PDA

View Full Version : Audio distortion question...how do you get great audio in VT?



TAV Media
03-07-2006, 11:43 AM
Hello,
We have the latest version of VT hardware and software (4.6c), and we're using an SX-8. When recording audio, we get two problems:

1. Recording a stereo source in 1L and 1R, and hard panning the left side to the left, and the right side to the right (keeping the stereo image), and bringing the levels even, the sound becomes inaudible. If we lower one side slightly, you can hear the audio again.

2. Audio is always distorted if recorded near/below unity. I always get better audio if i initially record outside of VT.

For example, we record these segments to tape and dump them back on the VT for editing a couple of weeks later. I checked the audio quality by doing this:

Scenario1
Video = from VT4.6 - to tape
Audio = from Mixer - to VT4.6 - to tape

Scenario2
Video = from VT4.6 - to tape
Audio = from Mixer - to tape

Scenario2 produced better audio by far, but I had to do some alignment work in VTedit because the audio was delayed from the video.

Can anyone help?

Dan Hong
03-07-2006, 04:01 PM
The problem in scenario one is that the stereo tracks are phase cancelling. If you have another audio program, you can reverse the phase of one of the tracks and you'll be fine. As far as the other scenario, I'm not sure.

Rich Deustachio
03-07-2006, 04:45 PM
I run into this problem all of the time using wireless mics for event interviews. The mic is only fed to one channel on the camera and then in VTedit when I send the audio to both channels the volume level drops way off. If I split the XLR from the wireless mic and sent it to both channels will I get the phase cancelling that way as well?

TAV Media
03-08-2006, 06:44 AM
The problem in scenario one is that the stereo tracks are phase cancelling. If you have another audio program, you can reverse the phase of one of the tracks and you'll be fine. As far as the other scenario, I'm not sure.

can you explain that a little more dan? I have Acid Pro 3.0 and maybe one other audio program, but dont remember the name at this time. Have you dealt with this before? If yes, what program do you use?

Also, is there a way around this, keeping my stereo input minus the "phase cancelling."

vanderwielen
03-08-2006, 07:05 AM
The most common reasons that audio gets out of phase is either mis-wiring of your XLR cables where pin 2 and 3 are reversed in one cable, or the use of unbalanced 1/4" cables and plug-in 1/4" to XLR adapters or using balanced audio on one channel and unbalanced on the other. In any event, use exactly the same cables for left and right.

Dan Hong
03-08-2006, 11:28 AM
I use Adobe Audition, but most audio programs will do the same thing. Take the wav file into your audio program, select either the right or left channel only (in Audition it's Edit/Edit Channel) and reverse or invert the phase (in Audition it's Effects/Invert)

ottis41
03-09-2006, 10:45 AM
R1 and R2 are for mic level only no line level. thats th first problem i see.
I have a DVC-Pro deck and A Beta SP deck and a DSR-11 conected to my SX-8.
I do not use any adapters or extenders to go from XLR to RCA or RCA to XLR, that is a big NO.
I use my SX-8 with Sony Vegas, Aftereffects, and many other software apps with no problem.

TAV Media
03-09-2006, 12:12 PM
R1 and R2 are for mic level only no line level. thats th first problem i see.
I have a DVC-Pro deck and A Beta SP deck and a DSR-11 conected to my SX-8.
I do not use any adapters or extenders to go from XLR to RCA or RCA to XLR, that is a big NO.
I use my SX-8 with Sony Vegas, Aftereffects, and many other software apps with no problem.

So how are you suggesting i connect my sound board to the VT4.6?

Your Beta SP inputs and outputs are Line or Mic Level?
Your VT outputs are Line or Mic Level?

ottis41
03-14-2006, 08:29 PM
On the SX-8 i use in 2 XLR L and R for my mixer, a Tascam TD D1000, My Beta SP deck is Line level XLR if i Plug my Deck in in 1 L& R i get over modulated sound., The same with the DVC-Pro deck.
I only use live mic's in 1 Left and right.