USB Audio CRACKED!
Title: Procedure for using multiple USB microphones
Introduction:
Apple iBook computers only come with USB audio inputs. This makes the Logitech 350 headset a good choice for audio input/output for this machine. Unfortunately, Podcasting with a group often requires more than one microphone. Mixing USB audio is a little tricky and not at all like mixing analog audio. This document will describe how we mix USB microphone signals using the following materials.
Materials:
Macintosh Computer (OS X)
Audio Midi Setup (in utilities folder)
Garageband 3 (part of the iLife software from Apple)
USB microphones (We used Logitech 350 headset/microphone combos)\
USB Hub (we used a Belkin USB 2.0 4-port hub)
Procedure:
1. Plug the USB hub into the computer.
2. Plug the USB microphones into the hub.
3. Open the “Audio Midi Setup” program located in the utilities folder
4. Under the “Audio” menu, select “Open Aggregate Device Editor.”
5. Click the “+” to “add…aggregate devices to your computer.”
6. Put checkmarks on the devices listed as USB “In”. If you plugged in 3 microphones, then you will have three items checked.
7. Click the “Done” button. Once you have done this, the aggregate device will appear whenever you plug in your USB devices. Each USB microphoone will now be in it’s own channel (like stereo has two channels, your aggregate device has a channel for each USB microphone.) If you need to adjust the level of any of the microphones, The “Audio Midi Setup” program lets you do that too. Just select “Properties For” and popup the microphone you want to adjust. Sliders appear at the bottom (I set mine all to maximun volume.)
8. Close or minimize the “Audio Midi Setup” application.
9. Open GarageBand
10. You may need to select “New” from the “File” menu and then select Create a Podcast Episode”
11. Name your podcast and note the location it’s saved.
12. Under the “GarageBand” menu, select “Preferences”
13. Click the “Audio/MIDI button in the window that opened.
14. Next to Audio Input, select “Aggregate Device” from the popup menu.
15. Close the preference window.
16. Click on the “Male Voice” track.
17. Click the button near the lower right part of the window that looks like the letter “i” in a gray circle.
18. In the panel that opens up on the right, click the “Details” triangle at the bottom.
19. Where it shows the input, pop up the menu and change it to “Channel 1(Mono)”
20. You can repeat this for the Track labled “Female Voice.” Of course, select “Channel 2 (mono)” as the input.
21. To add additional USB microphone track’s, Select “New Track” from the “Track” menu. When adding the new tracks, make them “Real Instruments” when asked.
22. There are a number of settings for each of the microphone tracks. You can play with these. I have installed a program called soundflower and I directed the garageband output in preferences to sound flower. Then I use Soundflowerbed to direct the audio to a headset for monitoring purposes. Because USB audio introduces so much delay (read e-c-h-o), We don’t bother to monitor all the time. We just monitor to get levels set for everyone’s mic (using the Audio Midi Setup as described above in #7)
Conclusion:
USB audio is too messy! I’m shopping for a good tabletop omnidirectional microphone so that we can just keep it simple!
