LarryF Posted May 7, 2019 Report Share Posted May 7, 2019 14 hours ago, mattmattsn said: [snip] It turns out the original f8 does not have shielding that can deal with the RFI the Connect receiver puts out. If they are in the same bag (or within about a foot of each other in general) there is a loud buzz in the f8’s preamps. I’ve never had any interference from sennheiser wireless or from my plug on rodelink (which granted is a much much lower wattage). I messaged Deity and the solution they offered was to put a big copper plate covered in soft side Velcro sticking up out of my bag between the recorder and the receiver. Not super attractive. [snip] All transmitters with digital modulation have both an FM and an AM component in the RF carrier. The AM component, when close to audio pre-amps is very prone to causing interference. Think of it this way: A 100 mW transmitter 1 foot away is equivalent to a 1.4 MegaWatt AM station a mile away. Even if the digital signal is UHF, not fully AM modulated and some other seat of the pants factors, you can see why you get some bleed. The big copper plate idea is a pretty weak idea. You might get a small reduction in RF on Tuesday, but on Wednesday, a few moved audio cables will bring the problem back. I speak from lots of copper plate experience. Best Regards, Larry Fisher Quote Link to comment Share on other sites More sharing options...
mattmattsn Posted May 7, 2019 Report Share Posted May 7, 2019 From Zoom: Hello,Digital wireless systems can sometimes cause interference at close proximity with the F4, F8, or F8n. The most effective way to resolve this would be to increase the distance between the recorder and the wireless receivers. Some users have suggested using strips of copper tape on top of the device to shield from EMI/RF, or using gaff tape to hold folded strips of blackwrap to the F8. If the interference is coming in through the cable, you could also try using ferrite beads to shield the cable from EMI/RF. We cannot guarantee that these suggestions will eliminate the interference, but they should help in most situations. There have not been changes in shielding in production of the F8/F8n. Let me know if you have any further questions.Sincerely,CUSTOMER SUPPORT Sounds like more users are likely to have issues. Based on what Larry said, rf experts probably saw this coming. C’est la vie, send it back and keep saving. Quote Link to comment Share on other sites More sharing options...
borjam Posted May 8, 2019 Report Share Posted May 8, 2019 Ferrite beads on the audio cables should be more effective than a copper sheet I guess. After all the F4/F8 cabinet is metal, right? I am wondering about the internal antennas in the Deity receiver. Can they be disabled through firmware? Quote Link to comment Share on other sites More sharing options...
LarryF Posted May 8, 2019 Report Share Posted May 8, 2019 On 5/6/2019 at 8:05 PM, mattmattsn said: [snip] It turns out the original f8 does not have shielding that can deal with the RFI the Connect receiver puts out. If they are in the same bag (or within about a foot of each other in general) there is a loud buzz in the f8’s preamps. I’ve never had any interference from sennheiser wireless or from my plug on rodelink (which granted is a much much lower wattage). I messaged Deity and the solution they offered was to put a big copper plate covered in soft side Velcro sticking up out of my bag between the recorder and the receiver. Not super attractive. [snip] All transmitters with digital modulation have both an FM and an AM component in the RF carrier. The AM component, when close to audio pre-amps is very prone to causing interference. Think of it this way: A 100 mW transmitter 1 foot away is equivalent to a 1.4 MegaWatt AM station a mile away. Even if the digital signal is UHF, not fully AM modulated and some other seat of the pants factors, you can see why you get some bleed. The big copper plate idea is a pretty weak idea. You might get a small reduction in RF on Tuesday, but on Wednesday, a few moved audio cables will bring the problem back. I speak from lots of copper plate experience. Best Regards, Larry Fisher 2 hours ago, borjam said: Ferrite beads on the audio cables should be more effective than a copper sheet I guess. After all the F4/F8 cabinet is metal, right? [snip] The ferrite beads can be very effective. Ideally they would be as close to the input as possible or inside the mic input jack. Some small value (100 pF) shunt capacitors to ground after the beads sometimes work well. The problem is that these techniques are cut and try and try some more. Again, ideally, these protections would be done by the manufacturer after rigorous testing. We can dream. Best Regards, Larry Fisher Quote Link to comment Share on other sites More sharing options...
borjam Posted May 8, 2019 Report Share Posted May 8, 2019 I wonder if part of the problem is that envelope of the transmitted bursts is too sharp. I remember with horror the terrible GSM phones, I always wondered how that utter crap could be approved. Quote Link to comment Share on other sites More sharing options...
