per
Veteran Member
In 1988, there were two main MIDI hardware synthesizers for the PC, the Roland LAPC-I (Roland CM-32L) and the IBM Music feature card (Yamaha FB-01). As we all know today, the LAPC-I outran IBM's option after only a coupple of months on the market for various reasons. I have now been able to test both cards, and I'm therefore able to say a little about what I think these 'various reasons' are.
Interface:
Sound Engine:
Effects:
Amplifier
Of course factors like avaiablilty, compability and price also plays an enourmous role when it comes to the sale numbers.
Interface:
- IBM's card has a unique interface designed by IBM. Commands are sent/received as 8+1 bits per byte, and timer/interrupt cirquits are provided for timing. A large degree of hardware-controll is provided, which makes the interface flexible, but somewhat complicated to program. Any commands sent externally has to go through the internal MIDI interface, which is a part of the synth engine itself.
- The Roland LAPC provides the MPU-401 interface which can be either put into "intelligent" or "UART" mode. In "intelligent" mode, the card's hardware does all the timing and the host computer only has to send data on interrupr, but in "UART" mode the timing has to be done by the host. In difference compated to the IBM card, the entire synth is separate from the MIDI interface, which limits the low-level controll as the MIDI interface is the only way to communicate with the synth.
Sound Engine:
- IBM's card uses 4-op FM, which gives it it's distinctive "Yamaha"-ish sound. FM is generally great for making periodic noise, especially in the lower register, but it generally have issues with anything that's not periodic (like percussion). FM was never meant to sound like real instruments, so simulated real-world voices tend to sound a bit cheezy.
- Roland's card uses a special "Linear Artimetric" synthesis, which can remind a little about sampling and filtering. It therefore gives greater flexibility, and it's able to generate very good percussion sounds. It simulates real sounds quite well, but you can still clearly hear it's a synth playing. However, it's not made for generating sounds which change in timbre over time (this effect is possible on IBM's card).
Effects:
- The IBM card came completely without any effect generator. What you hear is what the synth produces of sound. However, the synth itself does have a volume envelope for every of the 32 operators.
- The LAPC-I, on the other hand, got a BOSS Reverb controller coupled to it's audio output. This does make quite a difference in the audio, but over-usage may make tunes sound like '80s pop songs.
Amplifier
- The IBM MFC is based on a set of 8x 4556 amplifiers and some analog components (transistors, etc..). It's earphone output is designed for High-impedance earphones (125 Ohm), and it sounds like the amplifier isn't capable of sourcing enough current through my 36 Ohm earphones. The output sound is of acceptable loudness, but not especially notable.
- The LAPC-I have a different amplifier, generally consisting of more amplifiers and analog components. Compared to the MFC, the LAPC-I amp is crowded with components. The LAPC-I plays WAY louder than the MFC, and it's able to source the earphones with such amounts of current that it's clearly audible that the left earphone got a deffect on the membrane (To do the same on my recent PC, I have to turn everything up to max plus I have to double the output volume of the data by using software).
Of course factors like avaiablilty, compability and price also plays an enourmous role when it comes to the sale numbers.
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