Zaxcom IFB system

[Larry Kaltenbach]

Here's a review of Zaxcom’s ERX1TCD “IFB” receivers for anyone curious about them. I own four of them, fed by a Zaxcom IFB100 audio/timecode transmitter, and have used them extensively for the past six months.

I place “IFB” in quotation marks because the units can be used for several other purposes, as detailed below. …

Client monitor—stupid easy to use. Obvious on/off switch and volume knob. Decent  audio gain into Sony 7506’s. Menu button locked out from client use. Here’s the real kicker—the receiver has an LCD time code window on the face! Anyone needing to take time code notes can be handed a unit. Backlight on the LCD isn’t perfect. That pesky 1K “noise” clients freak out about in monitors—the IFB100 and the receivers both have variable frequency notch filters to remove it. Delay can also be dialed into the receivers to match “delayed” picture.

Slate time code feeder—the unit is so thin and light it Velcro’s and stays on the back of my Deneke slate with no issues. The system supports all current time code formats.

Camera time code feeders—A poor man’s Ambient Lockit or Deneke SB-2, sort of. I work primarily in broadcast TV, where there is no budget for the latter two. We just string BNC time code cables around, or jam and free run TOD during hand held, and never genlock or tri-level sync. Trust me, there’s no time or money for it, and we never get phone calls with TC/sync issues. On multi-camera shoots, which practically every shoot is now, I ditch the TC cabling and instead just slap a light-in-weight Zaxcom receiver on each camera using an Anton Bauer accessory plate.

Camera audio return—I mount the IFB100 transmitter on the main production camera, for a wireless audio return hop that is so far away, frequency-wise, from my production wireless it’s almost laughable. I say almost laughable, because we all know how unfunny things can sometimes become when multiple wireless are running in close proximity to each other. One caveat regarding this set-up—I sometimes hear a low-level 2 K’ish tone in the IFB receivers’ audio path when cranking up the transmitter’s power level. As the transmitter needs to be powered from the camera’s 12-volt tap in this configuration (it has no internal battery capability) the issue appears to have something to do with a ground loop between camera power ground and camera audio ground. My solution—I crank the RF power down, from the highest “7” setting to “4” or “5” until the tone is inaudible, and I still get reliable coverage. From my testing, I have found the tone I’m hearing is not getting into production audio in the camera.  Still, I’d rather play it safe, and turn down the power. Speaking of power, the transmitter draws very little current, so camera battery drain is a non-issue.

Time-coded transcription feeder—With the IFB100 transmitter on the camera, as in the above configuration, I also send time code from the camera to my ENG bag and roll coded transcription recordings when requested. A transcription-friendly feature on the receivers—menu-adjustable output level of the time code, which makes code vs. audio level setting easier.

DSLR scratch track feeder—The ERX1TCD’s menus allows the user to disable the volume knob and pre-set an output level. For use with DSLR’s I set the output to –12 db for Canon 7D’s and at –6 db for Canon 5D’s. The receivers are so light and thin no DSLR operator has the right to complain about them. I made up some thin stereo 3.5 mm male-to-male cables about 4-5 feet long for each camera rig, because no DSLR hand-held operator wants anything mounted to their camera. They just pop the receiver in their pocket.

IFB—oh yeah, it can do that too. Perhaps a bit shy with levels into some IFB transducers. My solution— I carry 15 ohm transducers so there is no chance the deafest on-camera talent will complain about a lack of level. In NYC’s Chinatown I used the Zaxcom system for talent IFB for extended-length live shots for China’s CCTV and got two city blocks of coverage, using a corner reflector antenna on the transmitter, with only a few momentary hits at the two-block point during testing. During the live shots I kept my cart indoors a block from the talent standing out in the rain, with no worries of IFB failure. The “bat” or handle of the on/off switch, though a standard length, can be very dangerous in a live IFB setting. The talent can easily turn the unit off while reaching to adjust the volume—something talent does multiple times during use. I use common sense and gaffer tape the thing in the ON position!!! I’ve asked Zaxcom about a shorter switch and I think they’re working on it.

