Sunday, March 22, 2015

Recording Virtual Instruments with SampleRobot Part 4: Interface to Interface (Analog)

This is Part 4 of a 6-part series. Make sure to check out Part 1 for the introduction.

Method Three of Four: Interface to Interface (Analog)

If you have more than one hardware audio interface, you can skip all the virtual audio cables and ASIO wrappers and route your virtual instruments out of the analog outputs of one interface into the inputs of another interface. One particularly nice thing about this approach is that you can optionally route the audio signal through outboard sound processors to add a little analog warmth to your digital instruments before the signal hits your target interface's inputs. Things get even simpler if your audio interfaces happen to have physical MIDI ports (or if you have more than one discrete USB-to-MIDI interface). That way you don't even have to mess with virtual MIDI cables, and have a straightforward hardware-to-hardware solution. Actually, as long as both the MIDI and audio connections between your virtual instrument and SampleRobot are interface-to-interface, the plugin and SampleRobot don't even have to be on the same computer or operating system! For simplicity's sake, I'm going to describe things as if everything's done on the same PC, but it would be super easy to adjust for a multi-computer setup.
  • Difficulty: Medium
  • Advantages: High quality recordings with a low level of complexity. Ability to route your plugin audio through hardware processors.
  • Disadvantages: Expensive! (Requires two audio interfaces.) Might require a little bit of tweaking to get SampleRobot's note-in/note-out auto-detection working as expected.
  • Software Required: LoopBe1 (only necessary if your interfaces don't have physical MIDI ports), SampleRobot (any edition)
  • Hardware Required: Two audio interfaces, and the correct audio cables for their respective inputs/outputs (most interfaces work well with balanced TRS-to-TRS cables). If your audio interfaces don't have built-in MIDI ports, you will also need some kind of USB-to-MIDI interfaces like the MOTU FastLane USB or the MOTU micro lite.

In this model, one audio interface plays your instrument's audio. We'll call that the Instrument Interface. We'll call the other interface, the one SampleRobot uses to record the incoming audio, the SampleRobot Interface.

My desktop audio interface is a MOTU Track 16 and I use an RME Fireface UFX for most recording work. In my example, the MOTU will be my Instrument Interface, and the RME will serve as the SampleRobot interface. Here's the basic signal flow:

This diagram assumes both interfaces also have MIDI ports. The steps that follow will include instructions for other configurations.
Here's how to do it:
  1. First make your physical MIDI connections. You want to run a MIDI cable from the MIDI OUT port of your SampleRobot interface into the MIDI IN port of your Instrument Interface. If you have a standalone USB-to-MIDI interface like the MOTU FastLane USB or the MOTU micro lite , you can use those too- just remember which one is going to be for sending MIDI data out (SampleRobot), and which one will be receiving (Intrument).

    If you don't have enough physical MIDI ports in order to make a hardware MIDI connection, you'll need to use a virtual MIDI connection. In that case, download and install LoopBe1 now. Note: Restart your computer after installing LoopBe1.
  2. Next make your physical audio connections. If you are just recording direct from one interface to the other, run the proper kind of audio cables from the outputs of your Instrument interface to some inputs on your SampleRobot interface.

    If you intend to do some processing in between, just patch things up like this: Instrument Interface Audio Out to Processor Audio In, Processor Audio Out to SampleRobot Interface Audio In.
  3. Now launch your plugin host or standalone instrument. I'm going to be running an instance of Waldorf Attack inside VSTHost. (See Part 1 of this tutorial series for tips on setting up VSTHost.)
  4. Open your instrument's MIDI settings and make sure your Instrument-side MIDI interface is available, whether it's a physical interface or LoopBe1. Also ensure that the instrument is receiving MIDI on the correct IN port, if the interface has more than one.
    In VSTHost, I've already made sure my MIDI devices were available/selected in the Devices > MIDI > MIDI Input Devices screen. Now I've clicked the MIDI In jack on my Attack node and I've selected the Track16 port as my Intrument-side MIDI port.
  5. Open your instrument's Audio settings and select the correct audio outputs for your Instrument Interface. Depending on your interface's drivers and the specific instrument or host you're using, you may have multiple output options to choose from for the same physical ports. If this happens, make sure to pick the ASIO option, when available.
    VSTHost offered me many output options! I had to make sure to pick the ASIO output for my MOTU interface.
  6. Now launch SampleRobot and set up your typical project recording settings. When you've got your note range and velocity settings the way you like them, make sure to specify the following:

    MIDI Out Device: Your SampleRobot Interface's MIDI Out port. (Or LoopBe1 if you're going the virtual route.)
    Audio Format: The Sample rate and bit depth that you'd like to record. (Remember only the Pro and Sampling Suite versions of SampleRobot can record higher than 16-bit.)
    Audio In Device: Your SampleRobot Interface's analog inputs.

    All ready to go!
  7. Now that your project is all ready to record, click Rec in the Projects window, and then click Start Recording. You probably won't hear anything while recording is in progress. When recording is complete, little waveforms will appear under the virtual keyboard. You can test the recorded samples by clicking (and holding down) the left mouse on individual notes.
  8. If your samples seem to have completed successfully, go to the Import/Export menu to export the samples into your desired target format. If you're using the default settings, your exported samples will be trimmed down to only contain actual audible audio (which is good!). The final post in this series, Part 6, has some tips for tweaking SampleRobot's note-in/note-out detection to speed up the export process. I like to save my exported files into a new folder called Exports inside my SampleRobot project's Data Path folder. Here's a look at the resulting samples I got after exporting the above project. I am using Resonic Player to preview my samples.


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