The Truth About Bluetooth MIDI

Wireless MIDI? What about latency?

Many people (including engineers) who did not try Bluetooth MIDI assume a lot of things about latency with MIDI over Bluetooth.

MIDI is a serial based protocol that has been developed in the early 80s. It is not amazingly fast to begin with.

Bluetooth has been rapidly developing over the last decade. It handles a few megabits per seconds easily.

Therewith it is easy to say that MIDI over Bluetooth is capable of offering a professional low latency solution for musicians and producers. Both on stage and in the studio.

Roger Linn, the legendary designer behind the LM-1, MPC and LinnDrum, talks about WIDI Master and his MPE-based in Linnstrument by Roger Linn Design

Let me try to address some main ideas.

Bluetooth MIDI is not Bluetooth Audio and does not experience the same latency issues. They are two completely different technologies.

Latency is normal. It occurs in the human hearing and in the communication between an audio interface, computers, midi controllers, monitor speakers, and so on. Everything has latency.

Conversion time is negligible. When is latency really audible by the human hearing? Can your link it directly to a specific part of your system? Or is it a cumulation of parts that are in your system?

WIDI Master + Genki Instruments Wave + Roland Juno-60 + MIDI

Latency is just a number…

There are a lot of claims being made about latency and especially the ability of being able to really notice it as a human. Let alone link it to a specific part of your system. There are musicians who play their instruments based upon the limitations of that device. Latency can be just one of them. Therewith it becomes part of the deal.

Of course, latency is an important metric when it comes to music production and performance. Latency for Bluetooth MIDI does not stand upon itself. It depends on the environment and the connected devices.

Also, when you look at your entire system, it is complex for you as a musician or producer to pinpoint latency to a specific part of the system. What I mean to say is how are you able to say the latency you experience from your monitor speakers are caused by either MIDI communications or audio conversions? Or delays in translation by your operating system?

That is why I chose to keep this simple and not get stuck in a number. From my point of view, that number is not a given in every situation and therefore not something one should make its decision on. That would be a false simplification of the wireless technology (opinion).

In the end a proper musician can play with a stable latency. That is why jitter is also a very important metric. Especially when it comes to real time MIDI clock and sync purposes.

How Does WIDI Master Work?

The difference between a MIDI cable and BLE MIDI

First of all, with Bluetooth MIDI latency is always a bit higher compared to a regular MIDI cable.

That said, you can question yourself if you would be able to distinguish WIDI Master from a standard MIDI cable in a double blind test. We have noticed that this will always lead to the same discussion about latency.

This discussion is quite similar to the one we have had in the start of streaming and the download days involving MP3s and WAV files. Or that one of the supreme quality of vinyl over anything else….it is ongoing, never ending and also very much part of the process of developing innovating technologies.

Bluetooth MIDI and latency on iOS & Mac

When talking about latency of the WIDI technology you’d have to keep in mind we measure latency by using an oscilloscope. It is measured between two WIDI Masters. The lowest outcome is 3ms. The highest is 10ms. We measure an average on 5ms to 6ms.

The latency on iOS and macOS came from the limitation of the Bluetooth connection interval. This is a rule set by Apple. On iOS it is 11.25ms minimum. On macOS it is 7.5ms minimum.

Please note that these are “intervals” and not “latency” metrics. These intervals can cause latency and jitter due to the limitation of that buffer.

The main reason for this limitation is because Apple has no intention to place Bluetooth MIDI at a high priority compared to other more common services. Thus if you connect any Bluetooth MIDI device with iOS or macOS, you cannot get the connection interval lower than above mentioned limitations.

If we break away from the iOS and macOS Bluetooth connection interval, two WIDI Master can set itself with shortest interval that Bluetooth 5 supported. In this way, we can reduce the latency significantly.

To bypass limitations of iOS and macOS an interesting option is WIDI Uhost. It will also allow you to pair automatically, instead of manually setting your BLE MIDI connection every time..

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USB MIDI + BLE: https://www.cme-pro.com/widi-uhost/

Make decision based on real life experience..

I consider that you are perfectly capable of making your own decision. If latency is the only metric you make your decision on, and cables work for you, you just stick to your cables. Or at least wait until you and your musician friends can test our Bluetooth MIDI solution in real life at your local dealer. That is fair enough, right?

In the other hand, if you are interested in getting rid of those cables, advanced midi connectivity, app based cable management and wider range plus freedom of movement with midi (like on stage), then Bluetooth MIDI solutions might be of interest for you.

Jordan Rudess & CME WIDI Master

Here are some facts:

With the current BLE MIDI solution as developed with CME’s WIDI it is possible to reduce latency between two WIDI devices using BLE 5 to 3ms. When looking at a stable jitter it is considered that a 4–6ms latency is more accurate.