Production audio feeder—Ok, you’re thinking, this is where this guy is “jumping the shark”. Perhaps—but just a tad. The sound quality is amazing for the price, albeit a bit tinny. On a recent corporate meeting I was mixing, where I was running 12 channels of production wireless, I had an agency camera crew walk up to me 15 minutes before show and ask for permission to use a wireless link for a program feed. Not a chance—I insisted they take my feed via a Zaxcom ERX1TCD, safely up at 2.4 Ghz, away from my production wireless. They used it, their experienced sound guy agreed it sounded great / slightly tinny, and I didn’t get any phone calls about bad audio from the agency. The sound tech from that crew has since thrown a lot of work my way!! I owe him.

General Observations—

RF-wise, I’m surprised how well these things work, line-of-sight, up on 2.4 Ghz with the supplied rubber duck antenna. Does it saturate a space like a traditional production wireless? No—but these things are a fraction of the weight and cost of production wireless, and apples-to-apples with a rubber duck, perform as well as other “plastic box” monitors we’ve all used for years. Only, with the Zaxcoms, the user gets many extra features for a little more money, and the Zaxcoms sound far superior. With a corner reflector antenna, costing all of $175 with cabling, on the transmitter I get highly dependable dropout-free coverage over needed production distances. I expected to encounter interference issues with other 2.4 Ghz equipment running in residential and corporate settings and thus far haven’t encountered any. The system operates on 72 user-selectable frequencies, with clean frequencies identified via the receiver’s signal strength meter. In practice, I’ve had the system work so well RF-wise, that I don’t even bother to look for a clean frequency anymore—there’s always some other shoot task more pressing I need to get to.

In the receivers alkaline AA batteries last about 5 hours and 2600 mAh AA NiMh last about 10 hours.

I wish the transmitter had internal batteries. Oh well. I can’t seem to put a dent in an NPL7S battery connected to it all day though—it draws that little current. I commonly power the transmitter in my ENG bag via a BDS box. Even sitting right in my sound bag, the RF from the IFB100 does not have any effect on my production wireless receivers inches away.

The user must use a stereo 3.5 mini, not mono, with the Zaxcom receiver. The female 3.5 mm mini on the receiver sometimes won’t pass signal if you place a mono male connector in it, I’m guessing due to minor tolerance variations on male 3.5 mm mono males.

Although the IFB100 transmitter has a two-channel audio input, the resulting output from the receivers is a mixed-together mono summation. I wish it was stereo.

In terms of wearing the receivers—there’s no case included. But, as Glenn Sanders at Zaxcom explained to me, the unit was designed to fit in any iPod case. I bought leather iPod cases with a belt clip at a dollar store for, uh, a dollar each.

Some NiMh AA batteries seem to vary in length by a few thousandths of an inch, and I’ve sometimes had to quickly ditch a set of NiMh AA batteries from the receivers because of power intermittency. I’m leaning toward just using alkalines in ‘em, with which I’ve had no problems.

Is this system absolutely flawless? No—but what products are anymore? The more important question is, “Could I go back to working without this product in my kit?” The answer is a resounding “no”.

 

[Max Dumesnil]

"DSLR scratch track feeder—The ERX1TCD’s menus allows the user to disable the volume knob and pre-set an output level. For use with DSLR’s I set the output to –12 db for Canon 7D’s and at –6 db for Canon 5D’s. The receivers are so light and thin no DSLR operator has the right to complain about them. I made up some thin stereo 3.5 mm male-to-male cables about 4-5 feet long for each camera rig, because no DSLR hand-held operator wants anything mounted to their camera. They just pop the receiver in their pocket."

Can you output timecode with the minijack to the Dslr ? Or even better scratch track +time code.

[bigmaho]

Yes, you can assign time code to output to either the tip, the ring, or both, AND you can set the time code level independently of the audio level.  To feed both audio and tc all you need is a splitter cable.  Also, the time code output is accurate enough to serve as the master clock.  In the earlier software the tc would update every few minutes and there would be a brief jump (which Phil Squires at Sony caught).  After that, Zaxcom changed the software so it updates continuously so there is no jump.  We used the ERX receivers to feed code to the cameras to use for auto syncing on 'The Big C'.

