USB audio at 24/48, not possible to route 2 inputs with 2 channels each, to 1 output with 4 channels


When a USB is configured with N channels, it is only possible to set each USB jack with 1 to N-1 channels.

So for example :
At 24/48 we have 4 channels for each USB port.
Then It is not possible to route the audio of 2 iPad (USB1, USB2) to a DAW connected to USB3, because only 3 channels can be configured for USB3 output.

Will it be possible sometime ?



  • Hey kekule - Here is a list of the possible Audio Channel options that can be selected through iConfig:

    24bit 44100Hz, 4 Channels,
    16bit 48000Hz, 4 Channels,
    16bit 96000Hz, 4 Channels,
    16bit 44100Hz, 8 Channels,
    16bit 48000Hz, 8 Channels,
    16bit 44100Hz, 4 Channels,
    24bit 48000Hz, 4 Channels.

    Let me know if you were referencing something different.

  • Hi,

    To clarify my problem :

    I'm selecting "24bit 48000Hz, 4 Channels" :

    On the 3 USB Device Jacks I can configure any of this following combination :
    Out Channels = 1, In Channels = 3
    Out Channels = 2, In Channels = 2
    Out Channels = 3, In Channels = 1

    But I can't do :
    Out Channels = 4, In Channels = 0
    Out Channels = 0, In Channels = 4

    Because USB3 cannot be configured with 4 Output, I can't configure the following :
    USB1 In 1+2 --> USB3 Out 1+2
    USB2 In 1+2 --> USB3 Out 3+4

    The conclusion is that the 24 bits is limited to 3 output channels, or 3 input channels.

    My question is : will it be possible to use 24 bits with 4 channels (4+0 or 0+4) in a future release ?


  • Sorry for the delay kekule.

    You won't be able to make custom I/O selection when changing bit/sample rate modes through iConfig - if that is what you mean. You will have to work with the options available in each mode, instead of manually exchanging inputs for output and vice versa. If you run into a I/O limitation while using 3 computing devices, you may need to change your sample/bit mode to overcome.

    Although, If you wish I can make a feature request with the software dev team to see if there is anything that could be implemented in the future to change these options. Not sure if it's a possibility myself, but they could confirm. Let me check for you.

    Also, what kind of computing devices are connected to your device jacks? All PC/Mac or are you working with more iOS devices/apps?

  • I would like to work with 2 iPads connected to USB1 and USB2, and a Mac with a DAW connected to USB3.
    With the current firmware, it is not possible to work with it at 24 bits because we have only 3 channels output for USB3. Of course I can do it at 16 bits, but it would be better at 24 bits...

    It would be great to be able to configure an USB with 4 outputs and 0 inputs.

  • OK - I will file your feature request with the dev team.
    Thanks for taking the time to write to us!
    We appreciate the support.
  • This IS a bit disappointing. I'd planned to work with 24/44 myself and hoped for 4 simultaneous channels with a similar 2xipad into daw setup. It appears the only way to stripe 24/44 to a daw is non-realtime, ie. one pair at a time...and align tracks by hand? Ugh. I hope this doesn't turn out to be a hardware limitation.
  • Thomas, you want the iConnectAUDIO4+, or you could add an iConnectMIDI2+ to your setup. I wish I had a less glib answer for you, and I haven't asked our engineers whether it's a hardware limitation. But I've been to product planning meetings before (although not this one), and I can tell you that the feature list is determined by how *most* people are likely to use the product.

    In this case, most musicians are going to stream stereo audio out of their iOS devices into their DAW, or they're using them on stage and only need stereo audio... but they need the iConnectMIDI4+'s unique array of MIDI features. (Check out the OneRepublic video in the Blogs section of this site - it's remarkable what they're doing with four networked iConnectMIDI4+s in their stage shows. Plus it's a very interesting video in general.)

