FM Synthesis Chips, Codecs and DACs
This article is my attempt to provide some detail around the various primary chips used on PC sound cards, including FM synthesis chips and their associated codecs and DACs
There is a lot more to a sound card that can affect audio quality than just these three, but as the core components, they certainly set the baseline for a sound card's capabilities. There are about 120 different ICs mentioned, including drivers and datasheets where I have managed to find them. In some cases, I have also included the original press release.
For a summary of links to specific chips, here's a table of everything on this page:
Yamaha
YM3812 (OPL2)
YMF262, YMF289 (OPL3)
YAC512
YAC513, YAC516
YMF701, YMF711, YMF715, YMF716, YMF718, YMF719 (OPL3-SA)
YMF720, YMF724 YMF278, YMF704 (OPL4) YMF740, YMF744, YMF754
ESS
ES488
ES688
ES938
ES968
ES1488
ES1688
ES1698
ES1788
ES1868
ES1869
ES1878
ES1879
ES1888
ES1898
ES1938 Solo-1
ES1946 Solo-1E
ES1948 Maestro-1, ES1968 Maestro-2, ES1978 Maestro-2E
ES1980 Maestro-3, ES1983
ES1988 Allegro
ES1989 Allegro/ES1930
ES1970 / Canyon3D
ES1992 Canyon3D-2 / ES1990
|
Crystal
CS4215
CS4216-KL, CS4216-KQ
CS4248
CS4231-KL, CS4231A-KL
CS4232
CS4218-KL
CS4236, CS4236B
CS4237
CS4238
CS4235, CS4239
CS4280, CS4281
CS4297
CS4610, CS4611
CS4614
CS4622, CS4624
CS9233, CS9236
CX4235
Analog Devices
AD1815 / AD1815 SoundComm
AD1816
AD1819B, AD1881A, AD1885, AD1886A, AD1887, Ad1981A, AD1981B, AD1981BL, AD1981BW
AD1845
AD1846
AD1848
AD1882
AD18max, AD18max10, SoundPort AD1981HD, AD1983
AD1984
AD1985, AD1986, AD1986A
AD1987, 1988A, 1988B
|
OPTi
82C924
82C928
82C929 (MAD16 Pro)
82C930
82C931
82C933
82C941
Realtek / ALC / Avance Logic
ALC101, ALC202, ALC203, ALC250, ALC260
ALC262, ALC268, ALC269
ALC650, ALC655, ALC658, ALC662 ALC850, ALC861, ALC880
Illegitimate Clones
Embedded Chips, e.g. C-Media, Realtek
|
FM Synthesis Chips
The FM synthesizer determines the number of independent "voices" that can be output at the same time, as well as the sounds that are played, their duration and effects (attack, sustain, decay, etc). FM synthesizers modulate a waveform to produce a different pitch and timbre (the distinctive sound that makes it different, like the fact a piano sounds different to a guitar). Inside an FM synthesizer are typically a number of "operators". An operator is a group of components that interact with each other to make up a single building block of the FM synthesis setup. Each operator has an input, oscillator, amplifier, and an output. The operator's input sound can be manipulated by feeding in a MIDI input into the oscillator and an envelope generator can be fed into the amplifier portion of the operator to change the timbre that will be output.
In a 2-operator chip, the waveform input coming in is taken through two groups of these (Operator 1 and Operator 2), where the output of the first operator is fed in as the input to the second. This allows the final outgoing waveform to be manipulated twice, further changing what it sounds like. A 4-operator setup has four groups of these (Operator 1, Operator 2, Operator 3 and Operator 4), so the final outgoing waveform (the "voice") is manipulated with up to four different MIDI inputs and envelope generators. You can imagine therefore that a 4-operator FM synth chip can produce a more variable number of unique sounds over a 2-operator chip.
In a typical sound card scenario, the synthesizer chip has a certain number of voices, each of which would have 2 operators or 4 operators. In a stereo scenario the number of available voices is often thought of as being halved (split into left channel and right channel), where each set of two is usually programmed to output the same timbre. This does not change the fact that each voice has its own set of operators, so in theory the left side of the sound can be made to sound completely different from the right.
Audio Codecs
The job of the audio codec ("COder-DECoder") is to encode and decode a digital stream of data or signal, working in conjunction with the DAC (see further down this page). Codecs will often have more than one input line, and sometimes up to 6 stereo inputs (12 lines in total), coming from a microphone, line-in, and so on.
Usually a codec will perform a number of tasks, including conversion of the inbound analog signal to a digital stream of data, filtering it, mixing it with other inputs coming into the codec, then converting it back into an analogue audio signal to be output.
This page has some information on the more common codec chips found on PC sound cards.
DACs
DACs (Digital- to Analog- Converters) are used in almost all sound cards, since the FM synthesizer chip outputs its audio in digital form. The DAC converts these digital I/O signals into analog signals ready for your sound card to mix it or send it straight out to your loudspeakers.
In early FM synthesizer setups during the DOS era, Yamaha's YAC-512 (or a clone of it) was the most common DAC used. From around 1996 when Windows Sound System v1.0 arrived, sound cards tended to use the Analog Devices AD1848 DAC. The later Windows Sound System 2.0 used Crystal CS4231.
Yamaha
 Yamaha YM3812 (OPL2) 
Released: 1985
Type: FM Synthesizer
Voices: 9 or 11
Operators: 2 per voice
Channels: 1 (mono)
Yamaha created the YM3812 in 1985, a mono FM synthesis chip.
