Se Mi Sei Vicino (If you are close to me)
Electric Field Sensing responsive environment www.soniacillari.net/Se_Mi_Sei_Vicino_(If.)_index.htm
a work by SONIA CILLARI Produced by Netherlands Media Art Institute, Montevideo/Time Based Arts Interface developed by STEIM (Studio for Electro-Instrumental Music) With the support of Rijksakademie van beeldende kunsten Amsterdam 2006
Technical requirements 2 PC/Linux (CPU: AMD Athlon 64 X2 Dual-Core Processor for Desktop; CPU speed: 4400; RAM: 2 GB) Note: the Dual-Core part is extremely important. GRAPHIC CARD: GeForce 6800 Ultra, 512 MB SOUND CARD: One of the machines needs a multichannel sound card that works under Linux. Or it is possible to use: external emagic A26 usb SOUNDCARD. 2 LCD PROJECTORS High Resolution (according to room dimensions, front projection screens as big as possible. The projectors are installed hanging from the ceiling) 4 SPEAKERS (the size depends on the room dimensions. For a room of 7x7 meters: TANNOY REVEAL SPEAKERS + 1 subwoofer. For a bigger room: SATELLITE SPEAKERS + 1 subwoofer). Minimal requirements for the space A square room, minimum of 7x7 meters Time necessary to setup the installation A couple of days.

Logic 7.2 - Audio Devices (2006-1024)
http://homepage.mac.com/edgarrothermich/

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Logic Pro 7.2 - Audio Devices
(OS X 10.4 Tiger) Personal Manual by Edgar Rothermich <edgarrothermich@mac.com>

Introduction

Audio Applications.... 2 What is the Problem?.... 2

Basics

Device..... 4 Device Driver..... 5 Core Audio..... 6 Core MIDI..... 7 Physical Connections.... 8

Audio Settings

Setup Application..... 9 Audio MIDI Setup (AMS).....10 System Preferences - Sound.... 11

Audio Settings - Detail

Routing.....12 Clock Source.....13 Congure Speaker..... 14 Audio Stream..... 17 Source......19 Format......20 Level...... 21

Aggregate Device

Interface..... 22 Properties For:..... 23

Sound Preferences vs AMS

Default Input.....28 Default Output...... 29 System Output (Sound Effects)..... 30

Audio Applications

Comparison..... 31 Overview..... 35 Additional Settings..... 35 Summary.....36

Audio Setup in Logic

Conguration.....37 Virtual Busses...... 38

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There is a lot of stuff to learn and to understand about Logic. But if you try to get a grip on the whole audio thing, you will find out that many aspects are related more to the operating system OS X than to Logic itself. Setting up the audio portion of Logic and/or any other DAW, requires to you to dive into the Preferences and make the right choices. The content of various popup menus will depend on your specific machine and on what audio related software and hardware is installed. What Im trying to do in this Manual: cover some basic concepts, how OS X handles audio look at Core Audio, the architecture that OS X uses for all audio related issues explain all the audio related settings in the Sound System Preferences and the Audio MIDI Setup application Compare audio settings of different audio applications Check Logics Core Audio implementation
Audio has always been a big and important part of Macs. If you want to use an application that needs an audio input (iChat) or an audio output (iTunes), don't worry, because you have Apples built-in Audio capabilities with integrated microphones, speakers, Line in/out, Digital in/out. (Feature implementation depends on the actual Mac model.)
There are two kinds of application: applications that dont use audio. applications that use audio.

non-audio application

audio application
An accounting program or spread sheet doesn't need audio support but iTunes, DVD Player or iChat need the ability to get audio out and eventually into the program.
Audio applications vary over a wide range, depending on their "audio needs". iTunes needs only an audio out to play to your songs, where as programs like Logic, Garageband, Live - fully fledged music production apps - need much more control over how to handle audio. What do they have in common? A basic knowledge on how OS X handles audio and a solid understanding on using and configuring the audio preferences in OS X will help you stay on top of it and avoid lots of frustration and troubleshooting when it comes to setting up your audio system with your Mac.

