Troubleshooting Xx

Xx is generally very robust. There are a few commonly reported issues which this document will help you troubleshoot. Some users experience issues with Multi-Transform due to a misunderstanding of how it works. It applies to the selected time range (measure selection) rather than the note selection.  See the section Troubleshooting Multi-Transform if you are having trouble when applying (or trying to apply) the Multi-Transform command.

Audio Unit Issues and other strange problems. Misbehaving audio units can be responsible for some strange behavior that you might not think would be audio unit-related.  If you experience generally strange behavior such as instability, odd sounds being produced, problems with the audio output, or other strange problems, the problem is most likely caused by a problematic Audio Unit synth or synths (even if none are in use by your sequence). You may also encounter issues that are obviously audio unit related.

See the section Audio Units & Troubleshooting below if you are experiencing either strange problems or problems that you know are related to Audio Units.

MIDI INPUT SETUP. In version 5.0, Xx responded to any MIDI controller available when it launched. In version 5.2, it is necessary to enable MIDI input devices if you have more than one. You can have more than one MIDI input device enabled. To enable input devices, choose Preferences from the Xx menu (shortcut: command-comma) and choose any devices that you would like to use from the Set Midi Input Device popup menu. Shortcut: Control-click on the track output popup pops up the MIDI Input device list.

Audio Units & Troubleshooting

Some users have reported problems that have turned out to be related to audio units. These problems are much less common in version 5.2 than they were in version 5.0. We identified a few bugs in Xx and also a few common bugs in audio units that we were able to workaround. That being said, you may encounter issues that are caused by an errant audio unit synth. Most of these issues are caused by audio units that either violate Apple's audio unit guidelines or make incorrect assumptions about the host environment. Such audio units may work perfectly in popular apps such as Logic or Live (under which they have been tested and debugged) but behave poorly in Xx.

There are a few things that are important to know about Xx's Audio Units support.

• Limit of 48 Audio Units. For performance reasons, Xx loads up to 48 Audio Unit synths (in version 5.0 the limit was 16). If you have more than 48 Audio Units, some of your Audio Units won't be accessible from within Xx.If you have such audio units, you can load them into another host application (such as Rax or Apple's AU lab, or any app that accepts MIDI) and send them MIDI via MIDI IAC. Some Audio Units also come with a standalone version of the plug-in to which you can send MIDI.
• Audio Units that lack Carbon user-interface are not loaded. Xx is a Carbon-based application. The vast majority of Audio Units provide both a Carbon and Cocoa user interface. If an Audio Unit does not have a Carbon user interface, it cannot be loaded. If you have such audio units, you can load them into another host application (such as Rax or Apple's AU lab, or any app that accepts MIDI) and send them MIDI via MIDI IAC. Some Audio Units also come with a standalone version of the plug-in to which you can send MIDI. At this time, the Audio Units from SpectraSonics are the only ones we know of that do not supply a Carbon user-inteface. There may be others of which we are not aware.
• Audio Unit Delay compensation. By default, Xx assumes that Audio Units have latency for which it compensates. The default setting is 11 ticks as we have found this to be a generally useful setting. However, some Audio Units don't behave well when the latency compensation is enabled. If you have AUs that are not responding, or have notes that are sticking, try setting the AU delay to 0.

General AU Troubleshooting

If you are having strange problems, here are some general troubleshooting tips that resolve the vast majority of problems. Try these suggestions in order:

1) Reboot your computer.
2) Temporarily disable all of your Audio Units by launching Xx with the control-key held down. See the section Disabling Audio Units below for instructions about temporarily disabling Audio Unit loading in Xx.
3) Repair permissions and reboot. To do this, launch the Disk Utility application found in /Applications/Utilities. After launching Disk Utility, click on the hard drive's icon in the Disk Utility window and click on the button Repair Disk Permissions. After repairing permissions, reboot your computer.

PROBLEMS NOT OBVIOUSLY CONNECTED TO AUDIO UNITS

If you are having general problems that don't seem connected to a particular audio unit or which don't seem related to audio units at all (such as a crash on startup or garbled audio output), the first thing to do is to have Xx bypass audio unit loading. There are two ways to prevent audio units from loading:

1) In the Preferences window, turn off the Enable Audio Units checkbox. When this option is turned off, Xx does not load audio units. Quit Xx and relaunch it, after changing this setting.
2) Hold down the control key when launching Xx. You can release the control key after you see the message (in the startup screen) "Install Graph (Audio Unit Disabled)". Control-key startup also turns off the Enable Audio Units checkbox. To re-enable audio unit loading, you will need to open the Xx Preferences window and turn on the  Enable Audio Units checkbox. After changing the setting, you must quit and restart Xx.

If the problems go away when all audio units are turned off, the problem is related to a specific audio unit and you will need to troubleshoot your audio units to find the offending audio unit. Some tips for how to do that are found later in this section.

If disabling all your audio units does not solve your problem, follow the procedures outlined in the section General Troubleshooting below.

SOME AUDIO UNITS NOT LOADING
There are two reasons an audio unit synth might not be available in Xx:

1. There are more audio units than Xx can load (it loads a maximum of 48 audio unit synths at startup). Xx loads a maximum of 48 audio unit synths. We have limited the number because we have found that with a very large number of AU synths that software stability is reduced and load times increase dramatically. If you have more than 48 AU synths, you will need to manage your plug-ins. For more information see the section Managing Plug-Ins below.
2. An audio unit synth does not provide a Carbon graphical interface. At this time -- Feb. 2011 -- the synths from Spectrasonics are the only ones that we know of that don't support a Carbon AU, but there may be others of which we are unaware.
   

