Congratulations! The upgrade path you've chosen by way of this thread is a good and logical one based on what and how you are recording.
My comments below are based on the following posts-
I’ll be set up in DIN/ORTF when I can get DFC, otherwise I’ll go XY at 110 degrees PAS.
My understanding of the CM4s is that they aren't true subcardioids. The product description calls them "slightly wide". I'm not presently equipped to go any wider than DIN/ORTF...
The most important part of the
gear chain is the microphones, but the most important aspect of the
entire recording endeavor is your recording location, and along with that the microphone configuration used, which dances hand-in-hand with recording location. My suggestion is to put thought into those things, as small improvements here can produce significant improvements in the quality of the recordings with little to no additional monetary cost.
You may or may not be able to improve your recording locations. Even though this is the most important variable of them all, it is often constrained by practicality, permission, venue, and social constraints. But think creatively about it, because of all the variables over which we exercise some degree of control, this one has the most potential for making superior recordings.
In contrast, we have a significant control over microphone configuration, and can relatively easily adapt that to best suit the recording location. For this reason I suggest a mic bar that allows you to adjust the spacing between the microphones as well as adjustment of the angle between them. The solution might be two adjustable mic-bars: one wide, one narrow, or a handful of 3-printed ones that you can choose between, as those tend to be non-adjustable.
So then, what stereo microphone configuration to use for what location? You will do well to try the
Improved Point At Stacks technique, which automatically reconfigures a stereo microphone pair arrangement based on the geometry of the recording location, optimizing for both clean direct-sound pickup and good stereo imaging. It's relatively simple to implement in practice- stake out the best recording location you can manage and point the mics at the PA stacks, measure the angle between the microphones, and consult a little table to determine the spacing to use between them.
The technique aims to get the clearest sound possible from the PA and stage, which can be especially helpful indoors and in rooms that are less than ideal, and will keep those somewhat wider-pickup pattern microphones focused on the sound of interest arriving from the front. The essence of the technique is this: As the recording position is shifted farther away from the stage and PA, the angle between microphones becomes narrower, and as that angle becomes narrower the spacing between microphones should be made wider to compensate. This is likely to require a wider mic-bar than you currently have for many scenarios, and when recording from a significant distance the spacing becomes rather large.
Even if not following it's recommendations exactly, it remains a good general rule of thumb for improved recordings.
You can find more information on what, why, how to measure the angle, as well as the tables below in this thread:
https://taperssection.com/index.php?topic=167549.msg2087409#msg2087409Here is a simple example of the table:
And here's a more detailed one: