Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Amplitude Adjust really weak audio (Read 2815 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Amplitude Adjust really weak audio

I have several video captures with really weak audio.  I cannot redo the video as it was a wedding.
The problem then is how best to amplify the original to where it can be heard well.

I've discussed one aspect of this in another thread here, where AndyH-ha provided some help.
HERE

Now I want to take it the other way round.  Instead of asking how to fix it after I've introduced a lot of loud rumble, hiss and other noises resulting from just increasing amplitude until the voices are in good hearing range.

Is there a procedure I should follow in the first step of getting enough volume to hear it well?  So far I've used Audition's effect/amplitude/amplify to simply add some 16-20 db.  Of course this adds lots of unwanted sounds and I realize I will  never make it sound as if it were recorded at a reasonable input level.  But to get as close as I can, is there a better way using the tools I have to hand: Audition-2.0 SoundForge8-9,,

Or are there other software tools that were specifically designed for this kind of thing or have a better set of tools for it?

Amplitude Adjust really weak audio

Reply #1 –
The audio is all of a whole, regardless of its signal level. You are not introducing anything by amplifying, only making some of what is there more obvious. You can amplify only part of the frequency range, such as with the graphic equalizer or the parametric equalizer, or you can reduce unwanted parts of the spectrum with the same or other tools, where these results are advantageous. Generally, with unwanted noise, the approach is to remove what you don’t want.

Sometimes expansion, the opposite of compression, can make for more acoustic distance between low level noise and wanted signal, but I don’t think that is the solution very often.

However, if you are working in 16 bit, every transform you do increases the noise and distortion. For a little bit of work this may not be noticeable, but it is all cumulative. You will probably be better off to convert to 32 bit before doing anything else. Go back to 16 bit only after completing all work.

On this forum are some people who are more experienced at manipulating audio. Someone may take enough interest to provide greater insight, especially when you come up with specific questions.
http://www.audiomastersforum.net/
 

Amplitude Adjust really weak audio

Reply #2 –
Quote from: AndyH-ha on
On this forum are some people who are more experienced at manipulating audio. Someone may
take enough interest to provide greater insight, especially when you come up with specific questions.


Thanks once more for your input.  Reviewing and searching on that forum I happened onto one of your posts
You mention a `DC' offset.  Excuse my dense skull, but what are the initials for?

Also you mentioned examining things in `spectral' [in Audition]  view.. Where can I learn about how
to interpret the display in the various spectral views Audition has?  On that same forum? Or do you
think the regular Adobe Audition forum might be more appropriate?

The forum you sited looks to be very high level.

Amplitude Adjust really weak audio

Reply #3 –
DC offset means a variance in regard to direct current ground. All audio is essentially some combination of sine waves that cycle positive and negative, constantly. You see it in the waveform display, in the very center (of each channel). This is easiest if you are zoomed in close enough to see the single line of the waveform going up and down.

An offset exists if the waveform crossing that zero line (or - infinity line, depending on the right-hand scale you've selected) does not correspond to true electrical zero. It generally isn't good if there is very much offset; it really should be zero if you want some of the transforms to work best.

Normally, if an offset exists, it is because of a soundcard problem or a poor soundcard design. Running Analyze/Statistics will tell you what the offset is. There are a couple or three ways of correcting a recording that is thus ‘contaminated.'

Transform/Amplify has a checkbox for DC bias adjust (if necessary, of course). You probably just want to do ‘Absolute' rather than screw around to achieve some special effect. You can do it when you amplify. If you only want any DC adjust, make sure the amplification values are zero.

I think the concept of Spectral View is fairly simple, once you get familiar with it. Waveform View is amplitude variation over time, Spectral View is frequency variation over time. Colors are used to represent intensity, so it is essentially a 3-D display. It is very useful once you get comfortable with it.

I don't know what the default looks like in Audition 2. There is discussion of setting the display parameters in this recent thread
http://www.hydrogenaudio.org/forums/index....ic=56732&st

A fair number of the same people inhabit both forums. The audiomaster forum tends to attract and hold those with more experienced and more orientation to using the software towards "serious" ends. There are less frequent inquiries into ‘removing vocals' and similar topics that everyone except the true beginner has seen a hundred times.

Amplitude Adjust really weak audio

Reply #4 –
A DC offset can also be introduced by equipment prior to the soundcard in the signal chain.

But it shouldn't.