This is also known as "OPL2" as it was an incremental upgrade to the earlier Yamaha YM3526. It is pin-compatible with its forebear and uses the same serial DAC (digital-to-analog converter), but adds three additional waveforms.
The YM3812 found widespread use because it was the chip used on the very popular Ad Lib sound card and since the Ad Lib became the de facto backward-compatible standard for PC audio for many years, the OPL2 chip enjoyed a life beyond its natural years. Due to its huge popularity, it was illegally cloned by other chip manufacturers.
The YM3812 has 18 operators that are used as nine two-operator channels, or if rhythm mode is enabled you only get six two-operator channels (voices) and five channels (voices) for rhythm, making 11 channels (voices) in all.
OPL2 stands for "FM Operator Type L2". The "OPL2" as it was called, was later used on the first Sound Blaster card by Creative Labs, and two OPL2s were used on the early Sound Blaster Pro for stereophonic sound where it had up to 22 channels in total, divided between the left chip and right chip, so 11 channels on the left and 11 channels on the right.
Click here for the YM3812 datasheet.
The YM3812 was also used on the following sound cards:
|
 Yamaha YMF262, YMF289 (OPL3) 
Released: 1988
Type: FM Synthesizer
Voices: 18 or 22
Operators: 2 per voice
Channels: 1 (mono), 2 (stereo) or 4
Released in 1988, the YMF262 is also known as "OPL3". An extended version of the original OPL2 chip (the YM3812), it basically had the capabilities of two YM3812 chips in one. It was designed as a replacement for the twin-OPL2 arrangement fitted to the earlier Creative Sound Blaster Pro cards.
YMF262 added an extra register base to provide a total of 18 two-operator channels. The first cards to use YMF262 were the Sound Blaster Pro 2 and Ad Lib Gold.
It was mostly sold in a 24-pin SOP package (see pic above) and provides an 8-bit parallel interface to the registers, requires a stable clock source of 14.318 MHz and one or two separate DACs. The YMF262 is capable of four-channel output (front left, front right, rear left, and rear right, for example) using two of the YAC512 stereo signal DACs designed to accompany it, but most applications feature only two channels (left and right), so just one YAC512 is implemented on such cards.
The YMF289 is a low-power version of the YMF262, so is also "OPL3". Used in laptops and PCMCIA sound cards, it was also used in some Sound Blaster 16 cards. It was often paired with the YAC513 or YAC516 floating-point DAC (Digital-to-Analog Converter) chip.
Click here for the YMF262 and YMF289B datasheets. |
 Yamaha YMF701, YMF711, YMF715, YMF716, YMF718, YMF719 (OPL3-SA)   
Released: 1994
Type: FM Synthesizer
Voices: 18 or 22
Operators: 4 per voice
Channels: 1, 2 or 4
This is a later "OPL3" chip designed and made by Yamaha, called OPL3-SA, SA2 or SA3 (the model family is sometimes referred to as "OPL3-SAx"). The SA, SA2 or SA3 refers to the generation of OPL3-SA chip, as these evolved over time, adding further functions on top of the previous generation. Within all of them though is a real embedded OPL3, which provides the card with a core of Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System and MPU-401 (UART) compatibility.
Th core FM capability of the OPL3-SA is the same as the original OPL3.
| |
OPL3 |
OPL3-SA |
OPL3-SA2 |
OPL3-SA3 |
| Release Year |
1988 |
1994? |
1995 |
1996 |
| Chips |
YMF262,
YMF289 |
YMF701 |
YMF711,
YMF718 |
YMF715, YMF719 |
| DACs |
YAC512, YAC513, YAC516 |
Internal |
Internal |
Internal |
| Plug & Play ISA 1.0a |
No |
Yes |
Yes |
Yes |
| 16-bit Address Decoding |
No |
No |
Yes |
Yes |
| Hardware Volume Control |
No |
? |
? |
Yes |
| Power Management |
No |
No |
No |
Yes |
| CD-ROM Interface |
No |
No |
Yes |
Yes |
| Modem Interface |
No |
No |
Yes |
Yes |
| Zoomed Video |
No |
No |
Yes |
Yes |
| DAC for OPL4 |
No |
No |
Yes |
Yes |
| 3D Audio DSP* |
No |
No |
No |
Yes |
The original OPL3-SA was the first to provide ISA Plug & Play compatibility. YMF701 chips are OPL3-SA (1st generation).
OPL3-SA2 added a CD-ROM interface, modem interface, a zoomed video port, and a DAC for OPL4. YMF711 and YMF718 are OPL3-SA2 (2nd generation).
OPL3-SA3 added a "3D sound" digital signal processor. YMF715 and YMF719 are OPL3-SA3 chips (3rd generation).
There are several flavours of YMF719, including YMF719-S, YMF719B-S and YMF719E-S. Windows 2000 and XP support this chipset out of the box, so no external drivers are needed. They are known for their low noise and excellent compatibility. Their MPU-401 interface does not suffer from the "hanging note" bug present in other OPL3 chips. For best quality the internal amp should be disabled via a jumper and all settings in the mixer set to 0 and setting the output type to hi-fi.
Vogons contributor James-F discovered a bug in the YMF71x mixer.
He writes: "
FM = OPL/Wavetable.
