It levels the record, then splits the sound into five bands and holds each one at a fixed destination, then puts a ceiling on what comes out. That is what makes a radio station sound constant: every record arrives at the same loudness and with the same tonal balance, whatever it was mastered like. It is not an equaliser and not a compressor — those react to what you give them. This one has a place it takes everything to.

Those three are exactly what is inside it, and in that order: an AGC that rides the gain slowly so every record arrives at the same loudness, a five-band compressor that holds each slice of the spectrum at a fixed destination, and a final clipper that trims the peaks instead of turning them down. You can buy each of the three separately as plugins; what you cannot easily buy is the three tuned to work as one chain, which is the whole point of a broadcast processor and the reason a radio station sounds constant.

OptiBob is not a plugin: it is a Mac app that sits on the system output, plus this page for files. If you are looking for an alternative to a hardware broadcast processor — the kind of machine an FM station keeps in the rack — that is the shelf it belongs on.

It is an independent project, built by measuring how those machines behave — band by band, against real recordings — and writing our own engine to match. It contains no Orban code. Where a number is published we match it; where it is not, we measured it, and we wrote down how. The name is a nod to Bob Orban, who invented this way of treating sound.

No. OptiBob File runs entirely inside your browser: the audio never leaves your computer, there is no server doing the work and no account to create. Close the tab and nothing of yours remains.

OptiBob is not signed with an Apple Developer ID yet, so the first time you open it macOS stops you. It is not a warning about the app: it is macOS saying it has never seen this developer. To open it anyway: right-click the app and choose Open, then Open again in the box that appears. You only do this once. If the box has no Open button, go to System Settings → Privacy & Security, scroll down, and click Open Anyway next to OptiBob.

macOS 14.4 or newer, and no. OptiBob Live uses the audio taps that macOS provides, so there is no driver and no system extension: you open it and it works on whatever your Mac is already playing.

Yes. OptiBob Live sits on the system output, so it processes whatever is playing without needing anything from the app that plays it.

Both, and they are the same job. A web radio gets a chain it would otherwise rent; someone listening at home gets records that stop jumping in volume between one and the next. What OptiBob does not do is generate the FM signal itself — it stops at the audio.