No matter how many modules you have in your system, it seems like you can never have too many control signals. The DSP-based Malekko AD/LFO ($249) addresses this conundrum by placing six channels of 2-stage envelopes within a relatively narrow Eurorack panel. (In collaboration with LZX Industries, Malekko also offers the AD/LFO-V [$249], with 1V-scaled outputs that are optimized for use with modular video-synthesis systems.)
Each channel of the AD/LFO has a Gate input, a CV output with a 0 to +10V range, and knobs for setting the length of the attack and decay portions of the envelope (with an LED for visual reference). Although the Gate input accepts anything above 0.5V, the envelopes do not wait for a gate signal to end before the decay portion is triggered; the initiation of the decay depends on the attack setting.
The module’s six channels are grouped in threes, with a summed output below each group. This lets you set three discrete envelope shapes and have a separate output with a mix of them at the same time. You can also trigger all three envelopes at once with a single gate or pulse patches into the top Gate input as long as nothing else is plugged into the lower two inputs.
The DSP-based AD/LFO is a 6-channel envelope generator that can be configured into two sets of three LFOs. A combined signal of each set of three CV outputs is available at the Sum output jacks. The envelope cycles range from 24 ms to 2.9 seconds, though you can slow each group of envelopes down by using the associated divide-by-ten button: This results is an A/D cycle time ranging from 238 ms to 29 seconds. (Once I got a taste of the slow speed, I immediately wanted a divide-by-100 button!) Each section also includes a Loop button that turns its three envelopes into simple LFOs, with the A and D controls determining the frequency in both fast and slow mode.
The first thing I did after installing the AD/LFO was patch separate signals into the Gate inputs while altering the order or timing between the input signals with a gate delay, to create a complex function generator from the Sum output. But things got really interesting when I introduced sequencing, particularly something with shuffling capabilities—for example, the chaotic outputs of the Epoch Modular Benjolin, a Doepfer A-149-1 RCV Quantized/Stored Random Voltages module (with the A-149-2 Digital Random Voltage extension for 8 randomly generated triggers), or Melekko’s outstanding Varigate 4 ($229). (Read the Mod Squad review at emusician.com/varigate4.) The AD/LFO is also a handy module when integrating control signals from your DAW using the Expert Sleepers Silent Way plug-in suite and the company’s ES-series Eurorack-based interface modules (read a review at emusician.com/ExpertSleepersSilentWay).
In non-looping mode, I patched the Sum output of the top section into the first Gate input of the lower section to create slowly evolving textures with the six asynchronous envelopes. This sounded fantastic when modulating the Morph inputs on the Synthesis Technology E350 Morphing Terrarium while adding related modulation from the AD/LFO’s lower Sum output to a bandpass filter.
Overall, the Malekko AD/LFO requires little rack space, yet provides a surprising amount of functionality while remaining simple enough to use onstage, especially within an improvisational patching environment.