WAVE = PCM/Voice.
CD = CD
Line = Line-In
SB = A VERY BUGGY SBPro master volume slider.
Master VOL = Master volume of the card itself (keep at 15). In the process of digging deeper I discovered that the YMF71x mixer has a bug where if SB setting is other than 1 (out of 7) the mixer is non responsive to games and volume changes.
Setting SB to 1 doesn't actually lower any volume of the emulated SBPro but gives the other sliders more range, if it is set to 7 the other sliders do NOTHING and so are games that use the mixer.
Now that the SB volume is set to 1 the YMF717x works just like a normal SBPro and games like Wolfenstein3D and Duke Nukem 3D can control the volume of the mixer like they should."
James-F also worked out the correct way to get the low-pass filter working and sounding just like that
of the Sound Blaster Pro's:
"The lowpass filter DOES exist and it is enabled by default but the SMD cap is so small (250pF) that it has no effect on sound.
I soldered a 100nF cap for the quick test and it was too much and the sound was completely muffled from the right channel, but it proved my theory.
Replace C11 and C19 (left and right) with 6.8nF capacitors, preferably 0805 (2012) 6.8nF SMD Capacitors.
This will make the YMF71x sound similar to the real SBPro which has a functional Lowpass filter, and now the YMF71x has too.
After many capacitors and frequency analysis I found that 6.8nF is the most accurate value and sounded closest to the CT1600 example firage provided, even closer than DOSBox.
So now along with the SB = 1 mixer fix and the modification it makes my Yamaha YMF719 the best DOS card I own."
The YMF719 was the last Yamaha audio chip used on ISA sound cards. From YMF720 onwards they were all PCI-based.
I did a full review of a YMF718/YMF719-based sound card, the Yamaha Audician 32 Plus, in January 2023.
Click here for the YMF715E datasheet (all the above mentioned chips are very similar to this). |
 Yamaha YMF720, YMF724
Released: 1998
Type: FM Synthesizer
Voices: 18 or 22 (FM) + 64 (MIDI)
Operators: 4 per voice
Channels: 1, 2 or 4 (FM), or 1 or 2 (MIDI)
The YMF720 and YMF724 arrived in 1998 and were the successor to the YMF715 and YMF719 OPL3-SA3. Instead of being ISA-based like the OPL3-SAx chips, these were PCI. The YMF724 was the code given to the chip used on standalone PCI cards whereas YMF720 was for embedded systems (integrated directly on the motherboard).
They had an integrated OPL3-SA3 for backward compatibility to Ad Lib, Sound Blaster, Sound Blaster Pro and Windows Sound System, and also have the same MPU-401-compatible interface for external General MIDI synthesizers. In addition, the YMF724 includes a 64-voice GM/DS-XG wavetable synthesizer with 2-channel output, interface to AC'97 codec, S/PDIF output, a Dolby AC-3 decoder, and 3D positional audio via DirectSound3D and QSound.
DOS applications running under Windows 9x and ME could also take advantage of the Yamaha XG tone generator, available via Yamaha's VxD driver.
Most boards with these chips have good quality 18-bit DACs, providing low noise and low harmonic distortion levels.
Click here for the YMF724 datasheet.
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these Yamaha reference drivers:
DOS
Windows 3.x
Windows 95
Windows NT 3.51/4.0
OS/2 |
 Yamaha YMF278, YMF704 (OPL4)
Released: 1996
Type: FM Synthesizer
Voices: 24
Operators: 4 per voice
Channels: 1, 2, 4 or 6
The YMF278 chip , also commonly called OPL4, is usually accompanied with a separate 2 MB ROM chip which holds approximately 330 instrument samples that are compatible with the General MIDI standard.
It incorporates both an FM synthesizer and a PCM sample-based synthesizer. The FM synthesizer is essentially a YMF262 (OPL3) so is also backwards-compatible with YM3526 (OPL) and YM3812 (OPL2), but can support 6 channels instead of 4. The PCM sample-based synthesizer supports up to 24 simultaneous voices. It can access up to 4MB of external memory for wave data and a maximum of 512 instrument samples.
Yamaha created the YMF704 in late 1996, which is essentially the same as the YMF278 but with an integrated 1 MB ROM for samples and and MPU-401 interface. The sample ROM contains the same instrument set as the standalone ROM which was certified by Fat Labs.
Sound cards that use the YMF278 include:
Click here for the YMF-704C datasheet. |
 Yamaha YMF740, YMF744, YMF754
Introduced: 1999
Type: FM Synthesizer
Voices: 18 or 22 (FM) + 64 (MIDI)
Operators: 4 per voice
Channels: 4
An enhancement over the first of Yamaha's PCI-based chips, YMF720 and 724, the YMF740 and YMF744 provided 4-channel output instead of just 2.
The YMF754 was a low-power version of the YMF744.
Click here for the YMF740C datasheet. |
 YAC512
Introduced: 1988
Type: Digital-to-Analog Converter
Channels: 2
Package: 16-pin SOP
The Yamaha YAC512 was a DAC designed to work alongside the YMF262 or YMF289 FM synthesizer chip.
Click here for the YAC512 datasheet. |
YAC513 / YAC516
Introduced: 1988
Type: Digital-to-Analog Converter
Channels: 2
Package: 16-pin DIP or 16-pin SOP
The Yamaha YAC513 was a DAC typically paired to the low-power version of the YMF262, the YMF289.
