Overmodulation above -6 db

[ThroughAGlass]

I recently upgraded to Pro Tools 10. I noticed that anytime I bring the level of anything above -6 it distorts. Any ideas why? Is this normal for pro tools? I know other DAWs don't distort until 0, so I can't imagine this would not be the case for pro tools. What am I doing wrong?

Thanks a bunch

[sw rec]

Are you sending a +4 signal into a -10 input maybe?

[albee1952]

Nowhere near enough info

[jeam25]

Hi

Just guessing ...Maybe your preamp or converter is clipping before going to your audio card ..But like i said just gessing ...because i dont know all the hardware youre using and the configuration ...

Maybe more info could help !

[Craig F]

Not enough information but I will speculate that your system needs to be calibrated

[Bill Denton]

Is the term Overmodulation ever used in just an audio context? If so, what does it mean?

I'm familiar with Overmodulation from my AM radio days...in smaller markets we were not only DJs, we were also "transmitter operators", which meant we could get popped pretty hard by the FCC for something like "willful persistent overmodulation", but I've just never heard it used outside of a broadcast context...

[jeam25]

Originally Posted by Bill Denton

Is the term Overmodulation ever used in just an audio context? If so, what does it mean?

I'm familiar with Overmodulation from my AM radio days...in smaller markets we were not only DJs, we were also "transmitter operators", which meant we could get popped pretty hard by the FCC for something like "willful persistent overmodulation", but I've just never heard it used outside of a broadcast context...

Hi

Tought this is a not "standard" description for a distorted signal it is a right definition .

http://en.m.wikipedia.org/wiki/Overmodulation

The OP is right .

[Bill Denton]

Originally Posted by jeam25

Hi

Tought this is a not "standard" description for a distorted signal it is a right definition .

http://en.m.wikipedia.org/wiki/Overmodulation

The OP is right .

The OP is right

Well...not quite...

"... and distortion of the recovered modulating signal."

recovered modulating signal is the key phrase...

"recovered" is referring to the reception of the received signal, i.e. picking it up with a radio.

The audio signal itself is not distorted on the sending end. There is not any audio distortion at any point.

So, the OP was not quite right with his description.

The article mentioned "spurious emissions"...that is the cause of the distortion heard on the receiving end of the transmission. Basically, the broadcast signal gets "wrapped" in these "spurious emissions" which cause interference that results in distortion being heard, although the audio portion itself is not distorted.

And by the way...back in the day you could not call yourself a DJ unless someone had accused your entire radio show of being "spurious emissions"...

[jeam25]

Hi Bill youre right,

I agree that in the article in a knowledge sense it is intended to be interpreted as a radio signal .

But in practice ; on this camp ( audio recording ), there are : transducers ( guitar ) , there are mediums ( mics ) and there receptors ( ears ) .
So this principle applies on recording too my friend .

The last phrase says :

"Although overmodulation ( distortion ) is sometimes considered permissible, it should not occur in practice; a distorted waveform envelope ( audio wave ) will result in a distorted output signal of the receiving medium ( mic , converter or ears , depends on how do you see it )" .

So here another article from " TriggerTone " :

Over Modulation
From Chace Audio

Over Modulation occurs when a signal, (be it from an acoustic source, such as sound recorded into a microphone, or an electronic signal passing through a console), is too loud for its intended target to handle. When this happens, the microphone or recording electronics' acceptable operating levels are exceeded, and the result is distortion.

Tags:
ANOMALY, RESTORATION

Related Terms: CLASH, CLIPPING, DISTORTION, HOT, INTERMODULATION DISTORTION, PEAK DISTORTION



http://www.triggertone.com/term/Over_Modulation


So if your point is that the OP not right on the correct interpretation you're maybe right as long youre are seeing it as a radio station view point . But we are not here radio stations or something like that ... so I know everyone here including you known very well what the OP means when he said " overmodulation " that is that distorted signal .

So I think is right ! And pleassure to talk !


p.d. " sorry for my english "

[Bill Denton]

Originally Posted by jeam25

Hi Bill youre right,

I agree that in the article in a knowledge sense it is intended to be interpreted as a radio signal .

But in practice ; on this camp ( audio recording ), there are : transducers ( guitar ) , there are mediums ( mics ) and there receptors ( ears ) .
So this principle applies on recording too my friend .

The last phrase says :

"Although overmodulation ( distortion ) is sometimes considered permissible, it should not occur in practice; a distorted waveform envelope ( audio wave ) will result in a distorted output signal of the receiving medium ( mic , converter or ears , depends on how do you see it )" .

On this one I'll have to stick to my guns...You, my friend, are thinking like an audio engineer... Where you inserted "( audio wave )" in "... a distorted waveform envelope ( audio wave ) will result in ..." was incorrect...in AM broadcast you have essentially two waveforms...one, the carrier waveform (540–1610 kHz in the US)...second, the modulation waveform (audio between roughly 50 Hz to 7.5) hence their use of "waveform envelope", as the term refers to a wrapper for multiple waveforms...think of it in terms of a really long "Slinky" toy, which you have used to form a sine wave. The "Slinky sine wave" would represent the carrier frequency, while the actual "body" of the "Slinky" (the continuous circle part) would represent the modulating frequency...

So here another article from " TriggerTone " :

Over Modulation
From Chace Audio

Over Modulation occurs when a signal, (be it from an acoustic source, such as sound recorded into a microphone, or an electronic signal passing through a console), is too loud for its intended target to handle. When this happens, the microphone or recording electronics' acceptable operating levels are exceeded, and the result is distortion.

Tags:
ANOMALY, RESTORATION

Related Terms: CLASH, CLIPPING, DISTORTION, HOT, INTERMODULATION DISTORTION, PEAK DISTORTION



http://www.triggertone.com/term/Over_Modulation

On this one, the website wouldn't work for me (and I always try to look at "source" documents...even media I usually agree with will sometimes try to "fudge" things a bit.), so I'm not going to state an opinion on it...

So if your point is that the OP not right on the correct interpretation you're maybe right as long youre are seeing it as a radio station view point . But we are not here radio stations or something like that ... so I know everyone here including you known very well what the OP means when he said " overmodulation " that is that distorted signal .

So I think is right ! And pleassure to talk !


p.d. " sorry for my english "

Now where did p.d. come from? I've seen "p.s." for "post script", or literally "written after", but I've never seen p.d., does that abbreviation mean something in your native tongue?

"Modulate" means "change" which is why the term was originally adopted in broadcast: The modulating (audio) signal changes the carrier signal.

Which is in line with my original question as to usage of the term as it was being used by the OP. While I could see someone using, "Over Modulation occurs when a signal, (be it from an acoustic source ..." for a quick-and-dirty layman's explanation of distortion, he's wrong on two counts, not only is he misusing the word modulate, what he's actually describing is overloading an input stage.

But hey...it's Friday night...Does any of this really matter anyway? I've got my little miniature-dachshund-I-share-custody-of-with-my-ex-wife here to keep me company, along with two boxes of Girl Scouts "Thin Mints"...and that's a Friday night? God, I'm getting old...