How do I get Spooky to add two sine waves? I tried putting one sine wave on each channel and looked at the result via the boost cable on my scope set to spectrum analyzer.

Since you were using the boost to sum the two sine waves, you will most likely need to invert the sine wave on out 2 to achieve what you are after.

The output of out 2 is inverted by default by the boost wiring, so inverting the waveform for Out 2 by selecting the sine wave and using the invert tick box (not Follow Out 1) is required to keep both sine waves in phase.

Otherwise, the output of Out 2 will be a sine wave that is 180 degrees out of phase with Out 1. This will yield different results on your spectrum analyzer even if the frequency on Out 2 is different.

The alternative is to use Sine/Inverse+Sync and do your summation using Add F1 to F2. However, this will be limit your choice of Out 2's frequency to a multiple of Out 1.

I'll give you both methods so you can try both.

Method 1: Inverse+Sync + Add F1 to F2

Select Sinewave for Out 1, Select Inverse+Sync for Out 2.
Bottom left corner of the program, check and enable Add F1 to F2
Just above where it says F2 = F1 x 1 Hz 0 Phase, set X = to a value that will derive the frequency you wish to have on Out 2, relative to the frequency being used on Out 1.

Again this method requires that Out 2 be mathematically related to Out 1.

Method 2: Sine / Inverted Sine

Set Out 1 = Sinewave
Set Out 2 = Custom Waveform (4th from bottom). Specify Sine and check the invert waveform checkbox that follows the drop down list.

Set Out 2 = (Out 1 x #) + # - [checkbox] Hz to the value you wish to use.

Examples:

You can set Out 2 = (Out 1 x 11) + 0 - [unchecked] Hz to specify that Out 2 is 11 times the value of Out 1.
You can set Out 2 = (Out 1 x 0) + 17420 - [unchecked] Hz to specify that Out 2 is to be a static 17420 Hz regardless of what Out 1 is.

Hope this is enough information to get you going.

For more details, please check the link:
http://www.spooky2.com/forums/viewtopic.php?f=71&t=4821