How fast is Bluetooth MIDI?

Bluetooth MIDI allows musical instruments and devices to connect wirelessly using Bluetooth technology. It enables MIDI data transmission over Bluetooth wireless networks, providing cable-free connections for musical setups. The technology combines the widely adopted MIDI protocol with Bluetooth wireless standards for reliable, real-time MIDI communication.

The MIDI protocol was introduced in the 1980s as a way for electronic musical instruments and computers to communicate. It transmits digital data such as note, tempo, and volume information between devices. While incredibly useful, early MIDI required devices to be physically connected via cables.

Bluetooth MIDI emerged as a way to remove these cables and enable wireless MIDI connections. It allows MIDI data to be transmitted over Bluetooth radio signals rather than wires. This frees musicians from cable clutter and provides greater flexibility in instrument setups and live performances ¹. Bluetooth MIDI maintains the essential benefits of standard MIDI, while cutting the cords.

Bluetooth MIDI Overview

Bluetooth MIDI allows electronic musical instruments like keyboards, guitars, drums and more to wirelessly send and receive MIDI data to each other and to other devices like computers, tablets and smartphones. MIDI stands for Musical Instrument Digital Interface and is a technical standard that allows electronic instruments and devices to communicate.

With Bluetooth MIDI, the MIDI data is transmitted over Bluetooth wireless technology rather than a physical cable. This allows musicians and performers to connect their instruments and devices wirelessly, providing flexibility and mobility during live performances and recording sessions. The Bluetooth specification used for MIDI is optimized for the low data demands of MIDI information.

Here’s a quick rundown of how Bluetooth MIDI works:

A Bluetooth MIDI-capable instrument like an electronic keyboard will have a built-in Bluetooth transmitter.
Another device like a smartphone, tablet or computer will have a Bluetooth receiver capable of receiving the MIDI data.
The two devices pair with each other using Bluetooth, forming a wireless connection.

When keys are played on the instrument, the note information is converted into digital MIDI data and wirelessly transmitted via Bluetooth to the receiving device.
The receiving device converts the MIDI data back into musical information which might be played back through speakers, recorded in music software, or manipulated in some other way.

So in summary, Bluetooth MIDI allows electronic instruments and devices to wirelessly communicate and exchange MIDI performance data and information.

Bluetooth MIDI Latency

Latency refers to the delay between when a MIDI message is sent and when it is received. This is an important consideration for Bluetooth MIDI, since any lag can disrupt the timing of musical performances. There are several factors that contribute to Bluetooth MIDI latency:

One source of latency is the wireless transmission method. Bluetooth uses short-range radio waves to send data, which inherently takes longer than sending electrical signals through a MIDI cable. The precise delay depends on the specific Bluetooth protocol being used. For example, Bluetooth Low Energy MIDI has been measured to have around 30-50ms of latency, while Classic Bluetooth MIDI may have closer to 150ms of lag time (CME Pro).

The Bluetooth profile used for MIDI can also impact latency. MIDI over Bluetooth Low Energy tends to have lower latency compared to MIDI over Classic Bluetooth because of optimized data transfer rates. However, even Low Energy profiles like Apple’s CoreMIDI introduce some processing delays (Thomas Gerbrands).

Other sources of latency include audio buffer sizes, onboard processing, interference from other wireless sources, and compression algorithms. Overall, Bluetooth MIDI latency makes it less ideal for applications requiring precise, real-time control. However, latency continues to improve with newer Bluetooth versions and can be reasonable for many use cases.

Bluetooth Versions and Speed

Different versions of Bluetooth technology have varying speeds and capabilities when it comes to transmitting MIDI data wirelessly. Here’s an overview of the major Bluetooth standards:

Bluetooth 1.0 and 1.0B had a maximum data rate of 1 Mbps. The MIDI data throughput would have been quite limited on these early versions.

Bluetooth 2.0 + EDR increased the maximum data rate to 3 Mbps, allowing for faster MIDI transmission. However, latency and reliability may still have been an issue compared to later versions.

Bluetooth 3.0, also called Bluetooth Smart, operates in the 2.4GHz band with a data rate up to 24 Mbps. This improved speed and reduced power consumption. The throughput for MIDI data increased substantially.

Bluetooth 4.0 introduced Bluetooth Low Energy (BLE) protocol. While not as fast as Bluetooth 3.0 in theory, BLE helped optimize connections for MIDI and other low bandwidth applications.

Bluetooth 5.0 boosts maximum data rates up to 50 Mbps while adding extended range up to 800 feet. With higher throughput, Bluetooth 5.0 allows for excellent MIDI performance with minimal latency issues for most use cases.^[1]

In summary, newer versions of Bluetooth from 4.0 onwards provide the best MIDI performance and speed capabilities compared to earlier versions. Bluetooth 5.0 is the most advanced protocol available today in terms of optimizing Bluetooth MIDI connectivity and user experience.

Bluetooth MIDI Profiles

Bluetooth uses “profiles” to define specific use cases and capabilities. There are several different Bluetooth profiles used for MIDI communication:

The MIDI profile is one of the older Bluetooth profiles used for MIDI over Bluetooth 2.0 and earlier. It allows low-latency MIDI data to be sent over Bluetooth between MIDI devices. However, it has higher power requirements so isn’t optimal for mobile devices (cite1).

