[audacity4blind] Re: Using Amplify in the Effects Menu

  • From: David Bailes <david_bailes@xxxxxxxxxxx>
  • To: "audacity4blind@xxxxxxxxxxxxx" <audacity4blind@xxxxxxxxxxxxx>
  • Date: Wed, 17 Apr 2013 19:37:27 +0100 (BST)

Hi Rich,
the idea is to set up the input volume so that peaks in the recording are a 
safe distance from the maximum level. If you set up the input volume so that 
the peaks were exactly at the maximum level, then when you made the actual 
recording, peaks might be a little louder and be clipped leading to distortion.
So, say you want to peaks in the test recording to be about 6db less than the 
maximum level. If you open the amplify dialog, then the amplification value 
tells you how much the recording needs to be amplified so that peaks are at the 
maximum level. So you want this value to be about 6 db.
In your case, you've got a value of 0 db. This means that the peaks are at the 
maximum level, so they may be clipped.
So to make sure you don't getting clipping during the actual recording, it 
would be best to reduce the input volume a bit, and try another test recording, 
with the aim of getting the value of the amplification edit box in the amplify 
effect to be in the region of 6.
Does this make any more sense?
 
David.


----- Original Message -----
From: Rich De Steno <ironrock@xxxxxxxxxxx>
To: audacity4blind@xxxxxxxxxxxxx
Cc: 
Sent: Wednesday, 17 April 2013, 19:05
Subject: [audacity4blind] Re: Using Amplify in the Effects Menu

I still do not get this.  Here is an example.  I made a test recording.  
I went into Amplification in the Effects Menu.  It provided the 
following information:
Amplification DB 0.0
amplification DB slider 50
New Peak Amplitude DB 0
Because 0.0 appeared in the first box, I inferred that no change was 
required.  Where does this 6 DB come in?  If I change the first box to 6 
DB, the OK option disappears, I infer  that is because Allow Clipping is 
unchecked.  Please explain.

Allow Clipping checkbox unchecked

Rich De Steno

On 4/17/2013 12:28 PM, David Bailes wrote:
> Hi Gale,
> I don't think there's a typo in that section of the Jaws guide.
> My suggestion is to adjust the input volume so that if you do a short test 
> recording, select the audio,
> and open the Amplify effect dialog, then the value in the amplification edit 
> box is about 6 db, so indicating that the max amplitude in the recording is 
> about -6 db.
>  
> David.
>
>
> ----- Original Message -----
> From: Gale Andrews <gale@xxxxxxxxxxxxxxxx>
> To: audacity4blind@xxxxxxxxxxxxx
> Cc:
> Sent: Tuesday, 16 April 2013, 22:20
> Subject: [audacity4blind] Re: Using Amplify in the Effects Menu
>
>
> | From Rich De Steno <ironrock@xxxxxxxxxxx>
> | Tue, 16 Apr 2013 08:52:30 -0400
> | Subject: [audacity4blind] Using Amplify in the Effects Menu
>> I was under the impression that if you go into the amplify option under
>> the effects menu with a sound file loaded into Audacity, the first
>> item that comes up indicates how much change in volume is needed for
>> optimal sound.
> The first item "Amplification (dB)" indicates the amplification
> change required (if any) to make the peak volume 0 dB (as
> loud as it can be without clipping).
>
> A peak level of 0 dB doesn't necessarily mean "optimal sound".
> 0 dB could sound "too loud" in a heavily compressed pop song.
>
>
>> Thus, I thought that if it stated 0.0, then no change
>> was necessary.  However, the below excerpt from the Audacity
>> Jaws Users manual seems to indicate otherwise, apparently stating
>> that the number should be changed to 6.  So should that first number
>> be changed to 6 as this seems to state?
> Unfortunately there is a typo in that JAWS guide. It is probably
> trying to say that -6 dB (not 6 dB) is a good value to aim for in
> the "New Peak Amplitude (dB)" box (the second box).
>
> Certainly the official Audacity Manual suggests that you should
> set the input level so that you record at about -6 dB (for the
> reasons David states). However that advice is only relevant to
> setting the input level. Sighted users would gauge the input level
> "live" while recording was in progress by using Meter Toolbar.
>
> When you are deciding how much to amplify an existing audio file,
> aiming for a "New Peak Amplitude" of "-0.0 dB" (which happens if
> you just press ENTER after opening the effect) is much better
> advice than aiming for -6 dB.
>
> However many people these days prefer aiming for a "New Peak
> Amplitude" of  -1 dB. This is the default level to which Effect >
> Normalize amplifies. This gives a little leeway to speaker systems
> that may distort at the maximum 0 dB.
>
>
>
> Gale
>
>
>> (excerpt from manual)
>> If you select some audio, and then open the Amplify dialog on the Effects
>> menu, then the initial focus is on an Amplification edit box. The
>> initial value in this edit box is the amount of amplification in
>> decibels needed so that the recording uses the full dynamic range, and
>> it indicates if you need to change the value of the input volume.
>> Normally a good value to aim for if about 6db. This should ensure that
>> the recording level is both low enough so that distortion or clipping
>> doesn't occur, and high enough so that you don't get an unnecessary
>> amount of noise. So if the value's less than about 6, try lowering the
>> volume, and if it's more than about 6, try increasing the volume.
>
>
>
> The audacity4blind web site is at
> //www.freelists.org/webpage/audacity4blind
>
> Subscribe and unsubscribe information, message archives,
> Audacity keyboard commands, and more...
>
> To unsubscribe from audacity4blind, send an email to
> audacity4blind-request@xxxxxxxxxxxxx
> with subject line
> unsubscribe
>
> The audacity4blind web site is at
> //www.freelists.org/webpage/audacity4blind
>
> Subscribe and unsubscribe information, message archives,
> Audacity keyboard commands, and more...
>
> To unsubscribe from audacity4blind, send an email to
> audacity4blind-request@xxxxxxxxxxxxx
> with subject line
> unsubscribe
>
>


The audacity4blind web site is at
//www.freelists.org/webpage/audacity4blind

Subscribe and unsubscribe information, message archives,
Audacity keyboard commands, and more...

To unsubscribe from audacity4blind, send an email to
audacity4blind-request@xxxxxxxxxxxxx
with subject line
unsubscribe

The audacity4blind web site is at
//www.freelists.org/webpage/audacity4blind

Subscribe and unsubscribe information, message archives,
Audacity keyboard commands, and more...

To unsubscribe from audacity4blind, send an email to
audacity4blind-request@xxxxxxxxxxxxx
with subject line
unsubscribe

Other related posts: