By Cesar Arevalo | Audio Specialist.
Guitar amplifier simulators have been improving during the last couple of years. Right now we are able to use impressive tools like the BIAS Amp designer by positive grid or the circuit customizable Revalver by Peavey. While the first one gives you the freedom to customize your sound through a complex and long chain of preamps, tone selectors, power amps, equalizers, and even transformers; Revalver allows the user to modify the electronic circuit within your amplifier simulator in order to develop a more customized sound. About Bias, John Walden stated: “Select the preamp and a whole host of components and settings can be adjusted. While you would probably need a Ph.D. in electronics to make any informed choices when configuring the equivalent options in the design of a real (hardware) amp, in BIAS you are free to simply experiment and see where it leads you”.
I have spent a couple of years collecting impulse responses from many amplifiers’ cabinets, these impulse responses have been obtained by exciting different cabs with test measurement signals to record the signal through different types of microphones in order to capture the whole system’s behavior. The main reason to do this is the fact that the performance of a microphone interacting with a cabinet and a room is something that involves not only the acoustic characteristics of the place, but also the electronic and physical features of the diaphragms, circuits, and the technical equipment. This is the instance where simulators tend to lack accuracy. Usually, I would bypass the cabinet’s stage on the virtual simulator and use a convolver to load these impulse responses instead.
Finally, I would like to mention a variation of this method where instead of using the simulator for the amplifiers’ head, I have implemented an actual Marshall’s head, which signal was taken straight from its line output into Pro tools by using a DI box, and lastly using the IR-L convolver to apply an impulse response for the cabinet instance. This procedure was made in Studio B at the Maxwell building at Salford University (Manchester, UK).
