Sound Blaster 16
Sound Blaster 16 (CT2940), without ASP/CSP chip
|Date invented||June 1992|
|Invented by||Creative Technology|
Motherboard via one of:
CD-ROM Drive via:
|Common manufacturers||Creative Technology|
Sound Blaster 16
Sound Blaster 16 (June 1992), the successor to the Sound Blaster Pro, introduced 16-bit digital audio sampling to the Sound Blaster line. The Sound Blaster 16 also added an expansion-header for add-on MIDI-daughterboards with sample-based synthesis capabilities complying to the General MIDI standard, a socket for an optional digital signal processor dubbed the Advanced Signal Processor, later Creative Signal Processor (ASP, or later CSP), and an MPU-401 compatible UART for communication with external MIDI-devices.
The Sound Blaster 16 retained the Yamaha OPL-3 chip for FM synthesis, and was mostly compatible with software written for the older Sound Blaster and Sound Blaster Pro sound cards. Most Sound Blaster 16's with a discrete OPL chip used the YMF262 chip, though some mid-run boards used the YMF289 chip, which was fully compatible and offered broadly similar sound quality (though at a slightly lower sample rate of 44.1 kHz.) Later Sound Blaster 16 models integrated the OPL-3 function into the chipset (notably into the CT1747 chip, though later products including many based on the ViBRA chipsets featured CQM synthesis). The SB16's MPU-401 emulation was limited to UART (dumb) mode only, but this was sufficient for most MIDI software. When a daughterboard, such as the Wave Blaster, Roland SCB-7, Roland SCB-55, Yamaha DB50XG, Yamaha DB60XG was installed on the Sound Blaster, the Wave Blaster behaved like a standard MIDI device, accessible to any MPU-401 compatible MIDI software.
The ASP or CSP chip added some new features to the Sound Blaster line, such as hardware-assisted speech synthesis (through the TextAssist software), QSound audio spatialization technology for digital (PCM) wave playback, and PCM audio compression and decompression. Software needed to be written to leverage its unique abilities, yet the offered capabilities lacked compelling applications. As a result, this chip was generally ignored by the market.
The Sound Blaster 16 featured the then widely used TEA2025 amplifier IC which, in the configuration Creative had chosen, would allow approximately 700 milliwatts (0.7 watts) per channel when used with a standard pair of unpowered, 4-Ohm multi-media speakers. By setting an onboard jumper, the user could select between line-level output (bypassing the TEA2025) and amplified-output. Later models (typically ones with ViBRA chips) used the also then-widely used TDA1517 amplifier IC.
Early Intel PCs built after the IBM PC/AT typically only included support for one ATA interface (which controlled up to two ATA devices.) As computer needs grew it became common for a system to need more than 1 ATA interface. With the development of the CD-ROM, many computers could not support it since both devices of the one channel were already used. Several Sound Blaster 16 boards provided an additional IDE interface to computers that had no spare ATA-ports for a CDROM, though the additional drive interface typically only supported one device rather than two, it typically only supported CD ROM drives, and it usually could not support additional hard drives.
The Sound Blaster with the SCSI controller (SB 16 SCSI-2, CT1770, CT1779) was designed for use with "High End" SCSI based CD-ROM drives. The controller did not have the on-board firmware (Boot BIOS) to start an OS from a SCSI hard drive. Normally that meant that SCSI device ID-0 and ID-1 were not used. As well, if the computer did have a SCSI hard drive with the required SCSI controller then the settings for the SCSI controller on the SB card had to be selected so that the SB SCSI-2 interface did not conflict with the main SCSI controller.
The following model numbers were assigned to the Sound Blaster 16:
- CT12**: CT1230, CT1231, CT1239, CT1290, CT1291, CT1299
- CT17**: CT1730, CT1740, CT1749, CT1750, CT1759, CT1770, CT1779, CT1780, CT1789, CT1790, CT1799
- CT22**: CT2230, CT2290
- CT27**: CT2700, CT2740, CT2750, CT2770
- CT28**: CT2830
- CT29**: CT2910
Note: various PCBs with the same model number were shipped with a different configuration regarding CD-ROM interfaces, sockets and presence/absence of the ASP/CSP chip. The following models were typically equipped with an ASP/CSP socket: CT1740, CT1750, CT1770, CT1790, CT2230, CT2740, CT2950, CT2290. The Sound Blaster Easy 16 (CT2750) was sold with the ASP/CSP chip and a parallel CD-ROM port and 1 audio out.
Sound Blaster VIBRA 16
The Sound Blaster VIBRA 16 was released as a cost-reduced, more integrated Sound Blaster 16 that supported Plug and Play for Microsoft Windows operating systems. It lacked separate bass and treble control, an ASP/CSP socket and Wave Blaster connector. Several different revisions of the VIBRA chipset exist:
- ViBRA16S, the earliest model, which featured an external YMF262/YMF289 OPL-3 or CT1978 CQM synthesis chip,
- ViBRA16C, the first model to integrate Creative's CQM synthesis,
- ViBRA16X/XV, a much smaller chip extensively featured on later WavEffects cards, which also integrates CQM synthesis.
