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Matthew Steel

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Posts posted by Matthew Steel

  1. On 3/23/2024 at 8:16 PM, The Documentary Sound Guy said:

    It doesn't matter as long as you're sure you'll never modify the cable after you finish.

    If you want to prevent errors in future repairs or modifications, it's better to follow established conventions.

     

    Agreed that it doesn't matter which color conductor is "hot" and which is "cold" as long as it is the same on both ends.  If they are different then you will have a polarity reversal.  Which will also (generally) sound indistinguishable by itself but cause problems when combining coherent signals.

    As for me, "established conventions" is as simple as, there were about a hundred star quad cables in our inventory when I arrived here, and whoever built them chose to wire them "blue is 2."  So I wire all new cables that way as well.

     

    On 3/24/2024 at 12:07 AM, Derek H said:

    I think the more (potentially) consequential debate is to ground the shell or not. 
     

     

     

    I leave the shell unconnected.  The cable shield is still connected to pin 1, so the cable is still shielded for most of its length.  But where two cables meet, because the shells are not connected to anything they cannot act as a true shield.  As a result there is a small unshielded area that is susceptible to RFI/EMI and is a potential source of noise.  In practice, I have never encountered a situation where I think this is significant.

     

    On the other hand, a shell that is connected to shield is susceptible to introducing ground loops into a system if it touches "grounded" objects that are at slightly different potential.  The most notable example I have encountered of this was when a microphone had a significant buzz every time the shell touched a metal part of a building.  In that case, floating the shell made the noise go away.

     

  2. We use our HM and HMa transmitters in live settings, so not the same as you're asking.  But we have done some unusual things with them that might help give perspective.  One thing we do is to fasten the trasnmitter under a wooden lectern with a cable running up through it to a gooseneck mic on top.  We have also done things like putting a Crown (AKG) PCC160 with its TA3->XLR cable into a plug on.  Perhaps more like what you're asking, I have had press at an event ask me to give them a feed using their plug-on.  Once or twice I've plugged one straight into a press mult box without even a cable on it.

     

    I don't remember ever having range problems with any of these scenarios, with distances ranging from 50-150 feet from the receiving antennas.

     

    I presume that you are asking because you don't already have a plug on, but if you can manage to borrow, rent, or buy one with the opportunity to return it if it doesn't meet your expectations, then I'd suggest testing it in a scenario that matches your intended use as closely as possible.

     

    This next part is likely not the way you would go, but since cost is a concern, I'll mention that we regularly use a Sennheiser IEM G3 transmitter to transmit to LSP500 wireless speakers.  With a Lectro SNA600 I can get up to 300 feet at the transmitter's 50mW high power setting.  If I don't need that much range I use a whip on the back.  To go to Lectro your receivers would have to have compatibility modes.  I have not gone SennheiserTx -> LectroRx, but I have gone LectroTx -> SennheiserRx using mode 3 and Mode 6 compatibility.  Those modes are for other transmitters, so there is definitely a quality loss.  But for IFB it might be an option.

  3. On 2/11/2024 at 5:53 PM, r.paterson said:

    Does the zaxcom ammended patent mean that the patent doesn't end next year now?. 

     

    Some of them appear to expire next year, others do not.  Here is a sample:

    Patent 8,385,814 B2 appears to have an anticipated expiration date of 2025-07-14. (Google patents).

    Patent 9,336,307 B2 appears to have an adjusted expiration date of 2025-07-31. (Google patents).

    Patent 7,929,902 B2 appears to have an adjusted expiration date of 2028-08-22. (Google patents).

     

  4. Since we are talking theoretical, an audio recorder that is receiving timecode (not just getting word clock that is derived from timecode) could actually know where the frame boundaries are.  In that case such a recorder could pad the recording (using a prerecord buffer if necessary) to always begin every recording on a frame boundary.

     

  5. I do a lot of different types of work as a staff engineer.  Part of that is live, including musical theatre.  Absolutely the second mic is for redundancy.  And as others have said, it is almost never the RF side of things (if your coordination is good), but the mics getting sweated out and the cables getting intermittent or being ripped out of connectors.

     

    We are not a big time venue, but some of the shows we do have very large casts (I have had a couple where we have 48 channels of wireless for the show).  And we often bring in a few top artists for principal roles.  It was one of these that I had my most memorable experience with a principal sweating out a mic.  I had to cheat off other actors where I could for a scene or two until he went off stage long enough for the backstage tech to swap his mic.

     

    Since then I have doubled up mics when the situation called for it (like, a character that barely left the stage the entire show) and I had the equipment so that could.

  6. A while back we had one or two VHF systems repaired by JayCee.  No complaints.

    On 2/3/2024 at 2:05 AM, IronFilm said:

    We need a blackmarket repairer who does fixes under the table.... 

     

    (I didn't post that above! For legal reasons I shall claim that someone else hijacked my computer and posted this, not me 😉 )

     

    Anyone that can manufacture a new clone RF board for a UM400a deserves recognition :)

     

    I bet Rio Rancho can fix most boards unless they are burned/cracked/corroded or similarly damaged.  It's just that for some repairs, the time it would take to diagnose might be cost prohibitive.

