Pinball sound systems

Modern solid state pinballs have a carefully designed sound canvas including music, speech and sound effects. The game comments and instructs player by telling what to shoot for. But even in the old EM machines there were sounds present other than just clicking of relays. Let's see how the pinball sound systems have evolved during the years.

As early as 1933 there was a sound effect in pinball. Harry Williams's Contact had a bell that was hit by a ball going to a hole. Considering that this was the first machine to have an electric device moving the ball, it must be noted that Contact was quite an advanced machine! When the electromechanical score counters came into use, they often had a lever that stroke a bell in step with scoring. That soon evolved into two-bell system, where 10.000 points sounded one bell and 100.000 points another. Of course the replay knocker was present already then, making the rewarding noise when player scored a replay.

Left coil is the knocker, right one rings a bell.

In the 1960's, score reels replaced the advancing light scoring. Also score inflation was reduced by removing unnecessary zeros from the score. Accompanying the score reels was a three tone chime box, where a solenoid hits a metal bar with plastic head plunger, making quite nice sounds. The lowest chime was usually connected to 1 point scoring, next one for ten points and the high chime for 100 points. Not all machines had a three note chime, some used only one bell. On some Bally games, a plug could be moved from one hole to another in the backbox to select what score reel rings the bell. In this golden era of pinballs, noise and atmosphere at the arcades were quite high when tens of pinballs played their chimes.

A three tone chime box.

Sample of an EM pinballs chimes (83 kB)

The first solid state machines had a similar chime box. But now there weren't any relay clicks anymore, although Williams's first SS games had a single scoring reel hidden inside the game to confirm scoring to player. It was feared then that the players would not like a machine that doesnt make clicking noises, but fortunately that did not happen and the noise reel did not stay in use for long. The mechanical chime box had one shortcoming. Its volume could not be adjusted. Some operators damped the sound when the location demanded a quieter game, but most of them just disconnected the chimes. The game was totally silent then. Hardly fun to play anymore.

Because electronics had already replaced mechanical score counters and relays, it did not take long before also the chimes were replaced with electronic sound boards. Gottlieb's System 1 game Close Encounters was equipped with "new space age sound", or a three tone beeper, to be precise. Three square wave oscillators made of 555 timers and an LM380 amplifier made lots of sound, if not so beautiful then at least new. The principle was as before. 10 points made a low beep, 100 points a little higher and 1000 points a high pitched beep. And as the volume was now adjustable, usually a compromise was found between players and location owner. The three tones combined to very modest memory capacity of those games were not suitable for music playing, only very simple tunes could be heard at coin insertion and game starting. Bally and Williams skipped this simple sound board phase and started with much better systems. The Bally board could make better waveforms instead of harsh square wave, and it had an envelope generator to make sounds more chime-like. The Williams board made either chime tones, or quite strange bubbling sound effects, depending on switch setting.

Old Bally sounds (53 kB)

Soon the microprocessor found its way into sound cards. Gottlieb's System 1 games starting with Totem had a board with 6504 CPU, that could generate various sounds with an 8 bit D/A converter. Also these boards had two different sound sets that the operator could select by switch setting. Of course, Williams soon followed, adding a revolutionary feature to its board. That was the MC3417 CVSD decoder, sort of D/A converter that could generate sound with less memory capacity than plain DAC. That was important because the sound boards did not have many kilobytes of ROM space then. With the CVSD, mechanical sounding but still intelligible speech could be produced. Williams's Gorgar was the first talking pinball. Its vocabulary was only seven words, but they could be combined to form many sentences. Bally took a different way for its talking games, and used a Texas Instruments TMS5200 chip, that produces speech with even less bit rate than CVSD. But the CVSD could also make sound effects, when the Texas chip only produced speech. An interesting game was Bally's Centaur, where there was an analog shift register echo circuitry, or "Say It Again" module connected to the TMS5200 board, to make a dramatic echo to the speech. And we all remember Bally's Xenon, the first pinball to talk with female voice.

Gorgar speaks!(56 kB)

As the processor technology evolved and memory price dropped, the sound boards have developed on. A while before Bally / Williams merging Bally developed a new sound board that used a 16 bit 68000 CPU to play music and effects, and of course also speech. Williams stayed with 8 bit 6809 CPU and an FM synthesizer OPL2, familiar from early PC soundcards, and of course a CVSD. The OPL made music, CVSD generated speech and other noises came from an 8 bit D/A converter. This system was used until it was replaced by a DSP processor based board. It used an Analog Devices ADSP2105 DSP to play digitally compressed samples in 6 channels. The board was called DCS for Digitally Compressed Sound and first used in Indiana Jones. Actually, Twilight Zone was supposed to be the first DCS game but the board did not get ready in time, and Williams had to resample the sounds for the old sound board. DCS is like MP3 compression, and produces 16 bit sound with 32 kHz sampling frequency. Almost like CD.

CVSD/OPL2 sample (68 kB)

DCS sample (156 kB)

Bally and Williams sound boards have all been mono versions. Data East, later Sega, now Stern, has made games with stereo sound. The first was Secret Service, that had an OPL2 and DAC based sound board with stereo output. Unfortunately the DE sound design department was not quite at the same level with Williams, and the sounds are not nearly as good. Sega then developed a BSMT2000 sound system, that compresses the sound a bit like DCS. But its frequency range and sound quality do not match those of DCS, unfortunately.