Click here for the YAC513 and YAC516 datasheets. |
ESS Technology
I have a dedicated page for ESS Technology here.
OPTi Inc.
I have a separate page for OPTi, which has possibly more information.
OPTi 82C924
The OPTi 82C924 chipset is an integrated chip that supports Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System and an MPU-401 UART interface.
It can be found on the following cards:
|
OPTi 82C928 - MAD16
The OPTi MAD16 chipset is an integrated chip. Head over to the OPTi page for more details on cards that used it. |
OPTi 82C929 - MAD16 Pro
The OPTi MAD16 Pro chipset is an integrated chip that supports Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System, and an MPU-401 UART interface.
It can be found on the following sound cards:
|
OPTi 82C930
The OPTi 82C930 chipset is an integrated chip that supports Ad Lib, Sound Blaster, Sound Blaster Pro, Windows Sound System, and an MPU-401 UART interface.
Click here for the 83C930 Reference Guide. |
OPTi 82C931 
The OPTi 82C931 single-chip chipset was launched in 1996, and features Ad Lib, Sound Blaster, Sound Blaster Pro, and Windows Sound System compatibility.
It supports 22 voice channels, 52 operators and employs OPTi's own OPTiFM(TM) music synthesizer with enhanced bass. It also has an MPU-401 interface common for this era. It is Plug & Play so expect cards that use this to all be PnP (good for Windows, more difficult to configure in pure DOS).
This "OPTiFM" OPL3 clone is reported to be "wonky" by user Ace on Vogons, citing "[the chip has] several incorrect notes and even volume spikes. Not recommended".
Cards that used the 82C931 include:
|
OPTi 82C933
The OPTi 82C933 single-chip chipset features Ad Lib, Sound Blaster, Sound Blaster Pro, and Windows Sound System compatibility.
It supports 22 voice channels, 52 operators and employs OPTi's own OPTiFM(TM) music synthesizer with enhanced bass. It also has an MPU-401 interface common for this era. It is Plug & Play so expect cards that use this to all be PnP.
It also gets a built-in third-generation 16-bit Sigma-Delta codec by ECTIVA, which is further integrated with a low distortion complex mixer featuring 3D audio expansion. The OPTiSound 82C933 produces a spatial or widened stereo image from ordinary left and right channel inputs, without any initial encoding of input signals.
As was typical for OPTi, these fully integrated chips found their way onto a number of nondescript sound cards such as this one.
82C933 Datasheet |
OPTi 82C941 
The OPTi 82C941 chip was a wavetable synthesizer, usually found paired with cards that also have the 82C931. The '931 portion delivered Ad Lib, Sound Blaster, and Windows Sound System support, while the 941 handled wavetable effects that were General MIDI-compatible.
The wavetable portion needs no drivers to work - it's an MPU-401-compatible device, so responds to data received via the standard General MIDI I/O address at 330h.
According to an article on http://www.os2museum.com in order to get the wavetable working in pure DOS, you need to edit the SOUND16.CFG and changed from:
FDAC_SRC=OPL3
to
FDAC_SRC=SHARED |
Illegitimate Copies and Clones
There also existed some chips which are believed to be full 100% copies of the original Yamaha chips. Some of the more common ones are the LS-212 and LS-215 pair of chips. The LS-212 is a YMF262-M OPL3 copy, while the LS-215 is a YAC512-M DAC equivalent. "215" is "512" backwards (probably not a coincidence!). How do we know these are really copies? The OPTi 82C924 chipset does not include an OPL3-compatible core, yet boards that use this chipset claim to support OPL3, so the chip has to be there somewhere. So the LS-212/LS-215 pair is really the only suspect. Numerous Aztech cards were manufactured using these clones. There also exist less subtle chips blatently marked as LS262 (a copy of the YMF262 OPL3), LS512 (a copy of the YAC512 DAC) and LS245 (a bus trasceiver).
Another set of clones are the DSP24S and DAP16S combination. These chips have been seen on mid-1995 ProComp Pro-Multimedia cards next to an OPTi 82C929A controller. They appear to be straightforward copies of the YMF262-M (DSP24S) and YAC512-M (DAP16S), respectively.
Another copy is the FT6116, a Force Technologies 2Kx8 CMOS SRAM. The FT6116-100 however, is… certainly not. Obviously a cheap Taiwanese sound card has no need for a fast SRAM (static RAM) chip. What’s more, the Avance Logic ALS100 does not include an OPL3 core (unlike its successor, the ALS100+), so an OPL3 chip has to be on the board somewhere. Yes, it's the FT6116-100 chip!
Last on the list is the DXP44Q. This chip appears to be a pin-compatible copy of the Yamaha YMF289B, also known as OPL3-L. This was a low-power chip with power management suitable for portables (and found in the IBM ThinkPad 701C for instance). Once again, the OPTi 82C930A does not include an OPL3 core (unlike its successor, the 82C931). Once again, there has to be an OPL3 on the board somewhere, and the DXP44Q is more or less the only candidate. The 82C930A does include a DAC, which explains the lack of a separate DAC chip.
The fake OPL3 chips are most commonly, but by no means exclusively, found next to an OPTi controller. They have also been seen paired with ESS and Avance Logic controllers, and there’s no reason to think they couldn’t be used with others. The affinity with OPTi controllers could be simply a function of the fact that OPTi had well established and cost-effective controllers available in 1995. ESS and Crystal went relatively quickly from zero to integrating an OPL3 workalike (ESS1688, CS4235), obviating the need for external chips.
