Welcome to part 2 of making music with Logic Pro. In this article we will cover getting started with your MIDI keyboard in Logic including set up for your audio card and drivers, latency and buffer size.
Once you have installed your MIDI keyboard and audio card, you will need to make sure that Logic communicates with them.
For Logic to communicate with external MIDI devices, first you will to configure the Audio MIDI Setup. The Audio MIDI setup is an application located within the Utilities folder (in Applications folder). You can quickly access it in the Apple menu bar: Go >Utilities (or press Command Shift U).
Once in the Utilities folder, open the Application Audio MIDI Setup, and click on the MIDI Devices button. You should see an IAC driver button, a network button and buttons for other MIDI devices connected to your computer. Please note that if you use a multi port MIDI interface with external MIDI devices (Synth, drum machine, etc...), you will need to make the connection manually.
Drivers for Audio Cards
To use a sound card with a computer, the operating system typically requires a specific device driver which you will have installed in the previous steps.
There are a few different driver formats available depending on the computer, the operating system and the sound card itself. Apple mac OS X uses Core Audio This driver for Mac OSX is tightly integrated into the operating system. It works with external sound cards as well as the Mac's integrated sound card (known as built-in). Nowadays, many soundcards support Core Audio out of the box, you simply 'plug & play'.
Set Up Your Audio Card with Logic
Now you have to make sure that Logic communicates with your audio card. In Preferences, select Audio > Devices > Core Audio.
Now you need to select the correct driver for your audio card. Use the drop down menu Device in order to select the appropriate driver.
What Is Latency? When making music using software, the computer has a huge amount of information to process before being able to output the sound to your speakers.
This means that when you press a key on your MIDI keyboard to trigger a sound from a software synth for example, there will be a delay before you hear the sound. This delay is known as the latency.
As you can imagine, if the latency is too pronounced it will become extremely difficult to play any musical part, which is why it is important to use the best driver you can with your sound card. Furthermore there are certain parameters that you can adjust in order to improve your latency.
You can reduce the latency by adjusting the audio buffer size. A small buffer size will reduce the latency, where a bigger value will increase the delay time considerably. So why not have the buffer size to the minimum value all the time to make the system more playable? Well, it is not as simple as that.
There are several parameters that directly affect each other. If the buffer size affects the latency, it also affects the processing power available to the software. Software instruments need processing power (CPU), so that the more CPU you have, the more software instruments you can load at one given time. Basically a small buffer size will put more strain on your computer in order to get a smaller latency (delay), thus using more CPU.
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