Software Wavetables
25th November 2021In Part 1 we covered an introduction to software wavetables or software patchsets, and looked into Creative Labs' version of these - SoundFont files with extensions of .SBK, .SF1, and .SF2.
In this part, I look at another set of sound cards: Ensoniq AudioPCI, Advanced Gravis UltraSound and Aureal Vortex.
Ensoniq AudioPCI - ECW Files
The Ensoniq AudioPCI range of sound cards have no onboard ROM for patches, instead relying on what they called .ECW (Ensoniq Concert Wavetable) files - Ensoniq calls these 'wavesets'. Creative Labs later acquired Ensoniq, so these same wavesets can be used on many Creative Labs PCI sound cards too.
There are three official wavesets from Ensoniq:
- EAPCI2M.ECW (2 MB)
- EAPCI4M.ECW (4 MB)
- EAPCI8M.ECW (8 MB)
Apparently, the 4 MB and 8 MB ECW files were omitted from the Creative Labs Ensoniq PCI sound card install routine (after Creative acquired Ensoniq), so by default it installed the 2 MB waveset. You can get these larger files from the Creative Sound Blaster PCI 128 CD-ROM.
Ensoniq's AudioPCI cards only support this .ECW format (they are not Creative 'soundfont' compatible at all). Other cards that use this .ECW format are the Sound Blaster Live! and Audigy cards. For these cards, they can be configured using the Windows-based 'SBLive Software Synthesizer'. Sound Blaster Live! cards have the benefit of supporting both ECW and soundfont files in Windows.
Sadly, Ensoniq did not release the .ECW file format to the general public, or create any tools to allow others to make their own wavesets. There is only one "unofficial" waveset known to be out there, called 2MG4.ECW (2.9 MB).
Unlike the Creative Labs cards covered in Part 1, Ensoniq AudioPCI cards do not have any onboard RAM for samples. Instead, the waveset file gets loaded into system RAM when the "APINIT" DOS driver is run. In order to change which waveset gets loaded, you can edit SNDSCAPE.INI which is created when you install the AudioPCI DOS device drivers. The contents of this file looks something like this:
[sndscape.drv]; Product ID
Product=Soundscape
; Ports - Base/MIDI, Wave, and Sound Blaster Device
Port=330
WavePort=534
SBPort=220
; IRQs - MIDI and Wave/SoundBlaster emulation
IRQ=5
SBIRQ=5
; DMA Channel Wave/SoundBlaster emulation
DMA=1
; Switches - SoundBlaster/Soundscape emulation enable, Joystick enable
SBEnable=true
JSEnable=true
; Mixer Settings - Wave, Synth, and CD volumes
WaveVol=127
SynthVol=100
CDVol=96
; Waveset - path and file name of current waveset
SynthFile=C:\SYS\EAPCI\DEFAULT.ECW
The 2 MB waveset is the one bundled with the original Ensoniq AudioPCI card, as well as the Creative PCI64 and PCI128. You can see the last line in the .INI file, where it is called DEFAULT.ECW). This is the same file as EAPCI2M.ECW. Changing DEFAULT.ECW to one of the other waveset files will cause that different waveset to be loaded into RAM when APINIT is run (APINIT is put into AUTOEXEC.BAT by the DOS driver installation process, so it will pick up the chosen waveset each time your PC boots up).
John Engelmann did some work to reverse-engineer the .ECW file format, which you can read on his site here. It appears from his analysis that multiple 'sample sets' can exist inside the ECW file. Since the AudioPCI drivers allows for both a General MIDI (GM) mode and a Roland MT-32 mode, it could mean a waveset file contains two sample sets, or more likely, two separate mappings of instruments to suit GM or MT-32.
So how do they sound? Trawling the web for other peoples' opinions of the ECW wavesets didn't uncover much. Dave Flater provided some interesting background on the move of sound cards from ISA to PCI and the challenges that went with it. With what we know of the Ensoniq AudioPCI, these cards were right at the start of that difficult period. Dave has this to say about the 3 wavesets:
EAPCI4M.ECW (4 MB): "tested only enough to establish that it was a lot like EAPCI8M.ECW."
EAPCI8M.ECW (8 MB): "...has more realistic-sounding instruments and good drums but the guitars fade too much."
It's interesting that Dave thought the 4 MB and 8 MB wavesets were a lot alike. In earlier research I did, apparently Ensoniq planned to produce an 8 MB one but it never 'materialized' - since an 8 MB waveset file *does exist*, could it be that this is just the 4 MB one copied twice within the same file? I'm sure Dave would have seen that in his reverse-engineering if that were the case. One thing we do know is that the 4 MB waveset also contains Roland GS emulation in addition to 10 drum kits, which the 2 MB file does not. I looked in the 8 MB file, and its descriptor block claims it also has the full GM/GS implementation.
