A vehicle noise, vibration and harshness, NHV, testing method, the method comprising: sampling the frequency and amplitude of a noise at discrete intervals over a plurality of time periods to produce time domain sampled data; storing a copy of the time domain sampled data; performing a first processing operation which comprises: converting the time domain sampled data into a frequency domain signal; and comparing the frequency domain signal with a plurality of discrete frequency domain buckets, each bucket of the plurality of buckets corresponding to a respective predetermined frequency range of the frequency domain signal, wherein the comparing comprises comparing the amplitude of the frequency domain signal across the frequency ranges of two or more of the buckets; and selecting a bucket in which the amplitude of the frequency domain signal is greater than the amplitude of the frequency domain signal of at least one of the other buckets, wherein the frequency domain signal of the selected bucket represents a noise event; and performing a second processing operation on the frequency domain signal of the selected bucket to measure the amplitude and frequency of the noise event in order to evaluate the noise, vibration and harshness of the noise event, the method being characterised in that the second processing operation comprises: converting the frequency domain signal of the selected bucket into a time domain signal; subtracting the time domain signal from the stored copy of the time domain sampled data; determining an error value representing the difference between the time domain signal and the stored copy of the time domain sampled data; determining a frequency, phase and amplitude modification to the time domain signal to reduce the error value; and using the frequency, phase and amplitude modification providing the lowest error value as the amplitude and frequency of the noise event to more accurately evaluate the noise, vibration and harshness of the noise event. sampling the frequency and amplitude of a noise at discrete intervals over a plurality of time periods to produce time domain sampled data; storing a copy of the time domain sampled data; performing a first processing operation which comprises: converting the time domain sampled data into a frequency domain signal; and comparing the frequency domain signal with a plurality of discrete frequency domain buckets, each bucket of the plurality of buckets corresponding to a respective predetermined frequency range of the frequency domain signal, wherein the comparing comprises comparing the amplitude of the frequency domain signal across the frequency ranges of two or more of the buckets; and selecting a bucket in which the amplitude of the frequency domain signal is greater than the amplitude of the frequency domain signal of at least one of the other buckets, wherein the frequency domain signal of the selected bucket represents a noise event; and converting the time domain sampled data into a frequency domain signal; and comparing the frequency domain signal with a plurality of discrete frequency domain buckets, each bucket of the plurality of buckets corresponding to a respective predetermined frequency range of the frequency domain signal, wherein the comparing comprises comparing the amplitude of the frequency domain signal across the frequency ranges of two or more of the buckets; and selecting a bucket in which the amplitude of the frequency domain signal is greater than the amplitude of the frequency domain signal of at least one of the other buckets, wherein the frequency domain signal of the selected bucket represents a noise event; and performing a second processing operation on the frequency domain signal of the selected bucket to measure the amplitude and frequency of the noise event in order to evaluate the noise, vibration and harshness of the noise event, the method being characterised in that the second processing operation comprises: converting the frequency domain signal of the selected bucket into a time domain signal; subtracting the time domain signal from the stored copy of the time domain sampled data; determining an error value representing the difference between the time domain signal and the stored copy of the time domain sampled data; determining a frequency, phase and amplitude modification to the time domain signal to reduce the error value; and using the frequency, phase and amplitude modification providing the lowest error value as the amplitude and frequency of the noise event to more accurately evaluate the noise, vibration and harshness of the noise event. converting the frequency domain signal of the selected bucket into a time domain signal; subtracting the time domain signal from the stored copy of the time domain sampled data; determining an error value representing the difference between the time domain signal and the stored copy of the time domain sampled data; determining a frequency, phase and amplitude modification to the time domain signal to reduce the error value; and using the frequency, phase and amplitude modification providing the lowest error value as the amplitude and frequency of the noise event to more accurately evaluate the noise, vibration and harshness of the noise event.