Architectural Acoustics Digitool MX
Dec 1, 2004 12:00 PM,
By John McJunkin
A new, powerful signal-processing device.
Architectural Acoustics by Peavey has introduced the Digitool MX, a multipurpose digital signal-processing and routing device. It’s not just a patchbay or a crossover, but a powerful device that can be used to route and mix signals, restrict bandwidth, equalize, compress, gate, and provide delay. While there are many drive boxes available, this system provides more functionality to the integrator who needs to distribute signals and have the added ability to sculpt and mold the nature of the signal based on where it’s going.
Digitool MX
THE PHYSICAL ATTRIBUTES
The Digitool MX’s front panel is exceedingly simple. The program wheel, on the left, is a data encoder allowing menu navigation and control of the system’s parameters. To the right of the program wheel is the 64×128-pixel LCD display. There are three vertically aligned small data-encoding knobs to the right of the LCD display. The knobs provide parametric control beyond the larger program wheel. To the right of the knobs are two-color LEDs, which indicate active inputs and outputs.
The back panel of the Digitool MX is also relatively straightforward. On the far left are the IEC power connector and power switch. A pair of RJ-45 connectors reside just left of the middle of the back panel, enabling connection of a multi-drop RS-485 bus. A standard DB-9 connector just right of the RJ-45 pair allows RS-232 interfacing with a computer. Farther right are four control voltage connectors to accommodate 0V to 10V DC for external potentiometers. They are Euro-style receptacles that accept the included connectors intended for wiring. Finally, there are eight balanced analog I/O pairs, also represented by Euro-style receptacles.
WHAT IT DOES
The primary function of the Digitool MX is to route and mix any of eight input signals to any of the eight outputs. In the Mix View, the LCD shows the Mix Box, to the left of which are representations of the unit’s eight inputs. The user determines which output channel is displayed, and a bar graph display in the Mix Box shows how much level from each of the input channels is being sent to that particular output.
Each knob on the front panel has a specific function. The top knob controls the level of the selected output. The middle knob controls the matrix level, which controls one of 64 different signal paths in the 8×8 matrix, as determined by which input and output are selected by the user. For instance, if input-6 to mix-7 is selected, then “Level 6-7” is what the middle knob controls. The bottom knob is a master level control, determining the overall output level of the entire system. This is the quick-grab knob in the event of feedback.
The Route View shows a single input and multiple outputs. In essence, it is operationally identical to the Mix View, in that the three knobs perform the same functions. This is a handy way to route a single input to multiple outputs. It is useful for distributed audio situations or to use the unit as a crossover or drive box.
The Edit View (input or output) is opened by pressing the program wheel while selecting an input or output object. The various pages of the edit windows are ordered in the same sequence as in the signal path. First is the input channel hardware configuration, which determines mic or line level input. In Line mode, two parameters are available; Sensitivity, adjustable from 12dBu to 30dBu in 6dBu increments, and Trim, which provides gain or attenuation from -6.6dB to +6.5dB in small increments. Mic mode allows the user to turn the 24V phantom power on and off or to adjust gain from +15dB to +50dB in .5dB steps.
The manual describes the multipurpose filter as an initial low-pass/high-pass filter, but it can be used in numerous ways. The available modes are low-pass (12dB/octave slope), high-pass (12dB/octave slope), parametric, all-pass 1 (no bandwidth control), all-pass 2 (bandwidth control), low-pass (6dB/octave slope), high-pass (6dB/octave slope), low-shelf, high-shelf, band-pass, band-stop, and horn EQ.
The noise gate has controls for threshold, attack, hold, release, and attenuation. Four more filters follow the gate, each with the modes featured in the first filter. The manual describes these as a series: high-shelf, parametric EQ 1 and 2, and low-shelf, but they can be used whichever way you like.
The compressor has controls for threshold, ratio, attack, release, and makeup gain. The final stage in the input section is a simple gain control.
