Important stuff that often goes misunderstood, so I’m repeating it, and adding a further insight which emphasizes the point DSatz was making (I've added the bold emphasis, because that is the part I'm expanding upon below). If all these words make your head spin and you could care less about the 'why' and just want the 'what', feel free to skip to the part below the dashed line–
..the A#1 adjustment that needs to be made, and the only one which will be really effective, is to get your microphones distinctly closer to the sound sources. By that, I mean reduce the distance by more than half.
The advice which various people have been giving you about different microphone setups and more sharply directional microphones is not wrong, but it can't help you very much. You already were using cardioids, and cardioids are already about 85% as efficient at suppressing random-incident ("diffuse") sound as hypercardioids would be. If (as it seems) your microphones were at a distance where the sound field itself is mainly made up of reflected sound energy, then by switching to hypercardioids you wouldn't get much audible improvement.
By contrast, if you put your microphones where there's an appropriate mix of direct and reverberant sound energy, then you can make a plausible recording with almost any type (pattern) of microphone.
In sound engineering there is a figure called the "distance factor" for each microphone pattern. It represents the relative distance at which you can record, by comparison to an omnidirectional microphone, and get the same balance of direct and reflected sound as the omni would pick up. The highest "distance factor" you can get with a first-order microphone is only 2.0.
Say that you record with an omnidirectional microphone at a distance of 10 feet from a sound source; you'll get a certain percentage of direct sound and a certain percentage of reflected sound, adding up to 100%. Now take a cardioid microphone instead of the omni, and ("all other things being equal") you can place the cardioid about 17 feet away from the sound source, and the resulting mix of direct vs. reflected sound will be about the same as what the omni picked up at 10 feet. The cardioid pattern has a "distance factor" of 1.7, in other words.
But as I said, the maximum available distance factor is only 2.0 (hypercardioid pattern); the most sharply directional microphone available would let you record at a distance of 20 feet and still get the same balance of direct to reflected sound energy as the omni gave you (though the result would sound rather different for a variety of reasons). And my point is that the difference between cardioid and hypercardioid is just that 15% (3 feet out of 20) in terms of the distance factor. So you can switch to other, more strongly directional microphones, sure--but doing so won't reduce the proportion of room reflections by much.
There is another important thing to consider which further reduces the effectiveness of a more directional microphone’s distance factor when used in typical stereo configurations. The
distance factor of a directional microphone is applicable for sound arriving on-axis. If your stereo configuration orients the microphones so that they are angled apart as most configurations using directional mics do, then the ‘distance factor’ of the combined stereo pattern is even less than that of each individual microphone. Taken to a ridiculous extreme, if two cardioids are oriented 180 degrees apart, even though each microphone has an individual distance factor or 1.7, the combined stereo pattern would have a distance factor of only 1. The only way to make the distance factor for the combined stereo pair equivalent to that of the individual microphones is to point the microphones in the same direction. That’s one reason I’ve suggested substituting more spacing for less angle between mics when forced to record from farther back than what would be ideal. The extra spacing helps counter the negative aspects of having a reduced angle between mics.
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The practical configuration that many arrive at through experience around here without knowing anything about all this distance factor stuff is pretty close to that- Point At Stacks optimizes the distance factor for direct sound from the PA. The suggestion I would make is to space the mics apart more than I commonly see people doing with PAS when the angle between the mics is relatively small. Doing that will maximize the directivity factor of the microphones for pickup of direct sound from the PA, while using the spacing between the mics to provide a wider stereo image that is less ‘mono’ sounding.
If you want to get technical about your PAS spacing and know how to read the Stereo Zoom charts, check them for the microphone pickup pattern you are using and the inclusive angle you end up with and the chart will indicate an optimal spacing.
If you just want a general PAS spacing rule of thumb, then how about this-
if your carioids are angled less than 90 degrees apart, space them more than 12”, and
if your supercaridoids are less than 90 degrees apart, space them more than 8”. If you are so far away that the mics end up nearly parallel, then space them like you would omnis, say 2'-3', regardless of their pickup pattern.In my opinion, the most important statement in the entire thread is below, which bears repeating with enlarged bold emphasis, not because I have anything to add, but simply becaues it's so true! -
There are no miracle microphones that can "reach in" and pick up direct sound from distances where the sound field is primarily diffuse. That's why I'm saying that microphone placement is far more relevant here than any discussion of different microphone types or even of stereo miking arrangements, although they're important.
Like Chris and Bean also emphasised, get the mics closer!
Topic: Best taping methods/gear to record in "boomy" venues? (Read 11958 times)