To the right of the data wheel are six keys. Two of them are the Page Up/Down keys. These are used for selecting the various "pages" of the LCD display when editing effects or modifying system parameters. The Memory key accesses the different memory areas of the SPX-990. Successive presses of this key switches between the unit's 80 factory presets, the 100 user memory locations, and the 100 user locations of the optional Memory Card. Which memory area is selected is indicated by the Memory Area Indicator mentioned earlier. The optional Memory Card is inserted into the slot provided on the front panel. The 100 user locations can be saved to a card, and the 100 programs saved on a card can be recalled into the unit's user memory. The SPX-990 has more memory locations that both the SPX-900 and the SPX-1000, and this memory card capability simply makes the unit's storage capabilities endless.

The Store Key is obviously used to store edited programs. The 80 factory locations cannot be written over, but these programs can be edited then saved to one of the user locations or the memory card with the Store Key. Next to the Store Key is the Bypass Key which, of course, bypasses all effects and sends the inputs to the outputs.

The Edit Key accesses the various parameters of the SPX-990's effects programs. When pressed, the LCD display takes you to "page 1" of that effect. The Page Up/Down keys get you to the remaining pages of parameters for that effect. Editing the effects is quite painless. If you have any experience editing digital effects algorithms, you'll find editing on the SPX-990 a breeze. The data wheel comes in handy here as do the six function keys below the LCD display.

Enough about the controls; let's take a look at what effects the SPX-990 has to offer. Each effect program is separated into three separate sections. For each program, there is the Pre-effect section, the Main-effect section, and the Post-effect section. There are four Pre-effects: 3-band Parametric EQ, Compressor, Harmonic Driver, and Compressor/Distortion/EQ. The Post-effects are the same less the Compressor/Distortion/EQ algorithm. Any one of the four Pre-effects can be applied to the input signal before it reaches the Main Effect, and any one of the three Post-effects can be applied to the signal after the Main Effects are applied. The Parametric EQ effect provides control over a 20Hz to 16kHz range with frequency, gain, and bandwidth parameters for each band. The Compressor is a stereo compressor with a full array of parameters including threshold, ratio, attack time, release time, and more for each channel. The Harmonic Driver adds harmonics to the signal to add more "presence" or "crispness." The Compressor/Distortion/EQ algorithm (found in the Pre-effects section only) is a basic distortion algorithm for an electric guitar utilizing a pre-distortion compressor and a 2-band post-distortion equalizer.

There are thirty-six Main Effects. This is where the meat of the SPX-990 is found. These thirty-six effect algorithms are used in combination with the Pre- and Post-Effects to create the individual effect programs. Only one Main Effect can be used at a time, though a few of these Main Effects are "multi" effects. The thirty-six Main Effects are separated into eight categories. The first category consists of four Reverb Effects: Reverb, Filtered Reverb, Stereo Reverb, and Echo Room. The next category has four Early Reflection Effects: Thin Early Reflection, Fat Early Reflection, Gate Reverb, and Reverse Gate. There are seven Delay/Echo Effects: Delay L,C,R, Echo, Multi-Tap Delay, Stereo Echo, Tempo Mono Delay, Tempo Stereo Echo, and Tempo Quad Echo. The "tempo" effects enable the user to program delay times based on a song's tempo or note length. The user can also "tap" a footswitch to set the delay times to match the tempo of the song. Musicians will appreciate this function, but so can you. Next time you use some generous delay on a voice track over music, try setting the delay to match the tempo of the music -- nice effect!