On most later ViBRA-equipped sound cards, Creative utilized a cost-reduced replacement for the OPL-3 FM support termed CQM synthesis, which largely emulated the features of the OPL-3 chip. However, its emulation of OPL-3 was far from perfect, causing considerable distortion in FM-generated music and sound effects. Despite its flaws, it was still much more faithful sounding than the wavetable-generated output of the later AudioPCI-based sound cards.
It is worth noting that the quality of CQM synthesis tends to vary from board to board. While all CQM implementations produce distinctive distortion in the FM output, certain boards (notably the CT4180 with the rectangular Vibra16C chip) produce noticeably fewer defects and artifacts than others.
The following model numbers were assigned to the Sound Blaster VIBRA 16:
- CT12**: CT1260, CT1261, CT1262
- CT22**: CT2260
- CT28**: CT2800, CT2810, CT2860, CT2890
- CT29**: CT2900, CT2940, CT2941, CT2942, CT2943, CT2945, CT2950, CT2960, CT2970, CT2970, CT2980, CT2990
- CT41**: CT4100, CT4101, CT4102, CT4130, CT4131, CT4132, CT4150, CT4173, CT4180, CT4181, CT4182
Note: various PCBs with the same model number were shipped with a different configuration regarding CD-ROM interfaces and sockets. Even among the same models variations exist; for example, some OEM-specific cards were made without the TEA2025/TDA1517 amplifier to reduce costs.
Sound Blaster 16 WavEffects
The Sound Blaster 16 WavEffects was released in 1997 as a cheaper and simpler redesign of the Sound Blaster 16. It came with Creative Technology's WavEffects wavetable software. The WavEffects line use CQM synthesis for the Adlib/OPL support.
The following model numbers were assigned to the Sound Blaster 16 WavEffects:
- CT417*: CT4170, CT4171, CT4173
Sound Blaster 16 PCI
In 1998, Creative Technology acquired Ensoniq and subsequently released the Sound Blaster 16 PCI. The Sound Blaster 16 PCI was based on Ensoniq AudioPCI technology and is therefore unrelated to the ISA Sound Blaster 16, Sound Blaster 16 VIBRA and Sound Blaster 16 WavEffects. It has no dedicated hardware for Adlib/OPL support, instead using the Ensoniq wavetable to (very poorly) emulate it. Fortunately it is General MIDI compatible in most games.
The following model numbers were assigned to the Sound Blaster 16 PCI:
- CT47**: CT4700, CT4730, CT4740, CT4750, CT4790
- CT58**: CT5801, CT5803, CT5805, CT5806, CT5807
Capacitor and sound quality issues
As many Sound Blaster 16s are now well over 15 years old, many cards suffer from symptoms related to aging capacitors, ranging from muffled or distorted outputs to the cards working improperly. Re-capping the cards usually restores the audio quality and proper function. There are some notable caveats, however: regarding most cards fitted with the TEA2025 amplifier, Creative did not strictly follow the datasheet's recommended capacitor choices; as a result, capacitors of incorrect or insufficient values were substituted in several places (namely the 47uF feedback capacitors and 1uF input capacitors, which should have been 100uF and 0.22uF respectively, according to the TEA2025's datasheet) resulting in the amplified output having reduced bass and relatively poor treble. In addition, Creative used polarized capacitors where non-polarized capacitors should have been used, further degrading the amplified output's sound quality. On cards that use the TDA1517 amplifier, Creative again substituted under-valued capacitors for the outputs, this time using 470uF capacitors where the TDA1517 datasheet indicated 1000uF. Modifying the soundcard to use capacitor values as recommended in the datasheets can noticeably improve sound quality.
On another note, Sound Blaster 16 sound cards built around the CT1747 chipset often have the internal gain set a bit too high, causing clipping and crackling in the sound that wasn't present on sound cards built using the larger and less integrated CT1746B chip. This is most noticeable in the PCM sound output, which is still generated externally to the CT1747. The OPL-3 FM generally suffers much less from this, but there may still be occasional peaking when numerous loud tones are played simultaneously. Changing the mixer levels has no effect on the clipping; the only way to fix this would be to decrease the circuit's gain level.
A large number of Sound Blaster 16 cards have a flawed digital sound processor on board that causes various issues with MIDI daughtercards attached to the Wave Blaster header. The problems include stuck notes, incorrect notes, and various other flaws in MIDI playback. The particular Sound Blaster 16 cards that are affected carry DSP versions 4.11, 4.12 and some 4.13. Older DSP versions such as 4.05 do not suffer from this bug. There is no workaround for this flaw and it occurs with all operating systems since it is an issue at the hardware level. The DSP version can be checked by running the "DIAGNOSE" utility in DOS or looking at the DSP chip on the sound card. A version number is printed on the CT1740A chip usually near the CT1745A mixer chip.
- Creative Technology List of Sound Blaster Products: http://uk.creative.com/knowledgebase/10846.asp
- Linux Hardware Compatibility HOWTO: Sound cards, accessed August 6, 2007.
- Help! Stuck notes with SB16 and SCD-15, comp.sys.ibm.pc.soundcard.tech, March 1995.
- Roland SCD-10, SCD-15 specs (stuck notes), comp.sys.ibm.pc.soundcard.tech, April 1995.