What is the Problem?

There is a major shift happening in the world of audio, in the consumer and professional area. A shift from dedicated hardware to dedicated software running on a computer. Consumer: listening to music on your CD player -> listening to music in iTunes recording your favorite song compilation on your tape deck -> creating playlists in iTunes playing DVDs on your DVD player -> playing DVDs on your computer talking on your phone -> talking on your computer via Skype Professional: recording on your multitrack -> recording into your DAW mixing on your mixing board -> mixing in your DAW editing with tape and scissors -> editing in your DAW

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These are just a few examples. Of course there are still hardware devices besides your computer like iPods and the CD and DVD player that is now built into the computer as a disk drive. The difference, however, is that almost everything is centered around the computer that can handle everything by running the appropriate software. And the software part is where it can get tricky. An application software that mimics a tape deck, a CD player or a mixing board, runs on top of the computers operating software, which is nothing else than more software. All these software applications, coming from different developers, have to run smoothly together or next to each other. It is a changing interactive collection of software and every users hardware (computer) behaves differently depending on their specific collection of software used. With dedicated hardware like a CD Player or Cassette Player everything was much simpler. As long as users had the same model, operation and troubleshooting was simple because the unit is a closed environment and works the same for everybody (kind of). If users have the same software like iTunes or Logic, the picture looks quite different: Although a thousand users can run the same software, each one of them can use it in a different environment regarding the actual hardware (different computer models) and the software (different OS and other software that could interact with each other) This makes troubleshooting almost impossible, because there are infinite possibilities of what can go wrong and the developer of a software application cant test all possibilities. The conventional form of customer support is limited and troubleshooting is also shifting towards the internet community in the form of forums and mailing lists.

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Device Driver
Lets concentrate on the Audio Device. Connecting the Device to the Computer is only half the step. The question is, how does the application, running on your computer, communicate with the device, i.e. how does Logic send and receive audio signals from and to the audio device?

??? Device Application

The answer is through a Driver or "Device Drive". This is a little application that functions as an interpreter between the application and the device.
Driver Device Application

Software

Driver

Hardware

A device driver enables the proper communication between an Application (Software) and a Device (Hardware)
Each hardware device (keyboard, MIDI device, audio device, mouse, joystick) that connects to the computer needs a driver. There are two options: Built-in driver: an operating system usually includes a lot of generic driver.a This makes it possible for you to connect devices to the computer without installing a driver first. (i.e. keyboard, mouse, printer). This is also called plug-and-play. The more an operating system uses standardized technologies the bigger the chances are that you will use built-in drivers in order to use a third party device. You just connect your hardware device to the computer and the OS knows what to do with it. Customized driver: if a manufacturer develops a device with special functionality (tablets, PCI capture cards, etc), chances are, they are not supported by any drivers that are pre-installed with the OS. In that case, you have to install a driver for that device onto your computer in order to use the device. These devices are usually on a CD containing the installer application that puts the driver in the right place for the OS to find. (/System/Library/Extensions). Because a driver is just a little software application, it can be updated like any other app. A manufacturer can improve the driver software by eliminating bugs, optimizing it or adding new features without changing anything on the actual hardware device. The user just downloads and installs the new driver, thats it.

