23Bloom

Bloom adds harmonics instead of gain. It drives the signal into a transfer curve that lifts the quiet detail of a sound and holds the loud parts under full scale, so what comes out is denser and louder to the ear without a compressor’s grip on the dynamics.

23Bloom is that plug-in rebuilt on the Season 02 framework. One plug-in for Stereo and Mid/Side instead of two, a band split you can place, loudness tracking that works, and a signed and notarised installer on macOS. The name changed with the rebuild: another developer already ships a plug-in called Bloom, and that was my mistake to fix.

The curve

Input drives the signal in, up to 12 dB. Curve picks the shape, from −50 to +50: at zero it is the plain curve, negative is softer and lifts quiet detail less, positive is firmer and audibly saturated. Effect blends the shaped signal against the dry one, and Output trims what comes out. Clip holds the input at 0 dB on the way in rather than at 2, which is the difference between soft harmonics and a hard edge.

The XY pad draws the transfer curve as you drag it, with the curve the signal is actually hitting over the top of it while audio plays.

Three bands, placed where you want them

Bloom’s band split was a switch. It cut at 240 Hz and 2.4 kHz, fixed, and shaped all three bands the same way. Here both crossovers are controls — 60 to 800 Hz and 1 to 10 kHz — and each band has an Amount from 0 to 100 %, so the lows can pass untouched while the mids and highs take the curve, or the other way around. Drag the dividers, or the band heights, in the display.

The three bands add back to the input exactly. The split is the Oxford Inflator’s — a one-pole low-pass and a one-pole high-pass, with the mid as what is left over — where Bloom compensated its own split with a gain factor and left a tilt behind. 23Bloom nulls against RCInflator2, the open-source reproduction of that Inflator, and the check runs on every build.

Loudness tracking

Switch Loudness on and the programme level moves the Curve control: a positive Amount firms the curve up as the music gets louder, a negative one softens it. The detector is K-weighted — a high-pass at 100 Hz, a 4 dB bell at 2 kHz, a low-pass at 8 kHz — so it follows what you hear rather than the waveform. Response sets how it lets go: Fast in 40 ms, Slow in 800 ms, and Auto somewhere between the two depending on how sustained the material is, which keeps a pad from pumping and still lets a drum loop breathe. The rise is 2 ms either way.

In Bloom this did not work. The switch was wired the wrong way round, so the Amount knob only had an effect while the button was off, and the interface hid the knob in exactly that state.

Mid/Side

Mid/Side gives the centre and the sides their own complete set of controls — drive, curve, effect, bands, loudness, trim. Shape the mid for density and leave the sides alone, or lift the sides for width and keep the centre as it was. Solo listens to one half on its own while you set it up. The default is Stereo, with left and right shaped together, which is what Bloom did.

Hearing what it does

Four things, all of them about judging a setting rather than making it:

• Level Match offsets the output by what the input gain and the shaping add to pink noise at −16 dBFS RMS. Curve and Effect can then be moved without the level moving with them.
• Delta plays only what 23Bloom adds — the output minus the input.
• Density reads the change in crest factor, in dB, over the last third of a second: positive when the shaper has closed the gap between the peaks and the body, negative when the band split has opened it.
• Input and output peak meters, per channel, −60 to 0 dB.

Delta and Solo are monitoring only. Neither is stored in a preset or in your session, so a mix cannot be left soloed by accident.

Presets

18 of them, filed by what they are for — starting points, mix bus, mastering, drums, bass, vocals, and a set for the split modes — each with a line saying what it does. User presets save, rename, delete, import and export beside them, with undo. Presets saved in Bloom load through the same Import button: the stereo page maps onto the stereo section, the mid and side pages onto theirs.

Moving from Bloom

23Bloom is a separate plug-in with its own identity, so it installs alongside Bloom, and sessions that use Bloom keep loading it. Settings inside an old session do not transfer. Saved .preset files do — import one and it comes back.

The old Bloom downloads stay in your Gumroad library, marked as outdated. Nothing is taken away.

Tested before it ships

Every build is validated with pluginval on Windows, macOS and Linux and with Apple’s auval, and the engine carries a regression suite: the three bands sum flat at any crossover setting, the dry path is untouched at zero effect, silence in gives silence out, the output does not depend on the host’s buffer size, there is no burst when playback starts, every oversampling factor stays bounded at every sample rate from 44.1 to 192 kHz, bypass keeps the reported latency, and Level Match really holds the reference loudness.