Explanation of Config > USB/SD > Channel Assignment

[Terryfied]

I recently purchased a CQ-18T and really love it! I think I’ve gotten my head wrapped around 90% of it, but I am still unclear as to what the Config > USB/SD > Channel Assignment section is for and how it works. Could someone provide clarity? Appreciated!

[Anonymous]

From the manual:
CQ-18T and CQ-20B each have 4 assignable stereo outputs. These allow recording
and playback of stereo line inputs, FX units, Main LR output or outputs 1-6.

You can assign specific pairs of output for the recording.
If you change something under this Channel Assignment section, it will be reflected in the multitrack SD recorder page.

[Terryfied]

I appreciate your response. I’m still confused though. If we look at Processing > USB tab > USB > Source, it shows that by default the USB comes in on 19/20. If that’s the case, how could 19/20 be assigned to a hardware output?

[BloodyCactus]

the config->usb->channel assignment is just a mini matrix, and is because you have more outputs than “outputs” so you have to choose what you want routed to where, within limitations.

also be aware, you can use the bluetooth as another set of usb stereo inputs instead of being bluetooth, which is nice (on processing page).

[Terryfied]

OK so basically, these channel assignments are pretty much for what’s being recorded by the mixer and has nothing to do with outputs or inputs (other than internal matrix routing), right?

[BloodyCactus]

did you read the manual?

[quote]Channel Assignment – Mono input channels are permanently assigned to USB/SD outputs. In addition to these, the CQ-12T has 3 assignable stereo outputs and the CQ-18T and CQ-20B each have 4 assignable stereo outputs. These allow recording and playback of stereo line inputs, FX units, Main LR output or outputs 1-6.[/quote]

basically, you can assign the stereo input, the 6 aux outs, the main lr out, or the fx1-4 output to these and basically get a copy on a separate output to usb/sd card.

[Terryfied]

Yes, I have read the manual, I just don’t get the concept I think. I am assuming that the 16 physical inputs are mapped to the equivalent output for DAW and SD/USB recording. However, beyond that I just don’t understand. I guess I’ll have to figure it out for myself, because everyone who has responded just keeps repeating the same thing the manual says, which obviously is not clicking for me. Ty for the response.

[KeithJ A&H]

@Terryfied

Does it help to know that the channel assignments only affect outputs?

So in stereo USB-B mode and when recording stereo to USB-A, you will record whatever you have selected from the drop down in the last channel assignment box. By default this is the MainLR output.

In Multitrack USB-B mode or when recording to SD, as you say, the first 16 outputs always come from the first 16 input channels of the CQ.
Following this you have 4 stereo pairs and you can choose what these are, so you’re choosing what’s being sent to digital outputs 17 to 24.
For example, if you wanted to record the stereo line input to your DAW, you could set the first channel assignment box (17/18) to ‘ST IN’ then set the input channel in your DAW track to 17&18.

Thanks,
Keith.

[Terryfied]

Yes! OK! That makes sense then, that the settings there are for OUTPUTS 17 through 24. I was getting confused because I was thinking, ok, how can I set 19/20 to anything if USB in is 19/20? But actually, for USB, 19/20 are inputs and in the Channel Assignment page it’s referring to outputs. That makes total sense. Thank you!

I’d also take this chance to recognize your efforts with regard to your videos, they have been an amazing help, not only in using my CQ-18T, but mixing concepts in general. Thank you again!

[Hugh]

Keith,
For those of us that plan to use the SD card option for Playback of BU stereo tracks a U-Tube video explaining the specific SD card limitations when compared with the various detailed USB protocols.
1) Is all SD card recording facilitated in the Multitrack mode? Stereo recording is aparently restricted to USB A or B recording or streaming.
2) Is the 2hr 96K limit for all SD multitrack recording regardless of the number of active inputs?
Hugh

[KeithJ A&H]

@Hugh

1) All SD card recording is multitrack and records mono files. However, you can select which tracks are armed for recording, so it’s possible to only record 2 tracks (fed from a stereo channel) if you wish.
Stereo recording to USB-A will instead result in an interleaved stereo file.
Note that to playback to specific channels, the file names must be named/numbered to include those channel numbers
The stereo/multitrack mode only applies to the USB-B stream, and was mainly included to allow connection to devices (as a class compliant stereo audio device) for recording and streaming.
2) The limit on track length comes from the limit on individual file size. So a 96kHz recording will be twice as many samples and the maximum file size will be reached twice as fast, hence the maximum record time is halved. Similarly, an interleaved stereo recording will be twice the size because it includes 2 channels of data in one file, so half the maximum record time.
Because the limit is on each individual file and a multitrack recording is made up of multiple files (of the same length), the number of armed and recorded tracks has no bearing on the maximum record length (presuming you have enough free space on the drive of course!)

Thanks,
Keith.

[Hugh]

Thank you In a very big way Keith for the detailed Info I was asking for: I may not be the only CQ20b user that did not get a clear picture, out of the user guide, of the precise differences with the new SD recording protocol that is unique to the CQ line. The above clearly stated paragraph is really helpful.
Hugh

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