Live Sound

Dedicated Speaker Processors

Assuming that you've got the basics (decent speakers and solid amplification) in place, the best makeover for any live sound system can be a new digital speaker processor, a session with a fa

Assuming that you've got the basics (decent speakers and solid
amplification) in place, the best makeover for any live sound system
can be a new digital speaker processor, a session with a favorite
speaker measurement system and some choice music tracks for tuning. And
access to memory presets lets users store parameters to handle a
variety of events in a fixed install or recall setups for different
venues when touring.

Want more detailed info? Click here to see the "Specs at a Glance" chart
(Adobe PDF format).

Many of the digital signal processors on the market can be used as
full-function dedicated speaker processors. Most feature input delay
for zone alignment and output delay for component and cluster offsets;
parametric equalization of components on outputs; system and room EQ of
inputs; onboard limiters for driver/system protection; and increasingly
steeper crossover slopes and multiple user/factory presets.

These processors are primarily intended as full-featured crossovers,
but live engineers often employ them for speaker zone control, taking
the console's stereo mix and distributing it to main clusters, as well
as subwoofers, frontfills and delays. For those who want to drive subs
on an aux send, products with more than two inputs offer an advantage.
While their main applications are live sound systems, these processors
are increasingly found in studio control rooms where large-format
reference monitors benefit from their use.

An entire class of products not included in this article are
processors intended for installations with Phoenix or Euro-block analog
connections on the back or those that are normally programmed from a
computer. They generally have a bit less dynamic range, often lack
front panel controls and typically include contact-closure inputs for
use in ballrooms as room-combining processors. Most provide mic level
inputs, offering complete microphone-to-amplifier solutions for

As more engineers use digital consoles in live sound applications,
there's a growing interest in AES inputs, either standard or optional,
which can increase a system's dynamic range. Some users prefer to tune
a system with parametric filters, but a couple of brands permit graphic
EQ to be used instead, or a combination of both.

Whether using a manufacturer's proprietary software or Device
Control under SIA Software's SmaartLive, the ability to remotely
program, operate and archive a processor from a computer makes it more
powerful. Through use of wireless networking, this control can be
extended, allowing a system tech to move throughout a venue and make
adjustments from inside each zone. A wireless touchscreen device
control is the new paradigm for pro sound EQ. There's no mouse on the
bridge of the Enterprise.

With that in mind, let's check out a number of DSP boxes for sound
system control from a variety of third-party suppliers. The following
includes brief product descriptions; a chart later in the article
provides more information and offers at-a-glance comparisons of
features and functionality.

On the heels of its Intelli-Q stereo digital EQ, Belgian company
Apex (dist. by Transamerica Audio Group, introduced the Intelli-X
Equalizer and Speaker-Management System. Its four inputs can
simultaneously provide a half-second of delay, eight bands of
parametric EQ, two shelving filters, plus a 30-band graphic EQ.
There are also two stereo AES/EBU digital inputs. Multiple Intelli-X
processors can be networked with Windows software, allowing control of
combinations of Intelli-Qs and Intelli-Xs from the same PC via a USB
connection and the Apex RJ-45 serial bus. The Intelli-X has an optional
one-rack-unit Intelli-Sense speaker-protection system that continuously
monitors the true RMS power delivered to the speakers and adjusts the
Intelli-X's internal limiters to prevent thermal failure of

Ashly Audio's 4.24C ( is the crossover model in the
company's Protea System II line of digital processors. Like most
processors in this roundup, the Protea C can be computer-controlled
from an RS-232 connection via either Ashly's PC Graphic User Interface,
SIA's SmaartLive or MIDI. The front panel's 2-line, 20-character
display shows parameter, function and utility information.

The Behringer ( UltraDrive Pro DCX2496 is a
3-in/6-out unit with dynamic EQs and parametrics available on all
inputs/outputs, along with limiter protection. Other features include
four mono and stereo output operating modes; Butterworth, Bessel and
Linkwitz-Riley crossover types; 6 to 48dB/octave slopes; individual
delays; and an additional sum out signal. RS-232 and RS-485 interfaces
enable single or multi-unit control via free Windows-based editing
software, and presets can also be stored to a PCMCIA card slot.

BSS' ( Omnidrive Compact plus T is the
newest version of the only top-shelf processor with three inputs. BSS'
new FDS-366T provides a new crossover type from Australian audiophile
company Whise, designed by Neville Thiele. His filters are comparable
to Linkwitz-Riley topology, but with steeper roll-offs (36 and 52
dB/octave). The Neville Thiele Method filters maintain phase coherence
thoughout the crossover region and sum for flat response. Speaker
designers can use them to increase efficiency and widen a driver's
bandwidth. Most programs employing L-R filters can substitute NTM
filters without further changes, though steeper slopes can permit
further optimization of crossover frequencies and out-of-band EQ.

The BSS MiniDrive FDS-336T is the newest version of the company's
entry-level product. It now also includes the Neville Thiele filters
recently added to the Compact plus, and older units can be
flash-upgraded, as can the older 366s. While lacking a few features
such as dynamic EQ, the third input, AES/EBU ports and the Alignment
Assistant found on the plus, the 336T offers BSS quality to a wider
audience. It's also available with four outputs as the FDS-334T, which
is better suited to bi-amp monitor applications.

