I was wondering if anyone has any experiences using two Sennheiser Evolution G2 wireless units simultaneously. Up until now our crew have been using a boom pole (rode NGT-2) and/or a combo of 1 wireless Senn G2 or Azden mics. We are thinking of buying another Senn G2 wireless system because in some of our run and gun situations the wired boom pole becomes more of a burden and the audio always is much better from the Senn because of the close mic'ing. We are also hoping it will free up the boom op to run 2nd unit cam as we are a team of 3, sometimes 4 including host. The 2nd wireless unit would be used to mic the interview subject.

My main question here though is, it seems there could be a phase cancellation issue with running the 2 wireless mics so close to each other? Perhaps there are some other solutions I have not thought of or someone out there is already doing this?

I use two radio mics and a camera mic all the time you should have no problems, have a listen to the high force or craster items on www.inortheast.tv two G2's with the camera mic as well for GV cover.

Thats good to know Gary. Do you capture sound directly to the camera or a portable recorder? Also are you panning each mic hard left and right or routing to mono?
Are the two subjects who where the wireless mics close (standing next to each other?)

The audio on both films sounds great, I was worried there might be a thinning of the sound when the 2 wireless mics came in close contact.

You will only get phase problems if the mics are wired out of phase, the two G2's used on those films were straight into the camera (an S270 HDV) as two channels and it was actually set to auto gain as well.
I added some high end in post at around 3.6k and rolled off the bass at 120hz to cut down any wind rumble, on the high force film it was very windy but the G2's performed really well. The dialogue was mixed on pro tools in mono with the music in stereo.

Thanks Gary, thats kind of how I was planning on approaching it, sending both mics to it's own channel on the cam and then mixing both to mono in the NLE. - Appreciated!

Thats good to know Gary. Do you capture sound directly to the camera or a portable recorder? Also are you panning each mic hard left and right or routing to mono?
Are the two subjects who where the wireless mics close (standing next to each other?)

Try to keep each mic on its own track whenever possible. You can always mix is post but you can't "un-mix" if you've recorded as a mono mix in the field and later discover it doesn't sound quite right. Phase issues and "echo" can sneakl in when mixing them live, although it's usually not too hard to adhere to the rule of at least 3 times the distance between mics as they are from their respectve sound sources when putting lavs on several people. (This is true whether you're using wired or wireless mics. Never, ever, mix lavs and boom together in the field.)

I'm sure you probably already know this, but at the risk of belabouring the obvious, you do know that you can't operate multiple transmitters into one receiver, right? You need a transmitter AND receiver pair for each lav. Keeping the above mentioned 3:1 rule in mind as far as the mic capsules go, there should be no problem with multiple wireless worn by several people standing close to each other from the perspective of the radios interfering, as long as each transmitter/receiver pair is one a separate frequency well spaced from each other.

Hi Steve - Thanks for the additional tips. Anytime we have filmed with a boom and lav together they have been recorded on seperate tracks and mixed in post. Good advice on mic placement and 3:1 rule - will follow that. No probs on the second transmitter & reciever for second mic we are buying another complete G2 system. I have not done a great deal with Lav's in the past - ton's of studio and boom pool stuff but there seem to be several schools of thought about mic placement.

Some like to position it on the chest area and some on the collar, I have seen both on cable TV docs. In any tests I have done it seems the collar sounds more full and natural then on the chest. Do you know what the general consensous is?

Also hiding the mic's tend to be a bit tricky especially with someone wearing a t-shirt as the only obvious place to position is the collar.

Now I am on P2 with an HPX-301 I have four audio tracks so tend to standardise on the following track assignments for on-location work

Ch1-Camera mic
Ch2-Boom (Rode NTG-1 on a pole)
Ch3-Radio mic 1
Ch4-Radio mic 2

....

Some like to position it on the chest area and some on the collar, I have seen both on cable TV docs. In any tests I have done it seems the collar sounds more full and natural then on the chest. Do you know what the general consensous is?

