Downmix Preferences

Orbit always renders to 7.1.4 internally. Three smaller multichannel formats — 5.1.4, 5.1, and Quad (4.0) — are derived from that 7.1.4 bus via a deterministic fold-down. The Downmix panel is where you tune the coefficients that drive each fold-down algorithm: how loud the height channels sit when collapsed into the bed, how the LFE is handled, how the centre channel spreads when there's no centre speaker.

What this panel controls

Only formats smaller than 7.1.4 have downmix coefficients — 7.1.4 is the source bus, so it's deliberately excluded from the format picker. The format you select in this panel doesn't have to be the one you're currently monitoring; you can edit a 5.1 fold-down while listening in stereo, for example. An Active badge marks the format that matches your current output to make it clear which row of the picker is what you're actually hearing right now.

When you edit the active format, changes apply live to the audio engine — every slider drag is audible immediately. Edits to non-active formats are saved but not auditioned until you switch the output to that format.

Format picker

A segmented picker with three entries — 5.1.4, 5.1, Quad (4.0) — selecting which downmix configuration you're editing. The "Active" badge highlights whichever entry matches the current output format set in the Audio panel.

Stereo (2.0) is not in this picker — stereo fold-down is handled by the Stereo monitoring mode rather than as an editable downmix preset. See Monitoring for that path.

Per-format controls

Each format exposes a subset of the same coefficient family — only the controls that make sense for that target are shown (e.g. Centre Divergence has nothing to do for 5.1.4 / 5.1 because they keep the centre channel; LFE Routing has no work to do for 5.1.4 / 5.1 because the LFE channel passes through).

Defaults are chosen to match common reference renderers; the sliders are there for when you need to deviate.

Height Trim — gain applied to the height channels (Ltf / Rtf / Ltb / Rtb) when they fold into the bed for formats without dedicated heights. Lower values pull the height content out of the mix; higher values keep it prominent.

Surround Trim — gain applied to the rear surrounds (Lrs / Rrs) when they fold into the side surrounds (Ls / Rs) for formats without rear pairs. Similar idea: lower values back the rears off.

LFE Routing — two policies. Off discards the LFE channel entirely (appropriate for delivery formats that don't carry LFE). → L/R sums the LFE into the main left and right at a chosen attenuation. When → L/R is selected, an additional LFE Level picker appears with three options: −3 dB, −6 dB, or −10 dB.

Centre Divergence — controls how strongly the centre channel spreads into the L and R for formats without a centre speaker. Higher values produce a wider phantom centre image; lower values keep dialogue more locked to the original mix.

Rear → Front — a small amount of rear surround content folded forward into L and R. Capped at roughly −10 dB so it never overwhelms the front image; useful when you want some sense of the rears reflected in the stereo fold-down.

Summing — choose between Power (−3 dB constant-power normalization) and Voltage (−6 dB voltage sum). Power matches what most broadcast standards specify; voltage is occasionally requested for legacy comparisons. Default is Power.

Xfade — crossfade smoothing in milliseconds. When you switch between formats live, this is how long the transition takes. Higher values are smoother but introduce a perceptible glide; lower values are snappier but can pop.

Resetting

Reset Defaults restores all coefficients for the currently selected format to factory values. It doesn't touch other formats — each format has its own reset. Useful when you've experimented your way into something that doesn't sound right and want a known-good starting point.

WARNING

There's no Apply or Cancel — every change is committed live to the engine when editing the active format. If you don't like a change, drag the slider back, or use Reset Defaults to wipe everything for that format.

See also

• Audio — choosing the output format that selects which downmix is active.
• Monitoring — the binaural and stereo monitoring modes both rely on these fold-down coefficients to derive headphone and stereo feeds from the 7.1.4 bus.