Audio pros: can you explain this?

[Ignacio Rodriguez]

Hmm. Matt's statement make sense. I seem to have experienced what he describes but it's very subtle, at least in my setup.

The problem might also lie with the PD150/170's audio circuitry, the PD150 is famous for it's not-so-great audio. I don't have the PD150 at hand so I can't test it right now, but perhaps you are suffering from this, or from a combination of what Matt describes and some clipping in the preamp.

I usually att both the the camera's input and the wireless system (-3dB), otherwise the output of the Sony wireless is too hot for my taste and clips the preamp, even if you bring the input level down.

You could try bypassing the camera's preamp alltogether by setting the channel to line level and making a cable to connect the receiver using it's headphone output. Of course that will be unbalanced, but the cable is so short and you are using batteries so it really should not matter.

Hope this helps.

[Bryan Beasleigh]

You can't bypass the pre's. it only an attenuation. It does help but the preamps stay in the circuit.

[Ignacio Rodriguez]

> You can't bypass the pre's. it only an attenuation. It does
> help but the preamps stay in the circuit.

Really? How unfortunate. I thought the famous 'BBC mod' was only for the VX cams because the PD and PDX cams had real line level... it's so stupid, just a simple rewiring, how could Sony be so lazy?

[Bryan Beasleigh]

It's more involved than you might imagine. http://www.gregjwinter.com/modification2.htm

[Glen Elliott]

Matt thanks for your input- it has eased my mind greatly (well sort of). At least I know I don't have faulty gear, and it's something other people have experienced. Heck, I'm glad you understood what I was trying to explain- was worried people would shug and wonder what the he** I was talking about.

Anyway between my two lavs the ECM-44, and 77- like I said it seems the 77 produces a hair more noise tail (thanks for the clarification) than the 44. Despite this fact I'd still chose this lav over the 44 simply because of it's frequency response- it produces a much richer natural sound. The 44 sounds a bit tinny for my taste.

So doing on going extensive test in regards to channels and frequencies will be uneccessary? It sounds to me, the way you described it, that it IS something inherent of wireless systems though different mics react differently in any given situation. Oddly enough though you listed the ME66- were you using it in a wireless setup somehow? Thought it was for on camera shotgun or boom. Anyway it's pretty easy for me not to imagine using an XLR boom in a wireless beings my only experience with a wireless system has been this one (UWP-C1) which uses locking 1/8" ports rather than xlr.

I have heard that for wireless systems to work they have to compress the signal way down for transmittion and one recieved it's uncompressed and fed to the camera. Does that specific point lend to the fact it's inheren't to wireless systems.

Lastly the size of the diaphram didn't seem to make a difference (well in my finite tests at least). The 44 looks like the size of a marble, and the 77 a bit larger than a matchstick...yet the 77 exhibits a bit more noise tail- though, again, that could only be my perception because the mic is so hot compared to the 44.

[Matt Gettemeier]

Glen, that's why I said it doesn't seem to follow any logic. I'm sure there's a scientific reason why some mics bring out (or cause) more noise-tail then others, but I don't know what that explanation is.

The me66 has a "crispier" sound then the other mics I've used and I think that's why it masked the noise-tail more then the 4073a.

The one thing about this hobby that sucks is you NEVER have enough... there's almost always another level above what you can afford... Lectros are highly regarded, but they 'aint Zaxcom.

To address another point you made; a wireless boom is a real blast when you must use one. Imagine man on the street stuff and you've got a wireless boom guy. You can frame your shots from a distance, zoom in a bit, and the boom is still feeding you great sound. Even if you're right next to your sound guy it's nice to not have to think about each other's "cord managment" or worry about pedestrians and other surprises catching a cord. If you watch the news or "The Daily Show" (one of my favorites) you'll see the little plug-on "box", or butt-plug, as Hollywood decided to call it... That configuration of transmitter is cool 'cause you can plug it onto almost ANY xlr mic and turn it into a wireless mic. The plug-on supplies phantom power and transmits the signal too. The bummer is that sometimes you lose so much of a mic's soul that it's main useful purpose is strictly dialog... and at that it's for the words that convey information rather then feeling.

For the real sound guys with digital recorders it's not an issue 'cause the boom feeds the recorder that's on their belt... So they can get wired sound apart from the camera, but I don't have any of that gear... yet.

[Glen Elliott]

Wow, interesting stuff. Yeah speaking of the ME66 I have one and in dire need of the red "dot" mod, where they remove a capacitor in the K6 so the mic isn't so darn sensitive.

Here's another question for you- in all honesty I still think the quality of sound from the ME66 dwarfs even my ECM-77, should this be true....or is it completly expected beings it's a wireless system and not top of the line to boot. In other words what kind of expectations should I have from my wireless system compared to my camera mounted, phantom powered ME66?

[Matt Gettemeier]

That's a loaded question Glen. The me66 is a totally different kind of mic then the Sony lav. In my own experience I found the tram or mke2 to be about equally detailed to the me66... They had a very similar sound and that's why people like trams for mixing with shotguns. Most people won't notice one mic over the other. But combining a wireless AND a lav mic to draw a comparison to a wired shotgun isn't really fair. Speaking from my own experience I've gone through a phase with every new mic purchase. I buy it with a set of expections... many of those are met, but a few are left short... then I look for flaws in the system. Eventually I realize that's why people have so many different mics. It's because they all do different jobs. As you first go off the deep end of the GSA (gear sluts anonymous) you tell yourself that you're being irrational, but the fact is that the lav and the shotgun serve two different purposes and it's not a fair comparison to put them in the same boat.