AUDIO UNIT DOES NOT RESPOND CORRECTLY WHEN PLAYING BACK A SEQUENCE
We have found that a few (very few) audio units do not behave correctly when Xx's latency correction is turned on. If your audio unit synth is not playing notes correctly when a sequence plays back, open Xx's preferences window and set the AU delay to 0. You may want to experiment with settings for the latency compensation.

In the rare event that this does not solve the problem, you may want to load that synth into another host program (including a lightweight host like RAX or Apple's AU Lab application -- which is available if you have installed the Apple Developer Tools) and send MIDI from Xx to the host using MIDI IAC (which is easily set up in Apple's Audio MIDI Setup application).

XX CRASHES ON PLAYBACK OR WHEN MIDI IS ROUTED TO A PARTICULAR AU
There are a few audio units that assume that the host application is a Cocoa application and they make illegal calls that crash Xx. There are only a few AUs that we have found like this. The solution is to load that synth into another host program (including a lightweight host like RAX or Apple's AU Lab application -- which is available if you have installed the Apple Developer Tools) and send MIDI from Xx to the host using MIDI IAC (which is easily set up in Apple's Audio MIDI Setup application).

AUDIO UNIT INTERFACE DOES NOT DISPLAY CORRECTLY
Some (very few) Audio Units do not display their user interface correctly when hosted in Xx. This is rare and usually is the result of a bug in the audio unit synth. Please inform us about any Audio Unit whose interface is not displayed correctly.

Disabling Audio Units

Disabling All Audio Units

To disable all Audio Unit synths, turn off the  Enable Audio Units checkbox in the Xx preferences window. If Xx will not startup, hold down the control key when launching Xx. You can release the control key after you see the message (in the startup screen) "Install Graph (Audio Unit Disabled)". Control-key startup also turns off the Enable Audio Units checkbox. To re-enable audio unit loading, you will need to open the Xx Preferences window and turn on the  Enable Audio Units checkbox. After changing the setting, you must quit and restart Xx.

If you need to enter your serial number, hold down the control key (and keep it held down) before you press the OK button after entering your serial number. The Audio Unit loading happens after the serial number dialog is dismissed.

Disabling Individual Audio Units

If disabling all Audio Units solves your problem, you may want to identify the particular Audio Unit (or Audio Units) responsible. To do this:

1) Start by creating "hider" folders and moving all audio units into it.
2) When Xx is not running, move one (or a few) Audio Units from your hider folder to the Components folder.
3) Launch Xx and use it.

If Xx behaves well, quit Xx and move another Audio Unit (or a few). If Xx, does not behave well, the problem is one of the Audio Units that you just moved.

If you find an Audio Unit that is not compatible, you should hide it before launching Xx -- you can move it back to the components folder after Xx has finished launching.

Because this manual AU management can be tedious, you may want to make use of an Audio Unit manager which simplifies the process of enabling and re-enabling plug-ins. We mention a few Audio Unit managers in the section  Managing AU Plug-ins.

Managing AU Plug-Ins

If you determine that Xx behaves better with some or all Audio Units disabled, you will need to move/hide the offending Audio Units before launching Xx. You can re-enable (unhide) them once Xx has launched since Xx only loads Audio Units at launch time. You can either move/hide them manually or by using a plug-in manager.

Manually Managing Plug-Ins

To manually manage Audio Unit plug-ins, create a hider folder as described in the section Disabling Audio Units found above. Before launching Xx, move any audio units that you want to hide into the 'AU Hider' folder and move them back into the Components folder after Xx launches if you want them available in other applications.

Using and Audio Unit Manager (Plug-In Manager)

If you have and Audio Unit Plug-In manager, create a set named Xx that contains only the Audio Units that you want Xx to see. Before launching Xx, use the audio unit manager to select the Xx set. Once Xx has finished launching, you can select your preferred plug-in set if you need to access different plug-ins from other software.

Audio Unit Managers

There are several commercial and shareware plug-in managers. Below are a few that we know of. You may be able to find others by searching at your favorite download site (such as http://www.versiontracker.com or http://www.macdownloads.com)

Audio Unit Manager is a simple no-frills freeware plug-in manager that you can find at VersionTracker.com: http://www.versiontracker.com/dyn/moreinfo/macosx/34088. Note that Audio Unit Manager does not work if some plug-ins are installed in ~/Library/Audio/Plug-Ins. It expects all the plug-ins to be in the system-wide library (/Library/Audio/Plug-Ins...

AudioFinder - is a great audio asset management application that includes an excellent plug-in manager. A fully-functional demo can be downloaded from: http://www.icedaudio.com

Troubleshooting Multi-Transform

Some users experience what appear to be problems with the Multi-Transform command due to a misunderstanding of how it works. Multi-Transform acts on the current measure (time-range) selection rather than the note selection. When using Multi-Transform, drag out a time selection in the time bar found below the score area.

Do not Select All before applying Multi-Transform. Multi-Transform is applied to the selected time range. Selecting all creates a very long time range selection. Select just the time range that you want to transform rather than using Select All.