Beeblebrox
Well-known member
Anyone know if the DVX has a built-in limiter? If so, can it be turned off?
Built-in limiter?
- Thread starter Beeblebrox
- Start date
Re: Built-in limiter?
Yes the DVX has a limiter, and yes it can be turned off using the menus. Generally, I'd recommend keeping the limiter turned on--it only kicks in when you get close to distortion levels. A limiter shouldn't be confused with an AGC (auto gain control) circuit which kicks up low voltage signals (raising your noise floor) and attenuates higher voltage input signals--a recipe for bad sound recording. Confusingly, AGC is sometimes referred to as ALC (auto level control). Equally confusing is the fact that Panasonic refers to the DVX100's limiter circuit as ALC. They should just call it a limiter, period.
Yes the DVX has a limiter, and yes it can be turned off using the menus. Generally, I'd recommend keeping the limiter turned on--it only kicks in when you get close to distortion levels. A limiter shouldn't be confused with an AGC (auto gain control) circuit which kicks up low voltage signals (raising your noise floor) and attenuates higher voltage input signals--a recipe for bad sound recording. Confusingly, AGC is sometimes referred to as ALC (auto level control). Equally confusing is the fact that Panasonic refers to the DVX100's limiter circuit as ALC. They should just call it a limiter, period.
Barry_Green
Moderator
Re: Built-in limiter?
Except that that post makes the whole situation a little confusing, because the DVX calls its limiter an ALC... which I believe they call an auto limiting circuit...
The volume pumping circuit is also frequently called AGC for automatic gain control.
In any case, the DVX has the good one, not the bad one.
Except that that post makes the whole situation a little confusing, because the DVX calls its limiter an ALC... which I believe they call an auto limiting circuit...
The volume pumping circuit is also frequently called AGC for automatic gain control.
In any case, the DVX has the good one, not the bad one.
Beeblebrox
Well-known member
Re: Built-in limiter?
Awesome. Thanks for all the info.
Awesome. Thanks for all the info.
Barry_Green
Moderator
Re: Built-in limiter?
Perfect as always! Your posts are some of the most valuable reading on this board. Sorry I horned in there, just wanted to make sure that when people read the menus and saw "ALC", they didn't panic...
Perfect as always! Your posts are some of the most valuable reading on this board. Sorry I horned in there, just wanted to make sure that when people read the menus and saw "ALC", they didn't panic...
Re: Built-in limiter?
Barry, your comments are always appreciated. I try to be thorough and clear, but don't always succeed. I never claim to be definitive--that's for sure
. I'm constantly learning from everyone's contributions and appreciate different perspectives and approaches to problems.
Barry, your comments are always appreciated. I try to be thorough and clear, but don't always succeed. I never claim to be definitive--that's for sure
. I'm constantly learning from everyone's contributions and appreciate different perspectives and approaches to problems. Barry_Green
Moderator
Re: Built-in limiter?
Hey Barry_S, between you and oleg, this audio forum is just chock-full of excellent info. You guys are required reading!
Hey Barry_S, between you and oleg, this audio forum is just chock-full of excellent info. You guys are required reading!
Terry_Lasater
All about the Caption
Re: Built-in limiter?
I concur!
I believe that answering these questions is helping Oleg with his English as well.
Either that or I'm just starting to understand him better. ;D
Regardless, Oleg and Barry_S's advice is greatly appreciated.
I concur!
I believe that answering these questions is helping Oleg with his English as well.
Either that or I'm just starting to understand him better. ;D
Regardless, Oleg and Barry_S's advice is greatly appreciated.
Re: Built-in limiter?
sorry about my englis ,thats to many days on the beech durring the schooldays 20 years ago . now its to late and my memory isnt so good (you can see 5 differt way i can do spelling mistake in one word during 3 sentences) and i admit that iam to lazy export the letters to autlook and fix the spelling
sencirlly yours
Oleg Kaizerman ( gebe-Good Ears Bad English)
sorry about my englis ,thats to many days on the beech durring the schooldays 20 years ago . now its to late and my memory isnt so good (you can see 5 differt way i can do spelling mistake in one word during 3 sentences) and i admit that iam to lazy export the letters to autlook and fix the spelling
sencirlly yours
Oleg Kaizerman ( gebe-Good Ears Bad English)
Barry_Green
Moderator
Re: Built-in limiter?
