Reaper Routing and Sends: Complete Guide to Signal Flow

Reaper's routing system is the most flexible signal flow architecture in any DAW. Where other DAWs restrict you to fixed bus structures or limited aux send counts, Reaper lets you route any track to any other track, send audio and MIDI through unlimited sends, create complex parallel processing chains, and set up sidechain triggers with a few clicks. This routing flexibility is one of the core reasons producers choose Reaper, and at $60 for a personal license, nothing else on the market comes close to this level of signal control.

For beat battle producers, understanding routing is not about academic knowledge. It is about building mixes that hit harder, sound wider, and translate better across playback systems. The difference between a flat battle beat and one that punches through phone speakers often comes down to how the producer routed their signal.

Understanding Reaper's Routing Architecture

Every track in Reaper is simultaneously an audio track, a MIDI track, a bus, a send, and a return. There is no distinction between track types. Any track can receive audio from other tracks, send audio to multiple destinations, process MIDI, and host instruments and effects. This unified track model eliminates the artificial limitations other DAWs impose.

Default Signal Flow

By default, every track in Reaper routes its output to the Master track. Audio flows through the track's FX Chain (where your plugins process it), then out the track output to the Master bus. The Master track processes everything through its own FX Chain and outputs to your audio interface.

You can change this default by modifying the track's Master/Parent send. Open the track's routing dialog by clicking the Route button on the track panel or pressing Alt+R (Windows) / Option+R (Mac). The Master/Parent send checkbox at the top controls whether this track feeds the Master. Uncheck it if you want the track to route only through sends.

Channel Count

Reaper tracks support up to 64 audio channels internally. By default, tracks operate in stereo (2 channels), but you can increase the channel count in the routing dialog. Additional channels are used for sidechain signals, multi-channel effects processing, surround sound, and separating wet/dry signals within a single track.

The Routing Matrix

The Routing Matrix is a bird's-eye view of every connection in your project. Open it with View > Routing Matrix or press Alt+R (Windows) / Option+R (Mac) when no track is selected (or use the Actions List).

The matrix displays tracks along both axes. Rows are sources, columns are destinations. A filled cell at the intersection means audio flows from the row track to the column track. Click any empty cell to create a new send. Click a filled cell to remove or modify the routing.

The Routing Matrix is invaluable for complex projects. In a battle session with 20+ tracks, the matrix lets you verify your signal flow at a glance. No hunting through individual track routing dialogs. If a track is not reaching the master, you can see the break in the chain immediately.

Sends and Receives

Creating a Send

1. Click the Route button on the source track to open the routing dialog.
2. In the Sends section, click the Add new send dropdown.
3. Select the destination track from the list.
4. A new send appears with volume and pan controls. Adjust the send level to control how much signal reaches the destination.

You can also create sends by dragging from the Route button of one track to another track in the Track Control Panel. This visual drag-and-drop method is faster for quick setups.

Send Types

• Post-Fader (default) - The send signal follows the source track's fader. When you lower the track volume, the send volume drops proportionally. Use this for reverb and delay sends where you want the effect level to track the dry signal.
• Pre-Fader - The send signal is tapped before the track fader. The send level stays constant regardless of fader position. Use this for headphone mixes, parallel compression, or any scenario where the send needs to remain independent of the track volume.
• Pre-FX - The send signal is tapped before the track's FX Chain processes it. Use this when you need the raw, unprocessed signal at the destination.

Change the send type by clicking the dropdown next to the send in the routing dialog. Each send on a track can use a different type, giving you granular control over exactly where in the signal chain each send taps its signal.

Effect Return Tracks

The standard workflow for reverb and delay is to create a dedicated return track, load the effect plugin on that track, then send multiple source tracks to it. This approach uses one instance of the reverb plugin shared across all sources, saving CPU and creating a cohesive spatial environment.

1. Create a new track and name it "Reverb Return" (or "Delay Return").
2. Add your reverb plugin (ReaVerbate, ReaVerb, or a third-party reverb) to the FX Chain. Set the plugin to 100% wet since the dry signal comes from the source tracks.
3. On each source track that needs reverb, create a post-fader send to the Reverb Return track.
4. Adjust each send level independently to control how much reverb each element receives. The drums might get 10% send, the melody 30%, and the vocals 25%.

Bus Routing and Submixes

Folder tracks in Reaper function as submix buses. Any track can become a folder parent, and all child tracks automatically route their output through the parent.

