# Obtaining an IR from a sine sweep without the dry sweep

I have a test vinyl record that includes an exponential sine sweep as one of the tracks. I have a recording of the sweep through my turntable/mixer, and now I want to calculate the system IR. The problem is I don't have a copy of the clean sweep signal. What's the best way to approach this?

My first thought is to take a best guess at the sweep start and end frequencies and the $$\Delta t$$ between them, then use that to figure out the sweep rate and manually reconstruct the original sweep. But this seems kind of clumsy, is there a better way?