Topic: USB Stereo Mode Different Implentations
Hi,
I purchased 2 RME devices with the intention of using them to record 2-channel audio on iphone video. ADI 2 PRO and FF UCX I have an analog signal chain and really only need the RME devices for ADC at the end of the chain. Totalmix on the UCX is a bonus.
Before purchasing them I spoke to tech support at RME and I was told that the UCX has a usb stereo mode that will make it compatible with ios apps. From my testing as a user, I see that the implementation of "stereo mode" in FF UCX differs from that of the ADI 2 Pro. Can someone confirm my understanding?
ADI 2 Pro: When you select stereo mode, this requires creating a new connection to the computer. When stereo mode is enabled and a connection is made, the computer/ipad recognizes the adi 2 pro as a 2 channel usb device. It only sees those two channels.
Documentation: In the ADI 2 Pro manual look at pages 37ff (17.4 USB). It outlines stereo vs multichannel mode. In "Class Compliant Stereo mode", it is recognized by a computer as a 2-channel device. In "Class Compliant Multi-channel mode" it is recognized by a computer as an 8-channel device.
FF UCX: When you select stereo mode, there's no need to reconnect usb. It seems like there is some simple routing magic that allows all of the channels to be summed and routed to usb channels 1 & 2. In this case, the ipad recognizes the ff ucx as a multichannel device but audio is only going to 2 channels. When I open Garage Band, for example, I see that all the channels are available to be selected, although the signal is only being routed to 1 and 2. This is a clever implementation to allow a user to record all the channels in a single stereo track. However, there are cases where ios apps refuse to record audio if a multichannel audio input is detected. The camera app and many other video recordings apps reject the FF UCX unfortunately.
The Fireface UCX also has a "Stereo mode" that is not in the documentation. To access it, open the ios totalmix app, go to Settings > RME Interface settings > Output Channel count req. It will show two options: "Stereo", "Multichannel".
My simple question is: is there a way for the FF UCX be "be seen" by my iphone as a 2-channel device rather than a multichannel device with all audio routed to 1 and 2? If not, are there any plans to make this available or is it impossible given the constraints of the hardware design?