Also hiding the mic's tend to be a bit tricky especially with someone wearing a t-shirt as the only obvious place to position is the collar.

I'd go by what sounds best to your ears or achieves the result you're looking for. Most lavs are designed for upper chest but whatever works is what's right. As far as hiding them, first question I'd ask is whether we need to bother. For dramatic work where the audience is supposedly eavesdropping on reality, yes. But for most video work such as interviews or unscripted TV, we've come to accept unobtrusive visible mics and the need to hide it from view is much lessened. To get a chest level mic on a tee-shirt, you could use a vampire clip on the fabric or go under the shirt with moleskin and surgical tape on the skin. For a female, on the inside of the bra in her cleavage.

Thanks Steve, exactly my thoughts - why bother trying to hide it. Mostly our show is an unscripted reality TV / Travel Doc anyway, in some ways I prefer a boom but we are going to try all wireless because of the hassles trucking a ton of equipment around on motorcycles.

For the boom, many use the G2 500 series plug-in transmitter which supplies Phantom power. Of coarse the boom op would want to have some way to monitor, like a headphone amp with an out or through-put.

I dont bother to hide anymore unless its a drama production, if you look at my G2 mics on the video clips I have the stock sennheiser hard windshield on them with a radio shack soft foam wind gag added on top to diffuse any wind or pops.

As for placement chest is best as all omni mics like the G2 ones benefit from a bit of chest cavity resonance that is why lavs tend to sound worse on females as those frontal projections absorb a lot of the chest resonance.

I kid you not! at the top of the rib cage is about the best position and as said for females if you can clip it to the centre of the bra that is best for position.

Thats a good solution, yes our boom op always monitors with headphones as do I as a second failsafe. The senn G2500 is a good consideration, but we are trying to limit boom use unless we have a car as we are a bit hardcore and like to ride everywhere ~

Not sure if random females would like me messing with their bra straps but I am willing to try :)

This might sound crazy but just curious. If you get two G2's and they are both the A version can you utilize both of those just as long as they are on different channels and they each have a receiver and transmitter if that makes sense? I'm about to buy some wireless mics and I wondered could you have two A versions or do I need to buy an A version and a B version? Just wondering. I read through everyone's postings but just want to clarify.


Thanks
Nicole

Hi Nicole, yes as long as they have thier own reciever and transmitter they can both be on same band, just pick w different frequencies.

Watch out for C band as FCC has reclaimed these and they are ilegal to use now.

A = 518 and 554Mhz (good)
B = 626MHz to 668MHz (good)
C = 698MHz to 806Mhz (Bad)

We have an "A" and "B" band now - just won an ebay auction for a used G2 system for $340 ~

"Not sure if random females would like me messing with their bra straps but I am willing to try :)"

With pro actresses it's usually not an issue, but otherwise you will have to 'feel' the situation out. no pun.. -pun. With females in question, I usually instruct them how and where to put the mic, 7 out of 10 times, they say, you can do it. Oh course I'm a non-threatening 50 yr old. Later on I'll often say to the cam-op "nice-set-a-hooters on so-and so, huh?"
Sorry can't help myself. :)

Hi Nicole, yes as long as they have thier own reciever and transmitter they can both be on same band, just pick w different frequencies.

Watch out for C band as FCC has reclaimed these and they are ilegal to use now.

A = 518 and 554Mhz (good)
B = 626MHz to 668MHz (good)
C = 698MHz to 806Mhz (Bad)

We have an "A" and "B" band now - just won an ebay auction for a used G2 system for $340 ~

Thanks I thought so but when I'm unsure I ask. Congratulations on the Ebay Auction!!!

hehe.... thats too funny Rick :)

Thanks Nicole! eBay is a bit hit or miss, the last time I bought a used G2 system the transmitter died after a few weeks, but sennheiser have awesome support. It cost I think $70 for a flat fee service charge, (I had no warrenty) they ended up replacing the board and getting it back to me in under a week.

