Q: I can't find the MOTU AVB Discovery iOS app in the Apple App store. Where is it?

A: The app was posted in the Apple App Store on Monday, August 11, 2014, so if you looked for it before then, you would not have found it. For your convenience, here's the link:

AVB Discovery App for iOS

Q: Are all digital and analog inputs and outputs available simultaneously?

A: Yes. All I/O is simultaneously and discretely available for recording, playback, and monitoring.

Q: What is the maximum number of audio channels available to and from the computer?

Connection Sample rate Channels (in and out)
Thunderbolt / USB3 44.1 to 96 kHz 128
Thunderbolt / USB3 176.4 or 192 kHz 64
USB2* 44.1 or 48 kHz 64
USB2* 88.2 or 96 kHz 32
USB2* 176.4 or 192 kHz 24

*The 624 and 8A provide 72, 36 and 24 channels over USB2 connection at respective sample rates.

Q: Can I connect my MOTU AVB interface directly to a Mac through its network port (to the network port on the Mac)?

A: Yes, both for web app control and for audio I/O (as an alternative to USB or Thunderbolt). The ability to do multi-channel audio I/O over an Ethernet connection to a Mac is a new feature introduced with firmware update 1.1.1. Here's how to set this up. In addition, a network connection to the Mac's network port can be used for firmware updates for your MOTU AVB interface(s) or switch(es). It is okay to have an Ethernet connection to your Mac alongside a USB or Thunderbolt connection to the Mac.

Q: Can an input signal be routed to the computer for recording into my DAW, while simultaneously being routed through the interface mixer for zero-latency monitoring?

A: Yes. In fact, you can route an input signal to as many multiple destinations as you want, using the Routing tab in the web app.

Q: Can the on-board effects be used for monitor-only, record-only, or both?

A: Either or both. EQ, dynamics, and reverb can be applied to the live monitor signal while recording the signal dry in your DAW. Alternately, you can apply effects in-line before the signal is recorded in your DAW. Basically, monitoring and recording can each be either wet or dry. Your choice.

Q: Do I need an AVB switch box to expand the number of inputs and outputs?

A: Not necessarily. This depends on how many channels you need. One way to add more channels without an AVB switch is to connect a 2nd optically-equipped interface (MOTU or otherwise) to the optical ports of your MOTU AVB interface. One optical bank gives you 8 extra channels; two banks gives you 16 at 1x sample rates (or 8 at 2x rates).

Alternately, you can connect a 2nd MOTU AVB interface directly to the first via a single CAT-5e network cable. This single network connection lets you stream up to 128 channels (depending on the interface) between the two interfaces for additional I/O, mixing, effects processing, or whatever you need. Plus, the network cable can be up to 100 meters long.

If you would like to expand to three or four interfaces without using an AVB switch, you could combine these two techniques: connect two MOTU AVB interfaces to each other with a network cable, then connect additional interfaces to each one through their optical banks. In this scenario, the network connection carries 128 channels each way, so audio can be routed freely among all connected interfaces using the MOTU AVB interface routing grids. In addition, one of the MOTU AVB interfaces could be connected to a computer through Thunderbolt or USB, and the computer could have access to all channels on all interfaces.

All that said, however, if you are expanding to three to five MOTU AVB interfaces, the affordable MOTU AVB Switch gives you the most flexibility. Cable lengths can be 100 meters from each interface to the switch, and each device can stream 128 channels to/from the network for basic I/O routing, sub-mixing, effects processing in the mixer of another unit, etc. If you need more than five interfaces, you can use multiple switches (see example below, with two switches and six 16A interfaces for 96 channels of analog I/O).

Q: Do MOTU AVB interfaces work with third-party AVB switches?

A: Yes, but the MOTU AVB Switch is much more affordable than third-party switches.

Q: Do MOTU AVB interfaces work with third-party Ethernet switches?

A: For audio over the network, you need an AVB switch, but for controlling the hardware via your favorite desktop or mobile browser, any Ethernet switch will work.

Q: Do MOTU AVB interfaces work with other AVB systems, like Avid?

As of firmware version 1.2.3 (release on August 4, 2015), MOTU AVB interfaces support 2-, 4-, 6- and 8-channel AVB streams. This provides compatibility with the Avid S3 system, but not the S3L system, which employs 16- and 32-channel streams. Development is on-going. Please check this web page periodically for any further AVB compatibility information.

Q: I want 96 channels of analog I/O with my computer. How do I do that?

A: One possible configuration is to connect a 16A to the computer via Thunderbolt. The 16A can then connect to a MOTU AVB switch, which allows additional interfaces to be connected. 96 channels of analog I/O can be accomplished with six 16A interfaces. Therefore, two five-port MOTU AVB Switches will be required, as shown here:

The extra (6th) Ethernet port on either switch, or the available AVB ports on Switch #2 (4 and 5), could be used to connected an Airport (or other Wi-Fi router) for wireless control from an iPad, etc. AVB ports can do either AVB or Ethernet.

Q: I need a stage I/O box and I need to be able to record to multiple computers. Can I do those jobs with the MOTU AVB system?

A: Yes. The MOTU AVB system is a state-of-the-art stage I/O system. Multiple interfaces can be connected with up to 512 channels of I/O. The entire system, including preamp gain, phantom power, effects, routing and mixing can be controlled remotely. System control can be accessed from Mac, Windows, Linux, Android, and iOS. Multiple control points can be used simultaneously.

