I have tested, whether this external USB recording tool, works with my Samsung Galaxy S6 Smart-Phone, using an ‘StarTech.com’ OTG adapter. The results were mixed. In An Earlier Posting, I had tested whether this external USB Sound Card, works under Linux. And the answer to that question was a resounding Yes.
When we plug an OTG adapter into a smart-phone or tablet, this puts the mobile device into Master / Host Mode, that would otherwise normally work in Slave Mode. Thus, we can then plug in a USB storage device, and hopefully have that recognized, while by default, we can only plug our mobile device into a computer, and have the computer recognize this mobile device, as the storage device.
But it is also plausible to connect other external devices to our mobile device, when using an OTG adapter. All this happens because the OTG adapter itself contains an additional chip, that gives it the ability to act as a USB Host. Whether such external devices will work or not, generally depends on two factors:
- Whether the micro-USB port on the mobile device can output enough current, to supply the external / Slave device, and
- Whether the mobile device possesses the drivers needed, for the USB device in question. Under Linux, this last question is more likely to be answered in the affirmative.
The OTG adapter I was using, uses its micro-USB side as the only power-supply. This means that if the connected device draws a full 500mA of supply current, we are pushing the limit, that is generally set for USB 2.0 PC ports.
Also, my Samsung S6 is running Android Lollipop, 5.0.2 .
When I plugged the OTG adapter into its micro-USB port, with nothing connected to the far end of the adapter, the expected message was displayed on the phone, acknowledging that a USB connector was connected. Really, this proves that the OTG adapter contains a working chip, because if it was just a cable, then there would be no way for the phone to detect that anything had been inserted.
Next, I plugged the Focusrite Scarlett 2i2 USB Sound Card into the far, larger end of the OTG adapter. I was greeted on the phone, with the question, of whether having connected the external sound device, should launch an app I have installed, named “USB Audio Player Pro”. Because this was not the app I wanted to test my sound device with, I tapped to dismiss this possible, automatic action.
Instead, I launched the app named “Audio Evolution Mobile”, which is a DAW, and which also supports USB sound input, especially since the other possible mikes are so inferior. Would the reader think, that because we have a DAW app installed, we would use an in-line, phone-mike to record serious music? Of course not!
This app next asked me, whether I would want to use the Android-supplied driver, or the USB driver belonging to the actual app, which is called their “eXtream” driver.
What I found was that if I select the standard, Android driver, audio capture will not work, while if I select the driver supplied by this app, audio capture does work.
By that time, the Scarlett 2i2 had its green Power / USB LED lit, suggesting it was ready for action.
I next turned on the phantom-power button on the Scarlett 2i2, just to be sure that the phone would support the combined power drain. And I recorded a short track, using Audio Evolution.
Audio Evolution offered me 24-bit sample-format, and sampling rates ranging from 44.1kHz through to 96kHz. I did not wish to push the envelope, and so recorded at 24-bit, 44.1kHz successfully.
So why do I call this a mixed result? Because The native Android driver did not work. The native Android driver did not recognize or display the Scarlett 2i2 as an available sound device. Only the eXtream driver did. This means, that many audio apps written for Android will not work with this sound device. Presumably, the “USB Audio Player Pro” app would have worked just as easily, because it, too, has been authored by the software developer named – “eXtream”. So presumably, all the apps from that dev, will offer to support the USB device with their in-house drivers. But that would also be required.
I also tried the same routine, with my Samsung Tab S tablet, running Android KitKat, 4.4.2 . Here, I had no luck. When I plugged the OTG adapter into the tablet, the notification bar of the latter also confirmed that a USB connector had been connected. But when I then connected the Scarlett 2i2 into the same OTG adapter, a behavior took place, in which the LEDs on the external sound device flashed briefly, and then went dark again, roughly twice per second. The green Power / USB LED on the sound device never lit up fully. And this tablet displayed the message repeatedly, that in response to the external sound device being connected, it could offer to launch “USB Audio Player Pro”. Hence, the tablet was recognizing the same device, plugged in once, as if multiple connection attempts had been made. I tried disconnecting my setup and reconnecting it, but got the same results.
This result with the tablet is most likely to mean, that the Scarlett 2i2, drawing as much current as before, is actually overloading the current supply of the micro-USB port of the tablet.
Alternatively, this could mean that there is some deeper conflict.
But this result seems to be the reverse of what would be convenient, since the tablet has a much larger battery capacity, than the phone does. If the Scarlett 2i2 is in fact drawing 500mA, which I think it is, the reader can do the math, of how quickly having it connected will run down a battery – faster.
Now, there is some possibility that if I obtain a better OTG adapter, which would also have a separate supply-jack, and which would therefore not draw 100% of its supply current from the micro-USB, then the Scarlett 2i2 might also work with this tablet. I really do not see why it should not, as it did display the message correctly, that a sound device was detected, and that a specific app could be launched as a new default behavior. I also have the same eXtream apps installed on my tablet, that I have on my phone.
But with an OTG adapter that draws 100% of its supply from the micro-USB port, this is simply not possible, given the Samsung Tab S tablet. In fact after my efforts, the tablet was too confused, to display that an external USB connector had been connected again, until I rebooted the tablet. This was probably due, to having 2 connection attempts take place per second, over an extended testing period from me.
When and if I do obtain an OTG adapter with a split power connector, I should write another blog posting, telling any interested reader whether this improved the results with the Tab S tablet.