authenticity, but no one wants that in a studio recording. In Ensemble, you can load the EQ plugin through the FX dropdown menu. Here, there are a TON of presets on the right that are custom made for all of Vienna instruments, you'll find one preset for the harpsichord, which is listed as a Cembalo (search for cembalo). This will eq out much of the thudding you'll hear in the low end and sweeten the mids and highs just a tad.
I went off on a wild tangent here, but hey, hopefully this helps...
