Double Bass Mic users: Check this out

[seamonkey]

Forgive me for being skeptical, but technically this doesn't make any sense. All directional* microphones work by receiving sound from the sides and rear which is then canceled since it's out of phase with the sound coming from the front of the mic. If you block sound from entering a directional microphone from the sides and rear, you are effectively eliminating its directional properties. This is really basic stuff from an audio engineering standpoint.

Although I know the laws of physics haven't changed, I have been out of the audio business for some time and don't keep up with the latest, so please take this FWIW.

...

I have to agree. The bass isn't must making it's own sound, it's also reflecting sound from the rest of stage. The only chance the mic has to eliminate this reflected sound coming from the same direction , is by design, and cancel it out. Mic designers spend a lot of time figuring this stuff out, you would think if it's so simple they would have thought of it.
But I'm sure manufacturer of these could do a polar chart of stage noise with and without one of these and show the measurements.

 

[larry]

I have to agree. The bass isn't must making it's own sound, it's also reflecting sound from the rest of stage. The only chance the mic has to eliminate this reflected sound coming from the same direction , is by design, and cancel it out. Mic designers spend a lot of time figuring this stuff out, you would think if it's so simple they would have thought of it.
But I'm sure manufacturer of these could do a polar chart of stage noise with and without one of these and show the measurements.

You guys are thinking too much. It's not much different than using gobos in a studio. It's just a sound-absorbing physical barrier between the mic and sounds you want to keep out of the mic. That's all. I've used this gizmo on several dozen gigs, and it has made a big improvement.

 

[moles]

+1
AFAIK, to get the effect of cancelling out the polar pattern of the microphone, you'd have to actually block part of the mic from receiving sound. That's not what's happening here - really you're just controlling how much ambient sound reaches the mic. Whatever does reach the mic is still subject to the polar pattern of the mic.

 

[larry]

I was wondering how it sounded recorded, so I split the mic signal and ran it into a little recorder I have.

This is a gig in a very live room. This is my Lascala into a Beyer M88 which goes into the PA. No amp. I am standing next to the drummer's right side ride cymbal which is less than 2 feet from the mic with the IR filter.

It's not total isolation by any means, but it is WAY better than without.

 

[Chris Fitzgerald]

Sounds good, Larry. I don't know squat about the acoustics involved in the process, but that sounded pretty clean.