High-"eld, high-speed magnetic resonance imaging (MRI) can generate high levels of sound within and around the scanner. The process that produces the gradient magnetic "eld is the primary cause of this noise. With the push to greater background magnetic "eld strength and gradient "eld switching speed, in order to improve image quality and resolution, the noise situation is becoming worse. The noise levels generated increase the stress levels experienced by MRI patients. It is also suspected that the acoustic noise generated by the scanner during operation causes background magnetic "eld oscillations, which in turn degrade the image quality and resolution. Before any attempt to suppress the sound generated by the gradient coil cylinder can be made, the sound "eld and generating process both need to be characterised. This paper presents both the simulation and measurement results of a study of the sound radiation from a gradient coil cylinder within a 4 T MRI scanner. The acoustic frequency response function and the magnetic #uctuation frequency response function were also measured using triangular and trapezoidal gradient impulses of varying amplitudes and widths to excite the gradient coil. The measurement results and the FEA results for the sound pressure level distribution are presented and show close agreement. The results of the acoustic frequency response and the magnetic #uctuation frequency response measurements show the existence of strong responses in both acoustic and uniform magnetic "eld #uctuation spectra, while the gradient magnetic "eld #uctuation spectra show no such responses. In addition, the dominant amplitude peaks in both spectra #uctuate similarly with respect to varying trapezoidal gradient impulse #at-top widths.