I was able to find your speakers on EV's website, see here:
http://www.electrovoice.com/products/232.html
According to the data sheet, the NL4 (Speakon) connectors on the back of the
speaker are wired in parallel, and thus the labels by them do not refer to the
connector but rather to the
speaker's specifications (300W peak for HF, 1200W peak for LF). The 1+/1- pins are for the high-frequency
driver, and the 2+/2- pins are for the low-frequency
driver. As Sharyn said, it is likely that your amplifiers have option cards built-in that cross the signal over at the appropriate frequency and delay it.
So it appears that your
system is wired correctly based on a cursory inspection. This leaves two possibilities to explain the problems you're having. First, it is possible that someone blew out one of the
bass drivers. Second, one of the NL4 connectors on the speakers is wired incorrectly. The only way to determine which of these is the problem is to get up next to the
speaker and connect it directly to a pair of amplifiers that you know is wired correctly and listen to the output - if it is still distorted, then it is the
speaker; if it is fine, the connection from the
amplifier to the
speaker is incorrectly wired.
Now, a short note on
impedance.
Impedance is composed of two parts: reactance and resistance. Resistance is simply the total opposition to
direct-current flow. Reactance is defined as the total opposition to
alternating-current flow. In layman terms, it is a kind of resistance than can vary based on the frequency of the ac.
Impedance is actually a complex number, with resistance being the real part and reactance being the imaginary part. All of these things (resistance, reactance, and
impedance are measured in Ohms (abbreviated as a capital Omega). If you're not too comfortable with imaginary numbers, take a look at this
introduction to refresh yourself:
http://www.purplemath.com/modules/complex.htm
In terms of speakers (technically
cone drivers here), the
speaker's total
impedance is composed to two parts, resistance and
inductance (one of two types of reactance). The resistance comes from the length of
wire used in the
speaker, and the
inductance comes from the
wire being coiled around inside the
driver. You'll note that I said above that reactance changes with frequency. Thus, the
impedance of the
speaker is NOT a fixed number. If you look at the spec sheet for your
speaker, you'll see a graph on
page 2 at the top right that shows you the total
impedance of your
speaker across the audio spectrum. To come up with the number printed on the back of the
speaker (typically somewhere between two and sixteen ohms), the manufacturer takes the average across the audio spectrum and uses that.
There are two basic ways to connect speakers together, in parallel and series. When you connect two speakers in parallel, the total
impedance of the
speaker system is half of the original
impedance (if both speakers have the same
impedance). When you connect two speakers in series, the total
impedance is double the original
impedance (once again, assuming both speakers have the same
impedance). It is indeed possible to have a parallel/series connection or a series/parallel connection, and this is often done to keep the
impedance at a reasonable value when over three speakers need to be connected to one
amplifier (although this typically not a good idea because you’ll need a really powerful
amplifier to do this).
Now, a short note on
power.
Power is the total amount of energy used by a
speaker second, and is measured in Watts (W). This seems simple enough, but manufacturers love to quote different types of
power rating for amplifiers and speakers. There are three main types of
power ratings floating around: peak, program, and continuous. Good manufacturers will quote all of these ratings and will also describe how each one is derived.
Continuous
power (also called
RMS power) is based on the
power drawn by the
speaker by a steady signal, such as a
sine wave. While this is a fairly easy and safe way to measure the capabilities of a
speaker, it has two drawbacks. First, because
impedance changes with frequency, so does
power. Second, nobody actually feeds a
speaker a
sine wave! Thus, this is a fairly useless measurement.
Peak
power is another metric used by equipment manufacturers. Manufacturers like it because it is a big number. However, it is also quite useless. First, how long can the
speaker withstand this peak
power? What frequency is this at? Additionally, peak
power has no real bearing on how loud a show is. Again, we have a useless measurement.
Program
power is the final measurement given to us by manufacturers. This metric has the benefit of being the most representative of how we will use the
speaker. While it seems to be the most useful, it too has a drawback: what kind of program was
fed to the
speaker?! If the manufacturer uses bluegrass music to test and rate their speakers, the program
rating means nothing to a sound engineer about to do a heavy rock show.
The bottom
line with
speaker power rating is that they must be taken with a grain of salt. The program
rating is probably the best one to use, but just remember that the manufacturer doesn’t test their
speaker with your program material, and if you think you’re going to need more
power, buy a more powerful
speaker!
I hope this helps someone!