Hydrogenaudio Knowledgebase - User contributions [en]

ALSA

2010-09-21T15:28:00Z

Pieyohph: edits to: ALSA over OSS

=Introduction=
'''ALSA''' or '''Advanced Linux Sound Architecture''' is a project, which seeks to provide MIDI functionality to the Linux operating system. ALSA has the following significant features.
==Features==
* Effcient support for all soundcards from consumer to professional multichannel audio devices
* Fully modularized sound drivers
* SMP and thread-safe design
* ''alsa-lib'' in order to simplify the high level API
* Support for the older OSS API.
==ALSA over OSS==
There are many advantages ALSA has over the older (but perhaps not the newer) OSS API:

* multi-thread safe design
* transparent use of plugin architecture to handle format,rate,channel cnt and many other conversions
* support for non-interleaved interfaces
* user-space software mixing ''(dmix)''
* user-space "loopback/snoop" capabilities
* merging multiple cards into a single virtual device
* hiding non-ALSA-drivers behind a consistent user-space API (e.g. IEEE1394 drivers, or JACK)
* consistent and generic control API for managing hardware controls
* Flexible mixer architecture to handle modern audio interfaces fully (rather than reducing them to a simplistic device)
* consistent support for multiple instances of the same card
* linked operations of multiple cards

=Development API=
==Tutorials==
==ALSA Library API==
==ALSA Documentation==
==External links==
* [http://alsa.opensrc.org/ ALSA wiki] a large wiki pertaining to major ALSA related topics.

[[Category:Software]]

Microphone

2009-09-24T10:30:12Z

Pieyohph:

= Microphones for Computers =
This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

== Computer inputs ==
Analog inputs and outputs on computers use '''T'''ip, '''R'''ing, and '''S'''leeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

=== Microphone input ===
A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

=== Line input ===
Connects to ADC. The connector socket is marked with light blue.

== Converting audio to electrical signals ==
Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

=== Dynamic ===
do not need power.

=== Condenser ===
Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

* battery
* the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

== Connection or wiring schemes and electrical characteristics ==
There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

=== Low impedance ===
Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

=== High impedance ===
Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

=== Mixing Impedances ===
[[#teg|A low-to-high impedance transformer]] is the proper way to make the connection between low and high impedance devices. You will also need a ¼ inch to 1/8 inch adapter.

== Connection combination schemes in order of decreasing audio fidelity. ==
Dynamic or condenser with battery low impedance microphone to mixer to line in. A microphone can connect to line input after being processed by a preamplifier or a mixer which contains a preamplifier. Mixers are only a little more expensive than preamplifiers and provide phantom power.

Low impedance microphone not needing phantom power to transformer to line in.

High impedance microphone to microphone in.

== unix, including GNU, based OSes ==
There are 2 sound driver systems for Linux: [http://www.alsa-project.org/ ALSA] and [http://opensound.com/ OSS]. Some microphones with USB output function with ALSA. [http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux#USB-microphone_in_ALSA (Evidence)] IEEE 1394 (a.k.a. Firewire, iLink) is not supported. No sound device providing XLR is supported.

== Notes and references ==
=== External ===
A low-to-high impedance transformer [http://www.zzounds.com/item--AUTCP8201 example].

[[Category:Hardware]]

Microphone

2009-09-05T08:26:53Z

Pieyohph:

= Microphones for Computers =
This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

== Computer inputs ==
Analog inputs and outputs on computers use '''T'''ip, '''R'''ing, and '''S'''leeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

=== Microphone input ===
A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

=== Line input ===
Connects to ADC. The connector socket is marked with light blue.

== Converting audio to electrical signals ==
Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

=== Dynamic ===
do not need power.

=== Condenser ===
Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

* battery
* the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

== Connection or wiring schemes and electrical characteristics ==
There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

=== Low impedance ===
Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

=== High impedance ===
Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

=== Mixing Impedances ===
[[#teg|A low-to-high impedance transformer]] is the proper way to make the connection between low and high impedance devices. You will also need a ¼ inch to 1/8 inch adapter.

== Connection combination schemes in order of decreasing audio fidelity. ==
Dynamic or condenser with battery low impedance microphone to mixer to line in. A microphone can connect to line input after being processed by a preamplifier or a mixer which contains a preamplifier. Mixers are only a little more expensive than preamplifiers and provide phantom power.

Low impedance microphone not needing phantom power to transformer to line in.

High impedance microphone to microphone in.

== GNU ==
There are 2 sound driver systems for Linux: [http://www.alsa-project.org/ ALSA] and [http://opensound.com/ OSS]. Some microphones with USB output function with ALSA. [http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux#USB-microphone_in_ALSA (Evidence)] IEEE 1394 (a.k.a. Firewire, iLink) is not supported. No sound device providing XLR is supported.

== Notes and references ==
=== External ===
A low-to-high impedance transformer [http://www.zzounds.com/item--AUTCP8201 example].