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Core Audio
This buzz word pops up everywhere, together with its siblings Core MIDI, Core Data, Core Image and the new Core Animation. Core Audio is always mentioned in the context of Audio Devices and audio in general. It is not a bad idea to try to understand whats behind that word when dealing with Logic or any other audio application on the Mac. So what is Core Audio? That depends on who you ask: "Core Audio is a comprehensive set of services for handling all audio tasks in Mac OS X" "Core Audio is a fairly low-level API for dealing with sound in Apple's Mac OS X operating system" Let me try to explain that in a very simplified way:

Layers

A computer works in Layers. At the lowest level is the actual CPU, the brain of the computer. When you work in Logic, you could get the impression that Logic talks direct to the CPU. Dont we all say: Logic uses so and so much CPU, Logic uses both CPUs, etc? But when you click on something in Logic you are interacting with the GUI (Graphical User Interface) first, which communicates with the next level, maybe the Mac OS, that talks to the Kernel, that talks to the CPU. An operating system can use all kinds of different technologies: graphics, audio, video. The question is at what level in the hierarchy is that technology implemented. Although the Mac OS was always better with audio compared to the Windows OS, audio was still implemented on a higher level of the hierarchy, which means further away from the CPU. That changed dramatically in OS X. Apple implemented Audio (and MIDI) directly in the lower level of the operating system. This architecture is called Core Audio.
Core Audio provides a set of APIs (Application Programming Interface). APIs are basically small little applications that work as the building blocks of a bigger application, i.e. the Operating System itself. The functionality is similar to macros. All the different manufactures of audio applications have to write some code in their app to get the audio signal out of their app through the computer hardware to the external audio device. Apple, however, has written that part of the code already and provides it to all developers as an API that works as an interface between their app and the OS. This has the advantage that the developers dont have to re-invent the wheel over and over again and at the same time provides a common standard the developer and the end user can rely on, in this case Core Audio.

Latency

Latency is the time it takes for the signal to travel: from the audio device (i.e. microphone) to the computer through all the layers from the device driver down to the CPU and back up to the audio application from the audio application down to the CPU and back up to the device driver to the audio device (i.e. speaker)
In OS9 you needed an application (Sound Manager, MIDI Manager, or third party apps) that talked to the OS. So any audio application or the Audio Device had to go through a high level application that then talked to the lower level OS. Going through all those levels used up time. So playing an audio file in Logic didnt sound right away. There was quite a bit of latency, or delay. There were also different kinds of protocols to choose from
<< lower - LEVEL - higher >>

Core MIDI

Apple uses the same principle of low level APIs when it comes to MIDI. In the pre-OSX era and still nowadays in the Windows world, MIDI is happening on a higher Layer and is therefore further away from the CPU. This has the same two major downsides: Latency and Compatibility
The more Layers a signal has to pass through, the more time delay (latency) it will introduce until the data reaches its destination. In OS9, Apple provided the application MIDI Manager that handled MIDI. Due to its limitations, however, most musicians used a different program like OMS or FreeMIDI. But what they all have in common is that they are applications running on top of the OS and are not integrated into the OS like Core MIDI is.

Compatibility

Another disadvantage of a functionality not built into the OS is compatibility. A music application that uses MIDI (Logic, DP, Cubase) or a hardware device (MIDI interface) has to support a specific MIDI architecture. In the worst case, you could end up with a serious incompatibility, having a music app that supports a different MIDI architecture than the MIDI interface.
In the same way as with Core Audio, Apple included the MIDI architecture into the OS and provided a set of APIs called Core MIDI. Now every software or hardware developer who needs MIDI functionality has these advantages: no need to rewrite the MIDI functionality guaranteed compatibility with all other MIDI products on the market that follow the same standard low latency for their products due to the low-level implementation of the API

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Physical Connections
If you want to connect an Audio Device to the Computer, you can use any of the available connections (interfaces) on the Mac: USB - Firewire - PCI - Bluetooth
Audio Devices with a USB connection are usually priced in the low to mid range. There are two flavors with different speed: USB 1 USB 2