Billy Sarokin

Can you output timecode with the minijack to the Dslr ? Or even better scratch track +time code.

[Splendid]

Interesting to hear your feedback, thanks for posting! One question I have as I've been thinking of adding these to my kit…Any news of the Deneke/zaxcom slate with the receiver built in? I can see that being very useful if the ifb system can send metadata as well as time code so that scene and take info is digitally displayed on the board as well.

[Solid Goldberger]

Larry,

Thanks for the comprehensive review, its actually gotten me quite interested in the Zax IFB system, as I'm currently running my  Lectrosonics IFBs in block 28, and thinking that it might be smarter to just change systems rather then add to my collection of questionably legal gear.  One point that I have not heard in favor of going the 2.4 ghz route is that it would most definitely not be taken away from us by the FCC, as it is already so widespread in consumer electronics.  As the "how many Comteks" thread is showing, purchasing a large enough system can be a pretty big financial commitment, so it would be nice to know that at least that part of my wireless arsenal would have more certain longevity. 

I have a few more questions that I'd love to get answered from anyone that is currently using this system.

1.  For those of you who are using the IFB function on the QRX100 receivers, is there any trade off between using the QRX and using the IFB100?  My understanding is that the functionality should be identical, but I'd love to know from anyone who is using the QRX100 (and perhaps has used the IFB100 as well?).

2.  There seem to be many different ways that people are hooking up antennas to the 2.4ghz system--Whip antennas, External Uni- and Omni-directional antennas, and perhaps amplified versions of all three?  I would love to hear people's real world experiences with the operating range of these various systems and the IFB100 (or 992/942 boom systems).  Do you think I can realistically expect 125-150' (or hopefully better)?  My with the 2.4 ghz frequency range is pretty much limited to the Cordless Phone at my parents' house, which is not all that large.

I was lucky enough to hang with Jan for an afternoon right after she had gotten her new Antenna system for her 992s and tried a range test with her.  On that day, it seemed like the range was maybe 75' line of sight (and then perhaps another 15-20 through a wall before it dropped off considerably).  I understand that she got it sorted out shortly after that day, and her range had improved dramatically, but I've not heard anyone talk about the real-world range of the IFB receivers.  I've always been very impressed with the range of  Lectrosonics IFB systems--especially with the T1 pumping out 250 mW--but I'm intrigued by the Zax system.

3.  On the Receiver side, is it possible to switch between two IFB frequencies on the fly?  For example, on a reality show with 2 scenes going on simultaneously, the Producers can press the volume knob on my Lectro R1a receivers, and switch to the secondary frequency that I've programmed, so that they can alternate between monitoring the two scenes.  Can this be done with the Zax IFBs, provided I have two different IFB sources?

Thanks in advance!

e.

[glenn]

.  On the Receiver side, is it possible to switch between two IFB frequencies on the fly?  For example, on a reality show with 2 scenes going on simultaneously, the Producers can press the volume knob on my Lectro R1a receivers, and switch to the secondary frequency that I've programmed, so that they can alternate between monitoring the two scenes.  Can this be done with the Zax IFBs, provided I have two different IFB sources?

The ERX1 has an automatic voteing system. It would switch to what ever IFB transmitter it was receiving best. This would allow a producer to just goto the set and automaticly hear the audio with no buttons to press. If pressing a button was desired we could put in as many pre-set frequencies as you want.

Glenn

[Jack Norflus]

1.  For those of you who are using the IFB function on the QRX100 receivers, is there any trade off between using the QRX and using the IFB100?  My understanding is that the functionality should be identical, but I'd love to know from anyone who is using the QRX100 (and perhaps has used the IFB100 as well?).

I have the QRX with the option board and as far as I know there is no trade off using it in lieu of the IFB 100.

I am going to be purchasing some ERX receivers for this purpose as soon as I can scrape together the cash.

The advantage of going this route is I don't need to purchase an IFB100 since I already own the QRX - saving me $1200 and some valuable real estate in my bag as well. The other thing with using the QRX is it can send the ERX receivers any combination of the 4 audio channels I send to the QRX and / or what is being inputed to the 3.5 mini in on the QRX as well as time code.

