I am using USB connected iPad to play back multitrack audio. No problem. Now I want to also send back back some audio to the iPad. I have selected ”CQ20B - Audio” as the iPad’s input:
The audio returned is channel 1. How do I change channel? I was sort of expecting it to be the main mix returned.
Is it because the iPad input settings is hiding the channels of a connected audio interface and simply picking the first?
It’s typically up to the app on iOS to offer a choice of input channels when an input device offers multiple choices. Simpler apps, like Voice Memos may default to the first input (either input 1 or input 1-2 as a stereo pair), but more sophisticated apps like Logic Pro should offer options. What app are you using for recording?
(Edit: I just downloaded Garage Band to confirm my memory of how things work on iOS/iPadOS, and sure enough - selecting Input 23+24 picks up the main stereo output from my CQ-20B without issues.)
Thanks for your help! Well, the app is Photon 2 and it is not really recording but rather listening to the audio to infer tempo. Unfortunately, the app does not offer a choice of channel but it simply uses whatever iOS is set to.
It might be worth reaching out to the authors of the app to make a feature request because chances are you’re not the only one who could use it! There really isn’t a notion of a “selected” input at the OS level. The low-level audio API makes all the information about input channels available, but the app is either simply choosing the first (which is easy since there always is a first!) or using the default which happens to be the first. I haven’t worked with the iOS AVFoundation API enough to remember offhand which it is - but the difference is academic.
The easy workaround may not be ideal, but you can literally plug the main outs (or alt outs configured to mirror the mains) into input 1 and 2 configured as a stereo pair. Don’t mix them back into the main outs or FX busses for sanity’s sake! Just let the app pick up these inputs pre-fader from the USB connection and otherwise isolate them from anything else in the mixer. This is obviously not ideal as you lose inputs, but it’s the only thing I can think of offhand for an app like this.
I may have been taking the “multitrack” in your initial post too literally. If all you want is a stereo mix over USB, there’s also an explicit option for that in the Config > USB/SD/Bluetooth page. Select the leftmost USB/SD icon, and set Stream Mode to Stereo. This will send only the pair of channels designated in the lower right under “Stereo L/R” over USB, and this defaults to the Main LR mix.
That should work well for apps like Photon 2 that really aren’t set up for multichannel audio and expect just a stereo pair.
Not at all, I do use multitrack in the CQ so setting to stereo is not an option. Though, I did try it and it satisfies Photon 2. Right now I am working on a new solution which does not rely at all on passing the audio via the CQ and back.
