GL2 Automatic gain distortion at DVinfo.net

Jim McNally · September 5th, 2002, 10:42 PM

I shot a band in a club the other night and only needed the audio for a scratch track. I set the audio on auto so that I wouldn't have to worry about the levels. What I found however is the AGC was overpowered by loud music when I was in close proximity to the speakers. I picked up a lot of distortion when I was right in front, as I moved to the side the AGC worked as I expected and the audio was fine.

I also shot some footage at the same time with my Betacam and the auto audio was fine without any distortion.

Has anyone else experienced trouble with the AGC circuit?

Jim

Don Donatello · September 5th, 2002, 11:15 PM

i don't think the AGC on the GL was designed for recording in a club with live band and i know the onboard mic cannot handle loud level audio (db's) .. the beta has a better AGC circuit and more then that it probably had a better mic on it ...

i have had a little distortion ( GL1) also in a club but i have found it to be the onboard mic more the the AGC... the music in front of stage could hit 120-130db ? which only really good pro mic's could stand the high db level ...

IMO i would put the blame on the onboard mic 1st ....

Don Palomaki · September 6th, 2002, 06:29 AM

A couple throughts, in loud venues you should be using the MIC ATT setting to avoid clipping at the input preamps. This may help in many cases. Check the results to see if this is sufficient. I've found it to be sufficient for work near a marching band drum line.

However, sound levels above around 120 dB or so are likley to tax the mic and get into high distortion modes regardless of the AGC settings. As ntoed in theother post, in these cases an external mic designed for very high sound levels, a preamp, and appropriat attenuators between the mic and the GL1 are appropriate.

Jeff Donald · September 6th, 2002, 07:00 AM

Betacam is analog. Analog audio is much different than digital audio. Analog still distorts at high signal levels, but it enters a grey area where the listner doesn't find the distortion noticable or objectionable, yet. When digital clips (distorts), it clips hard. No grey area. The listner immediatly notices the distortion. Analog circuitry and tape can handle a certain distortion or saturation better than digital. This type of behavior is one of digitals few draw backs.

Jeff

September 5th, 2002, 10:42 PM	#1
Jim McNally New Boot Join Date: Aug 2002 Location: Lethbridge, Alberta Posts: 15	GL2 Automatic gain distortion I shot a band in a club the other night and only needed the audio for a scratch track. I set the audio on auto so that I wouldn't have to worry about the levels. What I found however is the AGC was overpowered by loud music when I was in close proximity to the speakers. I picked up a lot of distortion when I was right in front, as I moved to the side the AGC worked as I expected and the audio was fine. I also shot some footage at the same time with my Betacam and the auto audio was fine without any distortion. Has anyone else experienced trouble with the AGC circuit? Jim

September 5th, 2002, 11:15 PM	#2
Don Donatello Hawaiian Shirt Mogul Join Date: Nov 2001 Location: northern cailfornia Posts: 1,261	i don't think the AGC on the GL was designed for recording in a club with live band and i know the onboard mic cannot handle loud level audio (db's) .. the beta has a better AGC circuit and more then that it probably had a better mic on it ... i have had a little distortion ( GL1) also in a club but i have found it to be the onboard mic more the the AGC... the music in front of stage could hit 120-130db ? which only really good pro mic's could stand the high db level ... IMO i would put the blame on the onboard mic 1st ....

September 6th, 2002, 06:29 AM	#3
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	A couple throughts, in loud venues you should be using the MIC ATT setting to avoid clipping at the input preamps. This may help in many cases. Check the results to see if this is sufficient. I've found it to be sufficient for work near a marching band drum line. However, sound levels above around 120 dB or so are likley to tax the mic and get into high distortion modes regardless of the AGC settings. As ntoed in theother post, in these cases an external mic designed for very high sound levels, a preamp, and appropriat attenuators between the mic and the GL1 are appropriate.

September 6th, 2002, 07:00 AM	#4
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Betacam is analog. Analog audio is much different than digital audio. Analog still distorts at high signal levels, but it enters a grey area where the listner doesn't find the distortion noticable or objectionable, yet. When digital clips (distorts), it clips hard. No grey area. The listner immediatly notices the distortion. Analog circuitry and tape can handle a certain distortion or saturation better than digital. This type of behavior is one of digitals few draw backs. Jeff