This electronic crossover provides all the processing needed for signals that feed the drivers in PA speakers. Using the Alto Maxidrive 3.4, you can fine-tune multiple loudspeaker systems to optimum performance.
Product PointsApplications: Live sound, installation
Key Features: Three-way stereo crossover; a three, four, five or six-way mono; Bessel, Butterworth, Linkwitz-Riley filters; EQ; delay; limiter; 20-bit A/D-D/A
Contact: Alto Pro Audio at 585-436-2720, Web Site.
Italian-based Alto makes a wide range of pro audio components: signal processors, power amps, a headphone amp, a mic preamp, mixers and PA speaker systems.
The versatile Maxidrive can be used as a three-way stereo crossover; a three, four, five or six-way mono crossover; or a distribution amp with up to six outputs. This single-rack device accepts analog or digital signals, then processes them with your choice of dozens of editable presets that include filtering, EQ, delay, gain, polarity, limiting, and low-pass filter phase.
Basically it is a two-in, six-out device. Like any electronic crossover, the Maxidrive connects between your signal source and the power amps for various speaker drivers. Analog input connectors are two balanced Combo types (XLR/phone). The digital input is AES/EBU on an XLR-F connector, with sampling rates of 32 kHz to 48 kHz. Six analog XLR-M output connectors are provided.
The DSP section includes 20-bit A/D and D/A converters sampling at 48 kHz, with 40-bit internal processing.
A full complement of crossover filters are provided: Bessel, Butterworth or Linkwitz-Riley, with slopes of 6 dB to 24 dB per octave. EQ types include peak or notch (with adjustable bandwidth), 6 dB low-shelf, 12 dB low-shelf, 6 dB high-shelf, and 12 dB high-shelf. EQ gain can be adjusted up to ±15 dB in 0.5 dB steps. As many as 40 filters are available at once.
Each input signal can be delayed up to 2.5 seconds and each output signal can be delayed up to 300 ms. Input delay is used to delay the signal going to a loudspeaker enclosure, while the output delay is used to signal-align the individual loudspeaker drivers.
Communication with a computer or other Maxidrive units is via a nine-pin RS232, XLR-F RS485, or XLR-M RS485 connector.
Ten factory presets are included, along with 128 user presets and 128 card presets from a plug-in multimedia memory card (not included). Some presets on this card could be optimized for specific speaker models. Factory presets can’t be changed permanently, but they act as starting points for creating user presets and card presets.
Presets can be loaded, edited, and stored. A function called “Dump out preset” lets you download a preset through the serial ports to a computer or another Maxidrive. “Incoming dump” lets you accept or ignore a preset sent from a computer or another Maxidrive via the serial ports.
On the front panel is a MODE button that switches between four menus: Preset, Delay, Edit and Utility. LEDs indicate which mode is selected. Each mode has a submenu of other selections. For example, the Edit menu lets you adjust parameters for gain, EQ, crossover, polarity and limiting. The Utility menu includes such features as ganging, LCD contrast, security lockout, memory card formatting, and communcations setup.
Also on the front are rows of LEDs that display the input and output levels. A slot accepts a multimedia memory card that you can fill with presets. Other items include an easy-to-read menu display, buttons to navigate the menus, and a dial encoder for editing parameter values. Each output channel from 1 to 6 can be muted by a separate pushbutton.
As for specs, the claimed frequency response is 20 Hz – 20 kHz ±0.25 dB, while dynamic range is >117 dB analog and >120 dB digital. THD is rated at 0.05% from 20 Hz to 20 kHz.
Like most other digital processors, the Maxidrive requires a fair amount of button pushing and dial turning to set up. Here is the basic procedure:
1. Turn on the unit, mute the outputs, load the default factory preset.
2. Adjust the input signal gain while watching the level LEDs.
3. Choose and load a factory preset with the desired configuration of inputs and outputs. Inputs are Channel A, Channel B, or the Sum of A and B. Outputs are 1 – 6.
4. Customize the preset: For each output channel, set up the polarity, crossover frequency and slope, delay and gain. Store the edited preset.
Each preset shows up as a concise code on the display screen. These codes take some time to understand. If you use the Maxidrive infrequently, you may forget the codes and will have to search the manual for their meaning. For example, “2X3W+MSB+MAX” means “3-way stereo with mono sub + 1 mono full-range aux out.” “A13B24S56” means “Input channel A feeds output channels 1 and 3, Input channel B feeds output channels 2 and 4, and the Sum of A and B feeds channels 5 and 6.”
I would prefer to see each preset on the display screen as a block diagram, but space is limited. The codes and the limitations of each factory preset were confusing. I was not able to configure the unit quickly and intuitively for various applications. However, setting the processing parameters was an easy, logical process.
Alto’s website provides Windows software that lets you set up the Maxidrive more easily on a computer screen. This is a huge improvement. The main window in the software shows the processing block diagram. Click on any block to open a window where you can set parameters graphically. The GUI looks clean and is easy to use.
Although the user manual has some awkward translations in spots, it is thorough, well-illustrated and generally easy to follow. It could use an index. Helpful application diagrams are included, as well as a chart of the factory presets.
The Maxidrive 3.4 sounded clean, and all processing worked as expected.
The Alto Maxidrive 3.4 does a fine job as a digital crossover, providing a huge array of configurations and a high-quality signal. Its factory presets and display codes might be confusing to some users. You will need to read the manual to set it up, but once set, it works very well. Downloadable software makes the Maxidrive a snap to use.