Firewire

Audio Devices with a Firewire connection are usually priced in the mid to high range. There are two flavors with different speeds and different connectors: FW 400 FW 800
Audio Devices using a PCI card are common on the PC side. On the Mac, they are used more by high end gear (RME, Digidesign). A main problem with the PCI standard is that there are three different ones: PCI, PCI-X and PCIe. The latest Mac models are using the new PCIe (or PCI Express). They are not compatible with other PCI cards. Buying a new Mac will render your expensive PCI or PCI-X cards useless! PCI cards have a few disadvantages compared to USB or Firewire devices: can't move them around between machines easily limited number of PCI slots limits expandability I/O connections are sometimes cramped on the PCI card

Setup: Routing - Cong

(System)

Audio Device Driver

(Generic) (Built-in)

(DVD Player)

(iMic)

(Speech)

(Fireface)

(iTunes)

(MOTU)

(HD192)

(Logic)

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Audio MIDI Setup (AMS)
The Setup Application for Core Audio in OS X is called Audio MIDI Setup or AMS. It is located in the Utilities folder inside the Application folder: /Applications/Utilities/Audio MIDI Setup The application performs double duty as its name implies. The two tabs on the top of the window lets you switch between: MIDI Devices for Core MIDI settings Audio Devices for Core Audio settings

Routing

Conguration
The AMS interface has 4 identical Device popup menus They contain a list of all available Audio Devices (connected to your Mac and recognized by a valid Device Driver).

Routing:

AMS distinguishes between System and Default: System: these are all the OS X system alert sound, i.e. when you move files into the trash, the smoke sound when you move an item out of the sidebar. You can choose from the popup menu to which Audio Device you want to route those sounds. Default: These are all the audio applications that dont have their own Audio Device selection like iTunes, DVD Player, etc. You can even select a different Audio Device for the Input and Output, i.e. you could select your iSight camera as the Default Input and the Built-in speakers as the Default Output.

Configuration:

The Properties For: popup menu lets you select the Audio Device you want to configure. Selecting one Device from the menu will switch all the settings below to display and edit its properties. The layout of the settings is mostly identical for all Devices, however keep in mind: some controls may be inactive because they are not supported by a selected Device other controls are not available because the Audio Device may have its own control panel for that some settings can be changed (i.e. Sample Rate) but they might switch back because they are controlled by another application As you can see, there might be a lot of exceptions. So the AMS user interface looks very simple and organized and the Drivers might follow the Core Audio specs, the settings for each Audio Device might behaves a little bit different, which could make detailed configurations sometimes difficult.

Input / Output

Audio Input:

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The audio signal is fed into the Audio Device (Mic in or Line in, Digital in). In the case of an analog signal, it passes the Analog-to-Digital Converter (ADC). The ADC has to be set to a specific Format (Sample Rate and Bit Depth) that determines the signals audio quality. This is done in the AMS through the Device Driver. Remember that the Device Driver provides the communication between the Hardware and the Software. The digitized signal is sent as an audio stream from the Audio Device to the Computer via its I/O connection (USB, Firewire, etc). Core Audio takes the audio stream and converts it to a linear PCM 32-bit floating point data stream. All the audio handling/processing inside OS X is done in that format.
Audio Output: When an application sends an audio signal to an output (play iTunes), then the process gets reversed: The 32-bit floating point audio stream is converted to the audio stream Format set in the AMS for the Audio Devices output. The AMS sets the Format (Sample Rate, Bit Depth) on the Audio Device remotely via its Device Driver. Remember that Core Audio handles the audio signal inside the Computer at its highest quality (32-bit floating point). The Format Settings for the audio stream output determines the quality at the output of the Audio Device. Setting the Format (the DAC setting) to 32k/16bit will produce an inferior audio quality coming out of your Audio Device compared to 48k/24bit setting.