Analog Devices / ADI / SoundMax
AD1815 / AD1815 SoundComm
Introduced: 1998
Type: Single Chip Audio Subsystem
Sample Range: 4 kHz - 55.2 kHz
Package:
100-pin PQFP
The AD1815 is an audio chip with an integrated OPL3 clone that supports Sound Blaster Pro and DirectSound, and an
MPU-401 MIDI port.
The chip supports Plug & Play and
has a 16-bit input resolution with a
55 kHz maximum sampling rate.
The AD1815 can be found on the following:
Click here for the AD1815 Datasheet. |
AD1816 
Introduced: 1997
Type: Single Chip Audio Subsystem
Sample Range: 4 kHz - 55.2 kHz
Package:
100-pin PQFP or TQFP
The AD1816and AD1816A are audio chips with an integrated OPL3 clone that supports Sound Blaster Pro and Windows Sound System, and has an MPU-401 MIDI port.
The chip supports Plug & Play and
has a 16-bit input resolution with a
55 kHz maximum sampling rate.
The AD1816 can be found on the following:
Click here for the AD1816JS Datasheet. |
AD1819B, AD1881A, AD1885, AD1886A, AD1887, Ad1981A, AD1981B, AD1981BL and AD1981BW
Introduced: 1997
Type: Single Chip Audio Subsystem
Sample Range: 7 kHz - 48 kHz
Package:
100-pin PQFP or TQFP
An AC'97-compatible audio codec with 16-bit input resolution and 48 kHz maximum input sampling rate.
Signal-to-Noise ratio (SNR) range from 80-90 dB.
Click here for the AD1819A Datasheet. |
AD1845
Introduced: 1995
Type: Single Chip Audio Subsystem
Sample Range: 4 kHz - 50 kHz
Package:
66-pin PQFP or 100-pin TQFP
An MPC Level 2-compliant audio codec that supports Windows Sound System.
Pin-compatible with AD1848, AD1846, CS4248 and CS4231.
Found on:
Click here for the AD1845JP Datasheet. |
AD1846
Introduced: 1996
Type: Single Chip Audio Subsystem
Sample Range: 5.5 kHz - 48 kHz
Package:
66-pin PQFP or 100-pin TQFP
A low-cost alternative to the AD1848, the "AD1846 SoundPort Stereo CODEC" is a single-chip integrated audio solution.
Click here for the AD1846 Datasheet |
AD1848
Introduced: 1992
Sample Range: 5.5 kHz - 48 kHz
Package:
The Analog Devices AD1848 was the chip that brought us the Windows Sound System for the first time, being the core component of the card from Microsoft. This card also had an onboard Yamaha YMF262-M for Ad Lib and Sound Blaster support.
The v1.0a Windows Sound System drivers were released in February 1993. v2.0 drivers followed in October of that same year, which added support for third-party cards from MediaVision, Creative Labs and ESS Technology. These drivers also added an improved DOS driver (WSSXLAT.EXE) that provided Sound Blaster 16 compatibility.
Found on:
Click here for the AD1848 Datasheet. |
AD1882
5.1 channels.
24-bit input resolution,
24-bit output resolution.
96 kHz maximum sampling rate
Signal-to-Noise ratio (SNR) range from 90-95 dB. |
AD18max, AD18max10, SoundPort
No information on this audio chip.
Found on Digitan Systems DSAC-300 sound card with wavetable header. |
AD1981HD, AD1983
2 channels.
20-bit input resolution,
24-bit output resolution.
48 kHz maximum sampling rate.
Signal-to-Noise ratio (SNR) range from 80-85 dB. |
AD1984
4 channels.
24-bit input resolution,
24-bit output resolution.
192 kHz maximum sampling rate
Signal-to-Noise ratio (SNR) range from 90-96 dB. |
AD1985, AD1986, AD1986A
5.1 channels.
20-bit input resolution,
20-bit output resolution.
96 kHz maximum sampling rate
Signal-to-Noise ratio (SNR) range from 80-90 dB.
AD1985 supports the .DLS (Downloadable Sound) v1.0 format for wavetable samples/soundfonts, as does the AD1888 and AD1980. |
AD1987, 1988A, 1988B
7.1 channels.
24-bit input resolution,
24-bit output resolution.
96 kHz (AD1987 only) maximum sampling rate. All others 192 kHz.
Signal-to-Noise ratio (SNR) range from 90-101 dB. |
Realtek / ALC / Avance Logic
All the Realtek and Avance Logic codec chips have the prefix "ALC". Click here for my dedicated Avance Logic page.
ALC101, ALC202, ALC203, ALC250, ALC260
2 channels.
Input Resolution: ALC101 = 16-bit, ALC202/203/250 are 18-bit, ALC260 is 20-bit.
48 kHz maximum input sampling rate (ALC260 has 96 kHz)
48 kHz maximum output sampling rate on ALC101. 96 kHz on ALC202/203/250. 192 kHz on ALC260.
Signal-to-Noise ratio (SNR) is 70-75 dB on ALC101. All others range from 85-100 dB. |
ALC262, ALC268, ALC269
4 channels.
20-bit input resolution (ALC269 is 24-bit)
24-bit output resolution.
96 kHz maximum input sampling rate.