In order to gauge for myself how each waveset sounds, I recorded a number of games using each waveset file. I confirmed a different waveset was being loaded in an extremely rudimentary way - the time taken for the AudioPCI device driver, APINIT, to complete the card's initialisation on boot-up took a lot longer with the 8 MB waveset configured in SNDSCAPE.INI than the 2 MB one.
Duke Nukem 3D GM 2 MB + SBP OGG, FLACGM 4 MB + SBP OGG, FLACGM 8 MB + SBP OGG, FLAC |
Star Wars: TIE Fighter GM 2 MB + SBP OGG, FLACGM 4 MB + SBP OGG, FLACGM 8 MB + SBP OGG, FLAC |
Gabriel Knight: Sins of the Fathers GM 2 MB + SBP OGG, FLACGM 4 MB + SBP OGG, FLACGM 8 MB + SBP OGG, FLAC |
With Duke3D, I honestly cannot tell the difference between the 4 MB waveset and the 8 MB one, but there's a definite improvement between these and the default 2 MB waveset, with the latter being a lot softer and more 'basic'.
With both Star Wars: TIE Fighter and Gabriel Knight, it's tough to spot any differences between all three wavesets.
According to a thread on Vogons, the 2 MB AudioPCI waveset sounds similar to the Ensoniq SoundScape Elite instrument set, while the 4 MB one sounds radically different. There is also the belief that the AudioPCI cards only play MIDI samples at 22 KHz (the Elite does 44.1 KHz), so apparently the SoundScape Elite is still far superior.
Advanced Gravis - PAT Files
Advanced Gravis were ahead of the game in terms of the use of software patchsets. They developed "Patch" files with a .PAT extension, which contained their instrument samples. PAT files can be used on any sound card that has the GF-1 wavetable IC. Rather than being a single large file, .PAT files exist on a per-instrument sample basis.
The original Gravis UltraSound driver set contained a folder with 210 .PAT files. This contained some proprietary samples owned by others, and Advanced Gravis provided a licence for use by GUS sound card purchasers. A notice came out in 1997 that read "the GUS patchset is copyright by INI Productions and they contacted us [4Front Technologies] saying that the GUS patches were being illegally used in programs such as TiMidity and 4Front's SoftOSS Engine.". This is one reason why the original GUS patchset is difficult to come by in the wild.
Other 3rd-party patchsets are available, including the PPL150, PPL151 and PPL160 (Pro Patches Lite version 1.60) sound patches by Eero R„s„nen (Vogons user Elviz):
Aureal Vortex/Vortex 2 and S3 Sonic Vibes - DLS Files
The Aureal Vortex and S3 Sonic Vibes range of sound cards have no onboard ROM for patches, instead relying on .ARL files or .DLS (Downloadable Sound) files.
DLS files use the relatively common [at the time] RIFF file format with a form type of 'DLS ', and are the format natively supported by Microsoft Windows. Vortex-based cards came with a 4 MB DLS-formatted wavetable file on the driver disk.
DLS went through a few revisions to its standard. The first one was called DLS Level 1 (DLS-1) and came out in 1997. This supported one layer per instrument, a maximum of 16 instruments from the melodic range and 128 in a drum set, one LFO, global articulation for melodic instruments. The smallest amount of sample RAM is 256 KB. DLS-1 was followed by DLS Level 2 (DLS-2) in 1998 which added multiple layer support, per-region articulation, two LFOs and a low-pass filter. Both were 8- or 16-bit PCM mono, and supported loops, envelopes, and LFOs. A later standard called DLS-2+ introduced u-Law, A-Law, 24-bit and 32-bit PCM, DVI-IMA 4-bit ADPCM and MPEG Layer III compression. The final iteration, DLS-2++ added stereo support, fractional loop points, reverse and bidirectional loops, layer-level articulation, LFO ramp time, LFO shapes, and filter types.
Both are similar in structure to the SoundFont Bank (.SBK) format created by E-Mu Systems. Both revisions had more minor updates such as DLS specification v1.1, v2.1 and v2.2. There was also a Mobile DLS specification that was suited to mobile devices and limited to 7 KB of waveform data in the 'minimal device caps' version and 15 KB in the 'full device caps' version.
DLS files can be created and edited using the following tools (among others):
- Microsoft DirectSound Producer (for DirectX 8.1 and 9.0b)
- Awave Studio (a demo version can be downloaded and used free of charge, otherwise the full version is around $99)
In Part 3, I will look at the wavetable soundfonts for Dream/SAM, Turtle Beach, and more.