Audio Stream Application

Core Audio audio stream digital 32-bit oating point
Audio Device audio stream digital AMS Format
External audio signal analog or digital

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Source
The Source popup menu seems to be only available for the Built-in Audio Device. All other Audio Devices display a grayed out "Default" box
As I mentioned in the earlier paragraph, the Macs Built-in Audio Device is just like any other external Audio device that you hook up to your Mac via USB or Firewire. The available I/O ports vary depending on the Mac model All models have at least the built-in speaker Laptop models have usually a microphone built in Analog Line in and out are standard on all newer models Digital in and out are available on newer Pro models
in Analog Internal microphone
out Internal speaker Headphone
Line in Digital Digital in

Line out Digital out

Because the available I/O ports are different, depending on your Mac model, you will see the Source popup menus below only if the port is available. The output port diagram shows a PowerMac G5.

Output Ports

The checkbox in the Source popup menu is misleading! It just tells you what is selected in the menu and displays the Format values for that port. However the important question is: to which port is the sound routed? That actually depends on what you plug in to what jack. The popup menu displays all (!) the ports the audio is routed to. The content of the popup menu however changes as you can see below:

Logic Pro: Audio menu

(Built-in)

(Built-In)

(iTunes) Device cong audio routing

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The bottom sections of the AMS displays the level controls for the Audio Input and Audio Output. As with the other controls, they will be grayed-out and inactive if the driver doesnt provide that functionality. The six columns are: Channel: lists the available audio channels for the selected Audio Device. M stands for Mono, if there is a mono channel available. Volume Slider: Each channel has its independent slider which makes it possible to change the stereo balance by offsetting the volume of two channels. Value: displays the slider position as a linear number range from 0.00 to 1.00 dB: displays the slider position as a logarithmic decibel value. The value range varies depending on the Audio Device. Mute: this checkbox mutes the audio channel. Moving the volume slider all the way to the left will automatically set the Mute checkbox Thru: This checkbox is only available on the Audio Input section. This enables the Audio Input to be routed directly to the Audio Output.
Note the interesting GUI choice: The slider of output ch1 and ch2 are active but not their Mute checkbox means that you can mute only both channels at the same time
. The Mute button is only active in the M Mono row

. That

There is an additional display feature in the level section: Audio Stream: If the Audio Device provides separate Audio Streams then the Level section will mark the selected Audio Stream with a blue shaded area.

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The Problem: Audio Applications let you normally select only one Audio Device as their audio interface The Solution: Core Audio lets you create virtual Devices called "Aggregate Devices" (since OS X 10.4 Tiger) The Aggregate Device lets you combine any of the available Audio Devices into one virtual Device Selecting an Aggregate Device from an Audio Application lets you access all the channels of all Audio Devices that are included Creating and Editing of the Aggregate Devices is done in the Aggregate Device Editor of the AMS

Interface

The Editor Window has two sections: Aggregate Device List: The upper part displays the list of available Aggregate Devices Structure Table: The lower part displays the Structure of the Aggregate Device, selected in the upper section A divider between the upper and lower sections can be dragged up and down to resize the sections

This popup menu is disabled, because the clock source for the Aggregate Device is selected in the Aggregate Device Editor.

Configure Device

The button Configure Device will only be displayed when an Aggregate Device has been selected from the Properties For popup menu.
Aggregate Device Editor - manage and edit Aggregate Devices The Editor displays the upper section to manage Aggregate Devices (add, remove, rename) and the lower section to edit the selected device.
Configure Device - edit Aggregate Devices The Configure Device Button from the properties window opens a sheet displaying only the lower section of the Editor. It displays the Structure table of the Aggregate Device currently selected from the Property For popup menu.

