Boundary Mic for speeches
 

Hi All

I had a situation on the weekend where speeches were done with a handheld mic thru the DJ's PA system so it was tricky to get the talent to stay in one place (the DJ also forgot his mic stand!!)

My usual method is to clip my UHF lav to the mic in the stand so I can get reasonable audio and then use the Rode Videomic on the main camera as a backup. The talent stood at the end of the bridal table so they would have somewhere to put their notes so I decided to forego the usual lav and plugged one of my little AKG 401 boundary mics into the transmitter and dumped it on the bridal table.

Gosh!! Nice audio !! Even the audio from the PA was crisp and clean and sounded really great. The comparison channel with the Rode had the same output but was way more "echoey" The boundary mic was probably picking up a combination of the talent's voice and the PA output but the end result was excellent!!!

I just made one error and left the module close enough to the table end where papers could be placed on or near it!! Didn't seem to affect the mic UNTIL they started fiddling with their notes!!!! Next time the boundary mic will be placed out of the way of fiddling fingers!!!

Anyone else here tried a boundary mic in different places where the over-riding audio is likely to be from the PA speakers...?????

Chris

Wow interesting. I'd never heard of boundary mics and just quickly read up about them now. Still a bit lost - what exactly do they do? And what model mic do you have?

We've been struggling with this situation (wireless mic and nowhere to place our own mic) and I'm almost decided to just start lav mic'ing everyone who makes speech.

Hi Erik

Mine are AKG C400BL .. they are really tiny too about an inch long but do need to be powered. My friend Chip found a batch of these that came as pairs with a powered mixer which supplied the mic phantom power but they work beautifully from a radio mic transmitter... phantom power can be anything from 9v to 52v (My UHF Azdens run on 9v batteries)

The big issues with speeches is the fact that a lav will also pick up audio from the PA system (including bad audio!!) I must admit it's quite an issue trying to wire up a person before they come up to make their speech (unless, of course, you have unlimited transmitters!!)

They do seem to give a more crisp output than lav mics and are also pretty good if the talent to mic distance changes a lot. Asthetically the footage looks better without a big mic stand in the way. I usually use lecterns if the venue has them and the boundary mic works really well placed on the lectern and is completely hidden from the camera view

Chris

And this is why I use a mic in front of the DJ or bands speakers (well 1 speaker anyway) and my on board hypercaroid. Even if the person using the mic, which is usually some sort of SM58 type, down by their bellybutton, I still get the voice with the hypercaroid. Not as good as getting it with both mics but still usable.
In my area they never use a lectern at the reception, generally they stand at the head table OR on the dance floor so I can get in pretty close.
Again it just shows there are many many ways to "skin a cat".
O|O
\--/

We now use two boundary mics on the top table connected to a fostex frs2 recorder for all our weddings, the fostex provides the phantom power and records to BWF audio.
They do a really good job and we also use them during the service, hidden from view of course.
This combined with a wireless lav and on camera mic hopefully covers us.

As a fellow devotee of BL mics for weddings, I'd add two points to Chris's praise.

First is that the inserts in BL mics can be omni or cardiod (OK, actually half cardiod). Choose the cardiod to minimise pickup from the PA.

Second, because of the extra cabling, BLs are liable to pickup mobile phone interference. That's why we use AT's U series which are shielded. Ours are also white which reduces visibility.

Finally, the biggest downside is guests, often male and of a certain age who don't applaud the speeches but hammer the table. That's when you wish you'd clipped on an MKE2-4!

Thanks Philip!!

The only issue for me was the paper being put directly over the mic so they was some rustling noise (I used the audio from the Rode mic to cover my butt there!!!)

Our people tend to just clap and maybe a whistle or two but not violent table pounding at all thank goodness!!! I see my manual says that the mics can be painted too (the outer shell just clips off for this)

I wonder how effective the mics would be if the speeches were done on the dance floor and you placed the mics on the actual floor??? I see that BM's are often used on stage floors (front and centre) ??

Chris

Have you tried hanging your BLs on the walls (front, sides, rear)?
That will eliminate the localized sounds of paper rustling, cups/glasses clunking, pounding, etc.

Chris, I used one on the marble floor of a church a month back - for the priest who maintained a 10ft gap between himself and the couple for most of the ceremony - great sound.

Ed. the BL mics have to be in firm contact with the surface. That aside the surface can be at any angle. However, remember if you're using mics like ours which are cardiod, you need to consider the pattern. Omnis no problem.

I must actually try one on the floor...trouble is you do need a nice hard surface for good reflected sound and most venues are carpeted and most bridal tables are well covered.

The issue with the mics moving around is an issue as mine are extremely light ... Philip??? what sort of height can you raise them from the surface before you lose effectiveness???? I was a little worried that they might lose the boundary effect if I stuck little rubber feet on them... I was also considering something like velcro where both pieces are adhesive...that way I just stick a bit on the table or floor and the other piece on the underside of the mic will keep it in place....my CL400's are only a few grams and simply moving the cable causes the mic to move all over the place (I presently use gaffer tape on the cable so the mic can't move) That way they have a direct contact with the table surface!!

I think more trials are needed for optimal placement!!! Actually one on the wall into a transmitter would be great on a roving camera as your audio would stay constant!!!

Chris

We now just mic each of the speakers since we have 3 sets of lavs. Im a bit worried of using boundary mic since we cant monitor the sound...but i guess the benefit if we do use boundary mic connected to a h4n is u can just sort of move the mic to in front of whoever speaking on the bridal table. Is that right?

Philip, did u put the mic on the floor? What if he accidentally step on it? Did u put it on his side?

Thanks

Santo

We always convince the people to come up and do their talk from one specific position!! That way your mic distance is maintained.

Gosh I don't like the idea of using DVR's because you cannot monitor them...I was wondering although if they have a headphone output???? On my one camera I just plug in a 2.4Ghz BlueTooth dongle and then monitor with BT headphones ... My boundaries run thru my radio mics so monitoring is simple with them and I can hear what's going on all the time.

What do you guys do with DVR's if the loud mouthed groom (before the ceremony) suddenly turns into a whispering whimp when he has to do his vows...going thru my cameras and monitoring I can adjust channel levels anytime I need to (and often have to!!!) It's a bit tough if the recorder is in the groom's pocket and his voice is a mere whisper!!!

Boundary mics actually cover an amazingly wide area with very little drop off like you will find with a lav mic!! Mine were about 2 metres from the talent!! A lav would have got almost nothing that far away!!

Chris

us too, but sometimes they are too stubborn..

thats great idea using bluetooth headphones.. can u send me a link to one? the dongle and the headphone.[/QUOTE]

also can u plug in the boundary mic to a sennheiser g2 transmitter? will that power the mic?

we put a dvr and a wireless on the groom during ceremony. we had bad experience with signal interruption with the g2...

that sounds like a charm! u convince me to buy it now...

Santo

For those who like to understand how things work, Crown Audio has this helpful Application guide that explains the principles of boundary mics and how to mount them to best effect for your situation.

http://www.crownaudio.com/pdf/mics/127089.pdf