Using a blimp system indoors?

[Colbern Rae]

I was wondering, a general audio question, if I use a full blimp system on my shotgun mic indoors as well as outdoors, will the indoor audio where there is no wind suffer in some way by having an "over the top" wind protection system when there is no wind? should blimps be reserved for windy conditions and foam be used indoors or not?
Thanks!

 

[ericyoung]

Blimps are designed to be as near to 100% acoustically transparent & neutral as possible to audio frequencies while still protecting against wind noise & rumbling, so it's fine to use them inside too.

However, if there's the opportunity to lose it and somewhere safe to put it, then why not? It will save considerable weight & bulk which is always desirable, and none of them are actually 100% transparent/neutral, even if the best are very close.

Edit: I've never heard of this "black hoie" effect - blimps merely passively slow down airflow, but don't damp air vibration, so how can they produce a vacuum? I suppose it's possible they could act like an aerofoil in high winds outdoors (especially the ones which are larger at the front than at the back), and cause lower pressure on one side than the other, but that won't happen indoors with no wind.

 

[Brian F Kobylarz]

The blimp provides an acoustic envelope that can be beneficial both indoors and out. For example, one can introduce noise by simply moving a bare mic too quickly indoors.
While a foam windscreen can help in that regard, the foam versions do not have the built-in isolation mounts that blimps employ. Hence, more handling noise can be introduced...

Edit: Mark may have a point I am not aware of. Any chance you can provide a link to this issue?

 

[Marc Wielage]

I think it's a very bad idea to use a full zeppelin and windscreen indoors. In fact, full-size shotguns often don't work well indoors -- you need a mic with a different throw, one that can handle closer wall reflections, on indoor shoots. Hypercardioids are often a better choice, and you only need s small foam cover on the front just in the unlikely event you bonk the actor on the head and maybe give the capsule a little protection in the event of a quick boom move.

The one possible exception for a windscreen would be cases where there's uncontrollable blasts of air indoors, but in that case you've got bigger problems than wind to deal with.

 

[Brian F Kobylarz]

What Mark is mentioning about the use of full sized shotguns indoors is quite valid.

Selection of the right mic in any environment is part of the skill set of the person responsible for audio. Without that base knowledge and application, other choices are the least of your problems.

That said, as a personal preference, I will often utilize a blimp over a cardioid condenser such as the Sennheiser MKH40. I've had extremely good results - switching between the pistol grip and pole takes seconds and the iso mount inside the Rycote reduces handling noise considerably.

 

[PatrickFaith]

On the cmit5u there is a frequency contour switch for use with blimps, so the mic sounds ok with the blimp on or off. The problem with the switch is remembering to flip it if your going inside and outside a lot. I recently did a bunch of tests on this, with schoeps mics, with high end blimps using foam and the high end rycote fur. Outside atleast in california there is this background "white noise" so inside to outside mic comparisons didn't mean much because the ambient noise changed the sound characterstic too much. Inside if your not on a nice sound stage, the high frequency reduction of a full blimp on the cmit5u is ok (it cracks me up but it's important to comb the fur). Also if the room is "open" to the air, i.e. your in a barn and the barn door is open, I think it's good to use the blimp. If your moving a lot inside (i.e. following a person), the blimp is good. On the blimp it's the fur that really helps on air movement. If I had a controlled room for sound, the blimp for sure goes off, if there is anything slightly musical you can really tell if the blimp is on. If it's a "close" or whisper type of communication the blimp has to go off.

I have two nice high end blimps, both of them have a frame then foam then fur. The shotgun blimp i have to take off the fur in one step, but then the foam part comes off really easy with two twists. I now have a small plastic box to keep the blimps and the fur.

For inside i mainly use the smaller ccm41 supercardioids( like Marc was saying, the ccm41 is getting close to a hypercardiod and is just awesome inside, is really small too so it's not this huge distracting thing in peoples faces). [i don't work with full time actors so it's real important for me NOT to have the huge blimp on in the actors face since it's so distracting - for low budget actors doing anything i can so the lines aren't muffled and they are relaxed is my top priority] On my higher end surround blimps (using ccm41's), it's a bit of a hassle taking the foam and fur off. On my large blimp for 4 ccm41's the frame is independent of the foam, so I always have the frame on but the foam and fur is off. On the ccm41 supercardiod (these are small high end shotgun type mics) it makes a big difference not having the foam or fur on them inside (and there is no compensation switch).

On the cmit5u, the "speech enhancement" switch you need to turn on if the blimp is in place, it is on the back of the mic - so with the high end rycote you just twist the back of the blimp off and turn that switch on if your inside. Basically on the cmit5u I think it's fine to leave the blimp on if there is no place to put the blimp, but I always take off the blimp if I have my box. Also if inside there is a lot of movement, even with people walking or running by, I think there are some positives of keeping the blimp on. It's also very important to keep the fur clean, on the cmit5u, so I tend to just put the fur and the two ends of the blimp off inside (I think it's perfectly fine keeping the central frame of the blimp on inside minus the foam and the fur). I have a tendency to store the cmit5u with the blimp and fur on, just for space reasons and to not forget anything when I take it.

On my 416 really i don't use a blimp on that outside, low end blimps and foam HAS to come off inside, and I take it off outside too unless the window is real bad. (i.e. any blimp under $500 is low end, it's real expensive to create a blimp and mic combination that doesn't color the sound)