Jump to content

borjam

Members
  • Posts

    269
  • Joined

  • Last visited

  • Days Won

    3

Everything posted by borjam

  1. Yes, attenuators are really useful tools. I missed that feature. Touché!
  2. Sorry I wasn't explicit enough. It would help you explain apparently paranormal phenomena like interference even to wired microphones. Also, depending on what wireless equipment you are using you may have overload issues in the presence of strong off frequency signals.
  3. True, and guaranteed compatibility with Vantage, the spectrum analyzer software. By the way, I always recommend buying the input limiter/6 dB attenuator unit they sell. Otherwise strong RF might damage the input stage.
  4. Inexpensive and quite effective: RF Explorer. https://www.gothamsound.com/search?result=rf explorer Although the 6G combo model is overkill for users of wireless microphones. I would rather recommend the much cheaper WSUB1G model which covers the 240 MHz to 960 MHz range, or even the ISM Combo (240 MHz - 960 MHz plus an additional 2350 MHz to 2550 MHz to hunt for rogue 2.4 GHz stuff). The WSUB1G+ (note the plus sign) has a downwards extended frequency response reaching 50 KHz, which can help locate troublesome VHF or even HF/LF signals. The latter can have hefty transmission powers.
  5. You would be amazed at the experiments being made with contact microphones, though. There is a new unchartered territory being explored by wildlife recordists and sound designers now. Moreover it's inexpensive to explore, JRF's contact microphones and hydrophones are not expensive at all. That said, you can hear curious and wrong theories. Some time ago I heard a recording of curious underwater sounds recorded with a hydrophone and someone suggested it might be "photosynthesis" (like the tiny bubbles that you can sometimes see on the surface of aquatic plants, bursting). It didn't make sense because the crackles were periodic. Most likely it was some underwater insect.
  6. I was about to mention the excellent David Attenborough's "Life of Plants" which showed actual behaviors by using accelerated takes. Maybe with contact microphones it would be possible to achieve some results? However, the NY Times article is quite confusing and certainly lacks rigor. This paragraph triggered my alarm: Sound has also influenced interactions between plants and animals. For instance, only the vibrating buzz of a particular bee will trigger some plants to release pollen. Pitcher plants even create their own bat call to attract bats. And indeed, following the link, one can see that a pitcher plant has evolved to reflect the calls of bats, but it doesn't produce any sound by itself. The evolution of such a device is impressive enough, of course. That said, I have a plant at home that can make real noises. If you skip a watering or two its stems will tend to get flaccid. If that happens, when watered the stems can stiffen in a matter of an hour or so. If a leaf gets entangled with another one while the stems were flaccid, the increasing stiffness can make it get released like a spring, actually making noise. But of course it's not a noise making mechanism, but an accidental effect.
  7. I understand that the Deity S Mic 2 is not RF biased but a conventional DC biased design. https://tyfordaudiovideo.blogspot.com/2018/09/deity-s-mic-2-shotgun-microphone-third.html Rode has two RF biased models, however: NTG-3 and NTG-8.
  8. Comparable to the AKG ULS Series (11 dBA, but with 3 dB less sensitivity). Anyway, I guess that the only way to compare to a Shoeps or a DPA is to go and record an actual orchestra. Off axis response variations will make the biggest difference.
  9. I forgot, the test was especially evil. I connected the Rode NTG8 to channel 3 while channels 1 and 2 (muted) had unterminated 3 m cables connected. Despite being muted the cables could have conducted interference. Seems that the MixPre is a real "RF bunker".
  10. So I was wrong about the ARM processor (although I guess that will eventually happen!). As for the machine it's real overkill for most. My live jazz recordings use less than 16 tracks and of course I don't work with virtual instruments. A friend who composes soundtracks for movies and commercials will love it, though.
  11. I'll try the digital HT this evening anyway. Given that it transmits TDM pulses instead of a continuous FM modulated carrier it should be nastier. It's 2.5 W, not 5 W, on the same band as the analog one I tried (440 MHz).
