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Interference issues with the SD633 & IFB200 comb


Bax

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bax: " and i expect from them to work flawlessly, as simple as that. "

unreasonable expectations, particularly at the current price points.

JW said it well, but missed a bit with: " For example, some of the recorders from Sound Devices, I believe the 744T and possibly the 788T, have had demonstrated RF leakage from the battery compartment "

the original 7's had more RF "leakage", aka "spray", but the 788 was even more thoroughly tested, and tweaked to minimize the issue significantly.

mrl: " but something has to give when it comes to development. "

no it doesn't.

mrl:" This is what I'm getting at Glenn " + " My post was NEVER meant to be directed at him " = oxymoron

palmerT: " reason I bought the CL was so I didn't have to deal with the issues of remoting the antenna like I did with the original TRX 900/STA in the bag. "

you are also dealing with the laws of physics... and coupled with marketing! (aka keeping prices affordable for our market)

" I would love to hear another solution that doesn't dramatically affect the range of the unit and doesn't require remoting an antenna. "

you might not like the price, using current technologies... but the future is coming.

"So far I've only been told that it's a 633 problem and I don't agree with that."

well I agree with you, it is not a 633 problem, it is a current technology problem, and for the present, JW is correct: " we need to look to where there can be a fix or a workaround if you want to use all these things together. "

workarounds are nothing new, and we'll be using them in the future, too

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"Please, it is not a question of whether you "agree" with this or not."

I actually do think this is relevant. If I'm not allowed to say whether I agree with something or not, then I think opinions are being limited in any discussion. And like you later say, when I'm being told that this is a problem with the 633 when it is much more than that, this is what limits the possible solutions. I understand that you may not like if I agree with something or not, but I'm simply pointing out the fact that it is not a 633 problem alone.

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palmerT: " If I'm not allowed to say whether I agree with something or not, then I think opinions are being limited in any discussion. "

no one said you could not have, or express an opinion, or agreement; we just said we believe you are incorrect!

"So far I've only been told that it's a 633 problem and I don't agree with that."

well I agree with you, it is not a 633 problem, it is a current technology problem, and for the present, JW is correct: " we need to look to where there can be a fix or a workaround if you want to use all these things together. "

workarounds are nothing new, and we'll be using them in the future, too

 

Then I'm not understanding your posts, and you kind of said you agree with me. What is it that you think I'm incorrect about?

 

Jeff said it wasn't a question if I agree with it or not. I think it is part of it. Not agreeing that it is a solely a 633 problem is exactly what most everyone is saying. 

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"If I'm not allowed to say whether I agree with something or not, then I think opinions are being limited in any discussion" I don't see where anyone has said you are not allowed to say whatever you please. My comment "Please, it is not a question of whether you 'agree' with this or not." was merely commenting on the futility of what you had been told (that it was a 633 problem). It has been established now, I believe (if even in a somewhat circular manner) that it is NOT a Zaxcom problem (the initial thrust of this topic) or specifically a 633 problem (problems existed before there even was a Zaxcom IFB or a Sound Devices recorder). So, I am agreeing with but trying to keep this on topic. 

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It has been established now, I believe (if even in a somewhat circular manner) that it is NOT a Zaxcom problem (the initial thrust of this topic) or specifically a 633 problem (problems existed before there even was a Zaxcom IFB or a Sound Devices recorder). So, I am agreeing with but trying to keep this on topic. 

I still don't think that is necessarily true or fair to say. I love all my Zaxcom products and I'm not trying to put them down. The CL is an amazing piece of gear and does many different things that no other piece of gear can do alone. But this is something that people are experiencing with the IFB's and CL's with other gear in the bag. While it is ultimately the user's 'problem', to imply that it the CL or Zax IFB's didn't introduce this specific issue isn't really accurate.

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"While it is ultimately the user's 'problem', to imply that it the CL or Zax IFB's didn't introduce this specific issue isn't really accurate."