Hey Oleg, do not worry about it one bit! Your information is very valuable, and your english is completely understandable. We all very much appreciate your taking the effort to write it in English in the first place, too!
Hey Oleg, do not worry about it one bit! Your information is very valuable, and your english is completely understandable. We all very much appreciate your taking the effort to write it in English in the first place, too!
Terry_Lasater
All about the Caption
Re: Built-in limiter?
Thank you, Oleg!
Thank you, Oleg!
ullanta
Veteran
Re: Built-in limiter?
[quote author=oleg link=board=audio;num=1085627709;start=0#7 date=05/27/04 at 08:55:32]if i remember correctly the limmiter is in mike level posision only and it comes in -4.5 dbfs , it gang and effect bouth channels
[/quote]
I'm not sure... I've been planning some experiments to gain certainty, but in my experience the ALC seems to be operating on line-level signals as well. I'll let you know when I find out. Oleg, where did you find this information? Is it empirical?
Also, unless someone has an answer, there was another forum discussing the nature of the "ganging." Anyone know if it's watching one channel, or the peak on both? I'll check that out as well...
-Barry
[quote author=oleg link=board=audio;num=1085627709;start=0#7 date=05/27/04 at 08:55:32]if i remember correctly the limmiter is in mike level posision only and it comes in -4.5 dbfs , it gang and effect bouth channels
[/quote]
I'm not sure... I've been planning some experiments to gain certainty, but in my experience the ALC seems to be operating on line-level signals as well. I'll let you know when I find out. Oleg, where did you find this information? Is it empirical?
Also, unless someone has an answer, there was another forum discussing the nature of the "ganging." Anyone know if it's watching one channel, or the peak on both? I'll check that out as well...
-Barry
Barry_Green
Moderator
Re: Built-in limiter?
Testing would be welcome. I also remember reading that it sets the limit at -4.5db, and that it starts its limiting process at -6, so everything gets compressed in just 1.5db of headroom.
And I'm fairly certain that the limiter is ganged to both channels. We were feeding -20db tone from a mixer and trying to get the DVX to match the mixer's output, and had a devil of a time because adjusting one pot would cause the other channel's level to rise... until we turned off ALC, then everything worked as you'd expect.
Those are quick observations though, not controlled testing.
Testing would be welcome. I also remember reading that it sets the limit at -4.5db, and that it starts its limiting process at -6, so everything gets compressed in just 1.5db of headroom.
And I'm fairly certain that the limiter is ganged to both channels. We were feeding -20db tone from a mixer and trying to get the DVX to match the mixer's output, and had a devil of a time because adjusting one pot would cause the other channel's level to rise... until we turned off ALC, then everything worked as you'd expect.
Those are quick observations though, not controlled testing.
G
Guest
Guest
Re: Built-in limiter?
Does the limiter work only with the internal mic or does it extend to the XLR inputs?
Does the limiter work only with the internal mic or does it extend to the XLR inputs?
scottchapin
Well-known member
Re: Built-in limiter?
The last time I messed with this, I ran a test signal with my Neutrix Minirator through both channels. Oddly no matter how strong the signal, it would not break 4 red bars.
Obviously brief high level intrusions do in fact break the 4 bar level, but strong, steady signals do not. It's as though the compression ratio is variable and increases with signal strength to almost act as a brick wall limiter through which transient spikes get through.
The last time I messed with this, I ran a test signal with my Neutrix Minirator through both channels. Oddly no matter how strong the signal, it would not break 4 red bars.
Obviously brief high level intrusions do in fact break the 4 bar level, but strong, steady signals do not. It's as though the compression ratio is variable and increases with signal strength to almost act as a brick wall limiter through which transient spikes get through.
Barry_Green
Moderator
Re: Built-in limiter?
That's exactly how I understand it as well. If I remember correctly, the limiter starts at about -6db (3 dots down from max) and puts up a ceiling at -4.5db. Spikes may punch through, but overall loud noise gets clamped at -4.5.
That's exactly how I understand it as well. If I remember correctly, the limiter starts at about -6db (3 dots down from max) and puts up a ceiling at -4.5db. Spikes may punch through, but overall loud noise gets clamped at -4.5.