Overmodulation at DVinfo.net

August 27th, 2002, 10:27 AM

Hi,

I'm trying to figure out why my audio is overmodulated. I am running either a boom mic or lav into a MA 200 on the back of the XL1s. I set my levels manually for -12 db on the camera using the MIC setting and they sound great through my headphones.

Coming out of the camera is a different story. Going through a mackie mixer, I have to jack up the gain to get to 0db. Playing back the dailies on a standard tv or through the editing system sounds overmodulated. I know my other equipment is not faulty since I use it every day. The only audio trouble I have is with the footage shot on the XL1s

Thanks for any help,

Jeremy

Nathan Gifford · August 27th, 2002, 06:21 PM

Is it possible that you headphone volume is too low? Are you using a good audio cable going to your mixer?

Don Palomaki · August 30th, 2002, 06:05 AM

Sounds like you are using analog sound output from the XL1? How are you connecting to the Mackie mixer? What input are you using?

September 17th, 2002, 10:40 PM

I'm using the the RCA outs on the camera and running them through an RCA to XLR converter. It should sound pretty good I would think.

Thanks,

Jeremy

Jeff Donald · September 18th, 2002, 06:38 AM

What Mackie mixer are you using? What input are you going in? Why not leave it RCA (line level) and go into the Mackie? I suspect it is the XLR convertor and going into the Mackie on a mic input that is over modulating the signal.

Jeff

Don Palomaki · September 18th, 2002, 11:50 AM

How is the sound if you connect directly to a monitor with out going though the mixer. That can help isolate the point where the sound gets bad.

September 18th, 2002, 01:05 PM

It's the Mackie 3204 and I'm jacking into my patchbay. It's not the box because I use the same box to go from the VHS and 3/4 decks into my NLE with no problem. They also take the same route through the mixer. It's just the XL1 that is overmodulated. Very strange.

Thanks,
Jeremy

Don Palomaki · September 18th, 2002, 03:54 PM

What is the input impedance if the mixer where you are making the connection? The output impedance of the XL1 is on the order of 3 kohms. If connected to a 600 ohm input you might be overloading the XL1 output circuits.

Again, have you checked whether the output of the XL1 direct into a monitor (not thorugh your mixer) with unbalanced high imputs is good or bad

September 19th, 2002, 04:36 PM

Yes, I did check straight to a monitor and it is still overmodulated. I can switch to unbalanced audio input when connecting straight to my NLE which, I believe, negates the 600 ohms problem, but that does not seem to matter.

Thanks,
Jeremy

John Klein · September 24th, 2002, 07:05 PM

I'm still trying to understand it all, but from what I've read, Line level on things like a VCR, Cam, etc. is very different than line level to XLR (pro) connections.

Here's a quote about LL stuff going in to a PD150:

Line level on most XLR equipment is +4 dBu, about 1.25 volts. The PD150 is one of the few boxes anywhere that uses the RCA/minijack line standard of -10 dBV, about .3 volt. Lots of my pro location sound friends have gotten burned by this.

I'm guessing if you go RCA out of the cam into the RCA (an aux type) input on the Mackie you will be happier.

Let us know, won't you?

August 27th, 2002, 10:27 AM	#1
Jeremy Evans Posts: n/a	Overmodulation Hi, I'm trying to figure out why my audio is overmodulated. I am running either a boom mic or lav into a MA 200 on the back of the XL1s. I set my levels manually for -12 db on the camera using the MIC setting and they sound great through my headphones. Coming out of the camera is a different story. Going through a mackie mixer, I have to jack up the gain to get to 0db. Playing back the dailies on a standard tv or through the editing system sounds overmodulated. I know my other equipment is not faulty since I use it every day. The only audio trouble I have is with the footage shot on the XL1s Thanks for any help, Jeremy

August 27th, 2002, 06:21 PM	#2
Nathan Gifford Wrangler Join Date: Sep 2001 Location: Tickfaw, LA Posts: 1,217	Is it possible that you headphone volume is too low? Are you using a good audio cable going to your mixer? __________________ Nathan Gifford Southern Cyclist Magazine & Productions For quick answers try our Search! To see me and Rob Lohman click here

September 24th, 2002, 07:05 PM	#10
John Klein Regular Crew Join Date: Dec 2001 Location: Wisconsin, USA Posts: 182	I'm still trying to understand it all, but from what I've read, Line level on things like a VCR, Cam, etc. is very different than line level to XLR (pro) connections. Here's a quote about LL stuff going in to a PD150: Line level on most XLR equipment is +4 dBu, about 1.25 volts. The PD150 is one of the few boxes anywhere that uses the RCA/minijack line standard of -10 dBV, about .3 volt. Lots of my pro location sound friends have gotten burned by this. I'm guessing if you go RCA out of the cam into the RCA (an aux type) input on the Mackie you will be happier. Let us know, won't you? __________________ < >< . . . . . < >< . . . . . < ><

August 30th, 2002, 06:05 AM	#3
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	Sounds like you are using analog sound output from the XL1? How are you connecting to the Mackie mixer? What input are you using?

September 17th, 2002, 10:40 PM	#4
Jeremy Evans Posts: n/a	I'm using the the RCA outs on the camera and running them through an RCA to XLR converter. It should sound pretty good I would think. Thanks, Jeremy

September 18th, 2002, 06:38 AM	#5
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	What Mackie mixer are you using? What input are you going in? Why not leave it RCA (line level) and go into the Mackie? I suspect it is the XLR convertor and going into the Mackie on a mic input that is over modulating the signal. Jeff

September 18th, 2002, 11:50 AM	#6
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	How is the sound if you connect directly to a monitor with out going though the mixer. That can help isolate the point where the sound gets bad.

September 18th, 2002, 01:05 PM	#7
Jeremy Evans Posts: n/a	It's the Mackie 3204 and I'm jacking into my patchbay. It's not the box because I use the same box to go from the VHS and 3/4 decks into my NLE with no problem. They also take the same route through the mixer. It's just the XL1 that is overmodulated. Very strange. Thanks, Jeremy

September 18th, 2002, 03:54 PM	#8
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	What is the input impedance if the mixer where you are making the connection? The output impedance of the XL1 is on the order of 3 kohms. If connected to a 600 ohm input you might be overloading the XL1 output circuits. Again, have you checked whether the output of the XL1 direct into a monitor (not thorugh your mixer) with unbalanced high imputs is good or bad

September 19th, 2002, 04:36 PM	#9
Jeremy Evans Posts: n/a	Yes, I did check straight to a monitor and it is still overmodulated. I can switch to unbalanced audio input when connecting straight to my NLE which, I believe, negates the 600 ohms problem, but that does not seem to matter. Thanks, Jeremy