How Do I Invert The Y Axis Motion Of This?

Question

I'm making a little game for iPhone that involves whistling. The phone hears the frequency of your whistle, and sets the position of a sprite on the screen accordingly. Here is the code:

if frequency > 1000 then
    soundbar.y = (frequency-1020)/10+30
end

This makes the bar move between 30 and higher on the y axis, with the highest whistling register being at about y 400, which is fine. There is only one problem. The higher you whistle, the further down the bar goes. Is there any way I can edit my formula, so that the bar starts at 208, and as the pitch increases, the bar rises?

Thanks :) This has had me stumped for a while!

Answer 1

208 - ((frequency-1020)/10+30)

which simplifies to...

178 - ((frequency-1020)/10)

or even...

280 - (frequency/10)