    Again, I'm not saying this to belittle your feature request at all, and it may be possible in a future software update - I honestly don't know (and I'll ask). This is just an explanation of how this often goes.
  • No worries, Nick. Not an unreasonable response. In fact, the ica4 HAS been on my mind. (I already have the icm4) It solves a lot of conexion problems. Unfortunately, its not getting great reviews on audio quality. Not bad, but not quite good enough to consider, in what I hope to be an all 24bit audio environment. I'm hoping for a v2 with better specs at some point? With 24/44-48k audio S/N becomes a REALLY key metric. Thanks for the video suggestion...will def check it out.
  • I hope this doesn't sound like I'm protesting too much, but that internet rumor is to be taken with a lot of salt.

    Not only is noise is absolutely not a problem, I think you'd be very happy with the sound of the interface.

    People tend to buy iConnectivity interfaces because of their industrial-strength data management and their features, but the iConnectAUDIO4+'s noise spec is at least on par with any quality audio interface until you get to the really high end. Seriously, I defy anyone to put it next to another interface, close their eyes, and tell me which one is quieter.

    I know there was some stuff going around about the inputs being noisy, but I think it was because the combo inputs have a 20dB pad for instruments. Sure you're going to get more noise that way, but this has been a standard design common to most project studio equipment from the past couple of decades. It's for convenience - you just plug in mics, instruments, or line-level signals without needing a direct box.

    Actually, even my $2000 audio interface is like that. (I can confess to owning it because I bought it years before iConnectivity was founded, never mind before the iConnectAUDIO4+ came out. :) )

    Also, I don't quite follow what you're saying about the S/N being especially important with 24/44-48K audio. To me it's important at any bit/sample rate! But it's also not a spec I personally pay a lot of attention to with any digital audio equipment, simply because it hasn't been a factor for years.

    Digital audio is very quiet. When it first came along, I know at least one engineer who would add noise to his mixes - because it was too quiet!
  • edited September 2015
    I hear you, Nick. I didn't pass on the ica4 easily, trust me. But my instincts, plus some reviews by folks who've demonstrated tech/ee chops, not to mention my budget, and the somewhat less-than-intuitive iConnect interface, have me holding out for awhile on such a piece of kit. I don't mean to suggest that the ica4 is qualitatively inferior to any competitors out there. Just that I've decided what I need more than anything right now is simplicity--even if that means maintaining a 16-bit data path for the time being. What I've learned in the past 6 weeks setting up a live ipad rig is that there are so many variables that go into determining not just what I need to get the job done, but whether all the pieces are even compatible with each other. From midi-power (for bt-midi applications) to usb-types to op-amp chipsets, the research seems endless. Since I'm transitioning from desktop daw to portable rig, I originally thought I'd dispense with my Apogee Ensemble for all-digital daw-interfacing solutions that included the ica4, but in the end I decided to go with a small submixer into the Apogee for now. (Even as is, I can already pass 2ch digital mixes from the ipads to daw via the icm4) I just need to focus on making the music at this point. I'm still a happy icm4 owner. Its the nerve center of my current rig. I'm just going to see how this whole field shakes out for the higher end stuff before I drop more coin than I already have. And when that time comes, the ica4 is definitely an item i'll be considering. I will say this, for ipad musicians, we are living in interesting times!
  • Interesting times indeed.
  • Hi,
    The iCN4 is capable to work at 24/44-48 with 4 channels, but we can send only 3 channels into a DAW.
    Will it be possible to route 4 channels at 24/44-48 sometimes ?
    Currently, to work with 2 iPads, the only solution is to work at 16 bits...
  • Bandwidth is a finite resource, kekule, but I'll ask.
  • I'm sure it's possible because iCN4 can already manage 4 channels (3+1) at 24/44-48 and 8 channels (7+1) at 16/44-48.
    The bandwidth is around :
    4 Mbit/sec for the 4 channels at 48K,
    6 Mbit/sec for the 8 channels at 48K.

    Hope it will work...
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