Creating a Drum Bus

1. Create a track above your drum tracks and name it "Drum Bus."
2. Click the folder icon on the Drum Bus track in the Track Control Panel to convert it into a folder parent. Alternatively, select the track and press Shift+Tab to toggle folder state.
3. Drag your individual drum tracks (kick, snare, hi-hat, etc.) underneath the Drum Bus track. They become child tracks and their output now routes through the Drum Bus.
4. Add processing to the Drum Bus FX Chain. A bus compressor, EQ, and saturation plugin on the drum bus glue all your drums together.

Create submixes for each element group: Drum Bus, Bass Bus, Melody Bus, FX Bus. This organization gives you group-level processing and volume control. In a battle mix, adjusting one fader (the Drum Bus) changes the level of all drums relative to everything else, which is much faster than adjusting eight individual track faders.

Sidechain Compression

Sidechain compression in Reaper uses the multi-channel routing system. The concept: send a copy of the kick drum signal to the bass track on auxiliary channels, then tell the compressor on the bass track to listen to those channels for its detection input instead of the bass audio itself.

Step-by-Step Sidechain Setup

1. Increase the channel count on the bass track to 4 channels. Open the track routing dialog and change the Track Channels dropdown from 2 to 4.
2. Create a send from the kick track to the bass track. In the send settings, change the destination channels from 1/2 to 3/4. This routes the kick signal to channels 3 and 4 of the bass track, keeping it separate from the bass audio on channels 1 and 2.
3. Open the bass track's FX Chain and insert ReaComp (Reaper's stock compressor).
4. In ReaComp, click the Detector input dropdown and select Auxiliary L+R (channels 3+4). ReaComp now listens to the kick signal on channels 3/4 but compresses the bass audio on channels 1/2.
5. Set ReaComp's threshold, ratio, attack, and release to taste. A ratio of 4:1, fast attack (1-5ms), and medium release (50-100ms) creates the classic pumping sidechain effect.

The beauty of Reaper's approach is that the sidechain signal never mixes into the audible output. Channels 3/4 exist only for the compressor's detector and are not routed to the master unless you explicitly add them. This is cleaner than DAWs that require dedicated sidechain bus tracks.

Parallel Processing

Parallel processing blends an unprocessed (dry) signal with a heavily processed (wet) version. The classic application is parallel compression (also called New York compression), where you blend a smashed, heavily compressed drum signal with the original dynamics.

Method 1: Pre-Fader Send to a Compression Track

1. Create a new track called "Parallel Comp."
2. Add a compressor to its FX Chain with aggressive settings: ratio 10:1 or higher, fast attack, medium release, threshold pulled way down to compress heavily.
3. From your drum bus, create a pre-fader send to the Parallel Comp track.
4. The drum bus plays the dry drums through its normal output. The Parallel Comp track receives a copy and crushes it. Both signals reach the master and blend together.
5. Use the Parallel Comp track's fader to control how much compressed signal blends with the dry drums.

Method 2: Wet/Dry Knob on a Plugin

Many plugins, including Reaper's stock effects, have a wet/dry mix knob. You can achieve parallel processing within a single track by setting the compressor to 100% wet processing and then dialing the mix knob to 30-50%. This blends the compressed signal with the original inside the FX Chain. It is faster to set up but gives you less independent control than a dedicated parallel track.

Advanced Routing Techniques

Multi-Channel FX Processing

Reaper's 64-channel track architecture enables sophisticated internal routing. You can split a signal into multiple channel pairs, process each pair with different effects, and sum them back together, all within a single track's FX Chain. This is useful for multi-band processing, mid/side EQ, and other techniques that require parallel signal paths without additional tracks.

Hardware Inserts

If you use outboard gear, Reaper's ReaInsert plugin lets you route audio out of your interface, through external hardware, and back in, all with automatic latency compensation. Insert ReaInsert in your FX Chain, select the output and input channels on your audio interface, and Reaper measures the round-trip latency automatically. Your hardware processors integrate into the FX Chain as if they were plugins.

MIDI Routing for Multi-Timbral Instruments

When using multi-timbral instruments (plugins that play multiple sounds on different MIDI channels), create one track with the instrument plugin and multiple child tracks for MIDI input. Each child track sends MIDI on a specific channel to the parent instrument. Route the audio output of each channel back to separate tracks for independent mixing. This is the standard approach for multi-output drum plugins and orchestral instruments in Reaper.

Frequently Asked Questions