The output section starts with a crossover filter. There are nine designs: Butterworth (6dB, 12dB, 18dB, and 24dB/octave slopes), Linkwitz-Riley (12dB and 24dB/octave slopes), and Bessel (12dB, 18dB, and 24dB/octave slopes). High- and low-pass filters are available, and cutoff frequency is adjustable from 10Hz to 20kHz. There is a gain control for the filter.
Next up is a chain of seven filters, intended to default to a high-pass and low-pass filter and a five-band paragraphic EQ. Following the filters is a compressor, with controls for threshold, ratio, attack, release, and makeup gain. After the compressor is a phase-correction delay, with a coarse control adjusting delay from 0ms to 5000ms, and a fine control that adds from 0μs to 998μs of delay in 23μs increments. Finally, there is a control that determines the inherent hardware output level, from 6dBu to 24dBu in 6dBu increments. Phase can be inverted as well with this control page. The output, like the input, can be named.
In addition to the Mix and Route Views, there is also a Matrix View that allows you to easily route any input to any output or all inputs to all outputs, and all in-between. A mute control page allows you to easily mute or unmute individual channels or all channels with a single button. The utilities page gives access to preset storage and retrieval, external control configuration, test signal oscillators (providing sine, pink, and white noise), priority override (which causes the settings of one channel’s gate to serve as a master, with the other seven responding as slaves). Display adjustments, security configuration (including password), and display of software version all reside in the utility page as well. The settings of the entire system can be password protected.
VERSATILITY
The Digitool MX is a powerful routing device that enables sophisticated digital signal processing. The DSP happens courtesy of the unit’s two 32-bit ADI SHARC processors. Digital conversion is at 24-bit resolution, and sample rate can be as high as 96kHz. Remote control is a snap with Architectural Acoustics’ D1V rotary control panels and D45 button panels. Multiple remotes can be connected and programmed to affect various parameters. The Digitool is an excellent, low-cost solution for integrators who need extensive control over distribution, digital signal-processing, and crossover capabilities.
PRODUCT SUMMARY
Company: Architectural Acoustics aa.peavey.com
Product: Digitool MX
Pros: Powerful, versatile signal routing, mixing, digital signal processing
Cons: Placement of middle knob makes it difficult to turn
Applications: Distributed audio situations
Price: MSRP $1,700
SPECIFICATIONS
INPUT
Audio Channels 8 inputs (line or mic), 8 outputs
Analog Trim Range -6dB to +6dB
Line Sensitivity Settings +30dBu, +24dBu, +18dBu, +12dBu
Mic Gain Range +15dB to +50dB in 1/2dB steps
Input Impedance 6.6kΩ
Phantom Power +24V
Common Mode Rejection 55dB
Crosstalk >90dB at 1kHz
Dynamic Range 104dB (A-weighted, 150Ω input termination)
OUTPUT
Output Full Scale Settings +6dBu, +12dBu, +24dBu, +18dBu
Output Impedance 102Ω
Minimum Load Impedance 600Ω (maximum output at 600Ω = 22.5dBu)
Dynamic Range 109dB (A-weighted)
ANALOG INPUT-TO-OUTPUT
Total Harmonic Distortion and Noise 0.01% (20Hz to 20kHz, 22kHz BW filter, +4dBu signal with 20dB headroom)
Frequency Response 20Hz to 20kHz (±0.5dBr referenced at 1kHz)
Dynamic Range 103dB (A-weighted, 150Ω input termination)
Latency 1.4ms (propagation delay from input to output)
DIGITAL
Sample Rate 44.1kHz, 48kHz, 96kHz
Quantization 24-bit (256 x-over-sampled Delta-sigma)
Digital Processing 132 Mips (with two ADI SHARC processors)
Master CPU Clock Speed 6MHz
DSP Cycle Speed 66MHz
CONTROL
RS-485 half-duplex 57.6 kbaud (one port with two multi-drop RJ-45 connections)
RS-232 56.7 kbaud (standard dB-9 serial cable connector, female)
CV Inputs 0V to 10V (external voltage applied or remote passive potentiometer connection)