If you want to find out more about WIDI Master and latency: go read this!

Bluetooth MIDI is the standard as developed by Apple and approved by the MIDI Association already 5 years ago. Many industry icons including engineers from Moog, David Smith, Yamaha, Roland, Korg, Apple, Google, Microsoft etc. worked together to verify this standard.

Learn more: https://www.midi.org/specifications/item/bluetooth-le-midi

There are many professional keyboards and synthesizers already equipped with Bluetooth MIDI features. Tens of thousands professional musicians use it on the stage or in the studio for over several years. If you search on Google, you can find many examples.

For instance: https://www.roland.com/uk/products/ax-edge/specifications/

CME implemented this Bluetooth master and slave MIDI technology in the renowned Xkey Air (2015 www.xkeyair.com) and WIDI BUD (2016 www.widibud.com).

Up until this day CME never received complaints by professional musicians about instability of connections and latency. Therefore MIDI over Bluetooth has already been approved over the time and proven to work by over 4 years of usage.

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5-PIN DIN MIDI + BLE: https://www.cme-pro.com/widi-master/

What is the big challenge?

The real challenge is to convince people and allow them accept the innovation. It might be out of their comfort zone and conflict with everything they know and learned. It takes time.

So if you arrive in a discussion about latency, feel free to forward them to this specific blog to get a better understanding: https://www.cme-pro.com/how-to-connect-two-midi-hardware-via-wireless-bluetooth-midi/

Or forward them to this Facebook group to join the discussion and contribute: https://www.facebook.com/groups/CMEXkeyusers

or — if they really know it all and have years of experience as an engineer — welcome them to join the MMA https://www.midi.org/join-the-mma

Here they can contribute their professional knowledge to allow the entire music industry and all musicians to benefit from it by improving the MIDI standard.

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Moog, MMA and Roger Linn about WIDI technology

CME WIDI Master VS Yamaha BT-01

Of course CME is not the only company that is into the game of wireless MIDI adapters. Looking more specifically there are others to be found. One of them is the Yamaha BT-01.

The Yamaha BT-01 is a OEM model of the Quicco M1. This means it is exactly the same product, only it carries another brand. When comparing WIDI Master with BT-01 the main difference is that the BT-01 implements Bluetooth 4 (BLE4) compared to WIDI Master implementing BLE 5.

Of course, with the pace consumer technology develops, the difference in performance between BLE 4 and BLE 5 is quite relevant. Leading to lower latency and wider range performance for WIDI Master.

Furthermore BLE 5 will allow the one-to-multiple feature. Something that will be available for WIDI Master after updating the firmware.

Also, Yamaha only implemented Bluetooth Peripheral (slave). Therefore you need a host operating system to function. You would need to use a mobile device or computer to benefit from the wireless capabilities of the MD-BT01

This is one of the unique selling point of WIDI Master. CME’s solution can function fully standalone. Therewith you can pair two vintage synths or your keytar with a keyboard. Without computers.

This is possible because the WIDI Master can fulfil a central role. It can be both the slave and the master in MIDI terms. In Bluetooth terms that means it can switch between the central role and the peripheral role. It can function as a host to any slave.

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

CME WIDI Master VS Roland WM-01

End of September 2020 Roland entered the Bluetooth MIDI adapter world as well when launching its WM-1 and WM-1D. As CME is just a small company, it is great for the wireless MIDI community that industry leaders such as Roland and Yamaha are interested in this niche market.

Looking at the WM-01 compared to the WIDI Master we see the latency performance is quite similar looking at 3ms best case between two adapter devices.

The main difference is that Roland WM-01 has a non-detachable design and is battery powered. Compared to WIDI Master being powered by the MIDI OUT of the device it is attached too and a smart design feature allowing you to detach both connecters. This is especially useful for MIDI devices with only MIDI OUT ports such as many keytars and electronic wind instruments.

Another important difference is the specified range and price. Although Roland is new to the market compared to CME, they report a 10 meters range against 20 meters by CME.

Also, another difference comes in the price where CME’s WIDI Master is US $ 10 to US $20 cheaper than its competitors by Roland.

If you are interested you can find a complete comparison here!

Shook created this amazing video ad for WIDI Master!

The Power of the Community

The best proof comes from the community itself. If you are interested on how real people use WIDI technology in a wide range of MIDI setups, feel welcome to learn more through these blogs:

Also there are many active community members already making videos of their use case. Watch for instance this one by Defcon Clark taking you into the world of guitar pedals and MIDI. In 3 minutes you see what you can do.

Feel free to visit our website and register for the next decade of wireless MIDI with WIDI.

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Unpowered MIDI DIN + TRS MIDI + 6-PIN DIN-mini: https://www.cme-pro.com/widi-jack/

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Music - Marketing - Management

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