I often use a shotgun and a lav at the same time, on different channels. Imagine a guy interacting in a group... there will be times when you want the sound of the "whole" and there will be times when you want only your speaker. If you use both mics you can choose.

I had a guy interviewing random people in a festival here in St. Louis. There were street performers and typical wack-jobs and sometimes my guy would make funny comments back to the camera. At this time I couldn't even hear him. He was too far away and I didn't want to spook the interviewEE... so I hung back. Ok so the girl being interviewed is being heckled by her friends and it's really funny. The shotgun hears them fine but I can't really hear my guy OVER them and I can't really hear the girl's voice seperate from her friends. Now which mic is better?

Take your pick. Do you want heckling comedy? Or do you want to hear your subject and the interviewee? If you're going to choose then you better go with the wireless! But there will be times when you want one or the other, or a mix of both.

Imagine the shotgun like a flashlight with a broad beam. If you want the sound in that beam then you want a shotgun. You'll hear things ahead of the subject and behind it AND quite a bit to the sides.

The wireless is like having a remote control bubble of sound capture. It MOSTLY gets sound within a 5 to 7 foot bubble around the omni. That can be damn handy!

At this point I pretty much use the wireless when I have to, but my normal instinct is to grab the best mic in the bag THAT WILL WORK... sometimes the best mic in the bag isn't the one that will do the best job. Make sense?

[Alessandro Machi]

I had the sizzle thing happen when I tried to use one lavilier wireless mike for two people.

This techique worked really well in the past when I used my samson $300.00 wireless, but when I rented a much higher priced Sony with 99 channels, the sizzle was there.

I was only doing audio acquisition so I shot it with both HI-FI and Dolby linear on S-VHS. The HI-FI did not like the sizzle sound and exacerbated it, the Dolby linear channels were much better.

I'd say it's the microphone. I forget which mike they put on the $300 Samson wireless but if you can get one of those mikes it would be interesting to see if the problem is reduced.

[Glen Elliott]

Yeah that makes sense. For upcoming weddings I'm planning on using my ME66 at the same time as my UWP-C1/ECM77 wireless/lapel combo. Set one for each channel (beings they are mono) and pan in post as needed.

Unfortunatly I don't have the cashflow to continue to buy lapel mics to test for noise tails. I already hashed out an additional $230 for the ECM-77 to upgrade the 44 that came with it- which, despite the slightly heightened noise tails, was well worth it for it's more rich natural sound.

Thank you greatly for all of your input. Maybe in the future I can get my hands on various lapel mics to test to see if they continue to have the noise trail problem. Hopefully they will be non-sony mics to see if it's a company specific lav issue.

[Marty Atias]

Wow, there's a bunch of issues in this thread.

1. The "sizzle" question. all wireless mics (except one) use a noise reduction technique called Companding. It acts like an automatic gain control in reverse. When it hears no sound over a minimum level, it attenutates (lowers) the audio level. This masks the noise inherent in the RF circuitry. This noise is always there, but your brain doesn't hear it under dialog or other audio. What you are hearing is the interval before the noise gate kicks in.

2. The differences between lav mics. Different mics have different frequency responses and different output levels. These differences interact with the companders in varying ways. A very hot mic will keep the noise gate open longer, so you hear more RF noise. A mic with a rising high frequency response (like the 77 or the Tram) will also fool the compander.

3. Difference between wired & wireless. Well, no compander, no RF noise.in the wired version.

4. Difference between lav & shotgun. Most lavs are omnidirectional. Shotguns are very directional and reject sound 90 to 180 degrees off axis. They also tend to have larger diaphragms which give netter noise specs, and are more expensive. Which would you expect to sound better - a $200.00 lav or a $500.00 mic?

Hope this helps!

[Alessandro Machi]

I hate noise gates.

I suppose if they had a true digital delay gate and the gate didn't "miss" the first millisecond of sound after silence I wouldn't mind it, (but they don't) but then you would have to delay the video an equal amount.

Since it appears that some digital cameras are adding their own mystery to the issue, do you guys ever hook your headphones up directly to the wireless receiver and compare that with how it sounds when the headphone is directly hooked up to the camera?

[Marty Atias]

Sure, you want to check the woreless' output beore you start shooting. But once tyhe audio is in the camera, there's not much you can do about it.

I should add a few things about companding to complete the picture because there's more than just noise gating in the transmitter. There is also compression. The transmitter compresses the dynamic range so it takes up less RF bandwidth (actually called "deviation" from the carrier frequency) and improve the signal to noise ratio. Then the receiver expands the audio back to something resembling the original.

[Dave Largent]

I posted recently about hearing this sizzle with a
Samson Airline system -- and this was when it was
not plugged into a cam -- just had phones
hooked up to receiver. Haven't had the chance to
investigate it furthur, and don't know if it has to
do with the phones monitoring. Haven't noticed it
with cam use, but maybe it's a developing problem.
It's like a whishhhhhhing noise at the begin and
end of words. Is that what you are experiencing,
Glen?

[Glen Elliott]

It's like a whishhhhhhing noise at the begin and
end of words. Is that what you are experiencing,
Glen?

Pretty much....Yeah. If you listen really closely you can even hearing DURING words as well.