Rode VR, Iriver, Offiant's wired mic
 

The Groom will wear the Iriver with a Giant Squid mic.
The Rode VR will be on my DVC30 a few feet away.
The Priest will use a wired mic connected to the PA.

Will I have to be careful with feedback \ interferance with this lot?

Thanks

no

only if the priest decides to wonder close to the speakers...

I am guessing this ceremony is taking place at a location where a portable PA system is being used. My answer is very likely! It will all depend upon the placement of the loudspeakers more than anything else. If the officiant's mic is an omni directional there is a higher risk of feedback. However, you can rest assured the mics you use will not be a factor in any feedback UNLESS they are connected to the PA system as well.

Most of the PA systems I deal with are managed by DJ's or audio technicians who want to set up quickly and get out quickly, so their idea of satisfactory loudspeaker placement is towards the back of the ceremony site and aimed towards the actual "altar" area. That is dead wrong and will very likely lead to feedback. The speakers are aimed directly at the officiant's mic. To add insult to injury the PA system usually has limited tone controls.

If the PA system is managed by someone who knows what they are doing they will place the speakers to either side and in front of the "altar" and aim them towards the audience.

For these reasons in places that do not have a permant, professionally installed PA I usually insist upon using my own PA, which includes a 1/3 octave EQ in addition to precise tone controls on each mic channel to eliminate the possibility of feedback.

Houses of worship usually have professionally installed PA systems and that should give you a comfort in knowing that feedback will not likely be an issue.

"However, you can rest assured the mics you use will not be a factor in any feedback UNLESS they are connected to the PA system as well."

One caveat is that it is possible, however unlikely, that you can get a feedback-like effect from two mics that are on incompatible frequencies. I had a situation once with a lower-end VHF mic that caused a whining sound to eminate from the house PA. The priest's wireless was somehow picking up something from my system. I was in no way connected to the PA, but when I turned off the transmitter the sound stopped. It was a nightmare. I switched to a UHF Lectrosonics model that works on frequencies not often used in my area and have never had a problem since.

Now that you have mentioned it, I remember a similar situation I encountered some years ago. It was an educational conference at a local college which I had been hired to document on videotape. The main podium mic was a Shure T3 series VHF wireless (then quite expensive) belonging to the college and I could not access a feed to my camera from its receiver. I placed my Adzen WMS-Pro hand mic close by the podium to at least capture both podium and panel discussion commentary. It turned out the broad cast frequenies of both mics were identical resulting in a whine and hiss clearly audible through the PA. I turned my transmitter off and the interference went away. I was able to get a clean audio signal on my receiver. Had the electronics of both mics been of the same quality there should have been no audio signal at all as the transmitters would have cancelled each other out. The superior electronics of the Shure system allowed its signal to be heard through the PA. Once again, one gets what they pay for.

I think my situation may have been that the harmonic frequencies of my mic and the room wireless were causing interference. It was really strange and I am probably grasping at straws for an explanation. My Lectrosonics has never had a dropout and usually works even beyond concrete walls. I probably should get an Iriver backup if I ever do one-camera weddings again, but so far everything has been perfect.

DON'T SKIMP ON YOUR WIRELESS LAV!!!!!!! You need a multi-channel UHF (not VHF) system! I am not using exclamation points frivolously. This can not be repeated enough. Audio is at least as important as the visuals. You could always put together a nice video/photo montage if you bought the rights to the photographs as long as you get the audio. If you don't get good audio, you will have serious problems. I recommend something like the Sennheiser G2 or a Lectrosonics with an Iriver backup.

To be honest, I, too am grasping at straws, but I feel harmonics as a sole culprit doesn't quite fit. Crosstalk between two adjacent frequencies still makes more sense to me. Continuing the crosstalk logic to the next level then allows the introduction of harmonics as a possibility.

I agree that one really can not skimp on wireless audio systems. I have skimped (note previous post) and continue to suffer.

However, I really don't like the idea that UHF is superior to VHF without a good explanation of the differences betweem them. Please Recognize virtually all public service communications in the U.S. (police, fire, Federal civic agencies, some military, and some Federal policing agencies) all use VHF radio well below the frequecies assigned to VHF consumer wireless mic systems (about 165MHz to 216MHz). They don't usually have issues like we do. The difference? Transmission power and exclusivity! The systems we use have the lowest power transmission available, is available to anyone, and requires no broadcast license.

The biggest issue with VHF is that it has been around for a long time and is quite heavily populated with users as well as the entire VHF wireless mic frequency band is also used by television broadcast. One has to know which frequencies are in use in one's local area and and which ones are not in use.

UHF has a much wider frequency range available as well as being relatively new on the market. This immediately translates into less population densitiy in terms of users, who are, as it were, "on-line". That will change in the near future when HDV TV broadcasts become more common, as it will be using more of the available UHF frequencies we currently enjoy as "vacant land".

The bottom line is that "wireless" means "without wires", and that means one has to understand the medium before they can master their message. I have a feeling VHF may become a more popular range for use to use in the future.

A top quality VHF system will match, if not out perform, a comparable UHF system. Quality of electronics will always prevail.

I agree with your reasoning behind VHF vs. UHF, except for one thing. All the good wireless mic systems in a moderate price range have converted to UHF by the turn of the century. If you don't have something that is the equivalent to today's $500 UHF multi-channel models, you don't have a sufficient system. I don't think it is necessary to go with one of the digital models yet, but a good quality multi-channel UHF is the standard to measure against.

Regarding the HD channels moving into UHF frequencies, about all the stations in my area that are going to ever broadcast HD already began doing so a few years ago. The frequency blocks were already known by Lectrosonics when I bought my system and I ordered a model appropriate for my region. Many frequency blocks will work in a given area, but some are more crowded.

Lectrosonics has an online list of frequencies used by region in a nice table:

http://www.lectrosonics.com/cgi-bin/tv_form.pl

It is found in the service/technotes area if the direct link doesn't work:

http://www.lectrosonics.com/service/technotes.htm