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alenK

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About alenK

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  • Location
    USA
  • Interested in Sound for Picture
    Yes
  • About
    Sound Mixer

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  1. alenK

    Comparison of different transmitters

    Hi Constantin, As a suggestion, rather than normalize the peaks to 0dBFS, it would have been possible to normalize the guide tone to a consistent level, and then use the exact same amount of amplitude required to line each of the guides on each respective sample of content. For example; if wave-1 was adjusted by +0.03dB to align the guide tone peak to -20dBFS then adjust the relative content +0.03dB. Likewise, if wave-2 was adjusted by -0.07dB to align the guide tone peak to -20dBFS then adjust the relative content -0.07dB. This procedure would account, somewhat, for the practical difficulty in aligning the guide tones with the actual wireless hardware, and it might reveal interesting inter reactive characteristics between the mic and the systems. I think it would seem interesting to see the character of the peaking before the peaks of the content were normalized to 0dBFS. For my own listening session, I went ahead and cut the start times to more exactly match each other by finding a cut point where I could identify the placement within one or two samples. I also trimmed the lengths so that they were exactly the same. This made lining up the examples for switching during playback easy. Having said that, after listening intently I can not appreciate a practical difference between any of these examples, and even though a post team may suggest that one example is more useful or malleable than some other, I suspect that the impetus for making such a comparison was inspired by the routine challenges introduced by other more influential factors than a choice of professional grade wireless system. In my opinion, this analysis suggests that issues such as talent timbre, mic selection, mic placement, ambient factors, etc. are far more influential on the final results than the choice of signal transmission system. Having said that, after listening intently I did dare to "look" at the wave files with various analysis tools. You can easily see some differences and compare what is easy to see to what seems difficult to hear. The low frequencies exhibit some variation that might excite the imagination, and the relative density of "noise" along the spectrum seems varied. Of particular note, the 4017-1.wav displays some spurts of energy up at 22kHz which is, perhaps an artifact of aliasing fold over. Is this the kind of artifact that anti aliasing filters are supposed to moderate? Regardless, of the fact that I can not hear 22kHz content, seeing the evidence of the artifact makes me curious to learn how this signal was transmitted. Thank you for sharing the wave files.
  2. alenK

    New Zoom H3-VR Recorder mic combo..

    While this may be true for the new fangled virtual reality presentations and perhaps some surround mixes, ambisonics has traditionally been employed to provide an opportunity, either while recording live or mixing in post, to isolate specific portions of the sound field from the whole, with greater precision and latitude of choice, than is possible with other traditional microphone array geometries, when used with similar near-far or distant placement. VR surround effects have come into vogue and currently receive attention, but the introduction of new microphones and advanced dsp software also promotes the ability to practice ambisonic techniques as in the past. The craft has certainly become more accessible, and an interest in applying the directional control techniques may become more widespread. ambisonics is not necessarily tied to VR, surround, or even stereo mixes. Personally, my interest in ambisonics has been motivated by an enthusiasm for mono, an ambivalence for stereo, and a disinterest in surround mixes. There is something for everybody when producing ambisonic material.
  3. alenK

    New Zoom H3-VR Recorder mic combo..

    This device looks fantastic, but I imagine it would be more readily received by aficionados if it was priced somewhere between $7,000 and $23,000. The combination of components in a compact integrated form factor seems like a recipe for over coming the many limiting factors in traditional setups. My first experiences with ambisonics was with a corporate owned CalRec system. I have been observing the evolution of technologies, and the elimination of real life problems with ambisonic production for quite a while. It does not seem hard to imagine that a mic array based on MEMS devices, a pcb with minimal length pathways, a few purpose built integrated circuits, an on board processor running optimized software, and an adjacent data storage system can easily provide superior results, when compared to the relatively complex big budget solutions, at a tiny fraction of the cost. This thing seems brilliant, even if it does put us all out of business. :-)
  4. alenK

    DIY Dipole antenna!

    Hi Borjam, Thank you for explaining. This has been very helpful. Thank you.
  5. alenK

    DIY Dipole antenna!

    Hi Borjam, Thanks for the detailed reply. "Romex" wire is not any sort of fancy wire. It is construction grade wiring used in the building trade. Here in the USA, Romex is a trademark brand name that has become a generic name for a wire packaged to suit electrical distribution within building structures. The name is used sort of like Fridge, or Kleenex. It is a very cheap, and easy to source solid core wire that comes in small gauges such as 14AWG and 12AWG. I am only interested in building receiving antennas and I am not experimenting with transmission scenarios. I did some experiments based on log periodic dipole array calculations for a 450MHz to 650MHz range but for the production work I do, with one or two transmitters for documentary and news gathering, the idea of using specially tuned, light weight and compact dipoles seems like a useful option. I will try some 1.5:1 turns ratios, and then start inquiring with my HAM buddies to see if anyone has a miniVNA. Thank you.
  6. alenK

    DIY Dipole antenna!

