Topic: Small cardiods - do you have negative results if you cover the "vents"?

[acidjack]

I made a recent recording with my SP-CMC-8's with the AT943 cardiod caps recently, also using the Sound Professionals hat mount. I had great luck using this setup with their omni caps earlier, and had similarly good luck using the cards in other situations.  I taped from the floor relatively close to center, not too far back, in a good-sounding room.  The recording is not unlistenable, but is definitely not as good as other results from these same mics in similar (or worse) rooms.

I am wondering if, because I had the caps sitting flush with the hat mount, with the side "vents" on the capsule covered, this negatively effected the recording?  Would it be better to push the mics a bit further forward so these vents were uncovered? 

The only other issues I can identify are simply that the venue sound was worse than I thought it was, or that the hat mount combined with the natural tilt of my head aimed the mics at too much of an upward angle.  I know a lot of folks use various types of mics in hats for low-profile recording, so I would be curious to hear if it's been a problem for others.

Any thoughts much appreciated.

[jnorman34]

yes, obstructing the vents on a cardioid capsule will degrade their performance.  martin schneider of neumann once commented:
"Sealing off rear sound entries will produce a tendency towards a really awful semi-omnidirectional microphone."

[Church-Audio]

I made a recent recording with my SP-CMC-8's with the AT943 cardiod caps recently, also using the Sound Professionals hat mount. I had great luck using this setup with their omni caps earlier, and had similarly good luck using the cards in other situations.  I taped from the floor relatively close to center, not too far back, in a good-sounding room.  The recording is not unlistenable, but is definitely not as good as other results from these same mics in similar (or worse) rooms.

I am wondering if, because I had the caps sitting flush with the hat mount, with the side "vents" on the capsule covered, this negatively effected the recording?  Would it be better to push the mics a bit further forward so these vents were uncovered? 

The only other issues I can identify are simply that the venue sound was worse than I thought it was, or that the hat mount combined with the natural tilt of my head aimed the mics at too much of an upward angle.  I know a lot of folks use various types of mics in hats for low-profile recording, so I would be curious to hear if it's been a problem for others.

Any thoughts much appreciated.

You can seal off one or two vents in a multi vent capsule with some change in the polar pattern. But putting anything near the vents will effect the sound of the mic and the directionality of the mic. That is why cloth is your best option for a surround.

Chris

[ideal77dlr]

When you say cloth, would covering the mics in acoustic cloth degrade the sound at all?

[Church-Audio]

When you say cloth, would covering the mics in acoustic cloth degrade the sound at all?

Covering the mics with anything will effect the frequency response to one degree or another but in most cases it will not effect the mics overall performance to much. But care must be taken to avoid cloth that does not breathe. I blow through a cloth if there is little resistance to my breath chances are there will be little resistance to sound waves.