Where does this noise come from?

[Abas-Avara]

Hi guys,

I want to capture VHS tapes, but again new problems
After lot problems with the first VCR I bought an another VCR.

I've 2 options, capturing trough a TV card or Camcorder (Firewire passtrough)
The camcorder has better quality but there is much more noise compared to the TV card.
Although It has much noise, I think if the audio was without all that noise it will be far better then the TV card.
I think the camcorder is much more Sensitive.

Now I'm capturing sound and video separtly (video over camcorder & audio over TV card).
It is much more time comsuming and the quality would be better if the audio was without so much noise on the camcorder.

What is the cause of this? Do I have to use better cables? I've bought a 3,5mm plug to 2 RCA jacks for 2 dollars on a cheap site, on the cable it says low noise dual cable. The cable looks good but the sound becomes mono cause of the black rings instead of yellow. It was hard to judge cause of the mono sound but will it had less noise if it worked?

By the way the original cable was this



A weird problem was also that a tape played normally on the Sony VCR (first VCR) but on the Daewoo (second where I played other tapes fine) it plays horrible, like a broken VHS tape.

[edDV]

When you cap sound through a DV camcorder you are capturing to PCM uncompressed similar to a wav. Camcorder setting choices are 12bit/32KHz (4 channels possible) or 16bit/48KHz (2 channel stereo). Use the latter as your default. Camcorder capture is more likely to keep audio in sync.

Please explain the noise issue further. This is audio noise? VHS HiFi audio requires precise tracking. There is a second low quality linear audio track that can be selected in vcr menus.

You will need a VHS HiFi capable VCR to play the high quality HiFi sound.

[Abas-Avara]

Thanks for you reply

When there is music or something loud the noise problem is not the biggest problem but when there is not that hard/bad sound (like someone talking) the noise is very high. So the biggest effect is on the low sound footages.
Normally there would be also a little noise on the tape but trough the camcorder the noise is much louder.

[Nelson37]

Is it noise like static on a radio, like a brass band playing in the backround, or is it a continous low hum?

Try to describe the problem in more detail.

[edDV]

Are these commercially recorded tapes or tapes you made? Does your VCR play the HiFi tracks?

It seems you are listening to the low quality linear tracks.

http://www.videomaker.com/article/1762/

[Abas-Avara]

Tapes I made, on the old videos the noise problem is bigger.
This has nothing to do with TBC right?

These are the VCR players I use, on both it says Hifi Stereo

[Abas-Avara]

I will upload a sample now

[2Bdecided]

You need the cable with the correct number of connections on the jack end - you say "different coloured rings" - if there are also a different number of rings, or rings wired in a different order, then the video may break through onto the audio signal, giving a horrible buzz.

The same thing could happen on a correctly wired but very cheap / broken cable.

Hope this helps.

Cheers,
David.

[edDV]

Both of those VCRs show HiFi audio logos.

Are you playing commercially made tapes with a HiFi logo or were they made on a consumer VCR. The latter may only have low quality linear audio tracks.

Most VCRs have a light to indicate HiFi track playback.

[The_Doman]

Tapes I made, on the old videos the noise problem is bigger.
This has nothing to do with TBC right?

These are the VCR players I use, on both it says Hifi Stereo

Ofcourse it could be the old tapes were recorded in mono?
Even with those recorders you never will get a Hifi Stereo signal from it.
The recorder also should indicate if there is Hifi/Stereo signal present on the tape.
Mono tracks on VHS are pretty noisy anyway.

And I can confirm capturing VHS with a DV-Camcorder will get you the best results possible.

[Abas-Avara]

I have deleted the DV-AVI files but I've found on youtube a similair noise
http://www.youtube.com/watch?v=TnfYWxv55us

You hear on 0.10 till 0.13 something like that.

[Abas-Avara]

TDK, Panasonic etc that kind of homevideo tapes

On the old tapes when people were talking with low volume the noise is dominating the sound, you can't really listen to the person. The sony shows something about the audio I will check it out now. The new cable I bought has 2 black rings (bought special for audio) but the standard has yellow rings. The standard has 3 yellow rings.

The Sony display:

L1 and in smaller red letters next to L1 stereo

[Abas-Avara]

Tapes I made, on the old videos the noise problem is bigger.
This has nothing to do with TBC right?

These are the VCR players I use, on both it says Hifi Stereo

Ofcourse it could be the old tapes were recorded in mono?
Even with those recorders you never will get a Hifi Stereo signal from it.
The recorder also should indicate if there is Hifi/Stereo signal present on the tape.
Mono tracks on VHS are pretty noisy anyway.

And I can confirm capturing VHS with a DV-Camcorder will get you the best results possible.

