Kassia Lemieux and Dan Rouleau put Montreal on notice with their circuit-bending and refinishing of audio electronics under the moniker Screwed Circuitz. Then, in 2022, the duo founded Days of Yore to develop creative tools with aesthetics inspired by mid-20th-century consumer electronics built into furniture. Their product line includes adventurous pedals, high-end spring reverbs, and the unbalanced Passive Matrix Mixer (PMM). When a box from Days of Yore arrived at my door, I knew what it was but had no idea what to expect. I transferred the PMM from its packaging to a table, where it was illuminated by the warm glow of late-afternoon sunshine filtered through the curtains. I paused to admire the walnut frame with its natural finish and the cherry-topped control plate gilded with shiny gold knobs. In that moment, the absence of control labels enhanced its allure. The vintage-furniture vibe is strong, but the minimalist design adds a touch of modern elegance.
The angled front panel of the Passive Matrix Mixer includes five control knobs and five toggle switches on each of the five vertical channels. All of the knobs are nicely spaced apart. There are no group or master controls because every mono input signal is summed into every channel. Knobs in the top row control the level of input 1 on each channel. Knobs in the second row control the level of input 2 and so on. The switch below every knob on the PMM is not simply a mute. In the down position, the potentiometer behind the knob is electronically bypassed to prevent unnecessary signal loss from its reactive impedance in the passive circuit. For best results, always begin with switches in the down position and activate individual switches only as needed.
I inserted the Passive Matrix Mixer between a passive bass guitar and an amp. Even with the input knob for that channel on the mixer all the way up and all other switches down, I observed a 12 dB drop in signal level. Then I added my Caveman Audio BP1 Bass Preamp pedal to the chain. I connected the PMM to the buffered effects loop on the BP1, but the amp output offered more gain to drive the channel input. Feeding a hotter signal into the mixer worked well with parallel effects chains on multiple outputs. Dan suggested building feedback loops on the PMM with guitar pedals. My assistant engineer, Brian, and I discussed the best way to do that before we strung together some stompboxes – including Stardust V3 overdrive and TI:ME analog delay pedals from Crazy Tube Circuits, a Pretty Bird Woman chorus/vibrato pedal from NativeAudio, and a Kinematic envelope follower from Dreadbox – in various configurations. We tapped the feedback sound on another channel and connected a Creation Audio Labs MK.4.23 Clean Boost pedal [Tape Op #168] to that output for makeup gain. That buffered signal met up with a line input on my audio interface, allowing us to document the indescribable results of our experiments.
Gain pedals get feedback loops started with ease. Such loops may be tapped as sources or sonic whirlpools for external sounds. Modulation effects, such as chorus and tremolo, or time-based effects like reverb and delay, may also be used without gain pedals in feedback loops for processing external sources. Up to four feedback loops may be connected to the PMM simultaneously, leaving one channel open for input, summing, and output. Exploring those configurations challenged me to think and create in new ways that may benefit my clients on future projects.
The Passive Matrix Mixer is nothing less than functional art. It can split and sum unbalanced sources of any impedance. Its ability to facilitate and tap into feedback loops is an asset to sound designers. Guitarists and synthesists can set up parallel effects chains alongside feedback loops. It can also be used creatively in hybrid mixing. Even when it is not in service, the PMM never fails to charm every colleague and client who visits my studio.