BOSS PX-1 Model Passes add HM-2, HM-3 and MZ-2

The knob marked Hi on a BOSS HM-2 was never really a treble control. It boosts or cuts midrange through two peaking filters at 1 kHz and 1.3 kHz, with around ±20 dB on tap, while Lo peaks at 88 Hz. BOSS ties the pedal to the “chainsaw” tone of Swedish death metal, and the HM-2 now loads into the PX-1 Plugout FX.

BOSS HM-2 Heavy Metal, HM-3 HYPER Metal and MZ-2 Digital Metalizer compact pedals side by side, all black, with orange graphics on the HM-2 and HM-3 and red on the MZ-2 — The original compacts behind the third batch of PX-1 Model Passes. Image: BOSS

It heads the third batch of PX-1 Model Passes, and the other two picks keep things heavy. BOSS says it crafted the recreations using original units, and its write-up on the trio explains where the HM-2's character comes from. A two-stage transistor amplifier sits up front, its bias fluctuations adding a subtly boomy low end. Then an asymmetrical overdrive stage, which BOSS traces to the SD-1-into-Marshall combination of '80s metal rigs, drives the signal into diode clipping.

HM-3 HYPER Metal, the '90s follow-up, keeps the overdrive-into-diodes recipe but swaps the transistor front end for op-amp gain, which BOSS describes as crisper and tighter. Its Color Mix EQ is gentler too: Low peaks at 80 Hz, High at 800 Hz and 4.5 kHz. BOSS counts Warren Haynes among its users, along with Kurt Cobain during Nirvana's final recording session.

The oddball is the MZ-2 Digital Metalizer, BOSS's late-'80s answer to digital rack rigs, which put analog distortion and digital chorus or doubling delay in one compact. A six-way Mode knob picks two chorus settings, three doubling delays of 15, 30 and 60 ms, or SGL for straight distortion. Its drive section drew on the OD-2 TURBO OverDrive and was voiced for hard rock rather than extreme metal. It was part of David Gilmour's pedalboard, and producer Tom Dalgety has used it on numerous recordings in recent years.

Model Passes are optional paid add-ons. You buy them in the BOSS Effect Loader app and send them to the pedal over Bluetooth or USB-C, where they fill its eight user locations. Each effect can be tried first as a demo that drops a short audio gap every 30 seconds. The PX-1 product page already lists the next trio as scheduled: CE-3 Chorus, FZ-3 Fuzz and PQ-4 Parametric Equalizer. Specs for the pedal itself are on our PX-1 Plugout FX page.