 

Again, no one has been saying that the Zaxcom products have not been at the heart of this particular problem --- what I have been trying to clarify (and I think we have all already spent way too much energy fine-tuning this topic rather than trying to solve some problems) is that the Zaxcom devices are the first 2.4ghz devices that we have been putting in the sound bags along with all this other gear. No one is going to have these 2.4 ghz related RF problems if there isn't any such devices working in close proximity to their other gear (and this includes cell phones, remote focus devices, etc., etc.). Actually, if you look at the history of "problems" people have had with RF interference getting into the recorder, the Comteks, the microphones, the monitor amplifiers, etc., Zaxcom as a company has done more to alleviate these problems than any other company. For example, when it was discovered that Schoeps microphones were particularly susceptible to noise issues when being used with Zaxcom Digital Wireless, Schoeps ultimately did a re-design and improved the microphone's rejection of RF interference. So, was it Zaxcom at fault for this interference issue or was it Schoep's fault for not designing a microphone with better RF protection? A similar situation with Sanken COS-11 lavs, a very good microphone, for sure, but very RF susceptible. Ultimately, Sanken did a re-design to the COS-11 (and to the CS3-e which already had terrible RF rejection, neon, fluorescent lights, cell phones, etc.) and the end result was we had a better product from Schoeps and Sanken.

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I believe the claim that this is a Sound Devices issue came from Glenn on the Zaxcom forum. Soooo, maybe give him a call with your frustration.

"The only things that seem to work are either reducing the power of transmission, or remoting the antenna itself."

 

I think these are the only solutions when dealing with 2.4 ghz RF transmission in close proximity to other devices that are susceptible to interference at this frequency.

 

"So far I've only been told that it's a 633 problem and I don't agree with that."

 

Please, it is not a question of whether you "agree" with this or not. I think when we discuss any of these sorts of problems it is most productive to analyze the problem and look for what are the possible solutions. It is, in fact, a SD 633 problem, a Nomad problem, a TRX-CL problem --- we need to look to where there can be a fix or a workaround if you want to use all these things together. Has Sound Devices done whatever they can to make their recorder less susceptible to this interference? Probably (and maybe more work can be done design-wise). Has Zaxcom done whatever they can to minimize the problems associated with 2.4 ghz? Probably (and still more work to be done I'm sure).

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"Again, no one has been saying that the Zaxcom products have not been at the heart of this particular problem."

Well, actually some have, but it doesn't help to get into it.

And I agree, in the end we end up with a better product. Sanken and Schoeps did do the redesigns though.

Ultimately we do get better end products discussing these issues, and I am grateful for this forum and the work that you put into running it. It is an amazing resource to us all, including mixers and manufacturers.

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I get your point regarding the cos-11 and cmit example. It is an argument that makes sense on certain level. The problem with this situation, as you pointed out yourself, is that it seems to happen with Zaxcom gear as well, which you would think they would have tested. In addition, as you pointed out, it seems to come up with all sorts/makes of gear at inconsistent levels. The only consistent thing is the Zaxcom 2.4 tx in some form. That being the case, it's logical to at least consider that the problem could be inconsistent build quality of 3rd party (to Zax) pieces in the bag, or just as easily inconsistent build quality with the Zax gear. Some better shielded/sealed than others. In my case the issue is present with my maxx/IFB 200 set up, but at a low enough level that I consider it manageable. Basically below the noise floor of almost all the locations I work in. I was recently in a nighttime forest where I had to turn the unit down (tx power) in a few locations. 

"While it is ultimately the user's 'problem', to imply that it the CL or Zax IFB's didn't introduce this specific issue isn't really accurate."

