Wireless from board to camera?

[Michael Clark]

I am going to a concert tonight and was wondering if it was possible to use my wireless in a way I've not ever used it, or if I should just not bring it. The idea was to hook my Sennheiser G3 transmitter into the sound board's output via 1/4" to mini. Then the receiver would be plugged right into my Canon T2i. Is this possible? Seems like it should work. Of course I'll test it beforehand, but since I haven't left for it yet, I wondered if it was even possible.

[Karl Winkler]

Hi Michael,

What you're suggesting certainly can be done. Here are some issues to consider:

1. Will it be allowed to video/audio record the show?
2. Do you know the sound person/board operator? Sometimes these guys are not warm to have anything connected to their equipment that they are not in control of. Fortunately, connecting a wireless transmitter should not induce a ground loop since it is battery powered. Nevertheless, if he/she is not comfortable with you doing this, you may not want to push too hard.
3. Be aware that the "board mix" is often not a good representative of the sound that the audience hears. This is because some things are amplified more through the sound system (voices, for instance) than others (drums or guitars). So what the audience hears is often a combination of the stage sound (amps/drums) and what is going through the PA system.
4. Usually, a board will put out line level, so you'll at the very least need to attenuate your transmitter input by quite a bit. Even then, it may not be enough. Just something to be aware of.

One thing you might try is to take one channel from the board (PAs are often in mono anyway) and then use your on-camera mic to capture the house sound. They will be out of sync, of course, due to the delay of sound from the stage/PA arriving to your camera position vs. no delay on the signal coming from the board. Thus, you would need to re-sync them in post, and this is not easy.

I don't mean to discourage you from doing what you propose, just to give you some prep info.

Karl Winkler
Lectrosonics, Inc.

[Steve House]

Originally Posted by Michael Clark

I am going to a concert tonight and was wondering if it was possible to use my wireless in a way I've not ever used it, or if I should just not bring it. The idea was to hook my Sennheiser G3 transmitter into the sound board's output via 1/4" to mini. Then the receiver would be plugged right into my Canon T2i. Is this possible? Seems like it should work. Of course I'll test it beforehand, but since I haven't left for it yet, I wondered if it was even possible.

Note that a standard 1/4 to mini is not wired correctly for the Senn transmitter. The Senns' mini is a stereo plug but with a unique wiring scheme. The cable designed for mic level sources send signal hot to tip, grounds the sleeve and shorts the ring to the sleeve. When interfacing with a line level source such as the 1/4 out from a sound board, the cable is wired signal hot to RING, signal ground to sleeve, and the tip is grounded to the sleeve. The means your adapter cable needs to be wired 1/4 tip to 1/8 ring, 1/4 sleeve to 1/8 sleeve, 1/8 tip to 1/8 sleeve if the board is a mono 1/4 unbalanced TS output. If it's a balanced TRS output, 1/4 tip to 1/8 ring, 1/4 ring to 1/8 sleeve, 1/8 tip to 1/8 sleeve, 1/4 sleeve to cable shield, cable shield left unconnected at 1/8 end. None of these is an off-the-shelf 1/4 to 1/8 adapter cable.

[Michael Clark]

Originally Posted by Karl Winkler

One thing you might try is to take one channel from the board (PAs are often in mono anyway) and then use your on-camera mic to capture the house sound. They will be out of sync, of course, due to the delay of sound from the stage/PA arriving to your camera position vs. no delay on the signal coming from the board. Thus, you would need to re-sync them in post, and this is not easy

.

I use a Canon T2i with Magic Lantern to film. This may be a question better suited for the T2i forum (not sure), but are you saying it's possible for me to get mono sound from the board and the camera's on board mic simultaneously recorded to the T2i?

[Jay West]

Originally Posted by Michael Clark

I am going to a concert tonight and was wondering if it was possible to use my wireless in a way I've not ever used it, or if I should just not bring it. The idea was to hook my Sennheiser G3 transmitter into the sound board's output via 1/4" to mini. Then the receiver would be plugged right into my Canon T2i. Is this possible? Seems like it should work. Of course I'll test it beforehand, but since I haven't left for it yet, I wondered if it was even possible.

I don't know about a T2i but I've been doing this for years with a G3 (originally going to a Canon XHA1 and now a Sony NX5,) Be aware that this only can give you a mono signal, however. Remember that one transmitter/receiver combo is only one channel.