The DriveRack 480 from dbx Professional ( is the
company's flagship, and can be used stand-alone, via PC or with the
480R DriveRack Remote, on which 32 instant-access buttons and 31 moving
faders can control multiple units. Two slave models, the 481 and 482,
lack front panel controls and offer a choice of XLR or Euroblock
connectors. It features separate house and show input EQ with
individual lockouts and dual RTAs for two of its four inputs that can
be used for measurement mics.

dbx's DriveRack PA is a stand-alone, no-frills processor, offering
graphic front-end EQ and 10 ms of transducer alignment delay. However,
it has extras such as a classic dbx compressor, 120A Subharmonic
Synthesizer, a dozen notch filters and a JBL/Crown setup Wizard. An RTA
mic input, pink-noise generator and Auto-EQ with 28-band RTA make the
DriveRack PA perfect for value-engineered installs or compact portable

The newest dbx DriveRack for live sound, the DriveRack 260, picks up
where the PA left off. Features include a full second of input delay
for zone alignment, nine parametric input filters, PC control via
DriveWare software or device control under SmaartLive. A line of five
different wall-panel zone controllers can mount in standard electrical
switch boxes and connect up to 1,000 feet away via Cat-5 cable. The 260
also has a full-time RTA for its pink noise and measurement mic

Australian firm DEQX ( offers the PDC-2.6
“ClarityEQ,” primarily intended as an active crossover
upgrade for passive two- and three-way control room monitors and
high-end consumer speakers. It comes with its own optimization software
for making EQ and delay adjustments. It employs FIR filter technology
to synthesize extremely steep crossover slopes. While not primarily
intended for live sound, there may soon be a sound reinforcement

Electro-Voice's ( Dx38 is the company-branded
processor based on the Dynacord 244. It includes Real Acoustic Cluster
Editor (RACE) software for controlling and programming the unit, which
calculates and displays the free-field acoustical output when used with
various E-V speaker products. Parameters can also be adjusted from the
front panel controls. An optional RS-485 interface can be installed in
place of the standard RS-232 port, allowing control over 650 feet of
mic cable or six times that with Cat-5.

JBL Professional ( has given new life to its DSC260,
upgrading it to 24 bits for higher dynamic range, adding new 2-stage
limiters and renaming it the DSC260A. The 260 has been employed by more
than a dozen other speaker manufacturers as a dedicated OEM system
processor, and this will continue to be a widely used product.

Klark Teknik's ( DN9848 is the original
high-density, 4×8, single-rackspace processor that was upgraded in
Version 3.0 with Smaart compatibility and four additional parametric
filters on its inputs, for a total of 96 filters. In addition to six
user memories and 32 system programs, there are 99 factory presets.
Summed inputs have a unique balance control. The RS-485 connections are
conveniently provided on XLR connectors, while the front panel RS-232
port is an 8-pin mini-DIN.

Contour from Lake Technology ( set
the live sound world on its ear with a new paradigm for speaker EQ that
employs 96kHz resolution, low-propagation FIR filters and wireless
Ethernet operation from a tablet PC. Its method of filter synthesis
allows unlimited EQ overlays, and unique topologies such as
“brick wall” and “mesa” filters are also
possible. Lake's new plug-in provides integration between its
Controller software and SmaartLive, showing RTA, spectrograph and FFT
displays directly in Contour's software interface. For more, see the
Lake Contour “Field Test” on page 100.

Sony's ( SRP-F300 is a little-known
SR processor that's been living in the shadow of Sony's more glamorous
pro audio gear. The F300 features 96kHz sampling, a choice of analog or
AES inputs, and either graphic or parametric filters that can be chosen
for input EQ. It has an internal pink-noise and sine wave generator,
and its compressor can accept sideband EQ. It is programmed from
Windows 95/98 software, and front panel controls allow only limited
adjustment for security purposes.

At the recent AES show in New York City, Toronto's Xilica
( introduced its new DLP4080, a
full-featured, 4×8 1RU processor. Any combination of inputs can be
summed as a source for an output. As with most DSPs today, its firmware
is flash-upgradeable, and refinements like dynamic filters and feedback
eliminators are in the works.

The DP226 from XTA (dist. by Group One Ltd.,
is an industry benchmark processor that's also been spun off into OEM
versions for several speaker manufacturers, while being the processor
of choice for others. Available with optional AES digital inputs
and outputs, it's controllable from its AudioCore software and
Smaart. Connections for RS-485, RS-232 and MIDI are standard. A front
panel card slot provides convenient PCMCIA storage and backup of
settings. A similar model — the DP 224 — has four

XTA's new DP6i has the same circuitry as its 226, but with a
stripped-down front panel at a fraction of the cost. Parameters are not
front panel-adjustable, but all of the rear panel connectivity of the
226 has been retained. Instead, there are four front panel push buttons
for recalling four presets. An internal switch puts the unit into Safe
mode where all front panel controls are disabled.

Mark Frink is Mix's sound reinforcement editor.

Want to read more stories like this?
Get our Free Newsletter Here!