LarryF Posted May 8, 2019 Report Share Posted May 8, 2019 59 minutes ago, borjam said: I wonder if part of the problem is that envelope of the transmitted bursts is too sharp. I remember with horror the terrible GSM phones, I always wondered how that utter crap could be approved. Digital modulation takes many forms, QPSK, 8PSK, Gaussian, etc. Typically the modulation is a combination of FM and AM. The amount of AM modulation varies with the modulation type and causes the most interference to low level analog audio circuits. The rate of modulation can also make a huge difference. The Lectro Quadra system used a very wide bandwidth with a high modulation rate and most the AM interference was supersonic and either not audible or filtered out by the following audio stages in the device it was near. However, narrower bandwidth systems (cell phones) and current FCC bandwidth rules for part 74 devices (wireless) force the modulation to have a much lower modulation rate which is can be very audible. As you mentioned, GSM phones are particularly bad. Lots of AM component at a low (audio frequencies) rate. Keep in mind, the phones are legally modulated. The problem is a lot of analog electronics is not sufficiently protected against common modern digital electronics. The Europeans are ahead of the US in this regard as -all- devices with CE approval are supposed to be tested for immunity to outside RF. And -all- consumer devices are supposed to have CE approval. Unfortunately there are a lot of devices with fake CE marks or that only conform to a subset of the rules. Plus with the long lifetimes of gear in the production sound field, a lot of perfectly usable older gear was never designed with GSM phones, video transmitters or digital body packs in mind. Best Regards, Larry Fisher Quote Link to comment Share on other sites More sharing options...
Constantin Posted May 8, 2019 Report Share Posted May 8, 2019 On 5/7/2019 at 11:36 AM, Vincent R. said: it is a known fact that TX and RX close to each other is not a wise idea. Maybe then it’s not such a great idea to put both of them in the same unit? Quote Link to comment Share on other sites More sharing options...
daniel Posted May 9, 2019 Report Share Posted May 9, 2019 15 hours ago, Constantin said: Maybe then it’s not such a great idea to put both of them in the same unit? Digital UHF systems seem to be able to incorporate some (intermittent?) RX-TX communications (for changing settings etc) but maybe the need for 2.4ghz systems to frequency hop means this is not an option and the 'traffic' is continuous and more of a problem to other devices. In very crude terms it seems like most digital devices chuck out RFI in someway and if we're lucky a design engineer has worked out a way to manage this. From the procurement perspective, is it impossible to tell on paper, from the published specifications for the device if the digital noise floor/RF spill (whatever the correct term) will be significant for the planned use - perhaps it's not possible? Would the RFExplorer show us anything meaningful in these terms? Quote Link to comment Share on other sites More sharing options...
borjam Posted May 9, 2019 Report Share Posted May 9, 2019 35 minutes ago, daniel said: Digital UHF systems seem to be able to incorporate some (intermittent?) RX-TX communications (for changing settings etc) but maybe the need for 2.4ghz systems to frequency hop means this is not an option and the 'traffic' is continuous and more of a problem to other devices. Digital systems such as Deity Connect rely on the feedback sent from the receiver to the transmitter in order to work. The receiver will acknowledge received packets and maybe send information on received signal quality so that the transmitter can decide to retransmit, switch frequency and/or even data coding. So, in an Orwellian way, war is peace and receivers are transmitters Larry gave a really good suggestion above, increasing the packet transmission rate so that interference moves to ultrasound frequencies. 35 minutes ago, daniel said: In very crude terms it seems like most digital devices chuck out RFI in someway and if we're lucky a design engineer has worked out a way to manage this. From the procurement perspective, is it impossible to tell on paper, from the published specifications for the device if the digital noise floor/RF spill (whatever the correct term) will be significant for the planned use - perhaps it's not possible? Would the RFExplorer show us anything meaningful in these terms? It depends a lot. As a general rule there are two possible effects here: Either the radio equipment is transmitting interference outside the intended frequency band (unlikely, the certification process should detect that) or the recorder/preamplifier/microphone is detecting radio frequency. The latter could be solved by proper filtering and shielding but it's pretty expensive to develop. The RF Explorer manufacturer sells a set of near field antennas for electromagnetic compatibility testing but they are intended for a different application, such as detecting harmful emissions from devices not supposed to transmit such as monitors, power supplies, etc. Now I got curious, I will try to torture my MixPre 3. I am a radio amateur and I can try recording while I transmit on HF or V/UHF frequencies and expose it to heavy WiFi traffic. But if I am not wrong according to the internal photos its inputs seem to be transformer coupled, and transformers are a natural low pass filter. Quote Link to comment Share on other sites More sharing options...
