Rachel Cameron

Hi folks, I spent two hours last night reading (and re-reading) the saga of James' work on this app. Holy smokes, very nice work James. What a brain. I learned a ton about intermodulation and RF issues. I post to JWS, as I'm sure the site's brain trust has this one by now. I realize that James likely doesn't have time to tutor me personally on the usage of this app. So, here I go (late to the party, as usual). I've just downloaded it for a job I have Wed-Saturday. I'll be using two wireless SMV-L/411a, Blk 22. I'm exploring the app and finding my way around it. After downloading: 1) On the TX list, I tap the "+" twice for the two TX's (after setting the TX types in the settings menu). The app spits out the proper frequencies which would be advisable for use: e.g. 563.200 for TX 1, and 563.700 for TX 2. 2) I set the SMV's to these freq's and should the TX's get too close in proximity to one another, James has me covered? And that spacing leaves some room for discretionary addition of other TX's, should I have more TX's? ~ which is not my case. I wanted to make sure I have the app's simplest workflow right, that's all. Rachel

PM sent.

Ahh..okay. So a D.I. box actually does do an impedance match? I'm glad I had that part right. At those tiny voltages, I guess mismatches still would cause load up, even though there's no real thermal issues. It's still doing an impedance match, as with the (hi-z) instrument pick up to a (low-z) input? So..okay, it's more about efficiency in the power transfer, not really protection from a meltdown, even though with those large P.A. systems, any inefficiency (or impedance mismatching) happens to cause thermal issues as a side effect of the poor efficiency? I guess I'm seeking the common denominator that impedance has through all these examples....which would be said efficient transfer of power? And I realize that with words..this discussion could only go so far. Scratching the surface is an understatement, I know. No way could I ever have this all figured out. I'll never have a strong grip on mathematics and its formulas. Though I stare and stare at them (same with wiring diagrams), I guess the best I could ever seek is a basic working, practical knowledge here, which is *very far* from having electronics figured out. I'm sure this is like quicksand, as the more I writhe in the math, the more I'll sink. It's probably hell on a math mind to try to get this into words, when the formulas say it all so succinctly. I know that's why they exist. And thanks for such patience and kindness. I feel badly that I dragged you into this. They're my own limitations. I so wish I didn't have such anxiety with math. I got as far as basic algebra/trig. Electronics seems to go way beyond that. I followed my brainy older brother (very adept at math) through school, and really frustrated the hell out of both him, and my math teachers. They all thought I'd be like he was. However, my literature, stage, and English teachers were okay with me. In the end..I have my ears..which is what I use when my feet are on the ground (and great agility). That, and some good meters.

...and he didn't even need to set limiters, as it was only a stand up interview. (yes, I just quoted myself)

Thanks to you both, for those explanations. Hugely helpful. John: It took me a few days of mulling, and about five reads of what you wrote (studying schematics, and then reading it again)..but I think I got it. Impedance matching (these days) would refer to matching impedances across passive speakers/powered amps..to the impedances of 2, 4, and 8 ohm loads (and that's all), in order to not overwork a power amplifier to a thermal shutdown or just a plain ol' meltdown, such as line arrays and live concert gear, which has little to do with what we do. I previously thought a D.I. box was doing an impedance match. Wrong again. The line/mic voltage issue is handled with the bridged circuitry you described, which seems to be just inside the input jack on a board. Glen: That's what I feared. Since I wasn't there when he set it up, it seems cam op didn't follow proper gain staging of the unfettered signal, before setting limiters. From his responses to my questions, he probably wasn't even aware that the G3 had limiters. It's nice to see the method confirmed so cleanly. That's what I normally do with my old 442 and 744T..or when I'm wiring to a camera's recorder: Move my way through the signal path making sure no part of the path is overloaded or underloaded? underfed? undermodulated?....ain't enough, before moving to the next gain stage. So it's highly likely that he didn't structure the signal path properly, and was paying that price. And thanks for clearing up the split XLR question. I still don't feel quite comfy splitting audio signals by soldering a Y-cable. It's creepy voodoo to me. I never know what to expect, not knowing all about voltages and electronics, like some of the brains here do. Constantin: Your comment about crosstalk and analog circuits was an eye opener for me. In my OP, I called the Red cameras about 'the most audio unfriendly camera' discussed in this forum. Wrong again. Sorry, RED. : ( DSLR's generally wear that badge these days. But what a great excuse to go double system. Incidentally, years back (OT alert), I got to send audio to what the camera owner called 'the very first RED ONE in the field'. They called it (him?) Elvis. It was RED serial #0006, because, as the story goes, the owner of RED kept the first five RED ONE's for himself. Did he? Maybe someone here can confirm that tale for me. The camera owner was from NYC, and just upstairs (or downstairs?) from RED, in the same edifice. That's my beat up old breakaway cable sullying the frame. Gracious thanks, everyone. Rachel