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This popup menu displays all the available audio streams for the input (under the Audio Input) and output (under the Audio Output). The popup menu is only active when all Audio Devices of the Aggregate Device are set to the same Clock. If not, then the popup menu is grayed out and displays "Master Stream"
Not all Audio Devices provide a label for their audio stream. In that case the audio stream will be listed as a generic label Stream n. Compare the following three Aggregate Device examples with different Audio Interfaces connected to the computer:

A26 + Built-in + iMic

Multiface + Built-in

Fireface + Built-in

Audio Device 1: A26 (1 stream) Generic Label "Stream 1" Audio Device 2: Built-in Audio (1 stream) Generic Label "Stream 2" Audio Device 3: iMic (1 stream) Generic Label "Stream 3" Built-in and iMic are 2ch streams, A26 is a 6ch stream
Audio Device 1: RME Multiface (18 streams) Specific labels: "HDSP (SLOT-2) Output 1-18" Audio Device 2: Built-in Audio Generic Label "Stream 19" A total of 19 Streams. RME audio streams are 1-channel, Built-in Audio is a 2-channel audio stream Audio Device 1: RME Fireface (28 streams) Specific labels: "Analog, SPDIF, ADAT" Audio Device 2: Built-in Audio (1 stream) Generic Label "Stream 29" A total of 29 Streams. RME audio streams are 1-channel, Built-in audio is a 2-channel audio stream
It is interesting that the newer the Audio Device is, the more precise the labeling of the audio stream gets. So the newer drivers are better written. This is good, because these labels can also be accessed from the Audio Applications when setting up channel routing. Having a list with the labels "Analog 3", "ADAT 8" makes live easier than a list labeled output 1-18.
This popup menu seems not available for Aggregate Devices

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This displays the Sample Rate of the selected audio stream. Sounds simple, but it gets really tricky when you try to understand which settings affect what. One thing to keep in mind is that you can set the Sample Rate (SR) for each Audio Device individually and you can set a separate SR for an Aggregate Device that just combines the existing Audio Devices. So which SR setting has priority? When you create an Aggregate Device, you have to set all the Audio Devices, included in that Aggregate Device (sub-devices), to the same SR. Any Audio Device that is not set to the same SR of the Audio Device that has the "Clock" radio button selected (Master Clock) will not be available. It will not be listed in the Audio Stream popup menu and its channels will not be displayed below as Volume sliders After all streams are properly displayed in the Aggregate Device, you can change the SR. This switches the SR of all the included Audio Devices to that SR. Please note that only those Sample Rates are available in the popup list that are supported by all individual Audio Devices of the Aggregate Device. (lowest common denominator) You still can go ahead and switch to the Property view of an individual Audio Device and change its SR. This will make it unavailable to the Aggregate Device. But going back to the Property view of the Aggregate Device and selecting any SR will switch all individual Audio Devices to that SR and therefore correct the previous step. It will bring "everybody back in line". All sub-devices that make up the Aggregate Device must be running at the same Sample Rate But it gets even more complicated when you have an Audio Application running that talks to the Device Driver directly (Logic, Live, etc). Just remember, there are two basic kinds of Audio Applications. Audio Applications that dont communicate directly with the Audio Device regarding the audio signal routing and format settings: Applications like iTunes and DVD Player rely on the AMS for configuring the audio signal routing and format setting Audio Applications that communicate directly with the Audio Device regarding the audio signal routing and format settings: Applications like Logic and Live can set the audio signal routing and format setting direct from within the application without needing the AMS. In detail however, each Audio Application that can "talk" directly to the Device Driver behaves differently, depending on how the application is written. I.e. if you select an Audio Device in Logic, then only Logic can control the SR. Trying to change the SR in the AMS will switch back to the Logic setting. That "tight grip" however doesn't apply to Aggregate Devices. It seems that Logic is not really up to date in that area, because when you try to change the SR in the AMS then Logic get stuck in the "spinning beach ball of eternity" (v7.2.2)

read only Sample Rate

Device Driver Built-in Audio

Channel - Bit Depth

This displays how many channels are in the selected audio stream and at what bit depth they are encoded. Please note that the bit depth is the one that the Audio Device uses to encode and decode the audio signal. Core Audio converts any digital audio signal internally to a linear PCM 32-bit floating point audio stream. Unlike the SR, the bit depth can be set differently for each Audio Device in an Aggregate Device
Core Audio 32-bit oating point