Hi Nicole, You can have many systems going in the one block. Always do a freg. scan, turning on and scanning one-system-at-a-time, sequentially.
Often I use a single transmitter to send audio (camera hops) to two cameras, both recvs. on the same channel.... However, you cant do this the other way around. two tramsmiters, one recvr.

Most questions Have been answered - but please note that the new G3 has replaced the old G2 systems.

The new G3 camera receivers are now diversity (using the output cable as the second antenna) and – also – there is a new “G” band for the USA (in-between the “A” and “B” versions).

I hope this helps.

It is possible for two Senny transmitters to interfere with each other, see page 32 of the G2 manual; for multi-channel operation you should use the free channels in one channel bank. We have had some intermodulation interference in using randomly-selected frequencies, even between transmitters such as one on A band and one on C band....no big thing, you just have to be aware to turn off the transmitters, scan a channel bank on a receiver and lock out conflicting frequencies, then apply the results to all your units, setting them all to open frequencies in one channel bank.../Battle Vaughan PS: I should point out, this is radio frequency interferance, it is not a phase problem from mic placement, that is an entirely separate problem.

There are two potential issues here. ANY two microphones (with cable or radio link) can exhibit partial or complete cancellation when used close together and then summed into mono, or placed in the same stereo location, sound field wise. It happens no end running microphones on stage. As the two people get closer, there is a characteristic hollowness that begins to get stronger as they get closer. In most cases, as the mics are omnis, as they get closer, our usual technique is to dip the audio from the mic on the strongest voice as this gets picked up on the other anyway. Sometimes you have to live with a slightly poor balance between the participants when they are close. The phenomena is called comb filtering - Google will provide details, but it is a pain. Using a radio system or not makes no difference to this problem. Live, and of course in post, it's often possible to prod a button and reverse the polarity on one or the other. The result will be worse, or better - so you can choose which works best. In radio systems, having two transmitters next to each other rarely causes issues with decently design products like the Sennheisers and others. Two receivers again cause little trouble if placed together. What radio systems don't like is a transmitter for one channel being right next to the receiver for another. The usual result of this is that the apparent sensitivity of the receiver is degraded. In video terms, if you have a person with one transmitter a way away, with a nice strong signal at the receiver on the camera, all is well until the person with the other transmitter comes and stands next to the camera, when the more distant person's signal appears to wither and die. Often, people blame the batteries, fit a new set and all seems cured, until the other person gets close again.

The common problem of comb filtering may not be noticed during recording if the sound guy has ch 1 on the left ear and channel 2 on the right. All sounds well, but in the edit suite, when both channels are panned into mono - it sounds hollow and boxy. Pan them apart a little, and experiment with the polarity, and it's usually possible to make it sound as it should.

"Not sure if random females would like me messing with their bra straps but I am willing to try :)"

Frankly, I always ask production for a female PA or somebody to help me with this. It's best for all concerned, trust me. The actress is reassured you're not a creep, the PA gets out of having to go get lunch, and I pick up an extra hand on the busy shots (but just the busy shots, don't abuse this).

... if you look at my G2 mics on the video clips I have the stock sennheiser hard windshield on them with a radio shack soft foam wind gag added on top to diffuse any wind or pops.

As for placement chest is best as all omni mics like the G2 ones benefit from a bit of chest cavity resonance that is why lavs tend to sound worse on females as those frontal projections absorb a lot of the chest resonance.



Are those the ME2s?

Paul this is pretty much confirms as I had suspected with the audio and comb filtering as I have seen it a lot in studio settings and figured it could be an issue, thanks for the advice. As far as the Bra straps are concerned Marco, that was just a cheap joke on my part :)

I know you were just joking Rich. Still, if you work with wireless much, you'll find this is a very serious issue.

Are those the ME2s?

The mics are the stock ones that came with the G2 set which I think are the ME2's