Creating multi-channel sound files in Audacity
The latest version of Audacity (2.0.0) has a different menu structure from earlier versions and the method for creating multi-channel files is as follows:
Creating multi-channel wav files in Audacity v2.0.0
In preferences, choose Import/Export
Under 'When exporting tracks to an audio file' check 'Use custom mix'
Open a new file and import your tracks - any combination of stereo and mono tracks that adds up to a maximum of eight discrete tracks. e.g. four mono and two stereo, or six mono and one stereo.
Make adjustments to taste.
Choose Export, or Export Selection if you've made a selection, from the file menu and from the Format-Options drop-down menu, choose WAVEX.
When you save the file, you'll be presented with a track map that allows you to decide which sounds appear on which track. Clicking on source and destination boxes will add or subtract links. At the bottom of the screen is a slider; moving to to the right will increase the number of interleaved output channels that will be created and you simply click source and destination boxes until you've got the setup you want. You can link a single track to multiple output channels if you so wish.
For beta versions of Audacity prior to 1.3.5d, go to preferences and select File Formats. Under "When Exporting Tracks" select "Use Advanced Mixing Options". Under "Uncompressed Export Formats", choose "Other", then from the pop-up menu choose WAVEX (Microsoft), then your choice of encoding. QLab seems fine with 24 bit signed. Once you've done this, click OK and return to your file.
Select export, or export selection, depending on what you want to do, and choose WAVEX from the menu. A window will open showing your selected tracks for export and a destination box. At the bottom of the screen is a slider; moving to to the right will increase the number of interleaved output channels that will be created and you simply click source and destination boxes until you've got the setup you want. You can link a single track to multiple output channels if you so wish.
Other Programs That Support Multi-Channel Files:
Sound Studio: Saving an AIFF or WAVE multi-track file will not auto-mixdown. You can drag the file into QLab using the same instructions as above.
Hold your mouse over the red 'X'
Holding your mouse over the red X of a broken cue will display a tool-tip describing the reason the cue is broken.
Group expansion shortcuts
You can use the right and left arrow keys to expand and collapse the selected Group Cue. You can use the '>' and '<' keys to expand and collapse all the Group Cues in the current cue list.
Assigning targets to Fade Cues
You can drag one Fade Cue on top of another one in order to give it the same target cue. (Of course, you can assign a target to a Fade Cue in all the normal ways, too. This just gives you a shortcut if you have a bunch of Fade Cues near each other that should all have the same target.)
Making a group a cue list, and vice-versa
Groups can become cue lists and cue lists can become groups. Just drag groups to the cue list drawer to make them into a new cue list, or drag one cue list into another to make it into a group.
Edit Waveform, Find Cue, Reveal in Finder
There are 3rd party AppleScripts that will:
- Open a selected sound cue in Audacity, Sound Studio, or Pro Tools LE.
- Reveal a cue's target file in the Finder.
- Search for text (such as the description) in the frontmost cue list.
You can also find additional AppleScripts for use in Automator or QLab Script Cues (and share your own) under QLab Scripts and Macros.
Locking a workspace in QLab 2 (and what to do if the lock button disappears)
The lock icon can be clicked to prevent changes in the Workspace. This can be thought of as putting QLab in "show mode". It doesn't mean that sound files or other system resources are locked, just that the workspace in QLab is locked.
But what if there is no lock icon in the toolbar? If you want to get your lovely icon back right click (control-click) on the toolbar area of the workspace. You will get a menu that will allow you to edit the icons in your toolbar, and you can drag the lock back in.
Assign "missing" keyboard shortcuts
You can assign "missing" keyboard shortcuts to any menu items (such as Copy Fade Shape & Paste Fade Shape) using "Keyboard Shortcuts" on the "Keyboard & Mouse" pane of System Preferences.
Quantised stopping & starting of cues
Or, "devamping non-looped Audio Cues" and "starting on the bar"...
Consider these two screenshots:
Log in to Mac using "Safe Mode" to ensure no conflicts
You can log in to your user account on the mac using 'Safe Mode,' which disables all non-system startup items and other third party plugins and the like.
This is useful for when your Mac is also your 'daytime' machine, as well as running a show.
Just hold down SHIFT after you login, and hold until you hear the log in sound.
Use Quartz Composer to access non-DV cameras (USB etc.) in QLab 2
This is a tricky one, but it's not too difficult, and can allow you to use many cameras that QLab can't speak to with the Camera cue. The basic steps are:
- Make a "dummy" video file that lasts as long as you'll need to see the camera's feed. The pixel dimensions of this file should match the pixel dimensions of the camera's output. I like to make a single black frame, and copy and paste it until I have the duration I need, then encode with H.264, so it stays a nice, small file. The content of this video file is irrelevant - it'll just be thrown away.
- Modify QLab's default video.qtz file to throw away the Image input, and replace it with a Video Input patch.
- Select your camera in the Video Input patch's Settings tab.
- Drop the dummy video file into QLab as a Video cue, using your new Quartz file as the custom renderer.
To make it easier, here's a pre-made camera.qtz file:
If you don't already have Quartz Composer installed, you'll need to install it from the Optional Installs on your system disc - just install the XCode Developer Tools. You can then open the camera.qtz file and edit the Video Input patch to use your attached camera.
Use Quartz Composer to do keystone in QLab 2.
- Download this file: msa_Quad Warp-QLab.qtz
- Drag it to "Custom rendering" under "composer" tab of a video cue
- Use Quartz Composer (available with XCode) to set keystone parameters.