  12. I tried. I didn't have the digital handheld here (which uses time division digital transmission, which makes it nastier, as LarryF explained). But I have tried with a 5 W FM handheld a few cm away from the recorder. Just pressing the transmission button (PTT) repeteadly I could hear some interference using an AKG Blue Line (CK93 capsule). However, I switched to a microphone with a good RF rejection (Rode NTG8(*), I read somewhere that it is really well protected)) and it withstood it without any problems. Not even maxing out the gain I could hear any kind of interference. Being a RF biased microphone it might be more susceptible to that. Of course I tried an iPhone running a speed test to my local network (it was transmitting like 250 Mbps) and nothing came out either. If the MixPre 3 has resisted 5 W with the antenna almost touching the unit, also close to the cable and microphone (the cable is a 1 m long thin star-quad from Canare) I really doubt that a transmitter such as the Deity Connect receiver can affect it. But it may depend on the microphone. If the microphone cable somewhat conducted interference to the microphone I am pretty sure that a ferrite core or two should help. I can try with the HF transmitter but of course I won't get so close, if I touch the loop antenna by accident while transmitting I can get a painful shock. Anyway, 5 W so close to the unit is a real torture (*) Nice mic, I am using it to try and record some birds. Although the strong metal tube used for transportation could get me arrested if I tried to board a plane with it.
  13. It depends on the application. Of course, in music applications microphones are usually close to a loud source. Except, for example, when recording an orchestra with distant miking techniques. In that case microphone self noise matters. And for applications in which microphone self noise is a limiting factor like some fx recordings, foley, or soundscapes, it matters. That's why the Rode NT-1A is popular for such kind of applications. I would rather say than the limiting noise problem is application *and* location based. For many applications equipment self noise doesn't matter. But for others it can be really noticeable. For example, at the jazz club I can't even think about self noise. My real concern is the bleed of a drum kit 60 cm away from a piano 😓 and a double bass with the microphone right below a cymbal. I must even engage the attenuators on the microphones.
  14. It's a pity I didn't hear of it, I would have crowfunded it. Now I'm pestering Filmin, a Spanish online platform specializing on independent movies, so that they add it to their catalog.
  15. I know it's a topic of more interest for post people, but I am really wondering wether they will finally release the modular Mac Pro they announced long ago. I am a happy user of a 2010 Mac Pro (I replaced the processor and I installed an improved graphics card) but so far the thing is kinking ass. But anyway wondering. It's quite puzzling why they took such a long time to design a new modular computer given that it's not rocket science. Well, good desing is always rocket science but making it large and easy to upgrade is much easier than tiny, which has been their focus lately. There are two possible reasons I can imagine for such a long delay. 1) They were waiting for some new Intel processor series (or even AMD) they knew about in advance. I imagine they have a peek at their product roadmaps much earlier than us, common people. 2) Given that it's not so hard and it could offer enormous advantages, maybe they will announce a switch to their own ARM processors. So, why ARM processors? There are several good reasons. 1) Apple are control freaks. And they have been bitten several times by their reliance on CPU manufacturers (Motorola, IBM and Intel). The last big switching, Power PC G5 to Intel, was motivated by the PowerPC platform being stagnated both on raw computing power and, critically, power/energy consumption ratio. 2) Intel's security track record has been a real disgrace. From a hidden computer running an obsolete version of Minix inside their control chips to serious design flaws in their processors. 3) They made huge investments on boutique processor design companies. It has paid off years ago with the excellent results obtained in the processors used in the iThings. Maybe it's time for the next leap. 4) It could even offer a cost advantage. Intel's processors (especially the high end ones) have been grossly overpriced because they hold a virtual monopoly. I guess these price reduction could be passed on to the customer. I know that some people will think that writing "their own ARM processors" is quite an overstatement, but it's not. ARM is an architecture for which Apple has a license enabling they to design their own processors based on it. And yes, Apple outsources chip manufacturing to foundries like Samsung and TSMC (it's been known recently that they approached Intel before launching the iPhone) but the designs are their own. Apple's A10, etc, are not Samsung or TSMC products. Claiming the contrary would be like saying that "1984" was written by Penguin Books Except for Intel, Samsung and a bunch of other chip manufacturers, most are what is known as "fabless" firms. Well, time for the guesswork before Monday!