 

Again, no one has been saying that the Zaxcom products have not been at the heart of this particular problem --- what I have been trying to clarify (and I think we have all already spent way too much energy fine-tuning this topic rather than trying to solve some problems) is that the Zaxcom devices are the first 2.4ghz devices that we have been putting in the sound bags along with all this other gear. No one is going to have these 2.4 ghz related RF problems if there isn't any such devices working in close proximity to their other gear (and this includes cell phones, remote focus devices, etc., etc.). Actually, if you look at the history of "problems" people have had with RF interference getting into the recorder, the Comteks, the microphones, the monitor amplifiers, etc., Zaxcom as a company has done more to alleviate these problems than any other company. For example, when it was discovered that Schoeps microphones were particularly susceptible to noise issues when being used with Zaxcom Digital Wireless, Schoeps ultimately did a re-design and improved the microphone's rejection of RF interference. So, was it Zaxcom at fault for this interference issue or was it Schoep's fault for not designing a microphone with better RF protection? A similar situation with Sanken COS-11 lavs, a very good microphone, for sure, but very RF susceptible. Ultimately, Sanken did a re-design to the COS-11 (and to the CS3-e which already had terrible RF rejection, neon, fluorescent lights, cell phones, etc.) and the end result was we had a better product from Schoeps and Sanken.

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Confession: I hath skipped most of the comments to utter these words before the notion is lost.

 

We are the testers.

 

The tech moves fast, sound ninjas.

 

To troubleshoot these new things is as much art as knowledge; as much of both as you can muster will boost your advantage.

 

We are on the cutting edge of ever-newer technologies.

 

We ride a series of big waves.

 

These inventor/engineer/entrepreneurs are our lifeboats in rough seas.

 

Bravo all.

 

I get it that the first thing young mixers think in The Pinch is, "To hell with this device and its creators." Used to be young. Now, I know more about the process of bringing a product to market and the people who make the gear that gets my ears and fingers where they need to be.

 

One of my solutions is to have more than enough of everything.

 

That very solution saved my bum yesterday when 2.5 transmitters went down within a few hours of each other.

 

A slate went down too.

 

I'd the great good fortune of sufficient backups all around.

 

The stuff gets beat up after all, mostly well out of our control.

 

The gear demands a lot of me.

 

This job have to check all bolts for tightness often; the truck is exceptionally vibrateous.

 

I aim to be a good customer and follow the manuals and have sometimes in the heat of battle and peace of prep, failed.

 

Manufacturers and mixers hold each other up.

 

Tempting as it is to blame the gear...I no longer do.

 

One concept to strive to understand is this: limitations; your own and others' and the limits of the tools.

 

Thanks for the inspiration to opine thus at the end of a lighter day than most, as the result of which was able to get my feet under the repairs process.

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"The problem with this situation, as you pointed out yourself, is that it seems to happen with Zaxcom gear as well,"

 

Every input and output from a Zaxcom product has RF filtering designed into it. These filters are there to prevent interference to the audio circuits. Zaxcom also uses full metal cases with multiple screw down points to eliminate internal pickup of external RF radiation over a very wide range of frequencies. When there is interference and as far as I can calculate it affects far less than 1% of our customer base and is usually solved by moving cables or antennas. The interference can be generated either in the source or the destination of the input or output in question. For all intensive purposes this is not a problem with Zaxcom gear even though it does pop up from time to time.

 

"That being the case, it's logical to at least consider that the problem could be inconsistent build quality of 3rd party (to Zax) pieces in the bag, or just as easily inconsistent build quality with the Zax gear."  

 

Build quality has never been the problem and has never been associated with any fix that I have ever seen in the last 25 years. The exact and undisputed cause of this problem is RF energy being rectified (converted) from RF energy into a changing voltage within the audio passband by circuits that do not have enough shielding to keep out the RF energy from the effected circuits. 

 

When this problem happens there are a few things that can eliminate the problem. Use microphones, mixers, RF receivers and recorders that offer a high degree of rejection to RF interference,  separate the antennas as much as possible in the sound bag or better yet get the TX antenna up onto the bag strap. Keep your bag cables away from the transmitter antenna. Keep your cables as short as possible. Use audio cables with a full tin foil shield not just a wire shield. If a specific input or output is sensitive get a clip on ferrite filter and put it close to the effected input.

