HD10 audio

[Steve Mullen]

I've gotten reports of good (and bad) audio. The good report came from someone using a Samson wireless mic and listening to analog audio direct from the camcorder--not via 1394 through a computer.

Some thoughts:

1) I assume the WIND FILTER was turned OFF for those reporting bad audio?

2) Does the camcorder analog output have an EQ filter to bring the rolled-off audio back to normal? If so, EQ must be applied in post.

3) Is over-driving the AGC causing a loss off the high-end?

4) Load matching issues:

The Samson Users manual notes the follow for unbalanced-out to 1/8-inch plug.

"Unbalanced output -- Use this unbalanced (1K Ohm max.) 1/8" mini-phone jack when connecting the UM1 to consumer (-10dBm) audio equipment.

Audio Output Level switch -- Sets the audio output level of both the balanced and unbalanced outputs to -30 dBm (mic level), -20 dBm, or -10 dBm (line level)."

I'll find out which setting he used--but I would expect the -30dBm output.

But the key may be the source/load match. Consumer equipment is designed for hi-Z mics not 600 ohm mics. It shouldn't matter, but maybe it does.


5) The fact that the on-camera mic sounds fine makes me reject the "MP2 is bad" theory."

6) Are there sample-to-sample variations?

[Kevin A. Sturges]

Can you switch the AGC off in the HD10U?

[Steve Mullen]

Nope. Nor would i want to. I beleive in the power of DSP to do a great job. :)

[Heath McKnight]

I wonder if there is more audio in the background (like planes, highway traffic and a guy using a gas-powered hedge trimmer) causes the canned sound...

Inside, with no sound, I could hear a bit of the canned sound.

heath

[Barry Green]

<<<-- Originally posted by Steve Mullen : Nope. Nor would i want to. I beleive in the power of DSP to do a great job. :) -->>>

You're kidding, right? I mean, do you also believe in the power of autofocus to do a great job? Who would ever want to turn that off, right? Auto exposure, anyone? Oh, yeah, you can't actually turn that one off either... sigh...

Seriously though... the HD10 can't disable automatic audio gain control? And that's a feature?

That's just... completely unacceptable.

<<<-- Originally posted by Heath McKnight : Inside, with no sound, I could hear a bit of the canned sound. -->>>

Some more testing is showing that the JVC cameras may actually be recording the audio channels to the tape at a slightly different point in time from each other. Perhaps the MPEG2 audio encoder is encoding one track, and then the other, and this causes a slight offset... and it is that offset that is resulting in a canned, echo-ey sound. Whatever the source is, the problem appears to be that the individual audio tracks are not in perfect sync with each other -- and that causes the "canned" sound.

Perhaps the "canned" effect is not so noticeable on the built-in mic because the built-in mic is stereo, and therefore it's recording a slightly different recording to each audio track, so they don't precisely match up and "echo". Whereas piping a single mic feed to both audio tracks seems to be revealing this echo problem.

[Steve Mullen]

Theres an easy way to find out and solve the problem. Plug in 1 mic and flip the XLR switch so the mic only records on 1 channel.

That's it, problem gone.

Modern AGC can handle audio with few if any problems. Basically it works as:

1. a VERY FAST limiter to prevent clipping. Something no human can do.

2. a SLOW gain adjustment that lets it handle different input signal levels--just what you do when you adjust signal levels.

If you could turn it off, you would lose the limiter, no a trade off I'd make with digital audio.

Those who are bitching are doing so out of their long held belief AGC can't work. AGC used to be bad. But with today's smart circuits, no problem.

I've never heard any pumping.

And yes, everythime a snap a still photo over the last 20 years AF has done the job of focusing.

[Heath McKnight]

Actually, and I'll double check this, I was recording on Channel 1 only...But I'll double check tonight after work.

heath

[Steve Mullen]

I'd love to believe recording to and listening to, 2 channels would solve the problem.

Frankly, I think it is a bug in the first shipment of HD10's.

Maybe in all HD1's.

[Heath McKnight]

I said it once and I'll say it again, DAT!

heath

[Jay Nemeth]

I just came back from listening to our off-line edit. The canned sound is still there. When taking one channel only, the weird stereo effect is gone, but the audio still has the thin boxy sound.

Some comments on your comments:

<<<-- Originally posted by Steve Mullen : Theres an easy way to find out and solve the problem. Plug in 1 mic and flip the XLR switch so the mic only records on 1 channel.

That's it, problem gone.-->>>

We were hoping, but not the case....

<<<--Modern AGC can handle audio with few if any problems. Basically it works as:

1. a VERY FAST limiter to prevent clipping. Something no human can do.

2. a SLOW gain adjustment that lets it handle different input signal levels--just what you do when you adjust signal levels.-->>>

Our mixers have state of the art limiter circuits, we want to use those and choose when. The SLOW gain is death. When we adjust signal levels, we don't turn up the gain when someone stops talking so that the air conditioner noise gets real loud, then quickly turn it down when they start talking again.

<<<--If you could turn it off, you would lose the limiter, no a trade off I'd make with digital audio.-->>>

Must have manual control of the audio.

<<<--Those who are bitching are doing so out of their long held belief AGC can't work. AGC used to be bad. But with today's smart circuits, no problem.-->>>

I think bitching might be an exaggeration, and has a negative connotation. There are some of us who want our projects to be the best they can be, it's really about positive energy, about correcting mistakes.