I can't speak for real world range tests on location - but when I picked up my QRX from Zaxcom after having the option board installed, Glenn gave me a demo of this and I was getting very good range. I was able to walk to the back of the factory with no issues (100 or so feet).

Jack

[Tony Johnson]

Delay can also be dialed into the receivers to match “delayed” picture.

I noticed on mine that the audio delay is only on the erxtc and not the plain erx . This is weird as I would use the erx for director/script on an HD shoot and I cannot implement any delay , I would save the erxtc for slates and cams where they need the tc function .

Is this the case? or is it in a software upgrade , or can it be implemented in an upgrade .

But apart from that this system is brilliant , that is apart from the Pesky 1k noise , on whip aerial only though .

Regards

Tony Johnson

[Philip Perkins]

"DSLR scratch track feeder— I made up some thin stereo 3.5 mm male-to-male cables about 4-5 feet long for each camera rig, because no DSLR hand-held operator wants anything mounted to their camera. They just pop the receiver in their pocket."

A small disagreement:  I've done over a hundred DSLR shoots in the last few years, and no DSLR operator I worked with wanted anything like something wired from the camera to their pocket--they want the camera to be one discrete piece w/ no wires.  They attach all sorts of gak to their cameras all the time--check the various Canon 5D forums.  No operator has ever complained about having a small RX attached to the camera, either to the hot shoe or velcroed to the back of a monitor.  The Zax stuff is cool, but for a scratch feed to a DSLR a cheap Senn. G2 works just as well, and it is much more possible to have multiples for multicam....

phil p

[ao]

I noticed on mine that the audio delay is only on the erxtc and not the plain erx . This is weird as I would use the erx for director/script on an HD shoot and I cannot implement any delay , I would save the erxtc for slates and cams where they need the tc function .

Is this the case? or is it in a software upgrade , or can it be implemented in an upgrade .

But apart from that this system is brilliant , that is apart from the Pesky 1k noise , on whip aerial only though .

Regards

Tony Johnson

according to the manual, only the erxtc can have the delay shifted.

ao

[Larry Kaltenbach]

Another handy use of the Zaxcom "IFB" system I've recently stumbled over...

I work with a few cameraman that own both XDCAMs and Canon XF 305s, often doing multi-camera shoots using both camera types, and handing the client (two of the Big 4 networks) mixed media formats post-shoot, which they're fine with.

That said, there's a little wrinkle when shooting "24" with this camera mixing. The Canon XF 305s don't do real "24", but rather 24 via 29.97. The XDCAMs do real "24" frames. (Please excuse my ignorance for not knowing the exact buzz word to describe "real 24 frames"-- "native" or whatever is used to define/describe this).

Attempting to lock TC between these cameras in 24 mode using cables won't work-- the cameras just won't recognize each others code. To this point I'd never seen a video camera refuse any TC running at any rate. At first I suspected faulty cables, but how many bad BNCs can a guy have? Then I suspected a menu funk. Nothing. Then I fiddled with the Zaxcom IFB system on the cameras. Guess what? In 24 frames the XDCAM would only accept 23.98 TC and the Canon XF 305 in 24 frames 29.97 NDF TC.

As each Zaxcom IFB receiver is capable of outputting any TC rate, I can now TC lock these cameras by simply dialing up the proper TC for each respective camera-- and I've ditched the cabling in the process.

Now, anyone care to explain to me what disaster I'm creating for post by running 23.98 and 29.97 NDF TC? So far, no phone calls. But then, I have producers and shooters telling me to forget the TC altogether at the slightest whiff of a shoot slowdown-- to just do a hand clap at the head of a roll!

[bigmaho]

2.  There seem to be many different ways that people are hooking up antennas to the 2.4ghz system--Whip antennas, External Uni- and Omni-directional antennas, and perhaps amplified versions of all three?  I would love to hear people's real world experiences with the operating range of these various systems and the IFB100 (or 992/942 boom systems).  Do you think I can realistically expect 125-150' (or hopefully better)?  My with the 2.4 ghz frequency range is pretty much limited to the Cordless Phone at my parents' house, which is not all that large.

