OK – to find out where you’re going you must know where you have been.... Pardon me while I reminisce.... In the good old days, the heart of any PA system was the drive rack, or all of the components minus the amps and speakers and mixing console that collectively make up the PA system. A typical (analogue) drive rack set–up could consist of the following items: a crossover, front-of-house EQs, front-of-house compressors, monitor EQs, monitor compressors, insert compressors, EQs, etc., and various effects units, reverbs, and delays. Now we still have to assemble and wire all of these components into a box or a permanent rack of some kind, and if you do the math, it could exceed sixteen to twenty rack spaces easily. So let’s review – the drive rack tailors various signals after the mixing console and before the amps and speakers.

A DSP or digital signal possessor does all of the above with the exception of effects possessing in a one– or two–space footprint! How can that be?? The key word is digital. Some of you may remember the first portable cell phones that were available in the early eighties – they were the size of a shoe box with an antenna. Fast forward thirty years and they are the size of a credit card! The same technology has made the DSP powerful, small and affordable...

Here is how it works: the first thing you need to know is how many goesinto's (inputs) and goesouta's (outputs) you need for your system. For this example, I will use a typical small church PA system. Let’s say you have a stereo mixing board with four monitor mixes, a 70 – volt feed (for the hallways, Sunday school classes, and a speaker in the nursery), assisted listening, and a recorder of some kind.

In this example a six–input to ten–output DSP would work fine.

Now that we have established our input and output needs, we can move on to the fun stuff: the actual system design inside the DSP.

Although there are many different DSPs available, for this design and, for that matter, all the DSPs we install are made by Biamp Systems. In this application, because of the number of outputs and the processing power needed, I am going to use a Biamp Audia Flex. We have established the number of inputs we need to be six, and the outputs to be ten. The Biamp Audia Flex allows many different combinations of inputs and outputs, as well as the ability to link multiple units together to make one big DSP. Using a laptop or a PC, I can connect to the Audia Flex and choose the internal components I wish to use and wire things up between the ins and outs. You kind of have to imagine the Audia Flex as a digital Etch A Sketch. You can change/reprogram things as needed. Above is a simple, but effective Audia program that will work great for our church – with compressors, EQs, feedback suppressors, levelers, and a matrix to route signal flow. All of this is in a two–space footprint versus sixteen spaces needed by the analogue gear. This program just scratches the surface of what can be done with the Audia Flex. Biamp products have an array of accessories that will allow for easy user interface, including the DaVinci software that allows the user to operate the system via computer.

Let the Doctor take a look at what ails your system so we can prescribe the solution that