About Delay Compensation in Reason

Delay compensation is desired because some effect devices have inherent latencies, due to internal processing
(re-sampling, FFT, lookahead compression etc). When a signal passes through such a device, it gets delayed and thus “out-of-sync” with other signals. This is especially noticeable if you're using Parallel Channels in the Reason mixer, because both the original channel and the parallel channel(s) carry the same source signal. If the effects on one of these parallel channels delay the signal, this will be heard as comb filtering, phasing, blurring, etc.

Traditionally, Reason hasn’t had any delay compensation, mainly because of the totally free routing possibilities. However, as from version 9.5 Reason features delay compensation for its native effect devices, Rack Extension effect devices and VST effect plugins.

Typically, there are two ways to achieve delay compensation:

By inserting “invisible” delays on the other signal paths, so that all paths are delayed equally.

By having the tracks with latency effects in their paths play back earlier.

•	The delay compensation introduced in Reason 9.5 uses the first method only, i.e. inserting delays in the other signal paths.

Activating the Delay Compensation

The delay compensation can be activated in the Master Section fader section, on the Transport panel, and on the
Options menu.

The Delay Compensation button in the Master Section of the Main Mixer.

The Delay Compensation button on the Transport panel.

Click the Delay Comp button to switch on/off the delay compensation.

When on, the delay compensation affects all configurations described in “Delay Compensation rules” below.

•	The total signal path latency is displayed (in no. of samples) below the Delay Comp buttons.

Hovering over any of these latency figures brings up a tool tip which also displays the latency in milliseconds.

Delay Compensation rules and limitations

Due to the free routing possibilities in Reason, delay compensation could become infinitely complicated. Therefore, we have chosen to keep it fairly simple by imposing some general rules and limitations.

The delay compensation aims at getting a coherent mix using the main mixer in a *standard* configuration. If you do unconventional routings, the delay compensation may not work as intended and things might sound off. See “Problematic configurations” for examples of problematic routings.

Delay Compensation rules

Here are the basic rules for delay compensation in Reason:

•	Delay compensation can be applied to Effect devices that are connected in series between an instrument device and the inputs of a Mix Channel device:

An ID8 instrument device routed via a Scream 4 effect and an RV7000 Reverb effect in series.

The configuration above can be described schematically in the following picture:

•	Delay compensation can be applied to Effects devices connected in series as Insert FX in the mixer channels (between the "To/From Insert FX" jacks on Audio Track and Mix Channel devices):

A Scream 4 and an RV7000 effect device routed in series as an Insert FX in a Mix Channel.

The configuration above can be described schematically in the following picture:

•	Delay compensation can be applied to Effect devices that are connected in series between the Parallel Out jacks of a Mix Channel or Audio Track device, to the Input jacks of another Mix Channel device:

The Parallel Outs of a Mix Channel (ID8 3) routed via a Scream 4 and an RV7000 to another Mix Channel (Mix Channel).

The configuration above can be described schematically in the following picture:

•	Delay compensation can also be applied to combinations of the three examples above.

This could be, for example, if an Instrument device is routed in series via Effect devices to a Mix Channel device, and the Mix Channel device has Effect devices in series in its Insert FX section. Then, the latency is summed for all effect devices in the serial signal chain.

•	Delay compensation can be applied to signals that are sent from the mixer channels to the Send FX busses.

This means that the signals from the Mix Channels are delay-compensated (if necessary) before they are sent to the Send FX busses.

•	Reason fully depends on getting latency values reported from the Effect devices/plugins.

In other words, Reason doesn’t measure any latency of the effect devices. However, you can manually adjust the delay compensation if needed (if things sound wrong due to plugins reporting wrong latencies etc.). See “Manually adjusting the latency values” for more details.

Delay Compensation limitations

•	Only signals routed to a channel in Reason’s main mixer will be compensated. There is no delay compensation for the channels on a rack mixer, such as Mixer 14:2.

•	Only signals that pass the Master Section will be compensated (not channels connected using Direct Outs, see “About using the Direct Out connections of the mixer channels”).

•	The delay compensation ignores the latency reported by devices connected as Send Effects (see “About Send FX Returns”).

•	With some non-standard routings (splits, loopbacks, cross-routing etc), delay compensation may not work or may be limited. See “Problematic configurations”.

•	Effects inside an Instrument Combinator are not delay-compensated (but Effect Combis are).

•	CV, MIDI and automation signals are not delay-compensated.

•	MIDI Clock sync and Ableton Link are not delay-compensated.

However, you can manually adjust the MIDI Clock Sync Offset, see “External synchronization considerations”.