<<<--I've never heard any pumping. -->>>

I heard it tonight when we did some pick ups.

<<<--And yes, everythime a snap a still photo over the last 20 years AF has done the job of focusing. -->>>

Interesting, I've never used an Arriflex, Panavision, or any broadcast TV camera with auto focusing. Maybe it's because they're not still cameras.

I think the core of the disagreement here is what each person is using the JVC camera for. Some people are coming from a filmmaking and storytelling background and have certain standards that they will not go below. They have proven procedures that work to achieve this quality i.e.: a sound man with a mixer and really nice microphones recording to a Nagra or DAT, or at least 20bit audio on a DigiBetacam.

Then there is a group that are recording events in a one man band configuration who at best, can plug a shotgun or wireless mic directly into the camera, and not fiddle with controls.

These are two completely different worlds that don't even speak the same language. I'm not trying to belittle anyone, but ENG is vastly different from production.

And before anyone says, "you can't get broadcast or film quality sound from a $3500 camera", I will wax nostalgic about my Sony VX1000. It too, was the first of it's kind and cost around $3500. It had manual audio control as well as an AGC circuit to pick between, and recorded clean full range audio that sounded wonderful. It also had fully manual exposure and shutter control, as well as an ND filter.

I will accept the shortcomings of this being the first consumer HD camera, such as poor latitude, a green spike on bright things, and even Mpeg2 artifacts. These trade-offs come with being on the cutting edge of technology.

The manual controls for picture and sound have been around since the beginning of DV camera technology, and of course, long before. There is absolutely no excuse for this camera to not have these controls also.

This little camera is finally giving a breath of life to all those no-budget projects that sat on shelves collecting dust. JVC should be proud of this achievement, and embarrassed of omitting basic controls found in my Uncle's home video camera.

Jay

[Steve Mullen]

What I don't get is why anyone with these standards and that level of audio equipment doesn't rent a Varicam or HDCAM.

It's not just ENG -- its EFG. When I lived in Japan every dramatic program was shot on video. That's more where I see the HD10 -- at best.

And for video, I just can't see why anyone one would worry about a little bit "off" audio when you've got to admit HDV video is so seriously compromised.

I just shot with a Sony 390L that had NO latitude problems. It had NO chroma noise.

I just projected DVCPRO50 tape shot at 24p using the SDX900. It blows the JVC away.


When you say you heard the A/C pump--just how loud was it? I doubt by the time it gets to the typical home HDTV you will ever hear it.

Of course, if you are in a sound studio you might hear the ambient noise be altered, but who listens that way?

I just heard great audio shot at Fashion Week. The ambient noise was horrible. The interview was clean--without a "canned" sound. But then it was a brand new unit.

I shot in Central Park, no problems at all. Heath shot at his office and at home, no problem.

Note I'm not claiming you aren't hearing something you don't like. But 20-bits for audio? I used to record audio on an Ampex 360 on only 2 channels. In Japan you get CDs from these 1950-60s tapes and they sound great. The audio field has become bizzare -- what with power conditioners and cables whoose atoms are lineup to better conduct high frequencies.

But, we do agree that what one will use the camera for -- determines what they will care about.

[Heath McKnight]

Not to self-promote, but when my DVD comes out, watch the Doc. Anything with me on the golf course or the guy with a white wall background was done with the JVC in DV mode. The audio is rough either way.

heath

[Betsy Moore]

Dear Heath (and everyone else of course!),

On a very, very limited budget, how can I record to an external source? I've seen tiny walkman style DAT recorders on ebay, would they work at all? I'll have the smallest of crews--one girl to operate the camera, one girl to work the boom--both adjusting lights between takes. Given these restrictions, is there a way for the mic operator have a DAT recorder slung around his shoulder and monitoring the sound? I also want to save all that time wasted on hiding and moving the sound cables when the DAT machine and sound board is tucked away in the next room.

If I just want good sound in a carpeted cabin, basically two actors talking to each other--is there a mic/audio recorder combo I can put together new or used for 500 or under?

Thanks again for all the great advice:)

[Jay Nemeth]

Hi Betsy,

Usually, with video cameras, a professional DAT is used that records and syncs to the timecode of the camera. If shooting film, the DAT generates timecode which is displayed on the slate (such as a Denecke Smart Slate). Unfortunately, there is no way to get the timecode signal out of the JVC camera to send to the DAT, so this feature of pro DAT machines is lost.

Even a consumer DAT recorder should record sound much better than the JVC does internally. Make sure to use a slate with a "clapper" so you can sync the sound later like in the old days.

Most sound men (or women) prefer a really good uni-directional or shotgun mike on a fishpole. They have a selective pattern and can reject unwanted noises in the "null" area of the microphone. For example, aim the back of the mic towards the offensive airconditioning noise to lessen it's level compared to your actor. Sometimes a really good RF lav can be hidden on your talent. These usually have omni patterns but since they are closer to your talents mouth, the gain can be turned down thusly reducing background noise.

This all assumes that you have manual control of the audio and aren't fighting an Auto Gain Circuit like the one in the camera.

Hey! How about hiring some guys on you crew! Good luck with your project....

Jay

[Betsy Moore]

Thanks, Jay:) Unfortunately it's all volunteers otherwise we'd be glad to hire a couple of token men. What brand/model of entry level boom mics/consumer DAT recorder do you recommend?