WITH THE INTRODUCTION of DriveRack PA, dbx has brought big-time touring technology to the masses in a one rack-space box that costs no more than a good equalizer. The smallest member of dbx's line of speaker management systems, DriveRack PA comes close to fulfilling dbx's claim that it is “the only device that you will need between the mixer and power amps.”

It seems as though every multifunction device gets compared to a Swiss Army knife. But the DriveRack PA is more like a machine shop, combining a 28-band graphic EQ, a Real Time Analyzer, a subharmonic synthesizer (for fattening up the bottom end), a compressor, an active crossover with parametric EQ, and automatic feedback suppression. It also has a limiter and speaker alignment delay on each output. The audio quality is quite good, and the A/D and D/A conversions do not degrade the sound with obvious “digititus.”

DriveRack PA has something to offer to all but the smallest sound systems. It must be connected between mixer and power amplifiers, so it won't work with certain powered mixers. (In order to benefit from DriveRack PA, such units must have a patch bay that includes mixer Out and power-amp In jacks, and the power amp input must be a switching jack that disconnects the internal path from the mixer when a plug is inserted. Otherwise, the power amp will see the processed signal combined with the direct mixer output, which will be ineffective and produce a comb-filter effect as a result of the processing time of DriveRack PA's digital engines.)

DriveRack PA can be not only your first upgrade to a simple P.A., but also a unit that can grow with your system as you expand it. Any band or performer who wrangles a portable sound system around without help from an engineer will appreciate both the audible improvements brought by the unit's Auto EQ function, as well as the security provided by its automatic feedback filters.

Then, when you decide to expand your system — lets say you add subwoofers — the crossovers, delays, and parametric EQ in the DriveRack PA are ready to help you easily integrate your new additions. In fact, the unit's software includes setup Wizards to take the trauma out of tuning biamped or triamped speaker systems. For the more technically inclined, there's also compression and a subharmonic synthesizer on board to allow further audio flexibility.

Unlike the other members of the DriveRack family, which can be operated by a dbx 480R remote control and networked, the DriveRack PA is a solitary creature. Its only connections to the outside world are two balanced XLR analog inputs, six balanced XLR analog outputs, and a 15V phantom-power-equipped mic input for the Real Time Analyzer (RTA). There are no data, MIDI, or digital audio ports. All functions are controlled from a field of 12 buttons, a separate button that engages the mic input, and a data wheel.

Operation is straightforward once you get the hang of it, and 25 user memories are available to store setups that you've customized for the different venues you play (see Fig. 1).

The Auto EQ function is one of the key features that the DriveRack PA offers for customizing a P.A. to match the acoustic response of a specific venue.

It has a pink-noise generator and Real Time Analyzer to adjust system response using the 28-band graphic EQ.

A flat-response omnidirectional mic acts as the RTAs “ear.” Dbx markets an inexpensive condenser mic, the RTA-M ($149.99), to mate with the DriveRack PA. Through the generosity of AKG, I also used an AKG C-480 B/CK 62-ULS mic during my testing.

The Auto EQ works impressively, although it's not without its bugaboos. The RTA requires a minimum sound-pressure level (SPL) at the mic (by my informal measurement about 82dB, A weighted) to do its thing. It prompts you to raise it to “performance level,” which means that it helps to have a rough idea of how loud a performance will be. (Having an SPL meter is useful.)

There are three levels of precision. At the highest level, the DriveRack PA sometimes took a long time to finish its calculations. On those occasions, I frequently opted for a lower setting to avoid the long waits. But even at the lower settings, the Auto EQ was very effective. For instance, I patched two DriveRack PAs into a theater installation, where the left and right clusters were Cerwin-Vega and the center cluster was JBL. The Auto EQ matched the sound of the two systems better than anyone had previously managed by ear, and the speakers also sounded quite good. Indeed, I needed to make no other adjustments to the system EQ during that show.

One shortcoming of DriveRack PA's RTA is that it works only during the Auto EQ process. The unit's versatility and value would be upped a notch were it able to be used as a standalone RTA, providing data to an operator who could then adjust another graphic EQ accordingly.

The Advanced Feedback Suppressor is as good as any that I've tried, but the technology has not yet reached the stage at which it has the judgment and intuition of an actual soundperson. Although antifeedback devices (such as what's in the DriveRack PA) suppress obvious feedback nicely, they sometimes can mistake a musical tone for feedback, while ignoring audible resonance that could easily turn into feedback at the move of a mic or the addition of just a bit more gain. Nonetheless, if you set the DriveRack PA's AFS at sound check it can be quite useful, particularly if your band has no soundperson to keep an ear on things. The combination of Auto EQ and AFS can tune your system pretty effectively.

The compressor, which goes across your entire mix, features both hard-knee compression and ten levels of Over Easy compression. (With the latter, compression starts below the threshold, and the ratio increases as the threshold is approached.) It's easy to overdo the compression and invoke breathing and pumping, but it sounds very good when thoughtfully applied.

Dialing in a 2:1 compression ratio and about 5dB of gain reduction allowed me to add a musical fatness to the sound of a Celtic instrumental ensemble during a Solstice concert. There are also individual peak-limiter modules for speaker protection before each of DriveRack PA's six outputs.

The crossover has several filter configurations and accommodates biamped and triamped speaker systems, including mono or stereo subwoofers. Properly tweaking the crossover and each output's parametric EQ should bring a biamped or triamped speaker system very nearly flat, leaving the graphic EQ free to handle environmental and creative EQ concerns. Each output can be delayed up to 10 milliseconds to align the drivers in time. I wish that dbx had gone a bit further and provided a full second delay, so that DriveRack PA could manage distributed speaker systems using delay speakers. (If you envision using delay speakers in your setup, dbx makes the DriveRack 260 [$999], which is designed to handle multizone routing.)

DriveRack PA has enough meat on the bone to be worthwhile even if you don't need all of its features. The Auto EQ and AFS functions can immediately benefit performers with modest P.A. systems who can't employ an engineer or spend a few years becoming one. The unit's setup wizards greatly simplify the process of getting up and running. To really master the DriveRack PA's deepest functions, however — and to get the most from them — takes some time. Of course, having such a rich feature set means that as your system grows, the DriveRack PA can grow with it.

Overall, the DriveRack PA is a great value. It combines the functions of a number of key processors (which would cost a great deal more if purchased separately) into a single, integrated unit. To do all this in one rackspace for less than $750 retail is nothing short of amazing.