    I bet JayCee can handle any reasonable repair too.  And might be willing to undertake some that the factory wouldn't care to.

  7. Fastest way to get official word is to call when they open up in a few hours.

     

    My prediction is that they will still do any repair if they have the parts.  But some repairs are only cost-effective by replacing the entire circuit board, and they cannot legally replace an RF circuit board on the UM400a because its FCC certification does not comply with the new ETSI mask requirements that took effect October 2018.

  8. There is a thread on here somewhere in the last few months with internal pictures of a Lithium pack.

    Personally I have opened a Sennheiser Lithium pack for LSP500 Pro that stopped working correctly.  Its plastic case was glued together, so it took some care to not destroy it.  Expect glue even if there are also screws.  On the Sennheiser battery the cells were spot welded into a series string of parallel pairs.  Conventional wisdom is that soldering directly to the end of lithium cells is risky business; replacement cells with tabs already attached seem to be recommended.

     

    The pack I opened up had only about 50 cycles on it and it appeared that all the cells were still good, but the protection circuitry was tripping for some reason and I gave up.

  9. In the live side of my work I use Allen and Heath dLive and it has "Dugan style" gain sharing automix built in.  I have never had the need to automix that many channels but I think it has the capabiity.  I think the Avantis line has the same/similar capabilities.  Where some other mixers are limited to 8 channels, etc.

  10. I wonder if it has to do with the fact that Lectrosonics manufactures the product inside the USA, and therefore the patent applies to the manufacture.  Whereas, if another company might be able to manufacture outside the geographic scope of the patent, in which case only sales are restricted by the patent.

     

    I have not heard one way or the other whether the hardware has the capability to do both simultaneously.  Personally I suspect it can and is limited only by the firmware.  If I remember correctly, the SMWB firmware package contains at least two separate programs, one for record mode and another for transmit mode; based on the chosen functionality, the appropriate code gets loaded into memory and executed.

  11. AES is specified to use 110 ohm cable, but in my experience normal mic cable will work just fine for shorter runs.  For example, I've used a 12 foot Canare star quad mic cable in a pinch on multiple occasions.  I have also used regular XLR to RCA adapters to go between AES and SPDIF because the specifications are close enough.

  12. I don't have any photos, sorry.

     

    The ones I had weren't "broken" but were no longer useful to us.  Our DPA mics tended to fail at the microdot connector and when that happened I hardwired them to TA5F.  Also the adapters we had were DAD-6012.  This was supposed to be the correct model for use with VHF transmitters, but it does not actually work for that application because it shorts the connector shell to pin 1 (the VHF transmitters use the audio shield as the VHF transmit antenna so the adapter shorts out the antenna).  The reason I opened them up was to attempt to rewire them as DAD-3056.  As I write this I am not 100% sure I ever tested them.

     

    They were purchased many years ago so I can't say for sure where we bought them but I believe that they are genuine DPA.

  13. On 11/21/2023 at 6:15 PM, DeafDave said:

    Pity they aren't unscrewable to access and repair inside.

     

    The ones I have actually can unscrew.  They have threads between the two sections of metal, which had a sealant/adhesive on them so they are quire stiff.  If I remember I had to put one end into a vise and twist the other with pliers.  I probably used a buffer of some sort of softer material to prevent/reduce scratches.

     

    The inside portion of the microdot connector was a sort of pin socket into which one of the component leads fit.  This allowed the two pieces of shell to twist when threading.  I suppose this is where a failure of these adapters is most likely.

  14. The

    On 11/9/2023 at 5:29 PM, Max SM said:

    Hi! Thank you so much for sharing such a valuable experience. Which cable did you use to replace it? Maybe there is a name or a model?
    I have been looking for some information about replacing the wire on the Sanken cos 11D microphones for a long time. Perhaps someone knows how to repair it yourself?

     

    The cable I used was original cable from MKE-2 microphones.  The version that comes without a connector is so long that I always cut it shorter.  I had saved a lot of these cut-off ends, so I had a good supply of original cable.

  15. Does the "Original Timestamp" match the "User Timestamp" for the clip you are exporting?

    I haven't looked for documentation about what is supposed to happen but I have wondered if the User Timestamp may be the one that gets written into the WAV file when exporting.

    The User Timestamp can be edited, I think it shows up in the same dialog used to rename a clip.

     

     

  16. In terms of "horror stories" I have had a few struggles.  Most of these are things that are related to to the fact that my devices are on a large general purpose network which I do not control.  We have our own VLAN, but there can still be effects from interactions between other equipment and traffic types:

     

    * Late packets when there is heavy non-Dante traffic (like file copies) on a network without Quality of Service measures.

    * Discrepancies in the implementation of IGMP version compatibility modes between different devices.  (See the Audinate FAQ about DVS on MacOS showing "Listening" status).

