"the labs"

Linux MIDI Command Line Cheatsheet

USB MIDI controllers and keyboards have come way down in price the last few years.  We really like the Akai MPK Mini mkII, and we’ve really enjoyed using the Numark Orbit because it has an accelerometer in it for sensing tilt and motion, and it is easy to send MIDI messages for changing its colors.

Use the command line to control the MIDI system


If you’re experimenting with a Raspberry Pi using USB MIDI input devices, you’ll probably get to the point where you are wondering if it is working correctly and if the MIDI information is getting into your Raspberry Pi.  This article lists some of the command line tools you can use to examine the information coming from these devices.
Read More »Linux MIDI Command Line Cheatsheet

How to connect an iPad to a Raspberry Pi – Video Tutorial

Introduction

There are a lot of good touch-MIDI controllers available for the iPad.  They’re fun to use and can be customized.  One such popular controller is MidiPads .  In the past, an owner of a Raspberry Pi wouldn’t be able to take advantage of this controller, since MidiPads speaks “Network MIDI” and the Raspberry Pi does not.  (Or did not, at least until now).

Read More »How to connect an iPad to a Raspberry Pi – Video Tutorial

Using rtpmidi from the Command Line

Did you know you can use rptmidi directly from the command line in a terminal?  When used this way, the GUI (graphical user interface) is not used, and Bonjour is skipped as well.  Instead, each invocation of the rtpmidi program creates a new Session that can be a Session Listener or Session Initiator.  Working at this level you can connect if you know the hostname or IP-Address of each computer, as well as the port the RTP-MIDI session is listening on.

Command line mode can also come in handy if you are developing a “headless” embedded computer application like the Zynthian Raspberry Pi Synthesizer.
Read on for detailed examples and explanations.
Read More »Using rtpmidi from the Command Line

Punching it Up: Low-latency notes

Sometimes you want a really “punchy” sound. To a musician, this means a sound with a rapid attack and a quick reaction from the keyboard. To a software developer, this means a sound with a very low attack rate and a very low latency through the synthesizer from the keyboard to the audio output. To make a punchy sound, we’re going to use an external USB audio card, and also adjust the sound card settings.

What is Latency?

Latency is the delay from when you hit a note on the keyboard until you hear the sound. Musicians deal with latency all the time, because there are audio delays inherent in all of our equipment. Pipe Organ players have long been accustomed to experiencing a delay between the keyboard action and the sounding of a pipe. However,  organists learn to adapt.
If the value of the latency between the keypress and the sound is constant, a musician has a good chance of being able to compensate. If the latency is unpredictable, even a tiny bit, then a musician will have a harder time keeping their music sounding rhythmic. We are going to try to adjust our organ to reduce latency, and also the variance of the latency.

Why not the internal sound device?

The internal sound chip of the Raspberry Pi 3 is good enough for desktop sounds and casual listening to music, but if you want clearer sounds, and lower latency you will want an external USB sound card. The actual experience you have will vary with the sound card you choose. Here at McLaren Labs we use a Yamaha MG-10XU mixer with USB input as an external sound device and it works great.
Read about how we reduced latency and created a “punchy” sound below the break.
Read More »Punching it Up: Low-latency notes