Apple Logic Pro 7 - Manual (Page 283)

Chapter 6 Logic’s Mixing Facilities 283
You can switch other Object types in the same way, using the global Toggle (Mute)
Audio Inputs, Toggle (Mute) Audio Aux, Toggle (Mute) Audio Bus and Toggle (Mute) Audio
Outputs key commands.
Solo/Mute
Solo
All Audio Objects have a Solo button. This mutes all other Audio Objects of the same
hardware type.
Muted Objects are indicated by a flashing M in the Mute button. Please note that this
does not mute MIDI tracks.
You can also solo several Objects at once.
Option-clicking a previously unsoloed Object releases other active Solo buttons,
allowing the selected channel to be heard in isolation (“Interlocking Solo” or “Solo
Toggle”).
Option-clicking any activated Solo button disables the solo status of all Audio Objects.
Solo Safe
If you want to hear the signal of a soloed channel with any bussed effects, the effect
return channels obviously shouldn’t be muted. Unlike conventional mixing desks, Logic
can scan the entire signal path, and leave the effect return channels open.
The same applies when you solo an effect return signal. The channels fed into the
effect are muted, but their effect sends remain open, ensuring that the effect continues
to receive a signal.
This automatic mute-suppression only applies to the internal effect returns. If you are
using external effect units via Bus Objects, the scan will keep the effect master sends
open. Logic cannot, however, know which of the Input Objects you are using as effect
returns for external effect units. You need to manually switch these Input Objects to
“solo safe”—just like on a conventional mixing desk.
Control-clicking an inactive solo switch makes an Audio Object “solo safe”. This prevents
it from being muted when you solo another channel. “Solo safe” status is indicated by
an X on the solo button. A second Control-click defeats the solo safe status.
Mute Button
You can mute any Audio Object by pressing the button marked with an M. Pressing the
button a second time restores the previous level.