Introduction

Audio codec is a small chip measuring ¼ sq. in. (7 mm2) located on the motherboard in charge of the analog audio functions. Knowing the specs of a codec will allow you to compare the audio quality of different motherboards, allowing you to choose the right product for you.

For further details on audio codecs including an explanation of the specs we are publishing, please read our tutorial How On-Board Audio Works.

We will separate the codecs according to the manufacturer.

Analog Devices (ADI/SoundMax)

Analog Devices are also known as ADI or SoundMax and their codecs use names starting with “AD”. On Figure 1 you can see an example of an Analog Devices codec.

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Figure 1: Analog Devices AD1988B codec.

Model	Channels	Input Resolution	Output Resolution	Input Max. Sampling Rate	Output Max. Sampling Rate	Input SNR	Output SNR
AD1819B	2	16-bit	16-bit	48 KHz	48 KHz	87 dB	90 dB
AD1881A	2	16-bit	16-bit	48 KHz	48 KHz	87 dB	90 dB
AD1882	5.1	24-bit	24-bit	96 KHz	96 KHz	90 dB	95 dB
AD1884	4	24-bit	24-bit	192 KHz	192 KHz	85 dB	90 dB
AD1885	2	16-bit	16-bit	48 KHz	48 KHz	87 dB	90 dB
AD1886A	2	16-bit	16-bit	48 KHz	48 KHz	87 dB	90 dB
AD1887	2	16-bit	16-bit	48 KHz	48 KHz	87 dB	90 dB
AD1888	5.1	16-bit	20-bit	96 KHz	96 KHz	80 dB	90 dB
AD1980	5.1	16-bit	20-bit	96 KHz	96 KHz	82 dB	90 dB
AD1981A	2	16-bit	20-bit	48 KHz	48 KHz	85 dB	90 dB
AD1981B	2	16-bit	20-bit	48 KHz	48 KHz	85 dB	90 dB
AD1981BL	2	16-bit	20-bit	48 KHz	48 KHz	83 dB	90 dB
AD1981BW	2	16-bit	20-bit	48 KHz	48 KHz	85 dB	90 dB
AD1981HD	2	20-bit	24-bit	48 KHz	48 KHz	85 dB	80 to 85 dB
AD1983	2	20-bit	24-bit	48 KHz	48 KHz	85 dB	80 to 85 dB
AD1984	4	24-bit	24-bit	192 KHz	192 KHz	90 dB	96 dB
AD1985	5.1	20-bit	20-bit	96 KHz	96 KHz	85 dB	80 to 90 dB
AD1986	5.1	20-bit	20-bit	96 KHz	96 KHz	85 dB	80 to 90 dB
AD1986A	5.1	20-bit	20-bit	96 KHz	96 KHz	85 dB	80 to 90 dB
AD1987	7.1	24-bit	24-bit	96 KHz	192 KHz	90 dB	95 dB
AD1988A	7.1	24-bit	24-bit	192 KHz	192 KHz	90 dB	95 dB
AD1988B	7.1	24-bit	24-bit	192 KHz	192 KHz	92 dB	101 dB

Realtek (RTC, Avance Logic)

Realtek is probably today the most popular audio codec manufacturer. Old codecs from Realtek can be found marked as “Avance Logic” and both old and new codecs use model names starting with “ALC”. On Figure 2 you can see an example of a Realtek codec.

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Figure 2: Realtek ALC888S codec.

C-Media (CMI)

C-Media used to be very popular especially on low-end motherboards and they manufactured both codecs and complete audio controllers. Audio controllers usually need an external codec to do the analog-to-digital and digital-to-analog conversions, but C-Media’s low-end audio controllers have a codec embedded inside the chip and that is why we will include them on the table below. Because of that we included a column called “type” to let you known if the chip is just a codec requiring an external controller (e.g. connected the south bridge chip) or if it is a complete controller with an embedded codec (usually connected to the PCI bus). Chips from C-Media use names starting with the letters “CMI”, as you can see on the example shown on Figure 3.

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Figure 3: C-Media CMI9739A codec.

VIA

VIA manufactures both codecs and complete audio controllers. Their controllers (Envy24 series and Tremor) require an external codec and usually the motherboard manufacturer that choose to use a VIA external controller also pick a VIA codec. Since VIA audio controllers got some popularity in the past, we are including their main specs on a separated table. VIA use names starting with “VT” for their codecs.

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Figure 4: VIA Envy24PT controller (on the right) using a VIA VT1618 codec (on the left).

 

Other Manufacturers

There are some other audio codec manufacturers, but codecs from them are rarely seen on motherboards. A good example is Cirrus Logic, a company that manufactures very high-end codecs used mainly by home theater receivers. One of their codecs, CS4382, was used on a few very high-end motherboards from MSI (K8N Diamond Plus and K9N Diamond Plus, for example), providing a state-of-the-art audio quality for these products (signal-to-noise ratio of 114 dB, for example). In the past they also provided low-end audio codecs and controllers using the brand “Crystal”. Cirrus Logic and Crystal products start with the letters “CS” and you can see their current list of codecs by clicking here.

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Figure 5: Cirrus Logic CS4382 codec and Creative Labs controller on a MSI K9N Diamond Plus motherboard.

Another popular controller/codec manufacturer from the past was ESS, which had chips starting with the letters “ES”.

Originally at http://www.hardwaresecrets.com/article/520

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