Was Eva-Tone's only production facility in Clearwater? I used to pass that place as a kid and always wanted to stop in. Too late now, I guess.

Thanks so much John, for taking the time to hammer these points out. That's great information. All of this is very difficult voodoo for someone with no worthy mathematics or electronics background. Words, definitions, and simple wiring schema, though?...I can handle. I'm pretty sure I have a grip on balanced/unbalanced, regarding the +/- polarity conductors, and phase canceling of noise, balanced long cable runs vs. short unbalanced runs, for noise immunity, etc. I'm pretty sure I have a grip on proper gain staging (through my experience with mixing consoles). I've obviously confused line/mic matching (voltages, and a step up/step down transformer) circuitry, with impedance (resistance to voltage) matching circuitry, EG: bridging. Thanks for that. Big difference. In my original post, (of course, [cam op] had no cans available to hear what Simon, Chris and Marc all arrived at), the cam op said it 'sounded fine' which I would have to judge for myself, until he (purposefully, for demonstration purposes) overloaded the input (the Epic displayed a full, solid red meter all the way across, before the Epic would bleed over some, to the other channel), so I deduced..crosstalk issues, as there was sooo much signal. I always thought some of the better constructed analog audio circuits were immune to crosstalk, though. Wrong again. Of course, I couldn't tell whether the G3 was sending a line or a mic level, or what the Epic was expecting. It probably sounded 'sort of okay', just as Chris alluded. Thanks everyone. I'll RTFM on that one. And I guess I need to carry around a pair of cans.

Darn. I missed another one. : ( I'd love to meet you all...someday.

Spit take.

R.I.P. Patrick Macnee.

Off topic, but pictures like this are inspiring to me. That's a piece of important history ~ an image worthy of the Getty. Look at [Brian] go. I was probably two. Yes, we're ghosts in the machine. We seek a transparency that most will never understand. We work behind the scenes providing the ears history hears with. If our job is not done well, we've been noticed, and we've failed. But I respectfully feel that our elder soundies of the site should post more of these wonderful photographs, along with their stories. I'm aware that we typically don't seek the lenses ourselves, but we need these rare glimpses for posterity, lest the world lose these moments forever. We're often too invisible. Thanks, BVS. ~R

We'd love to hear a report.

We shouldn't have resurrected this thread. It's just unfortunate. I clipped this one from a side panel banner ad. And it has to do with audio, because AT&T makes cellphones, and they have speakers and microphones and stuff. Unfortunate ATT Add.tiff

That's all great advice from Philip. I always battery up, build and listen to the gear the day before, then use that nervous energy just like he says. Go over the load and consider a bunch of 'what ifs'. +1 I know it's off topic, but another one I like to do is leave for the location W A Y early. This is just in case of the overturned tanker, or terrible traffic (I'll be able to get off the highway, and wind my way through the city on back roads and STILL be there early), parking problems or a flat tire or car breakdown. This all keeps my nervousness to a minimum.

From the newbie department: I get nervous before almost every gig still, and then later (sometimes in the first hour of the first day), I find out that everything is smooth, and there was little to fret about. You're their ears and they trust your judgement. Just be cool. Fresh batteries. Hit record like VAS says. Monitor the return (or the record head), watch your on set p's and q's. If anything goes wrong, don't work to cover your tracks. Be honest and up front about it, quietly, with the powers that be, and get a decision. We're all human. Oh! If there's anything special to know about Mr. Scorcese, try to find out in advance. A couple of jobs I had came with special instructions, regarding the talent. E.G: someone else had to wire them, because talent doesn't like being touched, or there's a little noisy fan in the room that I have to live with, because the subject sweats profusely without it, don't look them in the eye or you'll turn to stone, etc. Usually there's an agent or handlers in the process who can advise sensitivities like that. +1 Rick's advice with the hardwire. If you don't have to use wireless, don't. Best of luck, and give a report back!