The 2 scenarios that work best are either using a whip directly on the IFB transmitter OR using and amp mounted directly to the antenna.  The whip works very well indoors.  It can easily cover a large stage.  The 2.4 gig signal loves to bounce around.  I use use the whip when I'm doing car rigs.  From inside the cab of the tow vehicle it has no problem controlling the transmitters in the towed car and ifb feeds for everyone on board.

On my cart rig I use an 8db high gain antenna with the amp mounted directly to it (the antenna comes pre drilled to accept the amp).  2.4 gig has severe cable loss, so I find it works best if I run a cable from the ifb to a DC injector (this sends the dc powering for the amp through the antenna cable) and from the DC injector to a bnc strip on my cart and from there to my antenna tree where the 2.4 gig antenna and amp live right inbetween my two UHF receiving antennas).  With this set up, my 2.4 gig signal pretty much equals my radio mic range (and sometimes exceeds it)

I was lucky enough to hang with Jan for an afternoon right after she had gotten her new Antenna system for her 992s and tried a range test with her.  On that day, it seemed like the range was maybe 75' line of sight (and then perhaps another 15-20 through a wall before it dropped off considerably).  I understand that she got it sorted out shortly after that day, and her range had improved dramatically, but I've not heard anyone talk about the real-world range of the IFB receivers.  I've always been very impressed with the range of  Lectrosonics IFB systems--especially with the T1 pumping out 250 mW--but I'm intrigued by the Zax system.

The Zax ifb range is not as good as my Comtek range (ie, my third can't listen in from the truck 2 blocks away),  so I currently run both systems on my cart but I'm gradually switching over because the quality and the features of the ifb system are so good.  I am currently on an episodic where the studio auto syncs, so they wanted every camera AND the sound recorder to use external code from  Denecke sync boxes.  After serious testing they are happy using the Deva as the master clock and ERX's to distribute time code to all the cameras. 

Best,Billy Sarokin

[Solid Goldberger]

Thanks so much for the explanation of your system, Billy, very informative! 

e.

[Tony Johnson]

2.  There seem to be many different ways that people are hooking up antennas to the 2.4ghz system--Whip antennas, External Uni- and Omni-directional antennas, and perhaps amplified versions of all three?  I would love to hear people's real world experiences with the operating range of these various systems and the IFB100 (or 992/942 boom systems).  Do you think I can realistically expect 125-150' (or hopefully better)?  My with the 2.4 ghz frequency range is pretty much limited to the Cordless Phone at my parents' house, which is not all that large.

I am running two IFB100s on a large set at present . One for me to control my trxs and send to my 942 and erxs for my crew and another set up on Video village sending sound to director/prod/script . I have them set 10 mhz apart . I use a similar antenna system to Billy , in fact Billy suggested it to me . It is a 1 watt rf amp with dc injector and 12db directional antenna . I use this inside and set the IFB100 to 4 on the output power setting . I get unlimited range on big stages with no drop outs but obviously it is all over once someone steps off the stage . The video village is running off a different antenna system (which had been purchased before i came on board) , it is an omni antenna with a 1 watt rf amp . It has less range than my set up and has dropped out occasionally so I am thinking of replacing it with my set up .

Interestingly I had the opportunity to test this gear a lot before we started shooting , I walked around the stages and had almost unlimited range . Now once every department gets on set it changes a lot . We have masses of 2.4ghz gear on this job . I don't think I would get away with just a whip on our set , but once again when I tested just the whip in pre prod with no other gear around it was very impressive . On a spectrum analyser you can see clearly where the IFB100s are as they are way stronger than all other gear on 2.4 , we have even managed to fix wifi by installing a 5ghz backbone to the system so if the wifi can't see the clients on 2.4ghz it goes to 5ghz . I think we are winning the range wars by stealth and I am happy with that despite the whinging from other departments .

Tony Johnson

[bigmaho]

942! Are you using the Super CMIT?  I haven't tried it yet.  Also glad to see you are using dual IFB systems.  I'm thinking of doing the same for shoots where the dir/prod want to watch and listen to playback off the video cart using the same headphones.  Only problem is I'm reliant on the audio output quality of the video cart which can range from funky to brilliant (often within the space of 5 minutes).

