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Matthew Steel

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About Matthew Steel

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    Live sound and recording for higher education
  • Interested in Sound for Picture

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  1. Seems like they solved this issue shortly after dinosaurs roamed the earth so if it got unsolved in a new model then somebody dropped the ball... https://www.lectrosonics.com/Support/component/com_fsf/Itemid,714/tag,Wireless, 48, phantom power, damage, receiver/view,faq/
  2. Might be worth a call to Lectro to see what their current wiring recommendations are. I found this note in my files (I know this is a different mic, but the principle of different opinions on wiring is a valid possibility): Sept 16, 2011 Talked with Rene (ext 171) at Lectrosonics because Countryman E6 mics were noisy on new UM400a transmitters. He said that the documents on the web showed the wiring recommended by Countryman, but that there in the Lectrosonics shop they prefer a different wiring: TA5F Wire Pin 1 Shield Pin 2 Jump to 4 Pin 3 White (or green, as in the 10/2016 mics) Pin 4 Jump to 2 Pin 5 Not connected This wiring has been tested and seems to work nicely on the following transmitters: M185 UM200c SMa UM400a (sound much improved over factory wiring) [And today I can also add LMb to that list]
  3. I have done some tests on used batteries like that. I put them in an SMa transmitter and logged the battery voltage on a Venue rack until the transmitter died. If memory serves, the battery indicators in both the SMa and Venue seemed to be based entirely on battery voltage. I was not able to come up with any consistent relationship between initial battery voltage and life expectancy. Here is the graph. Vertical scale is battery voltage. Horizontal is minutes. For reference we usually got 4-4.5 hours (so 240-300 minutes) on a brand new lithium in the SMa. My rule of thumb is that if you get a "good" reading for the first 5 minutes then the battery is not dead and you will get "some" use out of the battery - but don't count on any specific amount.
  4. I have heard of times with today's small transmitters where the transmitter itself has been hidden in the hair. This may have been in more forgiving theater situations though...
  5. This paper was helpful to me and addresses (at least to a small degree) the long run/short run nature of the question: http://audiosystemsgroup.com/Which_Coax_for_Wireless_Mics.pdf In short, the loss from mismatch is a one-time loss, where cable loss accumulates over distance. Thus, for short runs the mismatch loss is more significant (but still quite small). But for long runs, definitely the cable loss far outweighs the mismatch loss.
  6. Not sure if this is Larry's tumbleweed, but there is an FCC certification for the DPR: * Tunes anywhere in TV channels 14-36 - i.e. any legal TV frequencies. * Size and weight of the HMa so probably plug-on. * 50mw and 25mw power settings. Also there is a unit called the DBu that is digital encrypted wireless in the LT form factor. It might already be released because it was certified in 2017. It doesn't seem well advertised but the manual is out there if you search.
  7. Just for the record, I just paced it off and we're more in the range of 110-170 feet. Considerably closer than my mental estimate.
  8. We have a couple of things going for us as far as channel count - we are indoors, in a building that uses a wire mesh as a base for plaster. Also, we are in a small/medium city and so the TV stations are not totally crammed in. We routinely operate at 200-250 feet between transmitter and antenna but not much farther. I use Wireless Workbench for coordination. I found the WW default settings for Lectrosonics gear to be a bit too conservative and so I messed around with Wireless Designer to see what intermod spacings it uses, then I set up custom device profiles from that info. And, it helps that of the 49 channels there were 38 UHF and 11 VHF. Personally I think the diversity has more to do with the VHF noiseups than anything. And the fact that these are 30 year old units, some of which have never been sent back for a tuneup ever. I doubt the 50mW had as much to do with it since some of our UHF were also 50mW. Although we had 100mW stuff for that show it was our older 600mHz stuff, and with the 600MHz transition I have moved to 50mW or less across the board. This is mainly because I don't believe we meet all the FCC requirements for part 74 licensing and I prefer us to be compliant. As far as the LMb battery doors, I think it was confined to a small number of transmitters, possibly even only one. I was able to adjust catch for the door a bit tighter. We'll see how things go after that.
  9. Thanks Larry! I'll have to put a wideband multicoupler on my list of possible improvements, since one of our buildings has 5 inline Venues at this point. Thankfully we haven't seen any reception issues so far. In fact our last show was our biggest ever and we had an even longer antenna chain without troubles: SNA600 -> VRWBL -> VRWBL -> VRWBM -> VRWBM -> UMC16 25/26->(VRWBM, UMC200D, UMC200D). The show had 49 transmitters (all Lectrosonics) and the only transmitter issues were a few noiseups on the ancient VHFs and a couple of LMb battery doors coming open.
  10. This topic has raised a couple of questions in my mind: * There seems to be conflicting specs on the bandwidth of the SNA600. I have seen the 30MHz figure, but I have also seen the figure of VSWR <= 2:1 over a 100MHz range, and the comment that the SNA600 fully extended will operate satisfactorily from 440MHz to 600MHz. Does it come down to how we define bandwidth in a particular case? For instance I wonder if the 30MHz spec is -3dB where the 2:1 VSWR might correspond more with -6dB? (and VSWR is a spec more suited to transmitting anyway, correct?) * My personal experience includes feeding block 26 receivers with a pair of SNA600's fully extended with no problems, so I'm doubtful they would offer much protection from new 600MHz cellular interference. In this particular case it was also at the end of a long chain - (2) VRWB Lo, (2-3) VRWB Mid, a two-block UMC16 and a two-block UMC200d with the block 26 receiver in it. * And, would there be any benefit in converting a "chain" of VRWB into a "star" configuration where each VRWB is fed from a wideband UMC16a? It seems there might be slightly S/N for the downstream receivers but I'm not sure whether it would matter real world.
  11. Yes, the firmware at the link is low level, but these transmitters don't have an OS in the traditional sense of the word, just the firmware. The firmware can be updated in the field. Instructions are in the user manual.
  12. Here's my view from last night - front of house at Bob Jones University's first performance of Titanic: The Musical: This is by far the most involved show I have ever run: 49 channels of wireless with a cast of 65+ and 13 wired mics on a 25 piece live orchestra in the pit. The trailer below was shot by our internal media folks at a dress rehearsal. The audio is essentially my front of house mix, so please excuse the large number of open mics at times. We hired 6 professional singers for lead roles, but everyone else - cast, orchestra, crew, and designers - are students, faculty, and staff. EDIT: The embedded video worked for me but doesn't seem to be working for some. Here is a link that may work better: https://www.facebook.com/bjuedu/videos/411084119653155/
  13. So this one was certified in July, before the flurry of ETSI modifications. I should have looked further back.
  14. Geometry seems reasonable for 5-pin lemo... No FCC certifications since November so not likely a new transmitter.
  15. It looks like this has now been accomplished, since firmware v6.0 is now on the web site. From the release notes: VRWB v6.0 - 11 December 2018 Substituted NU Hybrid (NUH) and NU Hybrid with talkback (NTB) for 100 Series and Mode 6 compatibility modes, respectively. Removed REFUMAUS mode. Fixed rounding error in "mhz" serial update command. Thanks to all the folks at Lectrosonics for maintaining compatibility between this now-discontinued product and the current crop of transmitters.
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