Why did Amplify improve & clean my audio?

Hello everybody… first post.

I am using a Logitech C920 HD camera - it works great on XP but the software installs badly on 7 & 8.
When I speak, there is additional noise.

It is just bearable, but I figured I should learn more about ‘audio’ so turned to Audacity :slight_smile:
The video was downloaded as an MP3 using youtubedownloader(.com) and opened in Audacity.

The first thing I tried was effects - amplify (accepting the default).
This cleaned up most of the noise (wonderful).

Is this a designed feature, or should I be using a different effect, more specific to noise removal?

I’ve had a chance to spend more time with Audacity.
What a first class program!

Comparing the before and after amplification…
… the former showed waves that were barely smudges on the time line.

Perhaps the playback software contains some crude amplification that accentuates the noise?

I also ran it through ‘click remove’, ‘noise reduction’, and ‘leveller’.
I then used VSDC to re-embed the track into the video.
The end result being perfectly acceptable, and almost as good as if it was recorded with a correctly functioning microphone.
I’m just so impressed. :stuck_out_tongue:

It is certainly quicker than trying to get Logitech to produce good drivers for modern PC’s, and definitely more effective :smiley:
The C920 HD is a marvellous camera, when used on XP, but so far the software has failed to install correctly on both a win 7 box and a win 8 box.
On the win 7 box it simply failed to load (I copied in the XP files to get it to work(ish) .
On the win 8 box I repeat installed it 3 times… each time it got a bit further… perhaps I should have gone for a 4th install :unamused:


Glad you got it to work. Amplify has no noise reduction abilities. However, if your playback system is ratty, just making a wobbly show louder will seem to improve things.


That shouldn’t happen… Amplify just amplifies… But hey… If it’s improving the sound that’s a good thing.

The only thing I can imagine is if you have a noisy soundcard… When the signal is weak, you have a poor signal-to-noise ratio and the noise is more noticeable. And, if you turn-up the playback volume you are also turning-up the noise. If you can boost the signal before mixing with the noise, you’ll improve the signal-to-noise ratio. But I DON’T think that’s what you are describing.

…or should I be using a different effect, more specific to noise removal?

You can try [u]Noise Reduction[/u]. If the noise is bad, or not constant, the cure can be worse than the disease, but it’s always worth a try.

I am using a Logitech C920 HD camera - it works great on XP but the software installs badly on 7 & 8.
When I speak, there is additional noise.

Are you saying you only get noise with Windows 7 & 8, or is that a different problem?

Cameras usually don’t have great built-in microphones or audio electronics. Room noise and distance between the microphone & source are also common problems. For good audio, you usually need a separate microphone close to the source, a good quality studio or stage style microphone, a good audio interface, and a good quiet “studio”.

The audio/video was downloaded as an MP3 using youtubedownloader(.com) and opened in Audacity.

If it’s video from your camera, why are you downloading it from YouTube? You’ve probably got multiple generations of lossy compression/conversion, and although that may not be the main problem it’s likely contributing to your quality problems.

MP3 is a one-pass delivery medium. Do your production and editing in high quality, uncompressed formats and make the MP3 just before you post it on-line or submit for publication or deliver to an end-product client. There is no “open an MP3 and do production.” The instant you do that, multiple MP3 compression problems and damages kill you.

There is a poster who does a music show from downloaded internet works, submits the show to a radio station as MP3 and then the station makes another MP3 for its on-line presence. The third pass is honky, unlistenable trash.


Hey guys… thanks for all the replies and interest.
I’ve raised this topic, so I’ll do the best I can to provide the info required to understand what is happening.
To this end, I’ve uploaded 4 files to google drive regarding two audio files (before & after for each).
One pair is a successful implementation of Audacity filters/effects the other is a partial success (why… I don’t know.
You can use your ears, and if downloaded your eyes, to figure the problem and any potential solution.

The first thing to say is: that on the initial modded file… the results were as stated - original awful; modded ‘highly acceptable’.

re: kozikowski : making it louder - you may be right, but my ears told me different because the ‘noise’ actually reduced… judge for yourself below.

re: DVDdoug : soundcards - understood, but it was just crap, and then after Amplify, it was better… on the same sys.
re NR - the main gain was with amplify - the other mods were specific to areas (and good), but the primary problem was ‘within the actual voice (speaking) audio’ so, hard to isolate - examples below.
re win 7/8: noise & shite vis a vis camera mic’s: This kit is very good on XP (impressive and no sound probs) - I’m not a noob with PC’s… been working with them since IBM DOS… I complained bitterly to Logitech over a year ago re shite win 7 install fail - they produced another (not tested on win 7 yet) but win 8 install was bizarrely as described… literally: each install got better(???) but it was still crap - written in stone - examples below.
re: downloading from youtube, something I produced… very fair point; and it played on my mind… the knowledge of disappearing in a fog of noise… however, I ask forgiveness:

The sob story: The audio describes methodology relating to a win 7> prog… so I couldn’t conduct it on my XP box (it was ‘show & talk’).
My win 7 box is underpowered and anyway has XP camera code (not great) so I turned to my win 8 box, and you know the story there.

It was 3.00 am when the vid was done, so I uploaded it to youtube with youtube merge edits ie. it was a finished video lacking only a couple of text panels(introduction, and thanks for watching etc).
The problem this morning was the audio, and how to fix it… should I start again, editing with VSDC, or sort the audio problem… I went with the latter, and downloaded the combined video and audio track.

I have the original clips, so it doesn’t matter (I can rebuild the vid from original source)… the key is to fix the audio.
So yes, I accept the ‘copy noise’ problem, but honestly, this is not the issue (and neither is the sound studio, because I’m comparing this to very many XP produced vids).
But I accept all your points are otherwise valid. :slight_smile:

re kozikowski 2nd post - I accept the good advice, but we are dealing with something far worse.

The upload / download lossy issues were imperceptible.
The overriding issues are the gains from amplification, and the failure to make similar gains with the 2nd video (though improvement was seen).

Here are the files:

I have re-done both originals with purely ‘amplify’ and cut a short section.
You will hear the terrible audio in the originals… and the genuine improvement after amplification.
What do you think?


Okay… the plot thickens :astonished:
I decided to start afresh (with my new found knowledge) :slight_smile:

I pulled the original MP4 files recorded on the win 8 box.
For some strange reason I decided to view the video on google chrome… and the sound was fine!!!
I loaded it in windows media player and it was awful.

I extracted the mp3 soundtrack… it too played perfectly fine in chrome.
Again awful in media player.
Quicktime: awful
Spotify: awful
Firefox: awful
Audacity: awful

So chrome is the only prog that plays the sound track perfectly.
Of course that doesn’t help, because youtube played it badly also.

Anyway… I’m going to process the original file again with Audacity.
But it is interesting that chrome plays the sound perfectly.

Has anybody else experienced this?

The videos have now been recreated from the original files, by cleaning up the audio tracks.
The playback is perfectly acceptable.

After being assembled in VSDC and exported to MP4 - they will no longer play in chrome.
However, they play fine in media-player, and youtube.

So Audacity has saved the day.


If the file properties are anything to do with the variability of playback in Chrome and other apps you can obtain “MediaInfo” from http://mediainfo.sourceforge.net/en/Download/Windows to examine the files.

Get the version without installer, because the installer may have malware or adware.