Can the back of a large diaphragm mic be covered?

[EvanOz85]

If there is something directly behind a large diaphragm microphone (AKG 414) when recording using a cardioid pattern, will the sound quality be affected? Does the back need to be uncovered?? Thanks

 

[jcmastering]

Everything within the recording space affects the sound picked up by the microphone. In cardioid , sensitivity will be less at 180 degrees , but size , materials , and distance of the object to the mic will dictate how it affects the sound. Think of it as room acoustics , only closer to the mic.

 

[antichef]

Following some instructions on the web, sort of, I went to the container store and got a cloth box container that was roughly 14 inches per side, then I went to Guitar Center and got some acoustic foam, and cut it to fit the inside walls of the box. With the zipper top of the box open, I set it on its side, so that the "wall" facing me was exposed. I put my C414B-ULS in the box and recorded a vocal track. Then I moved the mic directly in front of (but not in) the open box and recorded a track. Then I recorded a third track without the box at all. The first two tracks sounded awful (but different from one another), and the third was much better -- so yes

 

[mshilarious]

Everything within the recording space affects the sound picked up by the microphone. In cardioid , sensitivity will be less at 180 degrees

Sensitivity may be increased at 180 degrees if you block the rear of the mic. But not overall; in a frequency-dependent manner. Your results will vary widely depending on the mic, the distance to the material, the type and size of material, etc. I would be surprised if it was an improvement though.

 

[mixsit]

If there is something directly behind a large diaphragm microphone (AKG 414) when recording using a cardioid pattern, will the sound quality be affected? ?? Thanks

To the first half of the question -yes.
Given that the mics only attenuates some of the sound from the back if there is something solid, like a wall near the back of the mic then it would stand to reason that the source is going to reflect back into the mic. Now this happens anyway even if the 'wall' is far away. The differences end up being the relative volume and qualities of the reflections vs the source -reflections with more distance are quieter, may be more diffuse and/or include more random reflections that tend to average out the deeper, fewer phase combing holes of a close reflection.
Does the back need to be uncovered? If a mic is placed directly on a baffle? -You might get a boundary mic effect (hemisphere pattern? Not sure on that one.

 

[studio139]

Most cardiod polar patterns depend on some sort of phase cancelation to generate their polar pattern . By covering the rear you may actually change the polar pattern . I know on SM58s when singers grip the mic close to the grill they become more omni and as a soundy you can begin to fight with feedback. Try telling that to a primadonna signer though!!