When streaming from phone to mixer does the CQ18T offer a longer range than the CQ12T?
Yes - the CQ-18T has an external aerial and gives better reception. The CQ-12T has a surface-mounted antenna.
In general, in both cases, the intended use-case is a device nearby the mixer.
Bluetooth as a low-energy wireless technology is very susceptible to interference from other devices so in busy environments, performance will vary (think - a room full of people with phones in their pockets)
Are you saying that the little wifi antenna on the CQ18T which can be lifted up to a right angle to the device also receives a Bluetooth signal? (Not sure what you meant by external aerial.)
My use case is that during performance breaks I need to play canned music over my PA, like an mp3 playlist. If at any point the playlist goes to a song which is surprisingly loud in volume, too low in volume, or inappropriate for some other reason I need to quickly make my way over to my gear to either adjust the volume or skip the track. So it would be convenient to either stream the playlist from a Bluetooth device so I do not have to race over to my mixer, or have a phone app which can allow me to make a volume adjustment on the mixer from a certain distance. (Of course in the case of an app controlling the mixer I would not be able to skip tracks on the mp3 player, only adjust volume.)
During performance breaks I’m usually hanging out not too far from the stage, but with my current wired setup it is still inconvenient to occasionally have to stop what I’m doing and walk back to the stage area to make a change to the music player.
Yes, the antenna on the CQ-18T also carries the Bluetooth signal. It’s external insofar as it sticks up out of the mixer itself!
If you’re on Android, you can use the CQ-Mixpad app on your phone for remote control - you can switch back and forth to a playback app, although Mixpad will likely show “Connection Lost” as modern mobile operating systems won’t allow it to maintain the network connection in the background.
(On iOS it’s only available on iPad)