Subject:For RednRoll or Chienwerks <BASIC>

Posted by: pb

Date:5/10/2004 9:04:10 PM

Here is the situation:

I am very bad with mic Model #s so please bear with me.

My DSR 570 has the diversity receiver that goes between the battery and the recorder body and I also used the Sony Broadcast diversity receiver that is honking huge and plugs in via an XLR.

The two people's audio levels are between -12 and -6.

When I play the track back as is it sounds fine, each mic playing through its respective speaker.

I need to add NAT sound so I combine the two tracks using the "make Mono" feature, wanting to centre the image. The audio level drops about 12 dB and sounds like it was recorded with a Radio Shack special.

What step(s) am I missing here?

This problem also manifests itself when I record voice on left and NAT sound on right then try to put voice on both channels. One work around was to double the tracks in Vegas using the swap channels feature but I much prefer to stay in Sound Forge and use Vegas strictly for mixing.

If you think the answer is embarrassingly simple please email me at psburn@shaw.ca or burn.peter@syncrude.com.

thanks guys,

Peter

Subject:RE: For RednRoll or Chienwerks <BASIC>

Reply by: Rednroll

Date:5/11/2004 7:36:20 AM

Peter,
It sounds like you have a phase problem. You described your mic setup but I'm not so familiar with it. Did you use the same mic or different mics for each voice? Sometimes 2 different mics can have opposite phase. It's always best to use 2 identical mics, from the same manufacturer. I have found in the past that Seinhiser mics are out of phase with most of the world. You could also have a problem where your mic cords are wired differently, so again identical mic cords. Anyways, to fix your problem. Select the entire left channel only....just the left and not the right. Then select PROCESS>INVERT.

Now try combing them to mono and see if it sounds better.

If that doesn't work, then go back to where you started. Now again select the left channel only. Goto EFFECTS>DELAY/ECHO. Select simple delay. Set dry level to -inf, delay out to 0dB. Set delay time to 5mS, hit ok. Now convert to mono and see how good/bad it is. In this scenario it tells me that you where using 2 mics that where spaced apart from each other. Not spaced far enough apart because you have considerable bleed from the non intended voice person. That persons voice is in both recordings channels. The only difference is that it arrived in the second mic 1mS/ft later, so the phase is not the same so a lot of the frequencies cancel when you add them (ie convert to mono). So with the use of the delay, we either have to retime allign them, or an easier method would be to move the time allignment diiference so the frequency cancellation starts to fall out of the audible range. So with the decribed method above I would start with the 5mS setting, convert to mono, if not acceptable, then UNDO and increment in 1mS steps. You can get close to a 20mS delay added before you will start to hear distinct echoes. You should find something acceptable before you reach that point though. If you find the delay time gets too high before the phasing disappears, then select the right channel and go through the same process. I can't tell you for sure, because I can't hear the recording to figure out which channel has the delayed signal with excessive bleed.

Subject:RE: For RednRoll or Chienwerks <BASIC>

Reply by: Chienworks

Date:5/11/2004 7:36:24 AM

I don't know what NAT is so i may be missing some clues here.

I would almost say it is a phasing problem, but those don't usually manifest themselves unless the two mics are picking up essentially identical signal. Since you have the mics on two different people this shouldn't be the case. However, you might want to try reversing the phase on one of the channels and see if this helps.

Subject:RE: For RednRoll or Chienwerks <BASIC>

Reply by: rraud

Date:5/11/2004 5:28:14 PM

NAT sound is what camera people and video producers refer to as "Natural sound", usually picked up by the camera mic. Of course it's usually far from natural, so I find the term... amusing.

As to our friends tech question , I'll re-read it when I have time and respond if nessesary.

Subject:RE: For RednRoll or Chienwerks <BASIC>

Reply by: pb

Date:5/11/2004 9:26:05 PM

Thanks for the tips. I followed the steps and restored the sound. THe phase problem was unnerving because it has never happened using the 810s with their stock mics. In this case, one of the 77s that comes with the 810 transmitter was broken so I borrowed a Tram mic (I think that's what he called it) for the transmitter. Since the transmitters are both 810s I guess the problem arose from having a 77 on one and a Tram(?) on the other.

Okay, NAT sound is jargon, how about if I refer to it as "ambient sound" as picked up by the camera's on board Sony 672 shotgun?

Glad I can call upon you lads for help when I am in a bind!

Peter

Subject:RE: For RednRoll or Chienwerks <BASIC>

Reply by: rraud

Date:5/12/2004 5:06:54 PM

Glad you found the problem Peter.

Most audio people do use the term "Ambient sound"..

That would indeed be a Tram, more than likley a TR-50. Many people swear by them. However I have yet to use any lav that I like, but in many a situation, you don't have much of a choice. So whenever posible, for interviews and such I use my Steven Paul (RIP) modified Neumann shotguns. BTW, the Sony 672 is a real nice sounding mic .