Controlling QLab using MSC from an ETC ION
- Connect hardware. With the USB interface the obvious label applies: In->Out, Out->In
- Make sure that the MIDI ports are enabled in the Local/IO section of the settings menu outside the Ion software. Make a note of the ACN channel numbers, these range from 1-32 and the Ion should default to 1.
- Start the Ion software and go to the 'Show' settings. Go to the remote settings, then:
- Make sure the ACN MIDI Tx ID matches the ID configured in the Local/IO section outside the software.
- Enable MSC Rx if you want control the desk from outside and MSC Tx if you want to control something else from the desk. Enable both if you want two way communication.
- Configure the channel numbers for Rx and Tx. These actually configure the MSC 'Device ID' and range from 0-126, 127 is the all-call ie broadcast ID.
- If you want to control QLab from the Ion then make sure that the MIDI Show control is enabled in the Remote section of the workspace preferences and that the device ID configured in QLab matches that configured in the Ion.
- I think if you want GO's with cue numbers attached then you need to enable MIDI String Tx as well otherwise the cue numbers don't get attached to the MSC GO command but I'm not sure.
- Cue numbers in QLab must exactly match the cue numbers in the Ion that is to say 1 and 1.00 are not the same.
System Preferences for show-mode computers
- Set all Desktops to a black image - that way, if QLab does crash, at least the projectors are only showing black.
- Ensure Screen Savers never start.
- Turn of the translucent menu bar - this isn't a big deal, but every bit of graphics power counts, and that effect uses graphics resources.
- Turn off all keyboard shortcuts for things like Mission Control, Exposé, Dashboard, etc. Also turn off Hot Corners.
- Add the system hard drive and any hard drives used for media to the Privacy pane of Spotlight preferences. Spotlight indexes the files on your disk periodically, and if that happens during a show, the disk access could cause a bottleneck when you're trying to read media files for playback.
- Turn off any Universal Access assistance.
- Set all CD and DVD automatic options to "ignore".
- Configure displays.
- Set all Energy Saver preferences (battery and power adapter) to Never, and uncheck "Put the hard disk(s) to sleep when possible".
- Kill extraneous keyboard shortcuts and mouse/trackpad gestures.
- Set the Sound alert volume to mute, turn off user interface sound effects and volume feedback.
- Remove any network devices that aren't used during the show.
- Turn off Bluetooth.
- Turn off Sharing of anything.
- Remove any unnecessary applications from the Login Items pane of the Users preferences.
- Turn off automatic time updates.
- Turn off automatic Software Updates and checks for updates.
- Turn off Time Machine.
- Turn off XProtect Updater. This one you'll need to do via a terminal command (all one line):
- sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.xprotectupdater.plist
I set up four show computers today, and someone wrote to us at QLab support (a great idea if you have questions) needing that information. I figured, since I typed it out, I should put it up here.
How do I rack mount a Mac Mini?
There are several companies which make suitable ironmongery for example:
Some of the Sonnet products allow a PCI-Express card to be located in the same Mac and connected to the Mini via Thunderbolt, although they also make less expensive mounts that just hold one or two Mini's.
What is an EDID Emulator and why might I want one?
EDID stands for 'Extended Display Identification Data' it is a data channel which allows a computer to query a display to discover what resolutions and refresh rates it supports. EDID is the mechanism by which MacOS X detects new displays when they are plugged in or when 'Detect Displays' on the display menu is implemented.
An EDID emulator is a small box which goes between your monitor and the Mac which supplies the EDID signal instead of he display. They generally come in two flavours: ones which capture the signal from the reason display when a button is pushed, and ones which are configured to always produce a particular signal.
So now I know what one of these things is why might I want one? There are a few main reasons:
- If you need switch your projector or other display device on during the show you don't want your Mac redetecting it and possibly breaking your video cues.
- EDID is fragile and can fail over long cable runs.
- EDID doesn't always work correctly, especially with niche products such as high end projectors which video card manufacturers won't have tested with.
Why is my external disk spinning down even though I've turned off 'put the hard disk(s) to sleep'?
Many external disks are not suitable for use with QLab this is because they do not respond to OS X's power management and attempt to implement their own. For the curious this is because OS X can only do spin control on the first logical unit. Many disks put a "sync now" button or "capacity gauge" on the first unit number then implement their own power saving due to breaking OS X's.
Disks known to behave correctly:
- Anything made by Glyph
- Anything made by G-Technologies
- Buffalo Drivestation Combo 4
Disks known not to behave correctly:
- Anything made by Seagate (at the time of writing)
- Anything made by Western Digital (at the time of writing)
- Most LaCie models
- Most Buffalo models
In some cases for disks which OS X can't control the problem can be worked around by configuring the disk to never spin down at all. Some LaCie models come with a utility to do this.
How Do I Use VNC to control my computer?
OS has both a built in VNC server and VNC client. You can enable remove access by:
- Turn on Apple Remote Desktop in the sharing pane of system preferences.
- Enable VNC users with password.
You can then connect by:
- Choosing 'connect to server' from the 'Go' menu and entering a URL starting 'vnc://MyMac' where MyMac is the name of the computer you want to connect to.
⌘, - Preferences
L - Load
N - Renumber
⌘R - Batch Renumber
Q - Rename
Esc - Stop Current Cues
S - Stop Selected Cue
T - Open Target Dialog
C - Change Follow Type (Do not continue, Auto-continue, Auto-Follow)
⌘T - Fonts
⌘[Arrow Keys] - Inspector Tabs
Option Click on an Input or Crosspoint Dial, or a fader, sets to 0 or -INF
[ - Pause All
] - Play All
Shift, Cmd, C - Copy cue levels
Shift, Cmd, V - Paste cue levels
Shift, </> - Collapse/Expand all groups in a cue list