Sound Blaster 16

Sound Blaster 16

Sound Blaster 16 (CT2940), without ASP/CSP chip
Date invented	June 1992 (1992-06)
Invented by	Creative Technology
Connects to	Motherboard via one of: ISA Slot PCI Slot CD-ROM Drive via one of: ATAPI IDE interface Panasonic / MKE interface Sony interface built-in SCSI adapter
Common manufacturers	Creative Technology

The Sound Blaster 16 is a series of sound cards by Creative Technology. They are add-on boards for PCs with an ISA or PCI slot.

Sound Blaster 16 (CT2230).

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 Pro's OPL-3 support for FM synthesis, and was mostly compatible with software written for the older Sound Blaster and Sound Blaster Pro sound cards. 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. Later models (typically ones with ViBRA chips) used the also then-widely used TDA1517 amplifier IC. By setting an onboard jumper, the user could select between line-level output (bypassing the on-board amplifier) and amplified-output.

Due to its popularity and wide support, the Sound Blaster 16 is emulated in a variety of virtualization and/or emulation programs, such as DOSBox, QEMU, Bochs and VirtualBox, with varying degrees of faithfulness and compatibility.

CD-ROM Support

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.

Most Sound Blaster 16 cards feature connectors for CD-audio input. This was a necessity since most operating systems and CD-ROM drives of the time did not support streaming CD-audio digitally over the main interface. The CD-audio input could also be daisy-chained from another sound generating device, such as an MPEG decoder or TV tuner card.

OPL-3 FM and CQM Synthesis options

An example of the considerable differences between OPL-3 FM synthesis and Creative CQM synthesis. 0:00 is OPL-3 FM, and 0:30 onward is CQM.

The majority of Sound Blaster 16 cards feature either a discrete Yamaha YMF262 OPL-3 FM synthesizer, or a CT1747 chip which has this synthesizer integrated. Some post-1995 cards (notably the CT2910) feature the fully compatible YMF289 FM synthesis chip instead.

Starting in late 1995, 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.^[1] However, its emulation of OPL-3 was far from perfect, producing considerable distortion in FM-synthesized music and sound effects. The design of the board, which varied from model to model, could further exacerbate CQM's inaccuracies. Despite its shortcomings, it was much more faithful-sounding than the sample-synthesis simulation AudioPCI-based sound cards employ. Boards utilizing CQM synthesis feature a CT1978 chip, or they may have CQM integrated in the case of ViBRA16C/X-based boards.

Models

The following model numbers were assigned to the Sound Blaster 16:^[2]

• 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, CT2840
• CT29**: CT2910, CT2950

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.^[3]

Sound Blaster VIBRA 16

The Sound Blaster VIBRA 16 was released as a cost-reduced, more integrated Sound Blaster 16 chipset targeting OEMs and the entry-level to mid-range markets. Some variants support 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 first revision, which requires an external YMF262/YMF289 OPL-3 or CT1978 CQM synthesis chip. The CT2501, CT2502 and CT2504 chips are ViBRA16S parts. The smaller CT2504 does not incorporate a bus controller, and may depend on external jumpers or a Plug and Play-compatible CT1705 chip for its logical configuration. The larger CT2501 and CT2502 integrate the bus controller.
• VIBRA16C, the next revision, which integrates Creative's CQM synthesis and a Plug-and-Play compatible bus controller into the CT2505 chip. The CT2505 is also featured as an on-board sound chip on some motherboards and on Asus Media Bus cards.
• VIBRA16X/XV, a much smaller chip extensively featured on later WavEffects cards, which also utilizes CQM synthesis.

Models

The following model numbers were assigned to the Sound Blaster VIBRA 16:^[2]

• 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

Sound Blaster 16 WavEffects (CT4170).

The Sound Blaster 16 WavEffects was released in 1997 as a cheaper and simpler redesign of the Sound Blaster 16. It came with Creative WaveSynth also bundled on Sound Blaster AWE64 Gold, a physical modeling software synthesizer developed by Seer Systems (led by Dave Smith), based on Sondius WaveGuide technology (developed at Stanford's CCRMA).^[4][5][6] The WavEffects line also supports CQM synthesis for Adlib/OPL compatibility.

Models

The following model numbers were assigned to the Sound Blaster 16 WavEffects:^[2]

• 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 sample-synthesis engine to (very poorly) simulate it. Fortunately it is General MIDI compatible in most games.

Models

The following model numbers were assigned to the Sound Blaster 16 PCI:^[2]

• 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 20 years old, many cards suffer from symptoms related to aging capacitors, ranging from muffled or distorted output to the cards working improperly. In addition, with regard to the amplifier design on most boards Creative did not strictly follow the datasheets' recommendations on capacitor uF values, negatively impacting the amplified output's sound quality. Replacing the capacitors with fresh ones of the recommended values can noticeably improve both amplified and line-level audio quality, in addition to restoring proper operation.

On many TEA2025-based boards, Creative used 47uF capacitors for the amplifier's inverting input DC decoupling (connecting the Feedback pins on the amplifier's pin-out), whereas the datasheet recommended 100uF units against an increase in low-pass cutoff.^[7] In addition, Creative installed 1 uF input decoupling capacitors on the TEA2025's inputs, which according to the datasheet should have been 0.22uF units and were only necessary when a volume control slider or knob was present, but were installed regardless if the volume knob was present. (These capacitors may be replaced with short jumper wires if no volume control slider or knob is present.) Finally, Creative used polarized capacitors where non-polarized capacitors should have been used.

On boards that use the TDA1517 amplifier, Creative used 470uF capacitors for the outputs where the TDA1517 datasheet schematic suggested 1000uF units.^[8] Depending on the board, an undervalued capacitor for supply voltage rejection (connecting pin 3 of the TDA1517 to ground) may also have been used; the datasheet recommends a 100uF unit for this application. The two output capacitors have a DC voltage present, so polarized units may be used.

Sound Blaster 16 sound cards with the CT1747 chipset frequently have the internal preamplifier gain set too high, causing clipping and crackling in the output that wasn't present on sound cards built using the larger and less integrated CT1746B chip. Changing the mixer levels has no effect on the clipping; the only way to fix this would be to decrease the preamplifier's gain level.

Some Sound Blaster 16 cards made after 1992 may have grounding loops and overall less effective filtering on the +5 volt and +12 volt DC traces coming from the ISA bus. A symptom of these cost-reduced designs is an audible hiss or buzz which is present even when the card is not playing any sounds, which may affect both amplified and line-level outputs. Fixing these problems may not be trivial depending on the card's design.

Daughterboard bugs

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.^[9][10][11] 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.

Reception

Computer Gaming World in 1993 stated that "We were not impressed with the quality of the digital audio" of the Sound Blaster 16 or 16 ASP, reporting "pops and extra noise" and incomplete Sound Blaster compatibility. The magazine instead recommended the "almost footproof" Sound Blaster Pro or the original Sound Blaster.^[12]

References

External links

• Sound Blaster 16 FM emulator and online player for FM music