192 kHz maximum output sampling rate.
Signal-to-Noise ratio (SNR) range from 80-85 dB. |
ALC650, ALC655, ALC658, ALC662
5.1 channels.
Input resolution is 18-bit on ALC650 and 658, 16-bit on ALC655, and 20-bit on ALC662.
Output resolution is 20-bit on ALC650 and 658, 16-bit on ALC655, and 24-bit on ALC662.
48 kHz maximum input sampling rate on all but ALC662 which is 96 kHz.
Signal-to-Noise ratio (SNR) range from 85-98 dB. |
ALC850, ALC861, ALC880
7.1 channels.
Input resolution is 16-bit on ALC850 and 861, 20-bit on ALC880, and 24-bit on ALC861-VD-GR.
24-bit output resolution on all but ALC850 which is 16-bit.
96 kHz maximum input sampling rate on all but ALC850 which is 48 kHz.
Signal-to-Noise ratio (SNR) range from 82-100 dB. |
Crystal
Cirrus Logic, Inc. produced some of the highest quality audio codecs, mainly used in home theatre receivers. In 1991 they acquired Crystal Semiconductor, a supplier of analog and mixed-signal converter ICs. The Crystal codecs were then marketed as Cirrus Logic's budget line. All these codec chips have the prefix "CS".
 CS4215-KL, CS4215-KQ
Introduced: Early 1993
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package: 44-pin PLCC (-KL) or 100-pin TQFP (-KQ)
Known Revisions: C (Rev.0), D (Rev.1), E (Rev.2)
CS4215 is an MwaveTM audio codec from Cirrus Logic/Crystal, designed to take multiple analogue audio inputs, convert them into a digital signal, apply filtering and then convert them back into a combined/mixed analogue audio signal. The chip's revision is the letter immediately preceeding the date code.
MwaveTM MDSP1020 and MDSP2780 was a line of DSP chips created by IBM in joint partnership with Texas Instruments in late 1993/early 1994. It was not only designed for gaming audio, but also for voice/fax/modem use, so don't be surprised if a sound card with an Mwave chip also includes an onboard modem.
Datasheet: CS4215 |
 CS4216-KL, CS4216-KQ
Introduced: Late 1993
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package: 44-pin PLCC (-KL) or 44-pin TQFP (-KQ)
CS4216 is an MwaveTM audio codec from Cirrus Logic/Crystal, designed to take multiple analogue audio inputs, convert them into a digital signal, apply filtering and then convert them back into a combined/mixed analogue audio signal.
MwaveTM MDSP1020 and MDSP2780 was a line of DSP chips created by IBM in joint partnership with Texas Instruments in late 1993/early 1994. It was not only designed for gaming audio, but also for voice/fax/modem use, so don't be surprised if a sound card with an Mwave chip also includes an onboard modem.
Apparently MwaveTM DSPs do support FM synthesis compatible with Ad Lib and Sound Blaster, though I have yet to confirm this. There's a possibility the MDSP1020 was a sound chipset of which the MDSP2780 is the wavetable-only part - in this assumption, the MDSP1020 has a separate chip to provide FM synthesis.
The Mwave DSP was integrated into IBM's ThinkPad 755-series and PC 300 desktop series.
Found on:
Datasheet: CS4216 |
 CS4248
Introduced: 1993
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package:
68-pin PLCC (-KL) or 100-pin TQFP (-KQ)
One of Crystal's first audio codecs for sound cards, introduced in 1993.
16-bit input resolution.
Not full duplex.
Up to 50 kHz maximum input sampling rate.
This is a clone of Windows Sound System.
Found on:
Click here for a CS4248 datasheet. |
 CS4231-KL, CS4231A-KL
Introduced: 1993
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package:
68-pin PLCC (-KL) or 100-pin TQFP (-KQ)
CS4231 and CS4231A are MwaveTM 16-bit audio codecs from Cirrus Logic/Crystal, designed to take multiple analogue audio inputs, convert them into a digital signal, apply filtering and then convert them back into a combined/mixed analogue audio signal.
The CS4231 is pin-compatible with the CS4248 and its Analog Devices sibling, AD1848, but adds MPC Level 2-compliance and further operating modes that enhance its functions. These include full duplex support, a programmable timer, mono output with mute control, mono input with mixer volume control, ADPCM and Big Endian audio data format support, and independent selection of capture and playback audio data formats.
The CS4231A is a pin-compatible upgrade to the CS4231 and CS4248, and is fully backward-compatible with those earlier codec ICs.
Found on:
Datasheets: CS4231 / CS4231A
Drivers |
 CS4232-KQ / CS4232-KM
Introduced: Early 1995
Type: Multimedia Controller and Audio Codec
Sample Range: 4 kHz - 50 kHz
Package:
100-pin TQFP (-KQ) or 100-pin PQFP (-KM)
The CS4232 was Crystal's first ISA Plug & Play and MPC Level 2-compliant codec, designed to take multiple analogue audio inputs, convert them into a digital signal, apply filtering and then convert them back into a combined/mixed analogue audio signal.
In addition to its codec functions, it had a joystick port, MPU-401-compatible MIDI interface, and an optional CD-ROM interface. It had no integrated FM chip so most cards that use the CS4232 would also have an OPL3 or compatible chip.
Requires DOS initialisation for the MPU-401 interface to work in Windows.
