Other hardware: Difference between revisions
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*[http://www.hydrogenaudio.org/forums/index.php?showtopic=32634 forums] | *[http://www.hydrogenaudio.org/forums/index.php?showtopic=32634 forums] | ||
*[http://en.wikipedia.org/wiki/A2DP#Bluetooth_profiles wikipedia] | *[http://en.wikipedia.org/wiki/A2DP#Bluetooth_profiles wikipedia] | ||
* [https://habr.com/en/articles/456182/ HABR] | |||
Standard baseline codecs: | |||
* Sub Band Codec (SBC) – not great | |||
* LC3 – the new baseline of Bleutooth 5.1. About Opus level, allegedly | |||
Standard optional codecs: | |||
* MPEG-1,2 Audio: = MP3, almost never used | |||
* AAC: relatively good support, transparency possible at bluetooth bitrates, but latency can be an issue | |||
* ATRAC: never used | |||
Vendor extension codecs: | |||
* AptX, LDAC, LLDC: in general lower complexity but higher bitrate (still within BT limits) than AAC, transparency possible; AptX and LDAC has wide support | |||
Bitrate is limited by bluetooth link | |||
=== Sub Band Codec === | === Sub Band Codec === | ||
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* Channel Mode - mono, dual channel, stereo, joint stereo | * Channel Mode - mono, dual channel, stereo, joint stereo | ||
The bitrate used for CD quality audio is 229 kbps and 328 kbps for middle and high quality, respectively. | The bitrate used for CD-quality () audio is 229 kbps and 328 kbps for middle and high quality, respectively. | ||
Reference: [https://www.bluetooth.org/foundry/adopters/document/A2DP_Spec_V1_0/en/ BLUETOOTH Advanced Audio Distribution Profile 1.0] | Reference: [https://www.bluetooth.org/foundry/adopters/document/A2DP_Spec_V1_0/en/ BLUETOOTH Advanced Audio Distribution Profile 1.0] | ||
Revision as of 10:34, 6 July 2023
This article is a stub. You can help the Hydrogenaudio Knowledgebase by expanding it.
Bluetooth (A2DP)
Advanced Audio Distribution Profile (A2DP)
Standard baseline codecs:
- Sub Band Codec (SBC) – not great
- LC3 – the new baseline of Bleutooth 5.1. About Opus level, allegedly
Standard optional codecs:
- MPEG-1,2 Audio: = MP3, almost never used
- AAC: relatively good support, transparency possible at bluetooth bitrates, but latency can be an issue
- ATRAC: never used
Vendor extension codecs:
- AptX, LDAC, LLDC: in general lower complexity but higher bitrate (still within BT limits) than AAC, transparency possible; AptX and LDAC has wide support
Bitrate is limited by bluetooth link
Sub Band Codec
- Sampling Frequency - 16000, 32000, 44100, 48000 (some are optional, see references)
- Channel Mode - mono, dual channel, stereo, joint stereo
The bitrate used for CD-quality () audio is 229 kbps and 328 kbps for middle and high quality, respectively.
Reference: BLUETOOTH Advanced Audio Distribution Profile 1.0
Headphones
Some Styles (smallest to largest)
- In the ear - outputs directly into the ear canal
- Earbuds - sits in the outer ear
- Supra-aural - sits on the ear
- circumaural - completely cover the ear
Terminology used for comparing headphones
- Noise Cancelling
- active
- passive
- Frequency response - The range of frequencies the headphones can reproduce
- Impedance - Doesn't mean much by itself, but in general, impedence should be matched across a system.
- SPL@1kHz, 1V rms - Sound Pressure Level. How efficient the unit converts electrical energy to sound energy.
- Neodymium - The magnet of choice for high end headphones.
Popular Headphones
- Sub $30
- Sub $100
- $100 - $300
- $300+