  16. Anyway it's better to make a distinction between the file format and the actual amount of information it contains. The actual amount of information stored by the recorder is determined by the properties of the A/D converters and the analog circuitry (and the microphone obviously) and it is much smaller than the total dynamic range that can be represented in 32 bit floating point. As @INARI pointed out, around 140 dB would be a very good value. So why 32 bit FP? It's a common sample format, you don't need to create a custom, say, 26 bit fixed point format. And floating point eliminates the need to adjust values in order to fit the more limited precision of fixed point. It's also much easier to handle when doing calculations (gain adjustments, etc). Of course it also offers a marketing benefit. Some readers will assume that being 32 bit FP it will have an almost infinite dynamic range.
  17. The limiters are analog and in that case the limiter parameters are governed by actual components (good old resistors and capacitors). So no firmware update can correct that unless the software defined electronics part allows some changes to circuit topology/components. Anyway, consider this. If the limiters were digital (like in the Zoom F8) you will achieve the same results by lowering microphone gain leaving more headroom and, if some dynamics correction is required, some post processing after recording. The result will be equivalent. I have never recorded shots but I guess it won’t be necessary to disable the limiters, just give it more headroom so that the limiter acts just on the highest peaks. The pres are so clean I doubt it will be an issue. Maybe a bit less convenient, though.
  18. The AKG modular ULS system (it has been mentioned here sometimes) could be a good choice. @ramallo has experience with them at least for live sound. The body is the c480b and you have different available capsules: ck61 (cardioid), ck62 (omni), ck63 (hyper) and ck69 (short and long shotgun). The noise specs are spectacular. https://www.akg.com/Microphones/modular-microphones-components/CK61ULS.html?dwvar_CK61ULS_color=Black-GLOBAL-Current I am not sure how long are these units going to be available. Since Samsung bought Harman Group I consider all the AKG products at risk of extinction.
  19. Surprisingly, I saw this piece on the Spanish newspaper “El País” (which is maybe the Spanish equivalent of The NY Times or The Guardian). https://elpais.com/cultura/2019/05/18/actualidad/1558186557_831686.html I haven’t heard of this movie, and I would have supported the Kickstarter campaign had I know. http://www.makingwavesmovie.com/trailer-and-other-links-2 Anyway, sounds really interesting. Hope to be able to watch it soon! Filmin, the Spanish platform specializing on non-blockbusters should carry it, they already have The Conversation and Apocalypse Now, it would even be possible to build a playlist about cinema sound.
  20. It’s really hard to say. From my own experience with powerful ultrasounds (as I think I mentioned on another post, I helped a friend test a proof of concept of non linear demodulation of ultrasounds) the sounds would have been demodulated when the beams collided with the outer walls. So, ultrasound carried sounds would have been heard mostly outside the building. Microwaves? Maybe I’ve watched too many movies (or being a ham operator I tend to think in these terms) but I guess that embassies, especially the US embassies, have well equipped radio listening posts. So I am sure they monitor the electromagnetic spectrum pretty thoroughly. Moreover, if powerful microwave beams were aimed at the building I guess it would have damaged sensitive equipment. Jay, we didn’t try crossed ultrasound beams, but we tried with a single AM modulated beam (I think the carrier was on 40 KHz) was effectively demodulated when colliding with a wall or even a human body due to nonlinear effects when changing the propagation medium. For example, if aiming at your back you heard the voice right behind yourself. Surprisingly a good HiFi amplifier was enough to make it work (my old Nad 302) with about 25 W of output power. We also used an array of ultrasonic transducers as a loudspeaker. It worked at a distance of several meters. If it was ultrasound I can only imagine something like beaming the building with near infrasonic frequencies carried by ultrasounds, making the whole building vibrate and causing some progressive “annoyance” effect leading to stress in the long term. We all know how irritating persisting sounds can be.