ADC DAC

Bit Depth

Channels

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The total number of available input and output channels is the combined number of all input and output channels of all the Audio Devices used for that particular Aggregate Device. The channels are just numbered and there are only two ways to find out which channel number belongs to which (Hardware) Audio Device: Open the Aggregate Device Editor and in the Structure table look at the order of the used Audio Devices and the number of the available channels. This way you can count through and see what channel 'n' on the Aggregate Device relates to what channel 'n' on the individual Audio Device. The audio stream popup menu will list the individual streams for each Audio Device. But be careful how you interpret the list. Remember, not all Audio Devices provide a label for their stream. Sometimes they have just a generic label Stream n A listed audio stream can embed one or more audio channels. The audio stream for the Built-in Audio Device is a stereo channel The best way to "de-code" the numbers is by selecting an audio stream from the popup menu. All the audio channels belonging to that stream will then be highlighted in blue so you can see its corresponding channel number
Stream 1: Stream 2: Stream 3:

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Multiple options are sometimes good but sometimes they can add to the confusion. That is the case when dealing with audio in OS X. You can set controls in different locations but having the same controls labeled differently could add even more to the confusion. The two applications I want to compare are the Sound System Preferences and the Audio Midi Setup.
Sound Preference has three tabs with the controls for Input Output Sound Effects displays all its audio
In the AMS, the left tab Audio Devices controls Sound Preferences window elements: Table to select an item: Device or Sound Settings for the selected item above
The Output Volume slider is visible in all three window tabs (Sound Effects, Output, Input). This is the Volume control for the Audio Device, selected as the Default Output.

Choose a device for sound output Name Line Out Digital Out Emagic A26 Aggregate Device 1 Port Built-In Audio Optical digital-out port USB Emagic A26 Aggregate Device 1 Default Output (popup menu) Built-in Audio
Source (popup menu) Line Out Digital Out
Parallel outputs: Please note that if you select the Built-in Audio Device , the sound will be available on the Line out and Digital out at the same time. The AMS Source popup menu with its checkbox corresponds to the selection in the Sound Preference but both are misleading. The list implies that you select either Line out or Digital out, where in reality the sound is routed parallel to both (the same is true if the headphones or speaker is available instead of the Line out).
The output level slider is the one on the bottom that is visible in all window tabs of the Sound Preference window. It is only one slider that controls the main channels of the selected Audio Device. There is one specialty about the output level for the Default Output. It can be controlled in up to four different places: AMS Volume Slider Sound Preference "Output Volume" Volume keys on the Mac Keyboard Volume slider in the menu bar (if selected in the Sound Preference)

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System Output (Sound Effects)
The Sound Effects that the OS X system uses for alert sounds ("delete item", "remove item from Dock", "wrong entry") can be routed to its own Audio Device, independent from the Default Output:
It looks really confusing if you compare the popup menu in the Sound Preference and the AMS application for that routing:
Header: Sound Effects (Play alert sound effects through: ) Selected sound output device
Header: System Output This is the routing for the sound effects that the system uses for alert sounds. I just used all 3 different names that the Sound Preference and AMS application uses to describe the same thing: Sound Effect, Alert Sound, System Output The Sound Preference has the option "Selected sound output device". That means, whatever device is selected in the "Default Output" is used also for the System Output. This is actually a nice option, if you switch your Default Output and always want the System Output to follow. However you can't see if that option is selected by just looking at the AMS setting. Another inconsistency: The AMS lets you select only the Built-in Audio Device without any specification of the actual Source (Line Out, Digital out, etc). It is not clear that the System sounds cant be routed to the digital output Any other external Audio Devices are listed the same in the Sound Preference and AMS popup menu The System Output doesn't allow the routing to any Aggregate Device

Cubase

Path Devices/Device Setup

Protocol VST Multitrack

Remarks could it be that Cubase is using its ASIO drivers under OSX and not Core Audio ?

