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Linear Arithmetic 32
LA32 - On a CM-32L.jpg
Developer: Roland
Released: 1987-??-??
Type: Chip

1.) LA Synthesis
2.) LA Synthesis
3.) LA Synthesis
4.) LA Synthesis
5.) LA Synthesis
6.) LA Synthesis
7.) LA Synthesis
8.) LA Synthesis
9.) Rhythm Synthesis

MB87136 aka Linear Arithmetic 32 (LA32) is an audio chip designed around 1987 by Roland and used in several of their synthesizers. The chip uses traditional subtractive synthesis combined with PCM-based samples on the attack portion of the instrument to give a sound superior to what subtractive synthesis can achieve alone.

The term "linear arithmetic" is derived from the facts that the synthesis is all digital (linear) and a summing (arithmetic) of sounds.

The chip features 8 melody channels of LA synthesis and 1 rhythm channel.


The following synthesizers and sound cards utilized the MB87136 or its variants:

Release Device Notes
1987-??-?? D-50 A keyboard synthesizer.
1987-??-?? D-550 Rackmount version of the D-50.
1987-??-?? MT-32
1988-??-?? MT-100
1988-??-?? E-20 A home marketed arranger keyboard.
1988-??-?? E-10 Cut-down version of the E-20.
1988-??-?? D-10 A keyboard synthesizer. Partially compatible with MT-32.
1988-??-?? D-20 D-10 with a build-in sequencer and floppy drive.
1989-??-?? D-5 Reduced version of the D-10 with mini-sized keys.
1989-??-?? E-5 Cut-down version of the E-20.
1989-??-?? Pro-E 37-keys version of the E-20 without speakers.
1989-??-?? RA-50 Modular version of the E-20. Compatible with MT-32, but requires hardware modification.
1989-??-?? LAPC-I
1989-??-?? LAPC-N
1989-??-?? CM-32L
1989-??-?? CM-64 CM-32L + CM-32P
1990-??-?? D-110 Rackmount version of the D-10 with a build-in sequencer.
1990-??-?? E-30 Enhanced version of the E-20.
19??-??-?? CM-32LN Version of the CM-32L for the NEC PC-9801N notebook series.
1991-??-?? CM-500 CM-32LN + CM-300


This chip has several different variations, electrically compatible with each other, but differing in pinout.

  • Original MB87136 - 88-pin PGA version. Was used in old revisions of the D-50, D-550 and MT-32.
  • MB87136 (LA32) - 100-pin QFP version. To distinguish from the 88-pin version, it's bears LA32 on its top surface. Was used in new revisions of the D-50, D-550 and MT-32.

Picture Gallery

Emulation Status

By its very nature, the Munt MT-32 emulator, emulates the LA32 chip.