The Oscillator Devices Siren is a Stereo MIDI Volume Controller: a pedal-sized unit with two fully analog volume channels that you set and recall over MIDI instead of rocking a treadle. Each channel can be set anywhere from -100dB (Mute) up to +20dB of boost, and the two channels can be controlled together or act completely independently1. It is developed and handcrafted by Oscillator Devices in Germany1.
Because the volume controls are driven by two internal LFOs, the Siren doubles as a MIDI-controlled analog stereo tremolo, with LFO speeds that run free from 100ms to 1.2s or sync to MIDI clock1. It sits in the same family as the maker's other MIDI pedals, including the Oscillator Devices SIREN8X and Oscillator Devices HYDRA4X.
Two analog channels and routing modes
The Siren's two channels are fully analog and each can be set independently across the full range from mute to boost1. How the channels relate to each other depends on the routing mode: the channels can be split before the volume control, mixed after the volume control, or used as a parallel FX loop1. A parallel blend mode lets you blend the dry signal with the parallel FX loop1.
Starting with version 3, the parallel FX loop can also be placed post volume, so the output of channel A is controlled by volume A as well2. That gives you wet/dry blending where the wet path sits after the volume control rather than before it.
| Routing mode | What it does |
|---|---|
| Split before volume | Channels separate ahead of the volume controls |
| Mix after volume | Channels mix together after the volume controls; in Mix Mode the Siren functions as an active ABY box, isolating and mixing both signals3 |
| Parallel FX loop | One channel carries the dry signal, the other the loop; from version 3 the loop can be post volume, so channel A's output is also controlled by volume A2 |
The maker also points players who only need switching at the dedicated Oscillator Devices ABY, but for volume plus ABY duty it recommends the Siren in Mix Mode, where it isolates and mixes both signals3.
Presets and MIDI control
The Siren stores 48 user presets on top of 16 factory presets1. Presets are saved through a learning function: you hold the PHASE button, just as when changing modes, and send a PC command2. The same PHASE button also flips the phase of channel A2.
MIDI connectivity is built around a 1/8" (3.5 mm) stereo jack wired to DIN 5-pin according to MIDI TRS Type A, the same arrangement as pedals from Boss or Wampler, and compatible with Morningstar MIDI TRS connections2. The jack is TS and TRS compatible1. The Siren is compatible with all MIDI 1.0 compliant controllers1.
The tremolo side comes from the two internal LFOs, which operate completely independently2. Each offers Sine, Triangle, Rectangle and Ramp waveforms in both directions, five waveforms in all1. Speeds run free from 100ms to 1.2s or sync to MIDI clock1, and firmware 3.1.0 added tap tempo for the tremolo4.
Power and connections
The Siren runs on 9 to 18V, which the maker describes as giving massive headroom1. Inputs and outputs are high-quality Neutrik sockets1. You can connect TS mono jacks into channels A and B, or a single TRS stereo jack into channel A, and this applies to both the input and the output2.
The maker describes the Siren as having outstanding crosstalk performance and as specifically designed not to color your tone, with high quality, low noise buffers in the signal path1.
Version 2 and version 3
The most recent version of the Siren is version 3, and the current documentation covers SIREN 3.2 (October 2026) alongside the legacy SIREN 2.1 (February 2025)2. Firmware version 3.2.0 is the current release4.
Recent firmware changes include:
The headline hardware-level difference between versions is the parallel FX loop placement: from version 3 onward the loop can be post volume, so the output of channel A is also controlled by volume A2. Firmware updates are distributed through the maker's WebMIDI Interface, which fully supports the Siren1.
If you are buying used, check which version you are getting. Version 3 and later can place the parallel FX loop post volume; earlier versions cannot2.
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Questions
Is the Oscillator Devices Siren stereo?
Yes. The Siren is a stereo MIDI volume controller with two fully analog channels that can be controlled together or act completely independently. You can connect TS mono jacks into channels A and B, or a single TRS stereo jack into channel A, and the same applies to the outputs.
Does the Siren color my tone?
Oscillator Devices says the Siren is specifically designed not to color your tone, with outstanding crosstalk performance, high quality low noise buffers and Neutrik sockets. The signal path is fully analog, and the maker describes the headroom as massive when powered at 9 to 18V.
Can the Siren sync tremolo to MIDI clock?
Yes. The two internal LFOs can run free from 100ms to 1.2s, or sync to MIDI clock. The LFOs offer Sine, Triangle, Rectangle and Ramp waveforms in both directions, and firmware 3.1.0 added tap tempo for the tremolo.
What MIDI TRS type does the Siren use?
The Siren uses MIDI TRS Type A, the same standard as pedals from Boss or Wampler, and it is compatible with Morningstar MIDI TRS connections. The MIDI input is a 1/8 inch (3.5 mm) stereo jack wired to DIN 5-pin, and the jack is TS and TRS compatible.
Can the Siren work as an ABY box?
Yes. Oscillator Devices recommends using the Siren in Mix Mode, where it functions as an active ABY box, isolating and mixing both signals. The maker also sells a dedicated MIDI ABY product for players who only need switching.
How much does the Oscillator Devices Siren cost in dollars?
Oscillator Devices lists the Siren at 169,00 € including 0% VAT plus shipping, as of October 2026. The maker does not publish a US dollar price, so the euro list price is the only published figure.
Sources (4)
- Siren - MIDI Volume Controller - Oscillator Devices, Oscillator Devices
- Stereo MIDI Volume Controller, Oscillator Devices, 2026
- ABY - MIDI Controlled TRS ABY Box - Oscillator Devices, Oscillator Devices, 2026-04-10
- Firmware Updates, Oscillator Devices