 

On affected XLR inputs try connecting the wire shield to the XLR shell as a last resort. Or use a 100pF capacitor in the connector shell if there are any negative effects to the audio by a direct wire connection. 

 

When the source of the problem is difficult to locate disconnect all cables from the effected device and then connect them up one by one in order to see when the problem can be heard. Due to the nature of RF standing waves it may be a combination of things that cause a problem rather than one single cable. In fact the sound bag itself may contribute to the problem or the solution if it is made with a metal frame.

 

We have been in contact with other manufactures to help with this problem and we have loaned out gear to help them identify any weakness that needs to be addressed in present and future designs. We are very pro active on this but in the end it is common sense solutions implemented by the sound mixer that will eliminate this issue.

 

Glenn

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What I get from this is: every other manufacturer needs to start designing their products with enough filtering protection in the case they end up in the vicinity of a Zaxcom device.

No.

What you should get from this is:

Every manufacturer needs to design their products with enough filtering protection in case they end up in the vicinity of a device that emits rf.

That device being a zaxcom device, a teradek, a remote focus device or even a cell phone.

RF is RF - Zaxcom is not changing the laws of physics. Stick another 2.4Ghz device in the same proximity in your bag and see if things are different.

A component that is prone to RF - what ever the affecting band is (vhf, uhf, or 2.4) - will be affected by RF in that band regardless of the source.

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"What I get from this is: every other manufacturer needs to start designing their products with enough filtering protection in the case they end up in the vicinity of a Zaxcom device."

 

Not correct. Please read Jack Norflus' post. As I pointed out before (but nobody wants to listen) RF susceptibility is a fact of life, to what degree it can cause problems is highly variable: the essential design of the gear being used, the overall RF environment, ALL the weird RF voodoo that relates to the type of cables being used, types of antennas in use, etc., etc. Problems with 2.4 ghz RF transmission getting into the gear we use is NOT a new phenomenon. The reason that this is being discussed specifically in relation to Zaxcom gear is that Zaxcom devices are the first devices being used in the bag that utilize 2.4 ghz RF transmission. If Lectrosonics had come out with a unit that used 2.4 ghz transmission and you put it in your bag it would most probably cause the same difficulties with associated gear in the bag.

 

Please, read Jack's post, again, and let's get on with solutions to these problems.

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No.

What you should get from this is:

Every manufacturer needs to design their products with enough filtering protection in case they end up in the vicinity of a device that emits rf.

That device being a zaxcom device, a teradek, a remote focus device or even a cell phone.

So if I said other devices to include Zaxcom it would be yes then. Same meaning, more PR words used, but that's fine I see what you're saying. It's strange that even with the filtering zax uses I still get rf spray or interference between their own devices.

Please, read Jack's post, again, and let's get on with solutions to these problems.

I think I speak for the 1% when I say, we've been patiently waiting.

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So in thinking about the problem I thought of a neat possible solution with a good side effect. If a directional patch antenna were to be put into a receiver pouch on the outside of the bag it would minimize the effect by at least 8dB in the bag. It would also double the range of Zaxnet in the direction it was pointed. Here is a link to an inexpensive patch antenna.

 

Glenn

 

 

 

http://www.l-com.com/wireless-antenna-24-ghz-8-dbi-round-patch-antenna-4ft-rp-sma-plug-connector

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jason: " I believe the claim that this is a Sound Devices issue came from... "

I don't, and would like to see the quote, with adequate context!

" it's logical to at least consider that the problem could be inconsistent build quality of 3rd party (to Zax) pieces in the bag, or just as easily inconsistent build quality with the Zax gear. "

I don't think so... fuzzy logic ?? faulty logic..?

 

 

Zack: " What I get from this is: every other manufacturer needs to start designing their products with enough filtering protection in the case they end up in the vicinity of a Zaxcom device. "

that isn't what I get... not at all!

 

and of course what Jack, JW, Glenn and Jan said... I like the patch idea, too...

 

" It's strange that even with the filtering zax uses I still get rf spray or interference between their own devices. "

it isn't strange, it is physics.

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