Low Latency Mode

Low Latency Mode reduces the plug-in and delay-compensation latency on the path you hear while performing. It optimizes one logical Output at a time without muting, disabling, or rerouting the other Outputs.

It is a session aid rather than a project edit. Its enabled state and target are not written into the project, do not make the project dirty, and reset when you close or reopen the project.

Choose the monitoring Output

When a project opens, Heron selects the first logical Output as the default target. This is normally Output 1–2, but it may be another Output if the project uses a different ordering.

To use a different destination:

1. Stop the transport.
2. Open the Mixer and find the required Output strip.
3. Select Set as Low Latency Mode monitoring target.
4. Select Low Latency Mode in the top bar.

Only one Output can be the target. Every Output continues to produce its normal signal; optimization applies only to monitored main routes that reach the selected Output.

You can enable or disable the mode, change its target, or change its plug-in budget only while the transport is stopped. Once enabled, it remains active during playback and recording.

Which paths are optimized

Heron discovers monitoring sources from the track controls. You do not need to mark a channel separately.

A path is eligible when it carries:

• effective audio input monitoring from a configured hardware input; or
• live MIDI monitoring through an instrument.

Record enable by itself does not create a monitoring path. A record-enabled track with monitoring off is recorded normally but is not optimized.

Heron follows the source's dry main route through shared buses and the target Output. Sends remain on normal compensation, so a wet return can arrive later than the dry monitored signal. A late side-chain signal also does not delay the monitored main input. Other Outputs and unrelated playback branches retain normal plug-in delay compensation.

Plug-in latency budget

Open Settings → Audio → Recording to set the Low-latency plug-in budget. The default is 5 ms, and the available range is 0–50 ms in whole milliseconds. Heron converts this value to samples using the current project sample rate.

The budget counts declared plug-in latency along each eligible main path. If a path exceeds the budget, Heron temporarily bypasses eligible effects, starting with the largest latency contribution, and recalculates the paths after each choice.

Instrument plug-ins are never bypassed. Their latency is reported as unavoidable, and the mode still activates even when that latency alone exceeds the budget. Effects on tracks, shared buses, and the target Output can all be temporary bypass candidates.

Temporary low-latency bypass is separate from a plug-in's own bypass or enabled state. It does not edit the project and disappears when Low Latency Mode is disabled. Unlike ordinary latency-preserving bypass, this temporary bypass uses a direct zero-latency pass-through.

Read the status

The top-bar tooltip shows the target Output, budget, and number of temporarily bypassed plug-ins. If the mode is enabled but no eligible source currently reaches the target, it reports no active monitoring path. This is a valid state, not an error.

The Effect Chain Graph marks latency-sensitive paths and effects temporarily bypassed by Low Latency Mode. It also exposes unavoidable instrument latency.

What the mode does not reduce

Low Latency Mode changes only the audio graph. It does not change:

• the audio-device buffer size;
• ADC or DAC conversion time;
• input-ring buffering;
• sample-rate conversion latency; or
• the project or device sample rate.

For the lowest practical round-trip latency, use Low Latency Mode together with a stable, appropriately small device buffer. If you hear XRUNs or dropouts, increase the buffer even if that adds some hardware latency.

Because the monitored path takes priority over playback alignment, a monitored track and any shared bus it joins may temporarily lose strict PDC alignment with the rest of the arrangement. This is expected. Disable Low Latency Mode when you want to judge final timing, effects, and mix balance with full compensation.

Session behavior

• Restarting the isolated audio helper keeps the current session policy.
• Closing, switching, or reopening a project disables the mode.
• The plug-in budget is an application setting and remains available across projects and application restarts.
• If the target Output is deleted, the mode turns off and Heron selects the first remaining Output as the new default target.