At the same time, the system can be patched into a computer for recording and playback. The Thunderbolt connection supports up to 256 channels of computer I/O (128 in and 128 out). USB supports up to 128 channels (64 in and 64 out at 44.1 or 48 kHz). Multiple computers can be connected to the AVB network, through any available interface, for redundant recording/backup systems.

Q: Does my MOTU AVB interface have a mixer? How does it work?

A: Each MOTU AVB interface has an internal 48-channel mixer that includes 12 stereo busses, effects processing and sophisticated routing capabilities. You don't actually need to use the mixer for simple I/O to and from your computer. Inputs and outputs on all connected interfaces can be directly routed to each other, as well as to any connected computers, without the mixer. The mixer is used if you want to create sub-mixes or direct monitor mixes, apply effects processing, or patch in external effects processors. A graphic interface for the mixer is available in the web app running on the computer, iOS, or Android screen, and you can use the web app to control the mixer in any interface on the network. Mixes can be cascaded and combined among connected interfaces. The mixer has a familiar design, similar to a large format mixing console. Consult the MOTU AVB User Guide for further details about mixer operation.

Q: How many mixer inputs do I get at each sample rate?

A: 48 at 1x (44.1 or 48 kHz), 32 at 2x (88.2 or 96 kHz) and 16 at 4x (176.4 or 192 kHz).

Sample rate Inputs
1x (44.1 or 48 kHz) 48
2x (88.2 or 96 kHz) 32
4x (176.4 or 192 kHz) 16

Q: Some MOTU AVB interface models can send and receive sixteen 8-channel AVB streams when operating at 44.1 or 48 kHz. How many streams can they handle at higher sample rates?

A: The 1248, 8M, 16A and 112D support 16 AVB streams at both 1x and 2x sample rates (128 channels of I/O). They support 8 streams at 4x (64 channels of I/O). This refers to the number of channels that the interface can send to, and receive from, the rest of the AVB network. In AVB parlance, a stream is a "bundle" of audio channels. In a MOTU system, each AVB stream holds 8 audio channels. So 16 streams represents 128 audio channels (16 x 8).

Q: Can I use MOTU AVB interfaces on my older Mac that is running OS 10.6 or 10.7 and does not have Thunderbolt ports?

A: Yes (although this is not officially supported. Official support requires 10.8 or later.) USB can be used to connect a Mac to the AVB system for up to 64 channels of input and 64 channels of output (at 44.1 or 48 kHz). Because MOTU AVB interfaces are USB audio class compliant, no driver installation is necessary under Mac OS X 10.6 or 10.7. As soon as you plug in the USB cable and switch on the interface, the Mac "sees" all the audio channels and makes them available to your DAW or other Mac audio software. Web app control (for access to device settings, the on-board mixer, etc.) can be accomplished through a direct Ethernet connection from the network port on the interface to the Mac's network port. The Mac accesses the web app (which is being served directly from the interface itself) through the network connection.

Q: If I want to use my MOTU AVB interface as a stand-alone mixer (with no computer connection), what's the best way to control it?

A: With an iPad and an Airport™ (or other Wi-Fi router). Connect the Airport to the network port on the interface. Set up the Airport Wi-Fi network and make sure the airport is configured as a DHCP server (so it issues an IP address to your MOTU interface). Connect your iPad to the Wi-Fi network. Download the MOTU AVB Discovery iOS app from the App Store™. Launch the app, tap your MOTU interface, and you are good to go. You can do the same thing with a non-Apple Wi-Fi device by launching any web browser on it, and then type in the IP address of your MOTU interface (push the ID button on the front panel to get its IP address).

Q: Do MOTU AVB interfaces support AES67 or RAVENNA?

A: MOTU AVB interfaces do not support AES67 or RAVENNA at this time.

Q: Do MOTU AVB interfaces work with Dante™ or Dante-based systems?

A: Not at this time. Dante is a proprietary system that requires licensed technology. AVB is a new, open industry standard developed by the IEEE and promoted by the AVnu Alliance that is now being adopted and deployed by companies like MOTU, Apple, Avid, Meyer Sound, Biamp and others.

Q: How do I get my AVB interface to provide 64 channels of I/O over USB (or the highest available channel count at my sample rate)?

A: Go to the Device Tab and choose the desired USB mode (and sample rate). Then go to the Computer Setup section of the Device tab and set the number of computer channels to the desired amount, up to the maximum allowed for that USB mode.

Q: How many AVB streams does my interface support?

A: The following table shows the maximum possible number of AVB streams in and out, depending on the sample rate, for each MOTU AVB model. Remember that each stream carries eight audio channels, regardless of sample rate. So, to calculate the number of audio channels, multiply the stream count in the table by 8. For example, 16 streams carry 128 audio channels.

44.1kHz and 48kHz 88.2kHz and 96kHz 176.4kHz and 192kHz
Input Output Input Output Input Output
1248 16 16 16 16 8 8
16A 16 16 16 16 8 8
8M 16 16 16 16 8 8
112D 16 16 16 16 8 8
624 8 8 8 8 8 8
8A 8 8 8 8 8 8
24Ai 8 4 8 4 4 2
24Ao 8 4 8 4 4 2
Monitor 8 8 8 8 8 8 8
UltraLite AVB 3 3 2 2 1 1
Stage-B16 3 3 2 2 1 1