The_Doman? van Tweakers? wat toevallig! (ikweetechtniet)

The tape is already noisy, but on the capture card the sound is better, well less noisy.

I will check tommorrow the VCR+menu and camcorder settings.
It is late and I'm very sleepy.

[edDV]

So shall I assume you can play commercial tapes fine?

That YouTube clip shows poor tracking. The tape was made on a VCR that was out of adjustment. The only way to play this tape is on the recorder that made it, or an expert would need to misadjust another VCR to match the original recording machine.

[Abas-Avara]

Commercial tapes are playing right. When you put a tape in the VCR on the top of the screen is giving the video information like standard play always on every tapes but with the commercial it also shows Hifi L+R.

I think the TV card for audio is the best option. The time consuming is not the biggest problem, when I do something I want to do it once and good. I would rather have the audio over the camcorder cause of the quality.

But why is the same audio better on the TV card than the camcorder?

I think the camcorder is more sensative in picking signal, cause the audio is also louder then the card, but when I adjust the volume there is still more noise on the camcorder file.

[The_Doman]

But why is the same audio better on the TV card than the camcorder?

Probably the camcorder has a more agressive automatic gain control (AGC) for the audio while the TV/Capture card probably does not use a AGC.
Then with the silent scenes it will crank up the audio level so the hiss/noise of the mono track becomes more audible.

Maybe a possible solution would be to filter out the noise of the recorded audio track with a audio-editor?
I often make adjustments to the audio tracks of my captures using my trusty Cool-Edit 2 8)
With the uncompressed audio of DV captures it is pretty easy todo.

Beside, it remembers me of all the audio issues we have had with the old Hauppauge PVR150 card.
The older drivers would boost up the audio to crazy levels making the line input unusable for serious captures.

[Abas-Avara]

I've tried to use Adobe Audition but the audio becomes weird or dull like they say on youtube. I will try it again (after 30 min I got a headache) and look to Cool Edit.

I will let you guys know the result, if there isn't much result I will use the TV card. Looking on the positive side I'm happy that the the video is good and I can live with the audio from the TV card. And there are only 1 to 3 tapes wich have very silent footage.
The rest are bomba (dancing, music etc)

[dLee]

The camcorder has better quality but there is much more noise compared to the TV card.
Although It has much noise, I think if the audio was without all that noise it will be far better then the TV card.
I think the camcorder is much more Sensitive.

When there is music or something loud the noise problem is not the biggest problem but when there is not that hard/bad sound (like someone talking) the noise is very high. So the biggest effect is on the low sound footages.
Normally there would be also a little noise on the tape but trough the camcorder the noise is much louder.

Camcorder AGC?

Edit: Missed The Doman's post.

[Abas-Avara]

I found this article on the internet

by Loren Alldrin
October 1998

Technology is a funny thing. Every now and then, someone comes up with an idea that---on the surface---looks just wonderful. In use however, that "great idea" may cause more problems than it solves. For example, take the camcorder's auto-gain circuit (or AGC).

The AGC's job is to keep a consistent level of sound, regardless of what's going on around the camcorder. If the camcorder picks up a loud sound, the AGC quickly reduces its level to avoid overload distortion. When things are quiet, the AGC slowly turns up the level in an effort to record something. In a world that bombards camcorders with extremely loud sounds one instant and quiet ones the next, having a circuit that will automatically compensate seems like a good idea. In the right shooting conditions, it is.

Unfortunately, AGC is a bad idea more often than not. Consider what happens when you're recording a person speaking in a moderately noisy environment. When the person is talking, things sound great. When the speaker stops, the AGC tries to fill the silence with anything it can get. In this example, the camcorder records background noise, which the AGC raises to a dull roar in a matter of seconds. When the speaker begins talking again, the auto-gain is cranked up and the first word comes booming in at an extremely high level. The AGC quickly compensates, bringing the record gain down to a level appropriate for the speaker. So it goes, with voice and background noises alternating up and down like kids on a teeter-totter (Figure 1).

Breaking the Chain
The most obvious way to whip these problems for good is to disable the AGC. Unfortunately, this requires a camcorder with manual audio record levels, which is a rare beast. Camcorders with manual record levels tend to fall on the expensive side of the market, making these controls out of the reach of most videographers.

For the rest of us shooters working with more modest budgets, here are five techniques to alleviate the AGC headache:

1-Trick the AGC with a Loud Sound or Voice
This technique uses a spoken word, handclap, fingersnap or any other moderately loud sound to drop the AGC to a reasonable level before taping. Making a loud sound lowers the record level quickly, at which point it begins slowly climbing up again. If you start recording while the AGC is still low, your shot won't begin with a blast of background noise. If your speaker begins talking soon after the shot starts, their first word won't be dramatically louder than those that follow.

