What the heck is the attenuator?

Don Palomaki · October 31st, 2009, 06:02 AM

You woke a long slumbering thread.

Where you want the average and peak levels depends in large part on what you are recording and you intended end use of the video..

For highest digital dynamic range you want the peaks to be as close to "0" as you can without clipping. This also provides the highest signal to noise potential. I say potential because it depends on factors both within and external to the camcorder. Occasionally exceeding "0" (clipping) might not be a bad thing, depending on the program material (e.g., clipping on a random door slam or hand clapping and coughing of the oaf sitting in front of you).

Similarly, where you want the average signal level depends on that signal. Around -12 is OK for most typical home video purposes, but may not be appropriate for serious acoustic music in a concert environment. Profession gear, which usually has a better sound system, often records average audio at more like -18, thanks to having a wider usable dynamic range (lower noise floor).

And for some, perhaps many things, such as speaking voices, AGC is fine, maybe even better than trying to ride manual gain while shooting.

I usually try keep the wanted portion of the audio peaks slightly below "0," do not worry about audio I intend to edit out anyway, and let the average levels fall where they may, which usually is around -12 or so. And I tend to use AGC for things that are not musical in nature (i.e., where it is not important to preserve the original dynamic range ).

Lee Sharp · October 31st, 2009, 10:42 AM

im talking for professional broadcast and TV where the peaks spcifically have to be no more than -10dbfs/8dbu, 0dbfs is the peak for dbfs in studio recording.

Don Palomaki · November 1st, 2009, 06:35 AM

If shooting video for a specific market/client, then do what they want you to do. The soudl will no doubt be subject to a lot of sweetening while being edited.

The golder rule applies; that is, the person supplying the gold makes the rules.

Marco Leavitt · November 10th, 2009, 04:15 PM

Yeah, what Don says. You generally want the hottest signal you can get without clipping.

On a side note ... sheesh, was that really me way back in 2002 wondering what an attenuator was? I hope none of my current clients see that ;)

Paul Bestwick · July 31st, 2011, 06:17 AM

Ok... I am a complete novice and struggling with the basics. I have a Canon XA10 with a Rode NTG 3 mic connected via XLR input (CH 1). The volume level was extremely low and I have turned attenuation off. The manual advises that the level indicator should be around -18 but that seems to low on playback. To get an acceptable level of voliume it seems I have to turn the input dial to Max..... Really confused here.

Graham Bernard · August 1st, 2011, 07:27 AM

Quote:

Originally Posted by Paul Bestwick

. . . . To get an acceptable level of voliume it seems I have to turn the input dial to Max..... Really confused here.

Do you use Headphones to check your mic/line IN?

Grazie

October 31st, 2009, 06:02 AM	#16
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	You woke a long slumbering thread. Where you want the average and peak levels depends in large part on what you are recording and you intended end use of the video.. For highest digital dynamic range you want the peaks to be as close to "0" as you can without clipping. This also provides the highest signal to noise potential. I say potential because it depends on factors both within and external to the camcorder. Occasionally exceeding "0" (clipping) might not be a bad thing, depending on the program material (e.g., clipping on a random door slam or hand clapping and coughing of the oaf sitting in front of you). Similarly, where you want the average signal level depends on that signal. Around -12 is OK for most typical home video purposes, but may not be appropriate for serious acoustic music in a concert environment. Profession gear, which usually has a better sound system, often records average audio at more like -18, thanks to having a wider usable dynamic range (lower noise floor). And for some, perhaps many things, such as speaking voices, AGC is fine, maybe even better than trying to ride manual gain while shooting. I usually try keep the wanted portion of the audio peaks slightly below "0," do not worry about audio I intend to edit out anyway, and let the average levels fall where they may, which usually is around -12 or so. And I tend to use AGC for things that are not musical in nature (i.e., where it is not important to preserve the original dynamic range ). __________________ dpalomaki@dspalomaki.com

November 1st, 2009, 06:35 AM	#18
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	If shooting video for a specific market/client, then do what they want you to do. The soudl will no doubt be subject to a lot of sweetening while being edited. The golder rule applies; that is, the person supplying the gold makes the rules. __________________ dpalomaki@dspalomaki.com

July 31st, 2011, 06:17 AM	#20
Paul Bestwick Tourist Join Date: Jun 2011 Location: Australia Posts: 1	Re: What the heck is the attenuator? Ok... I am a complete novice and struggling with the basics. I have a Canon XA10 with a Rode NTG 3 mic connected via XLR input (CH 1). The volume level was extremely low and I have turned attenuation off. The manual advises that the level indicator should be around -18 but that seems to low on playback. To get an acceptable level of voliume it seems I have to turn the input dial to Max..... Really confused here.

October 31st, 2009, 10:42 AM	#17
Lee Sharp Regular Crew Join Date: Aug 2009 Location: England Posts: 27	im talking for professional broadcast and TV where the peaks spcifically have to be no more than -10dbfs/8dbu, 0dbfs is the peak for dbfs in studio recording.

November 10th, 2009, 04:15 PM	#19
Marco Leavitt Inner Circle Join Date: Jul 2002 Location: Albany, NY 12210 Posts: 2,652	Yeah, what Don says. You generally want the hottest signal you can get without clipping. On a side note ... sheesh, was that really me way back in 2002 wondering what an attenuator was? I hope none of my current clients see that ;)