Found on:
- Acer Magic S32/S23 (S23 uses Crystal CS4232, S32 uses Creative's Vibra-16S chipset)
- Terratec Maestro 32/96 - with Crystal/Dream SAM9233 wavetable synthesizer
- Reveal SC500 Rev. 3 "SoundFX Wave"
- CrystaLake Multimedia 120 (1 MB) wavetable
- CrystaLake Multimedia 140 (4 MB) wavetable
- Ad Lib ASB4
- Turtle Beach Tropez Plus
- Orchid NuSound 32PNP
Click here for the CS4232 datasheet.
Drivers
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
Windows 3.x
Windows NT 3.51 and 4.0
Windows 95
OS/2 |
 CS4218-KL
Introduced: 1996
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package: 44-pin PLCC (-KL) or 44-pin TQFP
(-KQ)
A 16-bit audio codec from Cirrus Logic/Crystal, designed to take multiple analogue audio inputs, convert them into a digital signal, apply filtering and then convert them back into a combined/mixed analogue audio signal.
It was pin-compatible with their earlier CS4216 from 3 years before, but differs from CS4216 in that it runs from either 5V or 3.3V (CS4216 requires 5V), provides different serial modes and uses different digital filters.
Unlike its predecessors (CS4215 and CS4216), the CS4218 did not carry the MwaveTM moniker.
Datasheet: CS4218 |
  CS4236 / CS4236B   
Introduced: 1997
Type: Single-Chip Multimedia Audio System
Sample Range: 4 kHz - 50 kHz
Package:
100-pin TQFP (-JQ or -KQ)
The CS4236 was a complete audio solution on a single chip. It was fully compliant with the Microsoft PC '97 (MPC Level 2) and WHQL (Windows Hardware Quality Labs) audio requirements.
It supports full duplex, is Plug & Play, and features an FM synthesis on-chip compatible with Sound Blaster, Sound Blaster Pro and Windows Sound System.
In addition to its codec functions, it had a joystick port, MPU-401-compatible MIDI interface, and an optional CD-ROM interface.
CS4236 has low noise, does not suffer from the hanging note bug on the MPU-401 interface and decent compatibility with Sound Blaster, SB Pro and Windows Sound System.
The non-'B' revision requires DOS initialisation for the MPU-401 to work in Windows, whereas the B revision does not.
The non-'B' revision can be found on:
The 'B' revision can be found on Intel SE440BX motherboard (1998) as well as:
Click here for the CS4236 datasheet.
Drivers
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
Windows 3.x
Windows NT 3.51 and 4.0
Windows 95
OS/2 |
 CS4237 / CS4237B 
Introduced: 1997
Type: Single-Chip Multimedia Audio System
Sample Range: 4 kHz - 50 kHz
Package:
100-pin TQFP (-JQ or -KQ)
The same chip as CS4236B but with SRS surround sound (by SRS Labs) replacing Crystal's own "CrystalClear" 3D audio.
Click here for the CS4237B datasheet.
Found on:
Drivers
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS
Windows 3.x
OS/2 |
CS4238
Introduced: 1997
Type: Single-Chip Multimedia Audio System
Sample Range: 4 kHz - 50 kHz
Package:
100-pin TQFP (-JQ or -KQ)
The same as CS4237 but has QSOUND surround sound (from QSound, Inc.) instead of SRS.
Drivers
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
Windows 3.x
OS/2 |
 CS9233 / CS9236 
Introduced: 1997
Type: Wavetable Synthesizer
Package: 144-pin TQFP (-CQ)
A wavetable synthesis chip with reverb and chorus, so supports GM (General MIDI). No DAC. Requires DOS initialisation for the MPU-401 (UART mode) to work in Windows.
Usually coupled to a 1 MB or 4 MB wavetable sample ROM such as CS4110 or CS4111, with 128 melodic instruments and 47 percussion sounds, as it has no built-in memory for sample storage.
Its ROM soundfont is typical of old 1 and 2 MB ROMs. This is covered also in my Wavetable Audio page under Crystal/Dream SAM9233. |
CS4235 / CS4239
Introduced: Late 1997
Type: Single-Chip Multimedia Audio System
Sample Range: 4 kHz - 50 kHz
Package:
100-pin TQFP (-JQ or -KQ)
The CS4235 is a slightly later version of the CS4236B, adding what Crystal called "CrystalClear" 3D audio.
It supports full duplex, is Plug & Play, has an integrated FM synthesizer on-chip compatible with
Sound Blaster, Sound Blaster Pro and Windows Sound System.
In addition to its codec functions, it had a joystick port, MPU-401-compatible MIDI interface, and an optional CD-ROM interface.
Apparently the CS4235 got a very glitchy OPL3 FM synthesizer, so it's advisable to avoid cards or motherboards that have this chip. There are numerous reports of its FM audio sounding pretty dreadful.
A low-power version of the CS4235 was also released, called CS4239.
The CS4235 and CS4239 can be found on the following sound cards:
Click here for the CS4235 datasheet.
DOS Drivers |
CS4297
Introduced: 1998
Type: Audio Codec
Sample Range: 4 kHz - 50 kHz
Package:
48-pin TQFP (-KQ or -JQ)
The CS4297 is an AC'97-compatible audio codec. Its full name is CrystalClear SoundFusion Audio Codec '97. It is supposed to be paired with something like a CS4610.
