Bluetooth MIDI? What about latency?

Bluetooth MIDI and beyond

On the 12th of December (2019) we launched the concept of WIDI Master. By doing so we set the goal to reach at least 1,000 registrants before we could move into the next phase of production. We already reached that goal in the first week. We are thankful for your support for wireless MIDI over Bluetooth.

Along the way we've received several questions and a few concerns through our Facebook Group. Therefore we've taken the time to consider the next topics in this blog post. You can find them underneath.

MIDI over Bluetooth? What about latency?

When people hear Bluetooth, they think about latency and troubles with pairing. We ask ourselves is that true with Bluetooth MIDI? CME already delivered www.xkeyair.com and www.widibud.com to a wide range of professional musicians worldwide since 2015. Our wireless MIDI solutions are used by thousands of dedicated music makers. We have received much feedback over the years and never complaints about latency. Therefore we can honestly say that latency is not a problem with WIDI Master.

With WIDI Master we reduce latency even further by directly embedding the BLE MIDI protocol in the firmware of the device. You now can bypass your computer and play with wireless MIDI with limited latency. With that in mind, we are in an early stage of development. Therefore we are not able to share hard facts with you yet. Be sure to register at the end of this post. This way we can keep you updated along we develop further.

A little spoiler is that we expect to deliver a maximum round latency of 10-15 ms. Please read the next paragraph to understand what this means. MIDI over Bluetooth has been designed by Apple and is already used and acknowledged by top engineers of Yamaha, Korg, Roland and so on. It is the standard as approved by the international MIDI association.

Please keep in mind that every human hearing, every circuit, from audio interface to midi controller to monitor speaker, already has latency. When we mention 3ms minimum it is the latency minimum. It depends on the device you connect it with and which Bluetooth version you use. In this case it is tested with BLE 5. Until now we were able to measure latencies as low as 3 to 4 milliseconds, depending on the connected devices. Most often we measured latencies around 5 to 6ms.

Again, latency depends on the device you connect it with. Feel free to learn more in this special live broadcast with our CTO Jerome Dumas talking about latency and jitter concerning our WIDI Master.

When we say “a round latency of 10-15 ms.” for WIDI Master, we consider it a maximum when working with all other existing products. Round latency as mentioned also includes the latency in your system from your audio monitoring. If you use 2 WIDI Masters directly, since we implemented both master and slave firmware, you will get much less latency than the reference (10-15ms). That is because you do not need to add extra latency from computer OS and iOS. In addition, you can also pair WIDI Master with any other BLE MIDI adapters or controllers directly.

We are aware that "latency" is a big word in the world of MIDI. We understand that. Most of the manufacturers will never share such numbers. We are sure, and have proven in the past, that with our wireless Bluetooth over MIDI solutions you do not need to worry about latency. Check out the video above to find out what real professional musicians like Jordan Rudess (Dream Theatre) and Jim Gilmour (Saga) show and tell about our Xkey Air. Both on stage and in the studio. The Xkey Air was released in 2015. The WIDI technology is only getting better!

Also we'd like to point out once more that we've embedded automatic pairing. This means WIDI Master automatically wil pair with any Bluetooth MIDI device. Therewith there is no more need for manual scanning and pairing of your Bluetooth MIDI devices.

What is the difference with Yamaha MD-BT01?

We have received this particular comparison question multiple times. We hereby take the time to briefly explain the difference. Yamaha only implemented Bluetooth Peripheral (slave). That is why you still need to connect your computer or iOS device to use this solution.

WIDI Master gives you all flexibility to connect any Bluetooth MIDI device or adapter (including Yamaha) directly. This is because it implements both Master and Slave mode in the same device.

This means that you now can connect all your MIDI hardware directly to each other. Without a computer. Without cables.

How do I connect two MIDI hardware devices wirelessly?

With WIDI Master you can easily connect two standalone MIDI hardware devices. You just use two (2) WIDI Masters. One for each device. Due to the automatic linking they will pair instantly. Now you can choose which will be your master and which will be your slave. With WIDI Master you have the complete freedom to work with your favourite MIDI hardware without wires.

An important note is that WIDI Master is fully standalone and completely wireless. Therefore It is important to keep in mind that the device is powered by the MIDI OUT port of your hardware. If you only have a MIDI IN or unpowered MIDI Ports do not worry. We are working on a solution to deliver the power you need.

Last but not least. We all are aware that Bluetooth has limitations when we compare Apple (i)OS and Windows/Android. For this we highly recommend to use our WIDI BUD. WIDI BUD will instantly pair with WIDI Master. Every device can join the wireless party.

We will keep you updated on the progress.

Update April 2020: Extract from CME Live Broadcast with CTO Jerome Dumas

Latency is always a hot topic when it comes to wireless MIDI. Can you tell us more about the current tests and achievement of WIDI Master?

Yes, latency is definitely important in such a product, the most important. Please note we already developed two MIDI Bluetooth products. As mentioned previously these are the Xkey Air and WIDI BUD. These products were using BLE 4 technology, and we never had complaints about latency issues. Our Xkey Air was used on stage by professional musicians.

WIDI Master uses the latest BLE 5 technology. This is even faster than BLE 4. Latency depends on the environment, and how far are the two connected devices. We are fully compliant to the MIDI over bluetooth class. Furthermore we developed internal algorithms so both devices can negotiate the lowest possible latency. Until now we were able to measure latencies as low as 3 to 4 milliseconds, depending on the connected devices. Most often we measured latencies around 5 to 6ms.

To be fully transparent, we also measured some Jitter. This means the latency was not constant, but oscillating with a few milliseconds. This part was improved in BLE MIDI firmware v0.1.7.7.

Please note that there are cases reported that people experience an unacceptable jitter when syncing multiple devices via WIDI groups. In our tests we are unable to reproduce these. This does not mean they do not exist.

Please find the video of our test and the latest update in this blog.