One alternate technique is to have your speaker say "three... two... ONE..." just before the shot starts. This works well if you're not planning on editing your footage later. If you'll be editing after-the-fact, you can just roll tape and record their countdown at the head of the shot. This will allow the AGC to establish the proper record level before that crucial first word.

This technique doesn't really apply when your speaker stops talking briefly mid-shot---he or she can't very well clap their hands or do another countdown without looking ridiculous. If you plan to add music and do a little audio massaging with a mixer after you shoot, however, you can use a variation on this technique while tape is rolling.

Say, for example, your speaker is addressing the camera from one spot, walking several feet to another, then addressing the camera again. If you snap your fingers or clap about a second before the speaker resumes, their first words will sound natural. When you edit the footage, use a mixer to eliminate the loud sounds during the pause. Cover the whole thing with some music, and no one will know.

Before you try these techniques on a real shoot, experiment with your camcorder. Record yourself speaking in a semi-noisy environment, and try different sounds to trick the AGC. On playback, listen to how your camcorder's AGC responds, how quickly it recovers and how high it cranks the noise. Soon, you'll have a good grasp on the audio characteristics of your specific AGC, knowledge you can apply to trick it into submission.

2-Gate Your Audio When You Edit
In the music recording world, a electronic gizmo called the "noise gate" is used every day. It mutes or reduces the level of an audio signal when that signal is below a certain level--once the signal has enough strength, the gate lets it pass. In a nutshell, loud sounds pass through a gate unhindered while quieter sounds (noise) get reduced.

You can put a noise gate between two VCRs as you edit, between your camcorder and VCR as you dub or patch one into an audio mixer. If your AGC isn't making background noises as loud as your desired audio, you can set up a noise gate to differentiate between the two. This will reduce noise during quiet moments, and may even eliminate it completely.

You can do something similar with an audio mixer and good-old elbow grease. Simply watch your footage and lower the appropriate fader(s) when your subject isn't speaking. With practice, you can get quite efficient at this "manual gating."

Folks editing with computer-based systems have it easy, as they can just drag in volume changes to drop the audio levels during pauses. With some experimentation, you can perform fades that are the exact inverse of your AGC's level changes.

3-Shoot Where There's Less Noise
Since the main problem with AGC is fluctuating noise levels, shooting in a quieter environment can make AGC gymnastics less obvious. The AGC will still crank up its record level during quiet moments, but all it will have to work with is a little hiss from the microphone itself. Though nowhere near as nice as true silence, this is much less noticeable than the roar of an air conditioner or rumble of nearby traffic.

Every auto-gain circuit has a limit to how far it will turn up background noises. When the AGC finally maxes out, a quieter location will translate to considerably less noise on tape.

4-Use an External Mike
In addition to background noises, auto-gain circuits have a field day with noises coming from the camcorder itself. During quiet moments, your soundtrack may end up being a symphony of autofocus motors, transport gears and button presses. An external mike will eliminate noises emanating from the camcorder, allowing for dramatically cleaner audio tracks.

An external mike can also be closer to the subject than the on-camera mike. This makes voices and other desired sounds considerably louder relative to the noise, and results in less audio garbage on the tape.

For the least noise possible, try a dynamic microphone. Condenser mikes have built-in electronics that can generate a trickle of hiss, as do wireless mikes of all types. Dynamic mikes (at least those attached with cables) are passive devices, generating virtually no noise themselves. This gives the AGC less to work with during the quiet times, which translates to cleaner recordings.

5-Record to a VCR
One final way to thwart your AGC is to not use your camcorder for audio at all. Instead, run the video output of your camcorder into a VCR with manual audio record levels (these controls being far more common on VCRs than on camcorders). Then, wire an external mike or two into an audio mixer. Get good audio levels at the mixer (you can verify this with headphones), and route its line outputs into the VCR's audio inputs. Some VCRs have mike inputs, which eliminates the need for an audio mixer.

This setup works only when you and your camcorder are keeping still, such as in a studio or at a public performance of some kind. Just remember to monitor your audio with headphones plugged into the VCR, not the mixer. This is the only way to be sure sound is ending up on tape. Another just-in-case tip: pop a tape into your camcorder and record onto it as well as the tape in the VCR. If you're shooting a once-in-a-lifetime event, this simple backup may avoid a great deal of grief should something go wrong with your cabling or VCR.

Dirty Pause
Don't despair if all this sounds like a lot of work to thwart the efforts of a camcorder "feature." These tricks will become second nature in time, and your videos will sound much better for it. Nothing robs a finished tape of professionalism quicker than that familiar swell of background noise during a speaker's every pause.

Auto gain control---a good idea gone bad.