function addNote(instrument, index, data, pitch, velocity)
    local numNotes = 48

    local originalNumData = #data
    -- Only runs if index is bigger than #data, and populates 0's until index
    -- note that index is 0-based and inclusive
    for i=originalNumData+1,index-1,1 do
        data[i] = 0
    end

    local instrumentData = pcmSets[instrument]
    local numInstrumentData = #instrumentData

    -- Early pitching attempt, hopefully becomes FFT later

    local pitchMult = math.pow(2,((numNotes/2)-pitch)/12)
    -- Gives us 0.25 to 4 for 48 notes, or 1/4 to 4x freq

    local curDataIndex = 1
    for i=1, numInstrumentData, 1 do
    -- This handles both duplicating notes and interpolating
        while curDataIndex <= i*pitchMult do
            local curData = data[index+curDataIndex] or 0

            local newData
            if pitchMult < 1 then
                newData = InterpolateHermite(instrumentData[i-1] or 0, instrumentData[i] or 0, instrumentData[i+1] or 0, instrumentData[i+2] or 0, (i*pitchMult)-curDataIndex) * (velocity/128)
            else -- No interpolation when duplicating?
                newData = instrumentData[i]*(velocity/128)
            end

            -- Next we try a thing to mix them well
            local m
            -- Make them unsigned
            local newDataU = newData + 128
            local curDataU = curData + 128
            if newDataU < 128 or curDataU < 128 then
                m = newDataU * curDataU / 128
            else
                m = 2 * (newDataU + curDataU) - (newDataU * curDataU) / 128 - 256
            end
            -- Sign it...
            if m == 256 then m = 255 end

            m = (m - 128)*0.9 -- Keep volume from oversaturating...

            data[index+curDataIndex] = m

            curDataIndex = curDataIndex + 1
        end
        -- then keep duplicating it if it's still positive

    end
    return data
end