LarryF Posted May 9, 2019 Report Share Posted May 9, 2019 4 hours ago, borjam said: Larry gave a really good suggestion above, increasing the packet transmission rate so that interference moves to ultrasound frequencies. I wasn't clear in my explanation, but doing that requires more bandwidth and the FCC limits Part 74 wireless to 200 kHz of bandwidth. This forces some of the modulation energy to be at audio frequency rates. The Quadra system I described that was mostly supersonic, had a bandwidth of 1.5 MHz, more than 7 times greater. It operated in the unlicensed 908 band using spread spectrum. Unfortunately, so did stage lighting controllers, phone systems, etc. Best Regards, Larry Fisher Quote Link to comment Share on other sites More sharing options...
Mungo Posted May 9, 2019 Report Share Posted May 9, 2019 On 5/8/2019 at 6:17 PM, LarryF said: Unfortunately there are a lot of devices with fake CE marks or that only conform to a subset of the rules. Absolutely! The general problem is that the manufacturer can "certificate" the product on his own by just declaring that it is conform to the rules. Quote Link to comment Share on other sites More sharing options...
IronFilm Posted May 10, 2019 Report Share Posted May 10, 2019 On 5/8/2019 at 7:01 AM, mattmattsn said: There have not been changes in shielding in production of the F8/F8n. Hmmm... that is interesting, as it was suggested there was changes tweaked in early F8 models vs later F8/F8n (like for instance there was in making their screen more robust) Quote Link to comment Share on other sites More sharing options...
Kisaha Posted May 10, 2019 Report Share Posted May 10, 2019 Still haven't experienced any issues with my F8 though. Does anyone? And with what wireless system? Quote Link to comment Share on other sites More sharing options...
Shastapete Posted May 10, 2019 Report Share Posted May 10, 2019 I have a 3 year old F8 that has held up just fine. I even use a Zaxcom Zaxnet transmitter sitting on top of it in the bag that is known to interfere with other "more premium" gear Quote Link to comment Share on other sites More sharing options...
mattmattsn Posted May 12, 2019 Report Share Posted May 12, 2019 You can see/hear the problems I had in this video demonstration I made. This is not public, only visible to those with the link. I contacted Deity and they said it was a quality control issue from Zoom. I contacted Zoom and they said they’ve never changed the shielding in the F8. Kisaha and Shastapete, are you trying it with the Deity Connect system or just commenting on the general reliability of your F8’s? I got mine right when they came out and it’s been great as well. Quote Link to comment Share on other sites More sharing options...
Shastapete Posted May 12, 2019 Report Share Posted May 12, 2019 Just commenting in general. How does your F8 behave with a mic (or other load) plugged into a record armed channel? Sometimes things get funky when there isn't a load on an input stage. Just trying to give Deity the benefit of the doubt. Quote Link to comment Share on other sites More sharing options...
Mattias Larsen Posted May 13, 2019 Report Share Posted May 13, 2019 17 hours ago, mattmattsn said: You can see/hear the problems I had in this video demonstration I made. This is not public, only visible to those with the link. I contacted Deity and they said it was a quality control issue from Zoom. I contacted Zoom and they said they’ve never changed the shielding in the F8. Kisaha and Shastapete, are you trying it with the Deity Connect system or just commenting on the general reliability of your F8’s? I got mine right when they came out and it’s been great as well. Thank you for sharing this. Seems like there are some kinks to be sorted out. Wonder if it's Zoom or Deity that is to blame in this particular scenario. I have a friend with a F4 that thought of getting deity to replace his G1/2/3s so I wonder if this can potentially affect him too. And just out of curiosity, Borjam - I would be interested to hear the results from your Mixpre torture. Quote Link to comment Share on other sites More sharing options...
jakob123 Posted May 13, 2019 Report Share Posted May 13, 2019 7 hours ago, Mattias Larsen said: Thank you for sharing this. Seems like there are some kinks to be sorted out. Wonder if it's Zoom or Deity that is to blame in this particular scenario. I have a friend with a F4 that thought of getting deity to replace his G1/2/3s so I wonder if this can potentially affect him too. And just out of curiosity, Borjam - I would be interested to hear the results from your Mixpre torture. Hey, beside the Zoom f4/8 Problem, how is the sound quality and especially the noise floor. AS good or better then Roder Filmmaker kit? Thanks and best regards Jakob Quote Link to comment Share on other sites More sharing options...
