Friday, October 13, 2023

Is that a Cricket I Hear? - Contemporary Sound Options for the Apple IIc

The "c" in the Apple IIc stood for compact. The Apple IIc was designed to be the epitome of the Apple II series, providing the options most people used in a realistically portable form factor but sacrificing the internal expansion slots which made the predecessor models in the Apple II line so popular. While sound cards like the Mockingboard were not the most popular of expansion cards, about three dozen games and music programs supported them. As there was nowhere to plug in a Mockingboard into a IIc, that left the IIc with only the internal speaker for audio output. But at least two sound products were made specifically for the Apple IIc, and I will take a look at one of them, the Cricket, in this blog article.

The Cricket! was an external music, sound and speech module designed by Street Electronics Corp. and released in 1984, which was also the year the Apple IIc was released. It connects to the second serial port of the Apple IIc, the one intended for modem connections. (The first serial port is intended for printer connections). The Cricket can also be used with a Super Serial Card in an Apple II, II+ or IIe but you will need a DB-25 to DIN-5 adapter for the Cricket's serial cable (wiring instructions are given in the manual.) It has an internal speaker and a 3.5mm stereo audio output jack.

The Cricket contains a pair of AY-3-8913 Programmable Sound Generator chips, which are also found on the Mockingboards (except the Speech I), Echo+ and the Phasor sound cards. The chips in sound cards are clocked at 1.02 MHz and this frequency is further divided in the AY chips to produce tones, noises and envelopes at frequencies audible to the human ear. As the Cricket was released very early in the Apple IIc's life, it supports the somewhat non-standard serial port of the original revision of the IIc's mainboard.

Cricket Internals, courtesy of Blake Patterson

The Cricket! has a speech chip, the TMS5220C, which was used in other speech devices such as the TI-99/4A speech module, the IBM PCjr. & PS/2 Speech Adapters, several Atari arcade games and some pinball machines. The TMS5220 uses Linear Predictive Coding, which combines a small vocal sample with filters and LFSRs to make expressive sounds. The TMS5220 does not have any built-in memory, so speech data has to be written to the chip. This data can construct either words or phenomes, and The Cricket! has over 700 of these stored inside the module.

Around the same time, Sweet Micro Systems, the maker of the Mockingboard cards, released the Mockingboard D in 1984 for the Apple IIc. The features of the Mockingboard D are similar to the Cricket in that it connects to Serial Port 2 but the modules do not appear to have any cross-compatibility, software must support both. The Mockingboard D has separate left and right volume controls, a pair of internal speakers and a power switch. It uses the Votrax SC-02/SSI-263 speech chip. This speech chip relies purely on phenome generation to produce speech, but it can vary the phenome qualities to a greater degree compared to the sample-based method of the TMS5220.

One unusual feature the Cricket has that the Mockingboard D lacks is the ability to function as a real time clock (RTC). The date and time can be set via the included disk and can be used by programs such as ProDOS to set correct file date and time stamps. The included disk has a program which will modify ProDOS to work with the Cricket RTC. Apple II Desktop also has support for the Cricket's RTC. The green LED on the Cricket will blink when power is attached to the device and will turn solid once the date and time is programmed. Unfortunately if power is disconnected to Cricket, the date and time must be set again. 

Speaking of software, the amount of support for the Cricket is not great. Most Mockingboard software accesses the Mockingboard directly on the expansion bus. The Mockingboard is usually plugged into Slot 4 and the sound chips are interfaced through a 6522 VIA. The Cricket is connected via a Super Serial Card on Slot 2 and serial communications are handled through a 6551 ACIA. Any software that supports the card-based Mockingboards must implement Cricket-specific programming routines to get the music and speech to the external module. The same applies to the Mockingboard D, support for the external module must be explicit.


The included software for the Cricket came on a two-sided disk. When the software boots and the RTC has not been set, it makes you set the date and time. The top side then boots to a menu where you can select five programs. Basic sentence construction can be done via the program on the bottom side, but the program is really intended to play back speech using BASIC commands. There are at least two versions of the software, one dated February 15, 1984 and another dated September 18, 1984. Images exist only of the former. There is also a special dealer demo disk. These disks only work with a Cricket and no Apple II emulator I know of emulates the Cricket.

Street Electronics had a deal with Electronic Arts because both Adventure Construction Set and Music Construction Set support the Cricket. There is also an Xmas demo that uses the Music Construction Set music scroll and it has TMS5220 speech support for both the Cricket and Echo+, the latter of which is supported in MAME. The Echo cards were also designed by Street Electronics Corp. and the Echo, Echo IIb and Echo+ all contain TMS5220C speech chips but only the Echo+ has the AY chips and a VIA to interface with them. Finally, "The Music Disk" by Walter Marcinko Jr. has explicit support for The Cricket!

While I do not own a Mockingboard D, I know it is supported by Music Construction Set, the Sweet Micro Systems' release of Crowther and Woods Adventure, Under Fire and (I believe) The Music Disk. It's accompanying software is just the Stereophonic Sound/Speech Disk included with the later Mockingboards adjusted for the D's interface. In terms of software support, both the Cricket and the Mockingboard D appear to have five titles each.

The sound quality of the Cricket! is pretty good, with the AY chips being much more lightly filtered than the "Muffleboards".  The speech of the built-in vocabulary is clear and intelligible and uses a female voice. Words based on phenomes sound robotic (the manual says as much). I posted a video which demonstrates the Cricket!'s capabilities and its exclusive software. The power adapter is a 9v DC, 500mA adapter, center positive, using a Type A barrel jack, 5.5mm/2.5mm.

I am aware of Ian Kim's Mockingboards //c and //c+, but those are not contemporary to the Apple IIc/IIc+ and are internal upgrades. They obviously have much better game support and may be more available than the Cricket! or the Mockingboard D. They do not have speech support.

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