  21. My apologies, English as a second language I forgot that "damages" includes the costs incurred to solve the situation, not necessarily actual physical harm to yoru gear. So, indeed, someone should reimburse the costs incurred.
  22. Hmmm you mean damaging it permanently? I really doubt it. Of course wasted time sorting out problems is an entirely different matter.
  23. I am looking at their website. 1 mile on 5 GHz? That is a tall order, especially with obstacles. There is much less noise on 5 GHz than on 2.4, but with half the wavelength a wall is a large obstacle. If the claim is true they must be using quite a high power. So, FCC certification... The website is on a cheap hosting company, registered by a Glendale CA resident and other than the HPVIDEO name I don't see any formal company stuff. So it must be a really tiny company or a one man show. Searching for the registrant name I saw some hits on the Texas Instruments support forum. And there are obvious typos on the website: http://hpvideo.tv/index.php/online-store/wireless-video-audio/hd-wireless-2/white-red-jacket-detail What is a "3.5 Gb antenna"? I guess he wanted to write "dBi".
  24. Well, dosis venenum facit Even visible light can cause rather impressive thermal effects. Try a high power laser. So they are not sure at all, that's why it is in that cathegory. The conclusions of the experiment have been debated. To add more confusion check the attempt by the Ramazzini institute to duplicate that study. Again, there were statistical artifacts like just one mice among 400 or so (citing from memory) and a definite lack of dose response. Looks like low powers suggest a link to those tumors, while at higher powers there were no cases. When there is some crazy around it, certainly. I can recommend you an interesting website (https://microwavenews.com). It looks like a serious publication, turns out it hosts a lot of the crazy stuff about the matter. Theories about "non thermal effects" which would be quantum (or should I consider them "soul effects"?) but quantum level effects are ruled out unless someone earns a Nowel award describind something definitively new. On the other hand, if there is an effect but it's so statistically insignificant, well, turns out eating sausages or drinking a beer would be much more dangerous. Yes, again, contested and the evidence is really too faint. The Ramazzini study shows, again, nothing really consistent. In my case it's not a narrative. I have no reason to believe that there is some mysterious non thermal effect. There are a lot of bullshit "studies" pretending to prove that radio transmissions (again, electromagnetic radiation at a frequency below 300 GHz) are dangerous. The two studies that stand out and were well executed (in my opinion), the NTP and Ramazzini don't show anything really definitive. If you did it 20 times and you found the same results, well, there would be something. But in one case with the Ramazzini study we are talking about one affected mouse. And sadly they didn't perform proper necropies as far as I know. So the conclusion is really weak. I was talking about myself, I tend to get carried away in these cases and someone can get annoyed And hope a sarcasm or two is not taken as an offense! Well, as I said. so far there are no solid reasons think it is dangerous. Can it be researched? Good, of course. But if you read what is being written around this subject (I happen to be a member of the Spanish Skeptics association and I've seen unspeakable stuff at the Gates of Tannhauser) you will see that it's exactly the same bullshit. Someone (in the "anti radiation" camp) even said that the NTP and Ramazzini studies are not valid because they didn't use real phones, go figure. Maybe we should perform the tests using phones transmitting conversations in different languages and talking about different subjects. Football? Politics? Religion? UFOs? Those people who are spreading all this fear have absolutely no understanding of radio technology. In Spain we have a biologist who experimented by putting an aquarium full of tadpoles (funny enough, of a protected species and "supplied by an anoymous source" (sic)) on the roof "close to a cell tower" and he performed the measurements on the ground level! He played with toy instruments, stated signal levels in "dB" and whatnot. Search for Balmori. No, I am not insinuating that anyone who doesn't agree with me is a whacko, of course! But in any of these subjects there be dragons. Peruse the website I linked and compare it to, say, the anti vaccine movement or even flat earthers. By the way I really recommend to watch "Behind the Curve" on Netflix. I know there are serious people looking into the matter and doing serious experiments. Curiously, those experiments are always non conclusive. Now I go back to playing with my HF transceiver, at a much lower frequency (7 and 14 MHz right now)
×
×
  • Create New...