Ed Denton Posted May 15, 2019 Report Share Posted May 15, 2019 Not trying to be a dick about it, but I have to say: you get what you pay for. Expecting all the build quality and features of Lectrosonics and Sound Devices, but paying a third of the price for Deity and Zoom, you’re gonna be disappointed. Not to say that Deity and Zoom make “bad” products. But there are reasons why people pay considerably more for these brands, and you are experiencing them first hand. Quote Link to comment Share on other sites More sharing options...
jakob123 Posted May 15, 2019 Report Share Posted May 15, 2019 3 hours ago, Ed Denton said: Not trying to be a dick about it, but I have to say: you get what you pay for. Expecting all the build quality and features of Lectrosonics and Sound Devices, but paying a third of the price for Deity and Zoom, you’re gonna be disappointed. Not to say that Deity and Zoom make “bad” products. But there are reasons why people pay considerably more for these brands, and you are experiencing them first hand. In case of the zoom f8 I don't think you are right. I mostly care about sound quality and the preamps of the f8 are fantastic for the price. So I am asking people who own or really tested a deity connect, how is sound quality. There is so much talk about other (important) things but zero about sound quality... Quote Link to comment Share on other sites More sharing options...
Kisaha Posted May 15, 2019 Report Share Posted May 15, 2019 2 hours ago, jakob123 said: In case of the zoom f8 I don't think you are right. I mostly care about sound quality and the preamps of the f8 are fantastic for the price. So I am asking people who own or really tested a deity connect, how is sound quality. There is so much talk about other (important) things but zero about sound quality... Curtis Judd's review - mind that he isn't a real production sound man, just does corporate and stuff and work as 1 man band usually - which usually is truthful BUT very gentle with anything that reviews, has as cons - among others, 1) self noise 2) limiting limiter functions and options My take is that we will have a ver.2 in 12-14 months time that will fix most of the issues, like they did with their first Deity mic, with self-noise issues also.. It seems to me it is kind of lost between segments, not simple, small or cheap enough to go the Rode Go, Sennheiser XS route for consumer/prosumer use, but neither good enough to beat our established systems for prosumer/pro work. Quote Link to comment Share on other sites More sharing options...
daniel Posted May 15, 2019 Report Share Posted May 15, 2019 3 hours ago, Kisaha said: Curtis Judd's review - mind that he isn't a real production sound man, just does corporate and stuff and work as 1 man band usually - which usually is truthful BUT very gentle with anything that reviews, has as cons - among others, 1) self noise 2) limiting limiter functions and options My take is that we will have a ver.2 in 12-14 months time that will fix most of the issues, like they did with their first Deity mic, with self-noise issues also.. It seems to me it is kind of lost between segments, not simple, small or cheap enough to go the Rode Go, Sennheiser XS route for consumer/prosumer use, but neither good enough to beat our established systems for prosumer/pro work. +1. Version 2 may deliver what version 1 can't but the competition for the sales (to allow future development) looks strong with Rode Go. This might sound cruel but if Connect doesn't sound as good as Go and Go is also smaller, then Connect's USP features look a little wasted. Quote Link to comment Share on other sites More sharing options...
IronFilm Posted May 15, 2019 Report Share Posted May 15, 2019 50 minutes ago, daniel said: but the competition for the sales (to allow future development) looks strong with Rode Go. This might sound cruel but if Connect doesn't sound as good as Go and Go is also smaller, then Connect's USP features look a little wasted. In terms of feature set (dunno about quality! Nobody has done a shoot out of Go vs Connect yet) then the Deity Connect crushes the Rode GO. And the cost difference is really not that much either, once you factor in the extra cost of half decent ish lav mic for GO, then the cost per channel is not that far off at all from what Deity Connect costs. Quote Link to comment Share on other sites More sharing options...
daniel Posted May 15, 2019 Report Share Posted May 15, 2019 4 hours ago, IronFilm said: In terms of feature set (dunno about quality! Nobody has done a shoot out of Go vs Connect yet) then the Deity Connect crushes the Rode GO. And the cost difference is really not that much either, once you factor in the extra cost of half decent ish lav mic for GO, then the cost per channel is not that far off at all from what Deity Connect costs. At these prices and the target consumer I don't think difference between prices is very significant at all. If I was vlogging, OMB'ing or similar, choosing a consumer 2.4ghz system I would have similar criteria to choosing a pro UHF system (there are some some differences too especially regarding number of channels): Sound Quality > Range / TX Size > Number of channels and Features. Crushing the opposition with the least important of these maybe a bit of a pyrrhic victory. Quote Link to comment Share on other sites More sharing options...
IronFilm Posted May 15, 2019 Report Share Posted May 15, 2019 3 hours ago, daniel said: Sound Quality > Range / TX Size > Number of channels and Features. Crushing the opposition with the least important of these maybe a bit of a pyrrhic victory. If you're buying more than one channel, then per channel costs matter. Nobody has done a head to head test of them just yet, so can't answer the first two points yet. (but I strongly expect the Deity to have greater range based on the spec sheet) TX size matters far less to consumers than we think, thus the reason why the very bulky RodeLink is so very popular. Quote Link to comment Share on other sites More sharing options...
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