Electrovoice Sx200 Speaker System (part 3)
The Xp200 system controller comes in a 1U metal box which will rack up nicely with the power amplifiers. What wont rack up nicely is the wall wart power supply which I certainly would not have expected to see on what is meant to be a professional system. An additional insult is the fact that there is no marking on the power supply to indicate that it is for the Xp200, and getting your wall warts mixed up is a recipe for disaster when they come in all combinations of voltage, AC or DC, and DC polarity. This will not do, Electrovoice. You should take steps as soon as possible to put the transformer inside the controller so it can plug directly into the mains. To balance this one negative feature, EV have included a schematic diagram on the top panel which is something that they could easily have chosen to omit. But many engineers, even with only a little electronic knowledge, will appreciate this information being in exactly the right place, as well as in the manual, so not only can you make connections with absolute certainty that they are correct, but you can also clearly see what is going on inside the unit. For any speaker that uses a controller combining crossover, equaliser and possibly drive unit protection functions, you really do need to understand how the controller functions to be able to get the best out of the speaker and to use it within its capabilities. In keeping with the scale of the system, the Xp200 controller is quite simple, and since there is no form of drive unit protection, you will have to use your skill as a sound engineer - in the old fashioned way - to avoid speaker damage.
The Xp200 has electronically balanced inputs and outputs on three pole jack connectors. As far as the full range units go the controller is of course stereo, but the subwoofers are mixed into mono. The controls include input level, low frequency profile and subwoofer level. The power LED also serves as a clip warning for the controller and turns from green to red if you are giving the unit too much level, or applying too much LF boost. The controller is configured in such a way that the full frequency range always goes to the full range Sx200 unit, whether or not you are using subwoofers, so it wouldnt be completely correct to say that it functions as a crossover. The subwoofer provides additional beef to the bottom end, in an amount specified by the subwoofer level control. Through both main and sub outputs, the controller filters off frequencies below 37Hz at a rate of 24dB/octave since there is no point in stressing the speakers with frequencies they cant properly reproduce. To get the best out of the whole system you will set the low frequency profile control according to the requirements of the sound source, auditorium, and audiences expectations. Any small speaker will be light in the bass end and the Sx200 system is no exception. The low frequency profile isnt a simple EQ section but is tailored to the frequency response of the speakers, so that the low frequency boost applied results in a satisfactory subjective effect. The curve of the low frequency profile, shows a 12dB boost at 60Hz at its maximum setting, and oddly enough a sharp 18dB dip at 400Hz. I dont imaging this happened by accident, and the Electrovoice designers must have done this to enhance the overall perception of the sound produced. As with all such low frequency compensation systems, you dont get something for nothing and the extra low frequency energy that comes out of the boxes is paid for by a reduction in potential maximum undistorted output level. But I think that for the size of these speakers you will be well satisfied with the amount of sound they produce, with or without LF enhancement.