Microphone

2009-09-05T08:25:32Z

Pieyohph:

= Microphones for Computers =
This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

== Computer inputs ==
Analog inputs and outputs on computers use '''T'''ip, '''R'''ing, and '''S'''leeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

=== Microphone input ===
A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

=== Line input ===
Connects to ADC. The connector socket is marked with light blue.

== Converting audio to electrical signals ==
Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

=== Dynamic ===
do not need power.

=== Condenser ===
Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

* battery
* the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

== Connection or wiring schemes and electrical characteristics ==
There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

=== Low impedance ===
Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

=== High impedance ===
Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

=== Mixing Impedances ===
[[#transformer|A low-to-high impedance transformer]] is the proper way to make the connection between low and high impedance devices. You will also need a ¼ inch to 1/8 inch adapter.

== Connection combination schemes in order of decreasing audio fidelity. ==
Dynamic or condenser with battery low impedance microphone to mixer to line in. A microphone can connect to line input after being processed by a preamplifier or a mixer which contains a preamplifier. Mixers are only a little more expensive than preamplifiers and provide phantom power.

Low impedance microphone not needing phantom power to transformer to line in.

High impedance microphone to microphone in.

== GNU ==
There are 2 sound driver systems for Linux: [http://www.alsa-project.org/ ALSA] and [http://opensound.com/ OSS]. Some microphones with USB output function with ALSA. [http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux#USB-microphone_in_ALSA (Evidence)] IEEE 1394 (a.k.a. Firewire, iLink) is not supported. No sound device providing XLR is supported.

== Notes and references ==
=== External ===
A low-to-high impedance transformer [http://www.zzounds.com/item--AUTCP8201 example].

Microphone

2009-09-05T08:07:30Z

Pieyohph:

= Microphones for Computers =
This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

== Computer inputs ==
Analog inputs and outputs on computers use '''T'''ip, '''R'''ing, and '''S'''leeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

=== Microphone input ===
A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

=== Line input ===
Connects to ADC. The connector socket is marked with light blue.

== Converting audio to electrical signals ==
Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

=== Dynamic ===
do not need power.

=== Condenser ===
Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

* battery
* the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

== Connection or wiring schemes and electrical characteristics ==
There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

=== Low impedance ===
Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

=== High impedance ===
Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

=== Mixing Impedances ===
<ref A low-to-high impedance transformer is the proper way to make the connection between low and high impedance devices. You will also need a ¼ inch to 1/8 inch adapter.

== Connection combination schemes in order of decreasing audio fidelity. ==
Dynamic or condenser with battery low impedance microphone to mixer to line in. A microphone can connect to line input after being processed by a preamplifier or a mixer which contains a preamplifier. Mixers are only a little more expensive than preamplifiers and provide phantom power.

Low impedance microphone not needing phantom power to transformer to line in.

High impedance microphone to microphone in.

== GNU ==
There are 2 sound driver systems for Linux: [http://www.alsa-project.org/ ALSA] and [http://opensound.com/ OSS]. Some microphones with USB output function with ALSA. [http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux#USB-microphone_in_ALSA (Evidence)] IEEE 1394 (a.k.a. Firewire, iLink) is not supported. No sound device providing XLR is supported.

== Notes and references ==
=== External ===
<ref name="teg">A low-to-high</ref> impedance transformer [http://www.zzounds.com/item--AUTCP8201 example].

Microphone

2009-09-01T08:32:10Z

Pieyohph: New page: = Microphones for Computers = This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work ...

= Microphones for Computers =
This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

== Computer inputs ==
Analog inputs and outputs on computers use '''T'''ip, '''R'''ing, and '''S'''leeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

=== Microphone input ===
A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

=== Line input ===
Connects to ADC. The connector socket is marked with light blue.

== Converting audio to electrical signals ==
Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

=== Dynamic ===
do not need power.

=== Condenser ===
Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

* battery
* the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

== Connection or wiring schemes and electrical characteristics ==
There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

=== Low impedance ===
Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

=== High impedance ===
Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

=== Mixing Impedances ===
A low-to-high impedance [http://www.zzounds.com/item--AUTCP8201 transformer] is the proper way to make the connection between low and high impedance devices. You will also need a ¼ inch to 1/8 inch adapter.

== Connection combination schemes in order of decreasing audio fidelity. ==
Dynamic or condenser with battery low impedance microphone to mixer to line in. A microphone can connect to line input after being processed by a preamplifier or a mixer which contains a preamplifier. Mixers are only a little more expensive than preamplifiers and provide phantom power.

Low impedance microphone not needing phantom power to transformer to line in.

High impedance microphone to microphone in.

== GNU ==
There are 2 sound driver systems for Linux: [http://www.alsa-project.org/ ALSA] and [http://opensound.com/ OSS]. Some microphones with USB output function with ALSA. [http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux#USB-microphone_in_ALSA (Evidence)] IEEE 1394 (a.k.a. Firewire, iLink) is not supported. No sound device providing XLR is supported.

[[Category:Hardware]]