A certain form of stillbirth was brought on the market by Creative Music Systems (now Creative Labs) in the year of 1988.
Its soundcared, originally named identically to their company, was a little later marketed by Radio Shack, an electronics shop chain, as "Game Blaster".
Take 12 PC speakers, allow them a volume alteration of 16 steps, add a noise generator, that should reproduce 3 different drums, and allow moreover the playback in stereo. After all something, with which they could shine in opposite to AdLib!
Despite being only mono, AdLib offered essentially more for the money, and the Game Blaster didn't achieve much of a notable market volume. One particular part that Creative Labs was already good in its early times was to support game companies. This resulted that you can see lots of games of its time that played "music" on this card. To its unfortune, most games really only used it as multiplication of the PC speaker, instead of making use of its advanced capabilities.
The music making chips on this card were actually Philips SAA1099, but were labeled as "CMS 301" on the card itself. It was said that this should prevent curios persons from identifying the chips - although this was no real protection. Creative continued this practice with their first Sound Blaster cards.
Originally only marketed as external module under the name "MT-32", Roland dared the jump to a PC card, and reached something, which presumably nobody would have expected...
The card came without its own software, at least was marketed with Sierra's games. Nevertheless it offered 32 MIDI channels (however these are not simultaneous 32 instruments - see "technical"), with 12 bits D/A and 32 Khz mixing and reverb effect. It came 128 pre-defined instruments which were already similar to the later General MIDI standard. What made the card standing out of the crowd was its ability to upload your own instruments (patches) - which made this card a multi talent.
One instance where this probably happened rather often was the piano, because this instrument was reproduced by the card rather badly. However, it contains a brilliant drumset - 30 drums are pre-defined!
While some manufacturers merely converted their tracks from AdLib on Roland, the card was generally much better exploited in its possibilities than the AdLib card. Music playback in games almost always sounds full and balanced using this card. Depending on the skills of the composer, even today, this card should elicit some people an ecstatic "wow!". You may be surprised how well some of these old games sounded.
This all came with a price, namely approximately $500, that not everyone wanted to or could pay. So, this card didn't achieve a wide market spread. And even today, it is rather hard to find at Ebay - and if, then you may happen to pay the original price.
If you reduce yourself to use this card with plain MIDI playback (because that's what it does, actually), by present-day standards it sounds rather mediocre. But then again, that this is merely the only card fully compatible with the "Roland" option of many old games. Only this card supports, what newer cards, that call itself "LAPC compatible", even Roland's own ones, can't do - namely the upload of instruments. Otherwise it can occur that a laser shot suddenly sounds like a piano.
Only Roland's external synths represented an alternative, namely MT-32, CM-32L, CM-64, MT-100 and CM-500 - in connection with an MPU-401 compatible sound card. An interesting detail was that lots of game producers showed their names on the module display.
Whoever puts value on compatibility with old games simply can't avoid this card, or one of these external modules!
As a side note, there was a Roland LAPC-N produced for NEC PC-98 series. It had a different format and different connectors.
The LAPC was based on the MT-32 chipset, an external synth of Roland. "LA" stands on this case for "Linear Arithmetic", and is a special sauce by Roland: It combines sample synthesis with classical subtractive synthesis, specifically supporting samples to be used in the attack phase, to make them sound more natural, and then later fading to the classical synthesis. This is opposed to sample cards and sample playback, which use single samples at different speeds or layers of samples to produce a sound.
LA can be seen as refinement to this principle, specifically Attack (which can be a sample), Sustain, Decay and Release are individually calculated and overlaid.
This has the advantage that different playback speeds (as a result of a higher or lower pitch of the original instrument) didn't play a larger role, and as the result often sounded less artificial.
This also brings a disadvantage: Layering was possible, and doing so could eat up up to 4 channels for just one instrument. The LAPC-I therefore was theoretical only in the position of playing 8 instruments simultaneously, if all instruments in use made use of all possible layers.
Purchasing it used
You almost can't do anything wrong with an original LAPC-I (often also referred as LAPC-1, which is wrong, but probably happened due to Roland using a non-serif font). What you have to be prepared for though is to shell out quite a lot of money, the card is quite rare. But if you paid it, you'll be rewarded with the best sound you ever heard from your old games!
The card is partially available with the breakout box "MCB-1", that expands the proprietary connector on the back of the card with full MIDI in/out DIN connectors. You usually don't need it, maybe with one exception: Playing back MIDI music from the DOS box (but then again, what did you purchase your DOS machine for that contains the card?).
If you want an alternative to forward LAPC-I MIDI commands from DOSBox or can't find the card and/or want to play music from a DOS machine with an MPU-401 compatible interface (be aware, Sound Blasters aren't capable of the MIDI intelligent mode/UART and hence not all games may work with those). The Synthesizer compatible with most games. If possible, try to find out if you get the most recent ROM, since older firmware versions tended to get a buffer overflow in some games like Tempest 2000 or Monkey Island and hence do not work there. The ROM chips are in sockets and can be burned on your own with the fitting equipment.
The last way to get games to play could be via the more exotic external modules CM-32L, CM-64, MT-100 und CM-500 dar, which are compatible, too. Unfortunately I don't possess them and can't tell you about any experiences.