help me improve/increase volume of WAV file (attached) in Audacity

Posted on 2012-12-27
Last Modified: 2013-02-20
Dear Experts,

I have 8 hours of lectures from 1980s that I would like to digitize.
Please recommend me what kind of filters I should apply to make them sound better.

I did some learning of Audacity and I think I should:
1) remove noise - "Noise removal"
2) compress - "Compress dynamics 1.2.6" (external plugin) or "Compressor"
3) in the end, "Normalize"

I don't want to spend too much time learning Audacity since I will not use it regularly, that's why I chose the easier way - ask the Experts.

Please verify these steps, add extra steps, provide best parameters for filters etc.

I'm attaching one minute clip from training I'm digitizing so that you can recommend filter parameters etc.
sample WAV file

Many thanks for your help!

Question by:ja-rek
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Assisted Solution

by:David Carr
David Carr earned 50 total points
ID: 38724148
Normalize should increase the volume for you but if you need more than that, you can use "Amplify" Effect in Audacity after applying the first two filters you mentioned and do not use Normailize. If you want the entire clip, Choose the level of amplification or volume increase that you want. You can click "Preview" to hear a sample of the amplify effect. Click "OK" to apply the effect and increase the volume.

Pay attention to the peaks in the waveform. Please note that increasing volume with Normalize or Amplify could cause distortion for some of the peaks that are already high.
LVL 70

Assisted Solution

Merete earned 100 total points
ID: 38726359
Hello again Jarek
 I believe Audacity is too hard but here goes,
the things is your working wav ok it's not the same as mp3.
In Audacity drop your wav on,
 run the analyze, click on contrast
then press ctrl shift with T
I tested this using a wav and it fails
WCAG 2.0 Audio Audio Contrast Tool Help
WCAG 2.0, Success Criteria 1.4.7 is a guideline for accessible audio files on the internet. The goal is to help people who are hard of hearing understand the speech (foreground). This is done by making sure that any background music or noise is very quiet. Background music (or sound) should be at least 20dB lower than the foreground speech

Too hard anyway
if you don't need to fix them but just be able to play them better and take them with you,
stick them onto a USB stick download a portable version of VLC

With VLC you can increase the volume to 200% and then at the top go to TOOLS>Effects and Filters here you have a equalizer that you can adjust the sound quality
VLC volume increase and tool effects equalizer
LVL 70

Assisted Solution

Merete earned 100 total points
ID: 38726361
Sorry I missed your sample will test it for you. thanks for that
I'll get back to you with my results and how I did it.
Well it plays fine in VLC when I increase the volume to 200 % not too hissy.
In Audacity drop your wav on then with your mouse click the end and drag it to the start so it's highlighted, then go the top Effects and click on Noise Removal>
Noise removal also see amplify at the topthen click on Get Noise Profile ok
Noise profilethen click on Amplify and preview
Amplify and PreviewIf it sounds better and louder enough  or increase it
then preview again go to file and Export selection click ok on the first part then give it a name and save as mp3 or whatever
LVL 70

Expert Comment

ID: 38726536
Here's two samples I made for you using Audacity but I played it in VLC increased the volume in VLC  and set the Filters and effects to live and another where I reduced the treble and high notes
There is so many settings that can be changed during the playback in VLC with that little effects and filters sitting on the side.
Running Audacity in the background then recorded it in Audacity using the stereo mix ( what you hear in the speakers.
When you play them back which ever media player you use you have still some control over the treble side and bass side.
recording the piece sample in Audacitysample one with increased volume less treble
sample two using the live setting in filters VLC
LVL 38

Expert Comment

ID: 38729203

For what my opinion is worth, I think you have done a very good job recording from cassette tape to WAV.  I don't know if you used one of those commercially available cassette players with a USB interface, or whether you plugged the external output or headphone jack of a standard cassette player into the input of your PC audio card, but if it were me I would actually be pretty pleased with the results if I could capture the rest of the content just the way you have in the sample.

Noise removal is usually fairly hit and miss and it's very easy to accidentally remove some of the main audio content, especially in a very lengthy piece of audio that's far to long to "preview" the results without listening to the entire thing again and again.   The good thing is that you have a man with a fairly consistent and monotone voice and a nice length of silence with hiss after the "please turn tape" prompt that can be used to get the noise profile namually or automatically.

I'm about to install Audacity again, as I haven't had it on this particular PC, and will look and listen later.
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LVL 38

Assisted Solution

BillDL earned 50 total points
ID: 38729265
OK, All I would suggest is that you remove noise for now.  Leave Audacity settings at default.

Load the file into audacity and select the longest bit of "silence" available.
Effect menu > Noise Removal > "Get Noise Profile".
Select all unwanted audio including "silence" at end and hit delete.
Click purple bit to left of waveform to select all of audio wave form.
Effect menu > Noise Removal > Noise: Remove > Click OK.
File menu > Export > (no options for WAV) > Choose new file name > Save.
File menu > Export > MP3 > Options > Constant bit rate, 256 kbps, Joint Stereo or Stereo > Choose new file name > Save.

You should find that the hiss is pretty much gone and possibly the voice is ever so slightly richer and deeper.

MP3 will be less than half the file size of the saved WAV file, and in my opinion with no discernible loss in quality.  You could probably export it as 128 or 192 kbps and still have perfectly acceptable quality without hiss.  I believe that is all you need.
LVL 70

Expert Comment

ID: 38735975
ja-rek we are all dying to know if we helped you.
Happy New Year

Accepted Solution

ja-rek earned 0 total points
ID: 38892882
the best piece of advice (resulting in best quality recording - IMHO) I have found here:

I used Chris Dynamic Compressor plugin for Audacity.

Author Closing Comment

ID: 38908663
thanks for help!
I obtained IMHO best results with Chris compressoer
LVL 38

Expert Comment

ID: 38908787
Thank you ja-rek

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