Reply To: Qu-series: confusion about Buss/Matrix/Groups

[cornelius78]

A bus is an audio path that sums multiple signals together. In some cases a bus can have some degree of DSP applied (eg eq and compression.) TBH I’m not sure where the Qu16 gets it’s 16x busses, as I count mix1-10 +2x FX + LR = 14 busses. Perhaps they’re including the stereo PAFL to make 16.

The Qu16 has 10x “mixes.” 4 of these are fixed as mono, the other 6 are fixed as 3x stereo pairs. You can send any or all of your input channels (16x mono +3x stereo +4x stereo FX returns) channels pre or post fader (configured on a channel-by-channel basis) to these mixes. These mixes could be used to feed monitors so the band can hear themselves, they could be used to feed the internal FX engines, they could be used to feed external FX engines or recording devices, or they can be used as subgroups if you go out and come back in on a stereo pair.

The Qu16 also has 2x dedicated FX sends. These are used for feeding the internal FX engines (2 of the 4 anyway. The other 2x FX engines can be feed from mix1-10, or used as inserts on a channel/mix/LR, or used in a channel-return config.) These dedicated FX sends don’t have physical output sockets.

LR is obviously the mains bus.

In addition to the above, the Qu24 and Qu32 (and Qu-Pac) have an extra 2x FX engines, for a total of 4: one for each FX engine.

They also have stereo “groups” (2x on the Qu24, 4x on the Qu32.) A group is essentially a bus with the sends from whichever combination of inputs you assign (24/32 mono + 3x stereo + 4x stereo FX returns) locked at unity, post fader, and follows the contributing channels’ pan settings. These groups can also have DSP or FX inserted across them. Unlike the 10x mixes, the groups can be routed directly (digitally, without having to go out of the desk and come back in) to LR. As of firmware 1.8, A&H allowed these groups to be changed from groups (post fader fixed at unity, routed to LR) to act as additional stereo mixes like mix5-10, allowing for a total of 4x mono and 5x/7x stereo mixes on the Qu24/Qu32.

The matrices found on the Qu24/32 are like extra mixes, but instead of summing the signals from individual channels, they sum the inputs of buses (mix1-10, StGroups1-4 and LR.) Like the mixes they can also have their own peq, geq, comp, delay and inserts applied. I’ve heard them described as “buses for your buses.” They’re useful for things like setting up delay fills, having extra outputs for a vision feed, overflow rooms, recording etc.

DCAs are essentially remote controls for your faders (whichever inputs/mixes/groups/mains you assign to the DCA master.) They’re not an audio path, so they can’t have processing applied, but they are useful for level control, and they affect the post-fade level from the channels/mixes too, which can be quite handy. Unlike a mono group, they allow the channels to retain their pan settings. eg if you used a group for level control over a group of stereo drum channels, you’d need to burn 2x mono groups and then pan those groups in LR to maintain the stereo image. You could instead use a single DCA and not burn any groups at all, and still maintain the stereo image.

In some cases you want to use groups. In other cases you want to use a DCA. In some cases you want to use a DCA to control a group.

As [XAP]Bob said, p75 (sec 11.18) of the v.18 manual describes pressing the “Setup” button, navigating to the “I/O Patch” tab, selecting the “USB Audio” tab and selecting which 32x streams are going out to your DAW via the USB socket. By default it’ll be the 32x inputs (if you get a Qu32,) but you can change them to be anything you want: fx returns, mixes, mains or your groups.