    Thanks for the additional info. My interest in making DIY 1/2 wave dipoles with the little PCBs I illustrated is related to the idea that it would be easy to connect antenna arms that are the relevant 1/4 wave length for some specific frequency within the 450MHz to 650MHz band. For example; I have been making some, minus the balun, out of "romex" solid core copper, and cutting them to length as needed. It is super easy to refresh the unit with a new length of romex in between projects. If the length is tuned (by choice of length) to resonate near the desired frequency, does that not address efficiency? Bandwidth can presumably be effected by the diameter of the arm, but I have more or less disregarded that by basing the premise on using cheaply sourced romex copper wire. Now I would like to wrap a few coils of wire around a nail and make a tiny balun but I have no idea what the turns ratio should be. Will a miniVNA really tell me the impedance and let me predict the turns ratio? Will using a miniVNA on a dozen examples of dipoles, each sized for some specific frequency found between 450mHz and 650MHz reveal that the turns ratio varies widely, or will such an exercise suggest that when each dipole structure is sized for and evaluated for some specific frequency, there is an average factor that may be suitable for the relatively limited range we work in? In other words, is it likely that a dipole sized to resonate at 500MHz, and another dipole, made of the very same materials, but sized to resonate at 600MHz will have similar efficiency or impedance? Am I over looking small details such as the implication of solder joints? PCB traces etc.? I can see myself buying a miniVNA but I'll be disappointed if I get one, make a bunch of tests, and find out that a 1.5:1 turns ratio will cover most of the builds I am interested in. :-) Thank you.
  7. alenK

    DIY Dipole antenna!

    Looking at the pdf files produced by the MiniVNA testing it seems like the impedance varies widely over a spectrum of frequencies tested. Does that suggest that a dipole structure, as sized in length for some particular frequency, will have some arbitrary impedance at the intended frequency, while at other, perhaps nearby frequencies, the impedance can be significantly different? Can the impedance be accurately calculated, or is a VNA type test the only way to arrive at an accurate figure? It seems that when I read about antennas with an interest in reception, matters that pertain to transmission are treated with more detail, and by the time I wade through those ideas I am left without a clear idea of how useful the information is with regards to reception.
  8. alenK

    DIY Dipole antenna!

    Thanks for the suggestions. You are correct that some of the SMDs I have found are Mini-Circuits brand, and I agree that it is possible for a DIYer to hand solder a SMD to a PCB, but the process is not what I would call convenient. I have been reading about receiver antenna design for a few years, but have yet to get to the point where I understand how to calculate, measure, and or anticipate the impedance bridge ratio necessary to make proper use of a balun when connecting a home made receiving dipole to a 50 Ohm transmission line.
  9. alenK

    DIY Dipole antenna!

    I have looked around for baluns for DIY dipole projects sized for use within a range of 470 MHz to 600 MHz, but have never found anything that seemed suitable. It's been a while so my memory is fuzzy. It seemed that some very tiny surface mount items may have had specs that seemed appropriate, but were inconvenient to implement in a home brew project. I would appreciate learning how to utilize two coils of wire to make a suitable device, so that the balanced function of the dipole structure can be taken advantage of. I think it could be fun to commission some small inexpensive project boards that a pair of antenna arms can easily be attached to with solder, or perhaps even substituting the through hole connections with screw terminal type fittings, but I have been stalled each time I try to learn about impedance matching with DIY balun design.
  10. alenK

    Updating firmware on Sound Devices 633?

    Thank you.
  11. Hi, I never had a reason to update the software on my 633, but next week we have a 6 input round table project that makes the Dugan Auto mix seem like a good option for the scratch mix. Has the latest 633 firmware been good to you? Thank you.
  12. alenK

    News from Audio, Ltd

    Perhaps someone can patent an inline balancing transformer widget designed to adapt an unbalanced lavalier microphone to the balanced input of a transmitting recorder and sell the new fangled devices to operators who promise not to get caught mounting the transmitting recorders on a human being.
  13. In the case of the Sling Studio you can hard wire a 2 channel audio mix directly into the Sling Studio Hub. If the live streaming production is patterned after a typical live TV broadcast, you will have an A1 doing the sound mixing while an A2 makes, or several A2s make, sure that the A1 has some sound to mix. Same as it ever was.
  14. alenK

    Countryman B6 caps?

    Hi Mike, Thank you for the warning.
  15. alenK

    Countryman B6 caps?

    Thank you for the suggestion. I have thought about doing something like this, but have never taken the step to try it out. Thank you.
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