Designing complex electronic music patterns with hardware synthesizers usually requires sitting in front of your physical gear, cables plugged in, and MIDI interfaces humming. But what happens when inspiration strikes on the train, in a coffee shop, or when you are simply away from your studio setup?
With the latest update to closeby.1, we have completely redesigned our local preview synthesizer. Say goodbye to generic sawtooth sound-alikes: you can now preview your tracks with a lightweight, native Web Audio synthesizer that mirrors the voice architectures, default oscillators, and MIDI Control Change (CC) layout mappings of your actual physical instruments.
The Problem: Silent Sweeps and Generic Sounds
Previously, when editing tracks without external gear connected, you were limited to a single, static sawtooth wave. Even worse, if you mapped complex CC automation curves (such as sweeping a filter cutoff or adjusting envelope decay times), the local synthesizer did not respond to those changes. You had to wait until you were back in your studio to hear how your modulations actually affected the sound.
The Solution: A Coupled Synthesis Preview Engine
The new closeby.1 PreviewEngine is a standalone, lightweight synthesizer built entirely on the native browser Web Audio API. It operates directly inside your browser and replicates the control behaviors of your hardware devices on a per-channel basis.
[!IMPORTANT] Managing Expectations: A Functional Sketchpad, Not a Sonic Clone The local preview engine is designed as a workflow helper—it is not a complete, circuit-modeled emulation of your hardware's sound. It does not model analog filters, sub-oscillators, cross-modulation, or custom digital engines. Instead, it approximates standard waveforms (sawtooth, square, triangle, sine) and maps your MIDI CC numbers to Web Audio graph equivalents. The goal is to let you program note structures and paint automation sweeps dynamically on the go, with the exact CC controls that will govern your physical hardware back in the studio.
Here is how it bridges the gap between software grids and physical hardware:
- Coupled Device Profiles: The engine automatically detects which hardware profile is active on your track. When you select a profile like the Moog Minitaur, the engine automatically selects a sawtooth wave and routes CC parameter adjustments to the Moog's specific control numbers (like CC 19 for Filter Cutoff). Choose an Arturia MicroFreak, and the engine swaps to a square wave and shifts the cutoff tracking to CC 74.
- Real-Time CC Mapping and Scaling: When you play notes or draw automation curves in the CC Grid, the engine translates those standard MIDI CC numbers (0–127) into actual synthesis parameters in real-time. Cutoff CCs sweep the filter logarithmically from a deep 20Hz up to 15kHz, resonance values scale linearly, and envelope sliders automatically adjust the built-in ADSR times (up to 5.0 seconds).
- Smooth Parameter Sweeps: Any adjustments made to your automated steps dynamically sweep currently sustaining voices over a click-free 20ms ramp, letting you hear fluid filter sweeps and volume changes instantly.
- Legato Voice Tracking: The engine manages monophonic legato behavior by applying a fast, click-free 5ms fade-out on cut notes, ensuring your synth solos are smooth and free of audio pops.
Step-by-Step: Customizing Your Preview
Getting started with the new engine is simple and works automatically:
- Open the Left Sidebar and click the gear icon on a track to open its settings.
- In the Instrument Profile dropdown, select your hardware synthesizer (e.g. Korg Minilogue). The engine will automatically set the default oscillator type (e.g., Triangle) and wire up the filter and envelope CC controls.
- If you want to override the default sound, use the Preview Oscillator dropdown to choose between Sawtooth, Square, Triangle, or Sine waves.
- Close the settings, verify that LOCAL SYNTH is turned on in the sidebar, and press Play or click notes on the grid. You will immediately hear the selected wave shape and any drawn CC automation shaping the sound.
Creative Applications: Studio Workflows on the Go
1. Pre-Production CC Automation Painting
Use your commute to sketch out expressive filter builds and complex envelope movements in the CC Automation Grid. Since the local engine mimics the CC mappings of your studio synthesizers, your filters will sweep exactly where you expect them to. When you return to your studio and plug in your hardware, your automations will translate perfectly to your physical knobs.
2. Sound Design Matching
By selecting the matching oscillator type (e.g. choosing a square wave to match your Microfreak's digital lead), your melodic structures and chords will feel much closer to the finished track. This makes it easier to write complementary basslines and drum arrangements without being distracted by mismatching synth timbres.
Wrapping Up
We designed the new preview engine to make closeby.1 the ultimate sketchpad for hardware enthusiasts. Whether you are running complex sequences in your studio or sketching out ideas on your laptop screen, your workspace now sounds and behaves like your hardware.
Give it a spin on your next track, and let us know what profiles you would like to see supported next!