HoRNet ZeroBus vs StemMaster

HoRNet ZeroBus is a stereo mix-bus processor combining automatic equalization with adaptive compression. AutoEQ continuously analyzes 31 frequency bands and balances the spectrum in real time, with a control range from 0% to 200%. Compression has two modes: FAT uses parallel 1176-style processing for punch, while GLUE uses serial SSL-style processing for cohesion. The compressor analyzes RMS and peak levels to set threshold and makeup gain automatically. HoRNet describes ZeroBus for mix or master buses, drum buses, and other stereo subgroups. It supports 44.1–192 kHz, automatic 2× oversampling below 88.2 kHz, and near-zero auto-compensated latency. Formats listed are VST3, AU, and AAX on Windows 10+ and macOS 10.13+. The one-time price is €2,499 as a one-time purchase. A Windows and Mac demo is available, but its volume turns down every 30 seconds and host automation is unavailable. The product page states free updates and a 15-day money-back guarantee.

StemMaster is a standalone app that analyzes audio stems, mixes and masters them, and explains its processing decisions. It balances, pans, equalizes, and compresses stems according to measured roles, and can detect song sections to automate gain, pan, filters, reverb, and stereo width. Tools include vocal riding and spectral unmasking. Users can supply a commercial reference track to guide tonal balance, width, and dynamics while retaining a selected loudness target. Listed targets are Streaming −14, Club −9, and broadcast EBU R 128 −23 LUFS. The app loads WAV, AIFF, FLAC, MP3, and OGG stems and supports exports including 24-bit audio and 32-bit float WAV. Its built-in analysis engine works offline. An optional AI engine uses the user's own API key and sends measurement summaries, not audio, to the chosen provider. The free demo is the full app, but exporting requires a license and unlicensed mastered playback has a periodic audio tag. It runs on 64-bit Windows 10 version 2004 or newer and Windows 11, or Apple Silicon Macs on macOS 15 or newer; Intel Macs are unsupported. Plans include $9.99 a month, $59 a year, or a 99.00 USD one-time lifetime license.