If your Sennheiser G3 is like mine, it came with both a mike and a cable with the round screw-down connector/mini plug on one end and a 90° mini-plug stereo on the other. I think they called it an "instrument cable." That is what you feed to the transmitter pack. I take an RCA feed from the record-out jacks on the board, using an adapter cable with twin RCA jacks on one end and a ¼" stereo jack on the other. These are available from a lot of places including Raido Shacks, some big-box electronics stores, and even some hardware stores. I plug-in a ¼" to mini-stereo earphone adapter jack and then plug the 90° transmitter cable into that. There are other combinations that will accomplish this, as well. This is just what I had in my kit when I needed to do it. ways to do this.

If the board does not have a record out, you may be able to use an earphone jack for the feed.

[Rick Reineke]

The CI-1 "instrument cable" is different than what you describe. 1/4" to 1/8" and feeds the ring of the 1/8" jack, which is unbalanced line-level in. The locking 1/8" to RA 1/8" cable would likely cause a distorted input from line-level source w/o a pad. The above 1/8" to RA1/8" is normally for dual mono input to a stereo consumer camera or recording device from the reciever
Unless I've misinterpreted your cable description.

[Jay West]

I did not think it would work, either, and for exactly the reasons you gave. I was surprised to find that it worked without problems (at least it works without problems as long as nobody else is using another wireless device that is transmitting on the same channel that had I selected.)

The cable connections work, but I may have the nomeclature wrong. ( I've been working out of town, I'm not in a place where I can make and upload photos, and am giving this answer from recollection.) The cable might be called a "jack cable." It has 1/8" mini connectors on both ends, and one of them has a threaded ring for plugging into the transmitter. Actually, the transmitter end might be slightly smaller in diameter than a mini-stereo plug but it is definitely larger than a sub-mini plug.)

When I first saw this cable a year and something ago and saw that the jack on my G3 transmitter pack is labled "mic/line," I could not find a menu setting or button to switch from mic level to line level, I tried on-line searches. I ran across a thread where somebody claimed that the G3 seemed to switch to line level when used with the jack cable. (Sorry, I can't find where I saved that post nor can I recall where I saw it.) So, I tried it and it worked fine. I thought I might need a stereo-to-mono adapter in the loop, but I did not. My recollection also is that there was a menu setting in the G3 transmitter for "cable emulation" with the default being "minimum" and I did not change that.

If I confused things by referring to ¼" jacks, I'm sorry. Let me make this clear: My Sennheiser cable does not have a ¼" jack or plug. I was referring to a different cable that I have been using for taking a feed from stereo RCA jacks, as from the "tape-out" on jacks on older sound board. I have also used this cable to take audio-out from a a device (say a DVD player hooked to a projector in the front of a room) and fed the audio wirelessly to a sound board in the back of a room.

[Steve House]

There is no mic/line input switch on the transmitter ... the changeover is handled by the wiring of the plug going into the input jack. For a mic level input, signal hot goes to the plug's tip, signal ground goes to the plug's sleeve, and the plug's ring is jumpered to the sleeve. For a line level signal the situation is reversed. Signal hot goes to the plug's ring, signal ground goes to the plug's sleeve, and the tip is jumpered to the sleeve.

If the end opposite the transmitter is going into an unbalanced mono out, the tip of that plug should go to the ring on the transmitter plug and the sleeves connect to each other. If going from a balanced mono output, you can either have a TS plug on the end opposite the transmitter connected the same way OR use a TRS plug on that end and connect the TRS tip (signal hot) to transmitter end ring, TRS ring (signal cold) to transmitter end sleeve, TRS sleeve to cable shield leaving the shield unconnected at the transmitter end and of course transmitter end tip still is jumpered to the sleeve.

Carefull about plugging into stereo sources. Stereo places left hot on the tip, right hot on the ring, and l/r grounds on the sleeve. Not sure what the transmitter would end up doing when presented with that signal mix but it's certain not to be good. To plug into a stereo output, the end opposite the transmitter should have the tip and ring jumpered together and connected to the ring at the transmitter end. This mixes both left and right onto the one mono channel the transmitter can handle.

If you don't already have one, pop in at the nearest Radio Shack or your local equivalent and get a $10 basic multimeter. This way you can easily check to see what terminal at the end going to the transmitter, the end with the locking collar, is connected to what terminal at the other end of the cable.

[Jay West]

Finally got back to the office where I had the cable and a multi-meter. There is continuity from tip to tip, none from ring to ring, and continuity from sleeve to sleeve. On the ring, there is no continuity to anything else, either.

