If the frequency response curve (on axis) has a substantial (say, more than about 4 dB) rise around 6 - 8 - 10 - 12 kHz, that's not going to sound well balanced if you aim it directly at the sound sources at close range. That type of microphone sounds more natural from farther back, where there's more reverberant sound energy (which has bounced off of various room surfaces along the way, and had a bunch of its high-frequency energy absorbed in the process). If you have that kind of omni, you might want to try aiming it (say) 45 degrees above the main sound sources to avoid getting exaggerated high frequency pickup, which can sound harsh and uncomfortable, like biting into tinfoil.
Good point.
I’ll interject to remind people that the important basic point there is the ability to modify frequency response of the omni microphone by pointing it either directly at something or not-directly at something. But which direction to best point them off-axis is more determined by the scenario.
Aiming 45 degrees above the main source may be the best “not-directly at” option for a number of reasons, especially when the microphones are located above or about the same height as the sources- it orients the elevated high-frequency axis away from the close sources and towards the diffuse room sound were it is more appropriate, keeps the horizontal response more even than angling them outwards or inwards, involves less potential floor reflections than angling down, etc. But I find I often have microphones mounted on stands which are lower than the highest sound sources on the stage, and that the highest sources as seen from the microphone perspective are cymbals producing more high-frequency energy than any other source. So that’s a twist.
When setting up and orienting microphones on stage, a primary thing I keep in mind outside of the stereo microphone configuration itself is the relationship of all the sound sources and how to get a good balance of them in terms of level, tone and perspective. Most musicians present one or a few sound sources at most, but a drummer is effectively playing many different instruments simultaneously.
With a drummer sitting at a traditional trap-set drum kit, her cymbals are likely the highest source (in elevation) on stage as viewed from the perspective of microphones mounted on stands low enough to not be intrusive. So a lot of what I’m thinking about is my proximity to the drum kit. After shooting for a direct line of sight to the snare if I can, the next thing I’m considering is the balance of the high-frequency content from the cymbals verses the lower-frequency thump from the kick and toms. The closer to the drum kit my mics are, the more spread out in space and distinct from one another the various sounds and frequency regions of different zones of the kit become, making the details of the microphone arrangement increasingly significant in balancing the drum kit itself in tone and level, as well as stereo perspective, in addition to balancing the kit with the other instruments. I’ve found that in that situation, pointing the mics upwards over the kit often ends up tilting the overall frequency balance upwards, rather than the other way, as it often puts the cymbals more on-axis than the other parts of the kit. So instead I might point them some other direction, like maybe directly outwards to get the kit and it’s cymbals off-axis while placing on-axis the musician sources to either side of the kit which may benefit from that extra bit “air” up top.
Knowing about the difference in high-frequency pickup of omnis on-axis verses off-axis and how that works is advantageous and applies generally to all situations, yet knowing how to best apply that knowledge in a particular situation is variable and situation dependant.
Topic: omnis on stage yay or nay (Read 3986 times)