Subgroups in Live Mixing: Organizing and Controlling Channel Groups

Subgroups combine multiple mixer channels into collective control points. Rather than adjusting individual drum faders to change overall drum level, a drum subgroup allows single-fader control. This organizational tool simplifies complex mixes while enabling group processing.

Understanding Subgroups

Subgroups (also called groups or buses) are intermediate mixing stages between channels and the main output. Channels assigned to a subgroup feed that subgroup rather than (or in addition to) the main stereo bus.

The subgroup fader controls the combined level of all contributing channels. Moving the subgroup fader raises or lowers all assigned channels together while maintaining their relative balance.

Subgroups then feed the main stereo bus. The signal path becomes: channels → subgroups → main bus. This hierarchy adds control layer between individual channels and final output.

Common Subgroup Assignments

Drums subgroup contains all drum microphone channels. Adjusting overall drum level requires moving one fader instead of eight or more.

Backing vocal subgroup collects all backing vocal channels. Group level control maintains consistent backing vocal presence.

Guitar subgroup might contain multiple guitar channels (two rhythm guitars, lead guitar). Group control adjusts overall guitar level.

Keyboards subgroup handles multiple keyboard channels—piano, organ, synth—as a unit.

Routing Channels to Subgroups

Channel bus assignment buttons select destinations. Assigning a channel to subgroup 1-2 routes its output to that stereo subgroup pair.

Channels can route to subgroups only, main only, or both simultaneously. Routing to subgroups only means the channel reaches main outputs only through the subgroup. Routing to both means direct path to main plus subgroup path.

Routing to subgroups only provides more precise control. The subgroup fader then controls that channel’s contribution to the main mix completely.

Subgroup Processing

Processing inserted on subgroups affects all contributing channels collectively. Compressing the drum subgroup applies unified dynamics control to the entire kit.

Subgroup compression can “glue” related channels together, creating cohesive sound from multiple sources. Drum bus compression is a classic technique.

EQ on subgroups shapes the collective tone of all contributing channels. Brightening the vocal subgroup affects all vocals uniformly.

Effects sends from subgroups send processed groups to effects rather than individual channels. This can simplify effect routing.

Stereo Subgroup Considerations

Subgroups typically exist in stereo pairs (1-2, 3-4). This accommodates stereo sources and maintains pan positioning.

Channels panned left feed more to the left subgroup; channels panned right feed more to the right. Center-panned channels feed both equally.

For mono subgroup operation, pan the subgroup pair to center. Both left and right subgroup outputs combine to mono main feed.

Subgroup Level Management

Subgroup faders should operate near unity for optimal gain structure. If subgroup faders are very low, contributing channels may be too hot.

Unity positioning on subgroups means they neither add nor subtract level—just pass through. This maintains proper gain structure through the mixing chain.

Riding subgroup faders during performance adjusts entire groups together. Bringing up the guitar subgroup during a solo raises all guitars simultaneously.

Subgroups vs VCAs

VCA groups also provide group control but work differently. VCAs (Voltage Controlled Amplifiers) remotely control channel faders without rerouting audio.

Subgroups create new audio paths that can be processed. VCAs control existing faders without creating new paths.

VCA control affects aux sends from channels (if post-fader); subgroup routing does not affect channel-level aux sends.

Digital mixers often call VCA-type control “DCA” (Digitally Controlled Amplifier) since no actual voltage control occurs.

Subgroup Applications

Show control: Subgroups enable quick overall adjustments. “More drums” becomes one fader move.

Processing efficiency: One compressor on the drum subgroup replaces individual compressors on each drum channel.

Organization: Subgroups provide visual and functional organization for complex mixes.

Parallel processing: Sending drums to both main and a parallel-compressed subgroup creates parallel compression effects.

Setup Procedure

Plan subgroup assignments before soundcheck. Determine which channels belong to which groups based on the band’s arrangement.

Assign channels to subgroups according to the plan. Verify assignments by adjusting subgroup faders and observing effect on output.

Set subgroup processing (if any) during soundcheck. Compression, EQ, or other processing should be set while hearing the actual sources.

Test subgroup operation before performance. Verify that subgroup faders control their assigned channels as expected.

Troubleshooting

No signal from a subgroup: Verify channels are assigned to that subgroup and the subgroup routes to main. Check subgroup fader level.

Channel missing from subgroup: Verify bus assignment on that channel. It may route directly to main instead of through subgroup.

Double signal level: Channel may route to both subgroup and main, doubling its contribution. Route to subgroup only if single-path is desired.

Processing not affecting expected channels: Verify those channels actually route through the processed subgroup.