The Low Energy MIDI profile was introduced with Bluetooth 4.0. As the name suggests, it is designed to use less power and work with Bluetooth Low Energy devices. The tradeoff is slightly higher latency compared to the classic MIDI profile (cite1).

Apple also has their own Core MIDI profile used on iOS devices and Macs. It uses Bluetooth Low Energy and has optimizations to reduce latency (cite1).

So in summary, while older profiles like the original MIDI profile provide lower latency, newer profiles like Low Energy MIDI and proprietary versions aim for power efficiency important for mobile use. There are always tradeoffs between latency, power, and compatibility.

Compression and Throughput

One of the key factors affecting Bluetooth MIDI throughput is compression. Bluetooth uses lossless data compression to reduce the size of MIDI data being transmitted wirelessly. This compression allows more MIDI data to be sent in each packet, increasing the effective throughput.

The Bluetooth MIDI profile uses a compression ratio of 1.5 to 1, meaning the uncompressed MIDI data is compressed to around 66% of its original size before transmission [1]. This compression happens in real-time during the Bluetooth connection. With compression, a larger amount of MIDI data can be transmitted per second compared to sending uncompressed data.

Higher MIDI data throughput means reduced latency, which is vital for real-time music applications. The compression allows the transmission of dense and complex MIDI compositions without losing information. So while the raw Bluetooth data rate may be limited, compression significantly boosts the usable throughput for MIDI.

[1] https://www.amazon.com/bluetooth-midi-adapter/s?k=bluetooth+midi+adapter

Wireless Interference

Bluetooth uses radio waves operating at the 2.4 GHz frequency which unfortunately can experience interference from other wireless devices like WiFi routers, wireless keyboards/mice, microwave ovens, and cordless phones. This is because many common household devices also transmit signals in the crowded 2.4 GHz band.

When interference occurs, it can disrupt the wireless Bluetooth connection leading to choppy MIDI transmission and increased latency. The transmitted MIDI data has to be re-sent if the connection is interrupted which slows everything down. Microwave ovens are one of the biggest sources of interference since they operate around 2.4 GHz and flood the spectrum while in use.

To reduce potential wireless interference when using Bluetooth MIDI, try to minimize other wireless device usage during critical moments. Turning off WiFi on mobile devices while performing can help. Also maintaining line of sight between Bluetooth devices improves performance. Using newer Bluetooth versions like 4.0+ helps utilize more error correction to combat interference. Ultimately, any disruption in the Bluetooth signal can negatively impact timing and feel when using Bluetooth MIDI gear.

Common Use Cases

Bluetooth MIDI is commonly used to wirelessly connect instruments, apps, and other devices for music production and performance. Some common uses and equipment include:

Connecting digital pianos to tablets/phones running music apps and DAWs.
Connecting MIDI keyboards, controllers, and synths to computers/mobile devices wirelessly.
Wireless MIDI control of effects, mixers, lighting rigs in live performance setups.

Connecting wearable MIDI controllers for wireless performance.
Jamming and collaborating with wireless MIDI instruments.
Recording musicians remotely via Bluetooth MIDI.

Overall, Bluetooth MIDI provides flexibility and mobility for music gear. Musicians can jam wirelessly, move around on stage freely, record parts remotely, and integrate mobile devices/apps into their rigs without cables. This makes workflow and performance setups much simpler and streamlined.

Tips for Optimization

There are several things you can do to optimize Bluetooth MIDI performance and reduce latency. First, use Bluetooth 5.0 or higher, as the newer versions have lower latency. Make sure to pair your Bluetooth MIDI devices correctly and avoid having too many other Bluetooth devices connected. Position your Bluetooth devices closer together and avoid obstructions to maintain a strong signal. If possible, use a dedicated Bluetooth MIDI adapter like the Yamaha UD-BT01 rather than relying on the built-in Bluetooth of a digital piano or keyboard. On Macs and iOS devices, using an app like MIDIWrench can help tweak settings for better optimization.

On Android, try using an app like MIDI Bluetooth Pro which allows changing the MTU size and SPP mode for lower latency Bluetooth MIDI. Some devices like the WIDI Uhost also optimize the Bluetooth MIDI connection and can lower latency. Avoid using WiFi at the same time as Bluetooth MIDI, as wireless interference can affect Bluetooth latency. Finally, for critical applications, use a wired MIDI connection for the most reliable and lowest latency MIDI performance.

The Future of Bluetooth MIDI

Bluetooth MIDI technology is still evolving and we can expect further improvements and innovations in the future. One exciting development is the introduction of Bluetooth LE Audio as part of the Bluetooth 5.2 specification. Bluetooth LE Audio will allow new Bluetooth MIDI features like multi-stream audio, broadcast audio, and audio sharing. This could enable new wireless MIDI applications like jamming and recording music collaboratively over Bluetooth.

Another innovation in the pipeline is aptX Adaptive for lower latency Bluetooth MIDI. Qualcomm’s aptX Adaptive can adjust latency levels dynamically based on the needs of the application. This could help Bluetooth MIDI get closer to the ultra-low latency of a wired MIDI connection. CME’s WIDI Bud Pro is one of the first adapters to include aptX Adaptive. Initial testing shows latency under 10ms which is a major improvement over standard Bluetooth MIDI.(1)

As Bluetooth specifications continue to evolve, we can expect further reductions in latency and support for increased bandwidth. This will enable advanced wireless MIDI applications like multiple keyboards/devices connected simultaneously. The future looks bright for Bluetooth MIDI!