    * An as-yet-not-completely-diagnosed issue where devices lose sync from time to time.  This might also be related to IGMP in some way.

  17. On 10/20/2023 at 3:32 PM, Philip Perkins said:

    What devices are you speaking of re: +/-26ppm?  Consoles?  Preamps?  Stage boxes?

    Those particular devices are Allen and Heath Dante 64 cards in a dLive console.  If I'm properly interpreting what Dante Controller is telling me, the 26ppm would be the clock in the card, because the card is getting its clock from Dante, and the console is getting clock from the card.

  18. PTP is accurate in the sense that the follower clocks will be nearly perfect with the leader clocks (like word clock is), but PTP in and of itself does not guarantee that the leader clock's accuracy is sufficient to minimize drift.  For the experiment @Philip Perkins performed, with only the AVIO and DVS in the system, the AVIO would be the clock leader (since DVS can only be a follower).  The tight sync demonstrates that the specific AVIO adapter he used has a clock that is very close to his 744T.  I would be curious about whether all AVIOs have that tight of a spec.  Dante devices in my network vary by as much as +/-26ppm from each other as reported by Dante Controller.

  19. What problem are you trying to solve?  Getting more range?

     

    For reference, I use a Sennheiser EW G3 IEM transmitter for some situations, and my maximum range is about 100m.

    I can achieve that reliably using a Lectrosonics SNA600 omni antenna 3-4m above the ground for transmitting, and Sennheiser EW G3 wireless microphone receivers with whips on the receiving end.  As an unlicensed user in the USA I am limited to 50mW, but even though I'm outdoors I have a relatively low RF noise floor and only a few trees for obstructions.

  20. As requested I have attached some pictures of MKE-2 capsules with the wiring exposed.

    Upon closer inspection, my initial description of the sides of the capsule as "concave" and "convex" is inaccurate.  Instead, the capsule has three leads.  Between the leads is something like a tiny printed circuit board.  Two of the capsule leads are soldered to one side of the board, and the blue wire of the cable connects here to both of these leads.  As this side of the board is at the center of the capsule, it appeared concave at first glance.  The third capsule lead is soldered to the other side of the board and the red wire connects here.  As this side of the board is near the edge of the capsule it appeared convex.  The shield is not connected at the capsule end on any of the mics I have opened up.

     

    Some of the mics are the older "non-gold" version whose serial number tags match the color of the cable (beige or black).  All of these so far have had a red dot on the capsule where the blue lead connects, and a gold-colored diaphragm.  The newer mics that have gold serial number tags do not have the red dot, and have a silver-colored diaphragm.  There is also a newer version of the MKE-2 Gold that has blue serial number tags, but I have not opened up any of these since all are still in service.

     

    Almost all of the MKE-2 mics that we have stopped using, we have taken out of service because of badly deteriorated jacket on the cable.  In most cases the mics still function but the bad jacket makes them ugly and difficult to use.  Inspired by this thread, I have now performed a few total cable replacements using cable left over from cutting new mics to length.  It is still early days, but results are guardedly positive:

    (1) mic appears to work as good as new.

    (1) mic had persistent popping sounds.  It is possible the capsule is damaged internally.

    (1) mic initially made a couple of popping noises, but they seem to have gone away.  I'm considering a theory:  In the process of replacing some of the cables, I had compressed the jacket, cut the steel and shield wires, and then allowed the jacket to slide back over the cut ends.  This microphone model is susceptible to cable noise, so maybe the cable jacket was sliding around readjusting to stresses and that was causing the noise.

    MKE-2 View 1.jpg

    MKE-2 View 2.jpg

    MKE-2 View 3.jpg

  21. Those of you who have done this repair, to what, if anything, is the shield connected at the capsule end?

     

    This thread inspired me to investigate resurrecting some of our MKE2s that I declared dead due to excessive jacket damage.  Now I am considering putting new cable on them as an alternative to buying new.

     

    I opened up a MKE2-Gold and the blue was connected to the concave side of the capsule, and the red to the convex side.  The shield did not appear to be connected, and I don't see a third independent connection point.  So it seems either it broke quite cleanly off one of the other solder points during disassembly, or it was not connected to begin with.

  22. I'm not used to seeing resistors with green colored bodies.  Are you sure the original wasn't a 10uH inductor?

     

    If you are concerned enough to open it back up you could measure the remaining original with an ohmmeter.  I would expect a 10uH inductor to have a DC resistance that is close to 0, definitely less than 10 ohms.  If measuring in-circuit make sure other components don't skew the measurement.

  23. At that size wrench, I'd say the 0.27mm could be significant.  Seems like an undersized wrench might turn the screw if it is loose enough but then slip.  I imagine you might be able to tell by feel if that is happening.

     

    I haven't had one of these open, so I'm guessing here - If your door operates properly and the XLR housing is firm, then I'd say there is a second screw that just holds the insert into the housing.  I expect that second screw, if it exists, would be the standard flat head screw with reverse threads that holds all Switchcraft inserts.

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