Ty and all: meter misleading???
Why is it that a recorder's meter (including a camcorder) can show good sound levels and yet the sound actually recorded can be way off. Obviously, it is good practice to use both the meters and a good set of headphones. But I just want to understand what is going on. For example, I tested a mono mic plugged into an xlr cord which was plugged into a short xlr to miniplug cord plugged into the cam's mic input. The meters indicated good sound levels but almost no sound was recorded. Then I checked the xlr to mini-cord. It had a stereo plug and I was guessing the wrong channel was being recored to the cam. I added an xlr adapter switched to mono and the problem was solved. But why did the cam's meter indicate adequate levels (between -12 and 0)?
Way too many unknowns. But my first guess would be that your XLR to miniplug cord was not wired properly for the application you were trying to do. It is possible that you ended up recording a DIFFERENTIAL signal on the two tracks (because of the way the cord is wired). And then when playing it back with L+R combined, they cancel each other. Do you still see a signal when you look at the meters (or in an editor?) Try listening to just one or the other channel by itself. Trying the adapter was a good debugging move. But you really need to know more details to arrive at any specific conclusion.
Furthermore, most camcorder miniplug jacks provide "plug-in-power" which is a DC voltage intended to power electret microphones. This DC voltage does not play well with many XLR microphones.
Of course, you are correct that meter motion should never be confused for recording a proper sound track. Recording sound without monitoring on a good set of headphones is exactly like framing and focusing without looking at the vewfinder.
The most important thing to remember about meters is where their pick-off points are - that is, where in the signal chain of the device they derive their signal input from. Some gear has a fixed point, other gear has multiple points; it depends on your particular piece of gear.
Bar and LED meters are for keeping track of relative levels (Peak and/or Program, Loudness, or others, depending on the unit and meter ballistics) in the device's analog and/or digital "circuitry". They will not tell you if a signal is distorted if it is within the safe operating range of the components.
This is where the headphones come in. Their pick-off point may be the same as or different from that of the meters. Maybe they receive their signal before the meters, maybe after. A look at the block diagram/schematic will tell you that (feel free to post if you're unsure).
In the end, if it sounds good, it is good...so use whatever means you have available to ensure good-quality audio throughout the entire signal chain, from input transducer (microphone/instrument) through to the recording device and its medium.
All the best,
Hello Craig and welcome to the Cow Audio Forum.
Richard and Wolf have it right. You can still mess up in post. I was hired to send the audio from the AV guys to a camera last summer at a hotel gig. I sent tone to the camera (0 for me, -20 at the camera). Line level to line level. As the show starts, the camera op says my -6dB camera levels are WAY TOO HIGH!!!!! He says, "This is DIGITAL MAN! No peaks higher than -20!!!"
I told him I would set them where he would like me to, but warned him that he was seriously underrecording. He later told me in post, my levels were too high. I suggested that somewhere in post he was feeding a line level source into a mic level input and that he put the tape back in the camera and listen to the headphone output.
Which reminds me. Yes, you need to make sure you're feeding mic level to mic level or line to line. If you don't you can actually set line level from a mixer to the mic input of the camera or recorder. If you're not listening, you'll never know you're messing up. AND.... just flipping the switch from mic to line isn't enough. You need to do the whole deal; send to and recalibrate.
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Thanks for everyone’s feedback. Simply from experience I’ve learned to play with and listen to sound as well as keeping an eye on the meters. Whether from a mixer or powered units like cordless lav kits, I’ve fooled with the line/mic switches, output/input levels etc until I’ve gotten it to sound good. But I would like a better understanding of just what is going on. In this particular case, I was working with no mixer. Just a handheld mono mike directly into the mic input of a Canon HV40, which has manual control to adjust input levels and a meter on its LCD screen. With the stereo plug from the xlr to miniplug cord the sound playback was at whisper levels even though the meter read -12.
No phantom power coming from cam.
Plus there is only one meter on the LCD – not two like on prosumer level cams.
"It is possible that you ended up recording a DIFFERENTIAL signal on the two tracks (because of the way the cord is wired). And then when playing it back with L+R combined, they cancel each other. Do you still see a signal when you look at the meters (or in an editor?) Try listening to just one or the other channel by itself. Trying the adapter was a good debugging move. But you really need to know more details to arrive at any specific conclusion."
Now that would be interesting. I’ll try this experiment myself and record with the stereo plug and see what reads in post.
Ps I would never record anything important without monitoring. I know the meters can read in a good range and the sound can be awful. But very low levels with meter readings high confused me.
OSX 10.5.8; MacBookPro4,1 Intel Core 2 Duo 2.5 GHz
; Camcorders: Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP certified; write professionally for a variety of media; teach video production in L.A.