Transfer Function measurements offer significant advantages over traditional Band Spectrum measurements for loudspeaker calibration, providing phase, coherence, and reflection arrival time data. This is crucial as more loudspeakers come with built-in signal processing, including phase correction. Transfer Function measurements ensure that such processing aligns with the speaker's phase correction. However, Transfer Function measurements require two channels: a reference signal and a microphone. In environments with limited routing options, this can be challenging. The paper introduces "Virtual Reference," a method that simplifies this by using a recording of the reference signal. Virtual Reference compares the microphone signal to this recording and plays its own reference signal when necessary, allowing the analyzer to operate normally. Additionally, Virtual Reference addresses samplerate discrepancies between devices, ensuring stable phase traces and accurate measurements despite minor deviations in samplerate.