Best,

Billy Sarokin

I am running two IFB100s on a large set at present . One for me to control my trxs and send to my 942 and erxs for my crew and another set up on Video village sending sound to director/prod/script . I have them set 10 mhz apart .

[Tony Johnson]

942! Are you using the Super CMIT?  I haven't tried it yet.  Also glad to see you are using dual IFB systems.  I'm thinking of doing the same for shoots where the dir/prod want to watch and listen to playback off the video cart using the same headphones.  Only problem is I'm reliant on the audio output quality of the video cart which can range from funky to brilliant (often within the space of 5 minutes).

Best,

Billy Sarokin

No Billy not using the super C mit as yet but thinking of going that way in a few months . Love the 942 as all you 992 owners will agree ,  I won't go back to a cable , my boom op loves it .

Funny about vid split sound . We are using the latest qtake program for 3D capture but the sound still goes through the apple mac audio chain via an analogue delay first , the sound is degraded a lot from what comes out of my cart . It seems the qtake video capture kona cards are only going to accept AES , good for those with a mix 12 I guess but I prefer to send audio to them in analogue from my mixer as I can easily control level and what I send . We tried going through an AtoD converter but could not get the system to work . Its an area that I think needs attention as they seem to forget about any decent sound when they design these systems .

Tony

[bigmaho]

Jeeze, what kind of delay does a system like that have, a minute and a half ;-)?

No Billy not using the super C mit as yet but thinking of going that way in a few months . Love the 942 as all you 992 owners will agree ,  I won't go back to a cable , my boom op loves it .

[rich]

good to hear that the 942's are working great. will be getting myself one as soon as zaxcom can get one over here.

wanting to get it specifically for use with my super cmit.

reckon the total system delay time is 10.6ms - 3.6 for the zaxcom and 6ms for the super cmit dsp output.

i know the dsp output delay varies depending on frequency but if i dial in 2.4ms to the zaxcom radios on my 788, it seems to work ok when i listen to a mono mix.

[Tony Johnson]

Jeeze, what kind of delay does a system like that have, a minute and a half ;-)?

It feels like it but is about 6 - 8 frames depending on the configuration of the rig so if you have one of the cameras inverted in the rig then the delay will be more as it takes a process to flip it , so vid split guys constantly have to change the audio delay depending on camera rig . Then there is a big debate if there is actual sync . I think the latency is always there and the sync is rubbery with HD.

Tony

[bigmaho]

wow, in the old days, 186,000 miles per second seemed fast enough for just about anything.... until 3D/HD came along....

[ao]

Interesting to hear your feedback, thanks for posting! One question I have as I've been thinking of adding these to my kit…Any news of the Deneke/zaxcom slate with the receiver built in? I can see that being very useful if the ifb system can send metadata as well as time code so that scene and take info is digitally displayed on the board as well.

still not available.  production I am on bought three deneckes,  which is why I put in the query.  was hoping to get the new zax compatible ones...

ao

[ao]

The 2 scenarios that work best are either using a whip directly on the IFB transmitter OR using and amp mounted directly to the antenna.  The whip works very well indoors.  It can easily cover a large stage.  The 2.4 gig signal loves to bounce around.  I use use the whip when I'm doing car rigs.  From inside the cab of the tow vehicle it has no problem controlling the transmitters in the towed car and ifb feeds for everyone on board.

when you say whip, are you talking about the supplied ifb100 antenna or something else?

ao

[bigmaho]

The supplied antenna. 

when you say whip, are you talking about the supplied ifb100 antenna or something else?

ao

[Tom Visser]

Does anyone know a source for a timecode / audio cable for the ERX1TCD? I need mini-TRS to Lemo-5 (tip to receive) and TA3 (ring to hot). 18" or shorter would be ideal.

[soundslikejustin]

Does anyone know a source for a timecode / audio cable for the ERX1TCD? I need mini-TRS to Lemo-5 (tip to receive) and TA3 (ring to hot). 18" or shorter would be ideal.

Custom. Trew made me a Lemo to 3.5mm Timecode I/O cable for my QRX, perhaps they can help. I made a 3.5 -> timecode and audio cable like to want myself, the most expensive part being the Lemo connector