The CS4297 Audio Codec ’97 and CS4610 PCI Audio Accelerator were the first members of the SoundFusion family. |
CS4610 / CS4611
Introduced: 1998
Type: PCI Audio Accelerator
Sample Range:
Package:
100-pin MQFP or 128-pin TQFP
The CS4610 and CS4611 are "CrystalClear SoundFusion" PCI audio accelerator chips. They fully support DirectX 5.0 3D Positional Audio, Dolby Digital AC-3, DDMA for legacy support in DOS in addition to Crystal's own proprietary CCLS (CrystalClear Legacy Support).
The CS4611 was an embedded audio chip found on the Intel SE440BX motherboard from 1998 alongside the CS4236.
Compliant with AC'97 2.0. Cards/boards that use these chips provide S/PDIF digital input and output.
Click here for the CS4610/11 datasheet. |
 CS4614
A PCI audio chip. |
 CS4622 / CS4624
A PCI audio chip, full name is CrystalClear SoundFusion PCI Audio Accelerator.
Among other things it provides an "Enhanced Game Port", able to send and receive digital data packets over the game port - designed for joysticks and other devices that require more than the 15-pin analogue game port could traditionally handle.
The CS4624 is a cost-reduced version of the CS4622, with no support for Dolby Digital AC-3 and a reduced clock speed.
Datasheets: CS4622/4624 |
 CS4280, CS4281
Introduced: 1998
Type: Single-Chip Multimedia Audio System
Sample Range: 4 kHz - 50 kHz
Package:
100-pin MQFP (-CM) or 128-pin TQFP (-CQ)
The CS4280 and CS4281 are PCI audio chips with legacy DOS compatibility via both PC/PCI, Distributed DMA and what Crystal called "CrystalClear Legacy Support". They have an integrated FM synthesizer, hardware volume control, an MPU-401 interface, zoom video port and game port.
The CS4280 is pin-compatible with the earlier CS4614, CS4622/CS4624, and is usually coupled with the Crystal CS4297 audio codec.
CS4280 is found on the JoyTech Twister 3D sound card.
Datasheets: CS4280 / CS4281. |
CS4245
Introduced: 2004
Type: Audio Codec
Sample Range: 4 kHz - 192 kHz
Package:
48-pin LQFP
Click here for the CS4245 datasheet. |
Embedded Sound Chips on Motherboards
In the late 1990s, motherboard manufacturers began embedding audio chips, effectively entire sound card technology, on their boards. Whilst these were convenient as PC builders no longer had to install a separate sound card and use up a free expansion slot, the audio quality was often very poor. This section lists the most common of these embedded sound chips.
For C-Media sound drivers, visit their website here.
C-Media ASC-9308
Compatible with Sound Blaster and Sound Blaster Pro. Still named "Compumedia", also gives nearly useless SB16 compatibility.
C-Media CMI8328
Compatible with Sound Blaster and Sound Blaster Pro.
Has an MPU-401 (UART only) interface.
Can be found on the following sound cards:
- AudioExcel AV500 (also has Crystal CS4231A which provides WSS support)
- Zoltrix Audio Plus 3200 AV500
- Zoltrix Audio Plus 3200 V2 AV305
Third-Party DOS Driver (courtesy of Eric Voirin, aka Vogons contributor Oerg866). Go to the GitHub page for source.
C-Media CMI8329A
Not sure of its capabilities, but likely SB and SBPro with MPU-401 as a minimum.
Can be found on the following sound cards:
- Zoltrix Audio Plus AP6400 - has a wavetable and a 3D sound header. The chip is branded "AD Chips", probably to make to appear to be an Analog Devices chip.
C-Media CMI8330
Often found on cheap PC Chips motherboards, these are sometimes branded "HT1869V+ SoundPro". Also found on some ASUS motherboards. Rarely used on sound cards.
Compatible with Sound Blaster, SB Pro, SB16, WSS, and has an MPU-401 (UART only) interface,
OPL3 clone integrated. Even though the chip has "PCI" written on it, it actually uses the ISA bus.
Plug & Play.
S/PDIF input/output.
Rare examples of a sound card with this chip is this one called the Bannsan BS-1 and this one from Elpina - there are other versions of this same Elpina card that are unbranded, but are identical in every other way. The card's DOS compatibility is supposedly very good, though FM output is incredibly quiet (low volume) and the card is susceptible to picking up lots of noise.
In fact the overall quality of the CMI8330 is downright appalling. In playback tests conducted by PCAVTech, it got a Signal-to-Noise ratio of just -33dB - this is about as poor as they come.
Drivers
It is usually recommended that you use the installation software from your sound card's manufacturer, but in the absence of those, try one of these:
DOS, Windows 3.1,
Windows 95
Windows 95 Driver update DirectX v5.0
Updated Mixer program v1.7A
Driver Update to Fix Windows 98 Problems
C-Media CMI8338
Often found on cheap PC Chips motherboards, although are sometimes branded "HT8338/PCI SoundPro".
C-Media CMI8738
Often found on cheap PC Chips motherboards, although are sometimes branded "HT8738/PCI SoundPro". This was the same as the CMI8338, but included an integrated PCtel 56K PCI fax/modem. It's also found on many cheap PCI sound cards, including the Mercury whose box indicates it supports DirectSound and Aureal A3D surround sound.
Realtek
Realtek embedded sound chips post-date the DOS era, so won't be covered here.