[Steve House]

Originally Posted by Jay West

Finally got back to the office where I had the cable and a multi-meter. There is continuity from tip to tip, none from ring to ring, and continuity from sleeve to sleeve. On the ring, there is no continuity to anything else, either.

Then that particular cable will not work properly to feed a line level output to the G3 transmitter. You'll be sending a hot line level to an input expecting a mic level.

[Jay West]

Steve:

In going through through the G3 transmitter’s menu, I see that I have “Sensitivity” set at “-30 dB.” Would that take the signal down enough that I am not supplying a line level signal to a mic level input?

Otherwise, I am completely puzzled that the "jack cable" works for taking a line level input and transmitting to the receiver. (I have seen the cable listed variously as the "CL-1" and the "CL-1-N.")

But, work it has, and quite well for a year.

I have not been able to find the post that started me down this road a year ago. Lately, it seems like the search engines have been redesigned to bombard you with junk. No matter which terms I use, I find the same six or seven posts here — which actually discuss other topics – and everything else either links to sites selling Sennheiser equipment or, worse, to dozens of sites that promise to find me links to places where I can buy Sennheiser stuff.

So, I am still puzzled as to how this can work.

[Colin McDonald]

I have not been able to find the post that started me down this road a year ago.

Is this the thread perhaps?

http://www.dvinfo.net/forum/all-thin...s-xmitter.html

The information re mic/line wiring to the transmitter was stated in post 17:

http://www.dvinfo.net/forum/all-thin...ml#post1543770

[Steve House]

The CL-1 is designed to go from the receiver output to feed the line-level input of a camcorder or other recorder, it's not intended to connect a signal source to the transmitter. http://www.sennheiser.com/sennheiser...on-wireless-g3

If you connect the CL-1 to the transmitter's input and plug the other end into a stereo line output, you're putting the left channel on the mic input at line level and the right channel is being lost since the rings are not connected. If the rings were connected, the right channel would be on the line input at line level. Lord only knows what the transmitter would actually do when presented with that mashup ... I don't know which signal would end up getting through.

The correct cable to send a mono line output to the transmitter is the CI-1 (that's an upper-case I, not a lower-case L) with a 1/4 TS on the signal source end. For mic level, the CL-2 with an XLR-F on the source end is the correct cable.

With that sensitivity setting you're padding the signal down to where it's apparently not overloading. It works but isn't optimum. Problem with that approach is that a strong signal can overload the input before the gain control - reducing the gain on a distorted signal simply gives you a lower-level distorted signal. I'm a believer in getting it right in the beginning rather than using what is essentially a kludge to fix a problem that could have been avoided.

[Jay West]

Originally Posted by Colin McDonald

Is this the thread perhaps?

http://www.dvinfo.net/forum/all-thin...s-xmitter.html

The information re mic/line wiring to the transmitter was stated in post 17:

http://www.dvinfo.net/forum/all-thin...ml#post1543770

Unfortunately, no. That posting is about Sennheiser's CL-2 cable which has an XLR connection on one end and, on the other, a TRS for plugging into the transmitter. This is made specifically for taking a line level feed from a board or other device with an XLR out and feeding it directly into the transmitter. As Steve has pointed out, the wiring of the TRS plug is what switches the G3 transmitter between line and mic levels.

What I take Steve's last post to say is that the jack cable may work sometimes with the transmitter's Sensitivity setting at -30 or less but it is too much of a kludge to be reliable, and, for that reason, is not a good idea.

[Steve House]

Yep. There can be a difference between reducing the transmitter's audio gain by 30dB and padding down the signal by 30dB as it goes from the source to the transmitter's input. I'm not privy to an actual schematic of the transmitter so I don't know precisely where in the circuits dialing down the sensitivity by 30dB actually affects the audio signal but in most cases there will be some components between the input jack and the gain, ie, sensitivity, controls. If the signal is too hot, it could conceivably overload those components and get distorted before the sensitivity control has a chance to tame it. Even if the control is a simple adjustable pad and the first thing the signal encounters when it leaves the jack, I'm a believer in keeping the pathway as clean and simple as possible ... if you have a choice of taking a line level signal through a pad into a mic level input versus taking it straight into a line level input, you'll be better off with the latter every time. Trying to get by with an improperly wired cable in order to save the trivial $$ it takes to buy or make the right one is a false economy in my book.