Thanks so much for the information, everyone. I took his number, so I'll get in touch and relay the suggestions. It'll also give me a chance to put my mixer on it, and goof with the Epic settings myself, some. I'm dying to see what it was, but with a 411/SMV...and then his G3. Acknowledging the crosstalk issue, I'm now itching to know if the output of the G3 was really that mismatched with the Epic's first gain stage. I guess I was looking at a giant impedance mismatch (with heinous crosstalk), that is, if the Epic is looking for a balanced mic level signal, and the G3 sends a balanced line.

Happy Birthday John! Make sure that extra birthday second is 30fps, so you can get that extra .03 in there! Rachel (wow, I just saw..this makes 100 posts of ridiculous comments and annoying questions)

I wanna talk video, so I'm giving 'em a call.

No apologies necessary, Jeff. Probably just me. And you're right about us gals. laurenbanjo posted a good thread about this. I also failed to mention, the collective sum of sound knowledge the site houses ~ particularly location sound knowledge, experiences, DIY tricks, protocols, ways not to get burned (or get burned)..well it's pretty darned hard to top. Cheers!

Unearthing an old thread for updates (since it's been a few years) from soundies here, regarding their successes and fails with these products. Which have you guys used? I live and work around a lot of moisture, sweat, watery environs, and sandwich baggies. I'm especially interested in those products that spray on (and I don't really feel like undercoating my SMV's).

I'll third that, Al. Jeff doesn't have to do this, but it's been home to me for a long time before I had the nerve to make my first post. I'm sure there are lots of others like me out here. Thanks Jeff, for making this site comfortable and accepting of others who do what you do. The stew of personalities make the site.

What a beautiful post! Thanks Al, for this. So nice to see. Congrats to the newlyweds!

Well, my question is more like: Why did the Epic crosstalk? Apologies for the confusion. EG: to demonstrate the crosstalk problem on the Epic, the camera op had to overload the G3 quite a bit (he should've set the limiter in the G3 to avoid this, and probably didn't), but I didn't expect to see such a hot signal crossing from Epic Ch 2, over to Epic Ch 1. He had to sort of 'thump' the lav head to illustrate the Epic's crosstalk, and yes, when he did, it took a full red meter on the Epic Ch 2, to show a fair amount of crosstalk on Epic Ch 1. But in essence, Constantin, you answered my question. Copious thanks!

Stumped on that one (I get thrown into the Gorge of Eternal Peril). Does that refer to bridging leads 1 and 3 on the XLR, making it an unbalanced signal?

Hey folks, Passing through a public building, I saw a camera operator with a Red Epic (no talent there yet). I had to stop to pester him. It turns out that he was having audio problems, so I was glad I did. The issue (seemed to be) crosstalk from channel 2 to channel 1 (during peaks from the receiver, but only when the G3 was really peaking hard, as in the Epic meters at full red overload), so I quickly looked over his gear patch. Dunno what the Epic gain levels were set at, but the metering seemed fine on channel 2 unless a hard SPL peak was introduced. Otherwise, (barring a listen on the cans) I saw several issues. 1). He was using a Red, which seems to be about the most audio "unfriendly" camera discussed here. 2). No mixer of any kind (also no soundie: the underlying issue). 3). No limiters in the signal path (didn't check the Epic's 'soft limiters' settings) 4). Overloading (poorly designed?) camera audio (the Epic manual calls them high quality) pre-amps. 5). Dividing a balanced line level with a split XLR cable. I never do this, and I've always wondered about the efficacy of splitting any XLR signal, mic or line level. There were no crosstalk problems as long as the receiver was not in full overload, so I'm guessing this was the issue ~ just too much signal for the Epic's pre-amps to handle. (Marc, you're right about the Red forums. Appalling.)