Presenter Ian Corbett, seen through a forest of drum microphones, discussing the his techniques for selecting and positioning microphones on acoustic bass and guitar amplifier.
Author, engineer, and AES Central Region Vice President Dr. Ian Corbett visited the Central Indiana Section for a workshop on live sound in the somewhat underserved area of acoustic jazz sound. Ian shared his vast experience (his own production company, Off Beat Open Hi-Hats, specializes in acoustic jazz reinforcement) with a mixed audience of both engineers and jazz performers in a workshop setting with performers and a full complement of PA equipment for comparing and contrasting microphones, techniques, and processing schemes.
Ian opened with a general discussion of providing a positive experience for both the audience and artists. Critical points such as keeping an organized and clean stage, keeping the pre-concert process moving, and not focusing so much on small details that the totality of the mix is lost. Ian particularly stressed ensuring that soundchecks do not wear out the musicians, allowing them proper breaks and to approach the actual performance as well-rested and stress-free as possible. Finally, he emphasized that any PA system's greatest limiting factor is the speaker system itself; an inadequate or substandard set of speakers and/or power amplifiers will likely have a substantial negative effect on the show's outcome, regardless of microphones, consoles, or processing.
Moving back to the console, Ian presented the attendees with two opposing sets of microphones for each instrument in the assembled combo: drums, bass, guitar, piano, and small horn section covering trumpet, trombone, and saxes. The first set of microphones represented standard items found at most venues and rental houses, and were not necessarily geared specifically towards the needs of a jazz setting. The second set of microphones represented Ian's preferred choices for most of the sources. While there were some overlapping items, perhaps the biggest surprise was that in a number of cases the preferred microphones were in the same price range as their more common counterparts.
Each instrument was compared between sets of microphones, and a discussion of required equalization and placement differences were noted. Highlights included the strong significant differences seen in overheads between mid-range and slightly higher-end condensers, the profound difference experience in acoustic bass microphones, and the profound difference between equally priced vocal microphones. A significant difference microphone positioning approach was also explored, with a traditional "maximum isolation" explored opposed to a more natural embracing of bleed between sources.
Throughout the demonstration portion, Ian provided examples of the different approach a mixer may take on a genre like jazz, with minimal alteration of sound from the source's acoustic sound within the space, contrasted to the more commonly-employed practice of manipulating signals heavily to "shape" the sound. While somewhat hard to articulate in writing, the session culminated with the results of these different microphone setups, position approaches, and processing paradigms on display by being able to switch between the strictly acoustic sound and each set of mics/approaches independently, giving attendees a powerful example how a series of subtle differences can lead to a substantial improvement in sound quality.
