Using a MixPre-6 II with Jamkazam

It’s not always possible to rehearse with other musicians in person. Enter Jamkazam: a website and application that connects musicians for real-time rehearsals online. Like other communications applications, Jamkazam requires a quality, low-latency internet connection. An Ethernet connection ensures the best results. Jamkazam also benefits from a high quality audio interface with enough routing flexibility to send and monitor exactly what you want. The MixPre-6 II is an ideal interface for Jamkazam since it has superb audio performance, four analog inputs, lots of routing flexibility, plus it can record.

Let’s walk through a possible setup for Jamkazam, a MixPre-6 II, and a MacBook Pro.

Gear List

  • Sound Devices MixPre-6 II 
  • Musical instruments
  • Modeler pedalboard for bass and guitar amp tones
  • Vocal microphone on floor stand for talkback
  • Quality closed-ear headphones
  • Three XLR-XLR cables
  • Computer, in this case a MacBook Pro
  • Ethernet adapter
  • USB-C cable for MixPre

Input Setup – MixPre-6 II

First let’s look at how the inputs are connected to the MixPre. In this case three local analog input sources are connected.

Track 1 – Modeler L analog output, linked 1-2

Track 2 – Modeler R analog output

Track 3 – Vocal Microphone

USB audio returned from the computer is used as audio sources for monitoring and recording. Those are routed:

Track 5 – USB 1, linking 5-6

Track 6 – USB 2

USB Setup – MixPre-6 II

Now let’s take a look at how USB outputs on the MixPre are routed:

USB 1 – Track 1

USB 2 – Track 2

USB 3 – Track 3

USB 4-8 – Not routed

MacOS Audio MIDI Setup

In order for the MixPre to operate as a multichannel interface, it needs to be set up in the MacOS Audio MIDI Setup. Navigate to Applications > Utilities > Audio MIDI Setup. Note that this is different from the audio selection in System Preferences. Here it is set as an eight channel audio input device at 24-bit, 48 kHz.

Jamkazam Setup

Now on to the Jamkazam setup. 

Jamkazam defines Input Ports as the audio source for a session. Below, MixPre-6 II (USB) channels 1 and  2 are selected as a stereo input, labeled as Bass Guitar. That is the stereo signal coming from the guitar modeler.

For the vocal microphone, MixPre-6 II (USB) Channel 3 is selected. That is the signal coming from the vocal microphone. Jamkazam takes this input and turns it into dual-mono.

In order to listen to audio from the session, it is necessary to route it to the MixPre. In Jamkazam output setting, set the MixPre-6 II left and right (USB input 1 and 2, respectively) as the destination for the session output.

Here is a summary of the audio setup in Jamkazam.

Monitoring Audio in a Session

Once a session has begun, there are a couple ways to listen to audio from the session.

Listen to L/R Stereo

At the MixPre-6 II, when the default L/R stereo is selected, all inputs are sent to headphones. This means that direct, local audio sources plus the return audio from the Jamkazam session appear in headphones. Jamkazam does not send a “mix-minus” signal, so listening to the L/R stereo mix will contain the direct local audio in realtime plus those same signals mixed with other session musicians, after round trip latency. That means your local audio sources will show up twice, so if there is meaningful latency, this may be apparent and annoying.

Listen to USB 1,2

When USB 1,2 are selected, no direct, local audio will be sent to headphones, only the mix sent from Jamkazam. This is Jamkazam’s preferred monitoring method.

Recording the Session

Since the MixPre-6 II is a recorder as well as an audio interface, you can record your Jamkazam session locally to your device. In this setup, arming inputs 1, 2, 3, 5, 6 for recording results in a polyphonic WAV file with your local audio sources on individual tracks 1,2, and 3, plus the full mix recorded on tracks 5 and 6. Jam away!