ASIO Driver

Ableton Live

Path Preferences/Audio

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Protocol Driver Type Core Audio

Input Input Audio Device

Output Output Audio Device
Remarks Live uses a clean GUI with the most correct terminology

Reason

Protocol -

Input Audio Card

Remarks

GarageBand

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Input Audio Input

Output Audio Output

Melodyne

Path Preferences/Hardware
Protocol CoreAudio included in the Device driver menu

Output Device Driver

Absynth (application)
Path Setup/Audio/Soundcard

Protocol Interface

Input -

Output Output Device

Audio Hijack

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Path (Main Window)/Input
Protocol Source Type: Audio Device

Input Input Device

Remarks For the Built-in Audio Device, both sources are listed: Line and Digital

Path Preferences/Video

Input Microphone

Output Sound Output

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Overview

Here are all the applications listed again in one table overview: Path Logic Cubase Live Reason GarageBand Melodyne Absynth Audio Hijack Preferences/Audio/Drivers Devices/Device Setup Preferences/Audio Preferences/Audio Preferences/Audio Preferences/Hardware Setup/Audio/Soundcard (Main Window)/Input Protocol Drivers: Core Audio VST Multitrack Driver Type: Core Audio (CoreAudio included in the Device driver menu) Interface Source Type: Audio Device Input Device Input Driver ASIO Driver Input Audio Device Output Audio Device ASIO protocol ? Output Remarks
Audio Card Audio Input Audio Output
Device Driver Output Device Output Device For the Built-in Audio Device, both sources are listed: Line and Digital For the Built-in Audio Device, both sources are listed: Line and Digital For the Built-in Audio Device, both sources are listed: Line and Digital

Preferences/Video

Microphone

Sound Output

Preferences/Audio

Audio Input

In Logic, the Sample Rate selection is listed under the main Audio menu. That is not too hard to find and most Logic users are used to it. But once you set it, you are not likely to change it. So why not put it into the "Song Settings/Audio" window? There is plenty of space. Logic provides a nice distinction between: * Global Settings (Logic Pro/Preferences): stored in the Preference files and affects all songs * Song Settings (Edit/Song Settings): stored in the song file itself and affects only the current song
Global Settings (Preferences)

Song Settings

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Display I/O channels The "Audio Configuration window displays all the Audio Components available to Logic, based on the settings made in Logics Audio Preference window. The "I/O Labels" window, selected from the view menu , displays only the I/O channels and their labels. Logic provides four different labels for the four columns: CoreAudio just numbers the channels Drivers I/O Label" should read the labels from the Device Driver, but it seems that Logic is not capable of that. It displays a dotted line and you have to look up your device to find that out, i.e. "channel 19" is actually "ADAT 5". The Fireface driver, for example, uses proper descriptions of its channels (SPDIF, Analog, ADAT), because the Audio MIDI Setup is able to read those labels and display them. Long I/O Label and Short I/O Label lets you enter your own Labels that Logic can use in various places such as the Mixer or Environment window. Routing I/O channels I/O channels can only be accessed by audio objects, which have to be created in the Environment (unless the Setup Assistant has done it for you) Think of I/O channels as like audio busses on a mixing board (not to be confused with the bus object).
Example: Any audio signal fed into channel 3 on your Audio Device ("guitar") will be available on that virtual input bus 3. Selecting input channel 3 on a Track Object will route that audio signal from "Audio Device: input 3 (guitar) -> Core Audio: channel 3 -> Logic: virtual input bus 3 -> Logic: Track Object, ready to record "guitar". The same thing works for the output signal: all available output channels from the Audio Device are represented by virtual output busses. Any signal routed from an audio object to an output channel, will be sent through that virtual output bus to the actual output on your Audio Device Logic: Track Object to output 1/2 -> Logic: virtual output bus 1/2 -> Core Audio: channel 1/2 -> Audio Device: output 1/2 (connect to speakers)