Hello to all & Questions.

GoldWave general discussions and community help
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Togglehead
Posts: 98
Joined: Mon Apr 10, 2006 1:37 pm
Location: Jersey

Hello to all & Questions.

Post by Togglehead »

First of all, let me just say thank you for goldwave. Best barebones audio editing ability ever, and all the nice "creature comforts" of an expensive program.....i use this everyday.

I do have a few questions though.....ver 5.10

Let me state that i work for a teleconference company, and i am primary engineer for all audio media. As you know, there arent many variables with phone audio quality....it just plain sucks, no matter how you look at it. Therefore, most of my job is cleaning and polishing up tracks, along with major cut n paste editing.

1. One question i have is volume leveling. Say during a one hour presentation, three different speakers discussed a topic....and one persons volume was too low.....how can i bring that one volume up globally, to mach everyone else's.....and vice versa?

2. I work with u-law mono files constantly as some of our system records in .vox files. There are three types of u-law files. What do each of the three mean? I recieved a file that was sampled with u-law mono, 8000Hz, 64kbps......i needed it sampled to u-law mono. Can i convert this?

3. NOISE REDUCTIONS. Static is my worst enemy. Can some explain to me how noise reduction works?
EDIT: Mainly i mean any telephone tips....

Thanks so much in advance.....and please know, that your dual button selection method has kept me a believer since the beginning!
Blandine Catastrophe
Posts: 253
Joined: Sun Jul 24, 2005 3:25 pm

Post by Blandine Catastrophe »

1) Volume levelling : The GW voice fx plug-in can equalize the volume all along a file or a selesction. Another possibility is the compressor-limiter, but it doesn't work as well on this situation.

3) Statics can be reduced with the function pops/clicks, then the smoother, and the hiss can be reduced by copying in the clipboard a section of noise without any signal, and by using the noise reduction button. In this case click the case "clipboard" in the dialog box, and adjust the settings in order to get the sound you want. If you have difficulties with artifacts like Science-Fiction-like noises, the best is to filter less and if needed do it in several passes if you really have still too much hiss noise.
Gloup? :-°
Togglehead
Posts: 98
Joined: Mon Apr 10, 2006 1:37 pm
Location: Jersey

Post by Togglehead »

great advice thanks........anyone got anything on the file types?
DougDbug
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Location: Silicon Valley

Post by DougDbug »

...was sampled with u-law mono, 8000Hz, 64kbps......i needed it sampled to u-law mono.
If you can open it with GoldWave, you should be able to save-as a "regular" u-Law file. (Whatever that is!) :?

GoldWave does have 3 options under the Sun (*.au) format:
Java/Web U-Law 8000Hz 64kbps Mono
u-Law Mono
u-Law Stereo

If not, you can find U-Law conversion programs on the Net.

I've never used the U-Law format.... And, I don't know much about it, except that it's a logarithmic technique. I sort-of assume there are "infinite" variations of sample-rate, bit-depth, etc.... So, I don't know what the 3 "standard" formats are.

When I was looking around the Net to see what I could find, I noticed that a sample rate of 22kHz seems to be common. 8000Hz @ 64kbps works-out to 8 bits. 8,000 x 8 = 64,000). I would have guessed that 8000Hz 64kbps would be about right for telephone quality...

NOISE REDUCTION -
Most noise-reduction works by taking a sample of the noise-only. You then make an FFT analysis to find out the noise level in various frequency bands.

When there is nothing but noise in a particular frequency-band, that frequency-band is filtered-out.

When the level in a particular frequency-band exceeds the threshold, it's assumed not to be noise. The sound is allowed to pass-through, along with the noise. If you have a strong signal, the signal masks the noise. If the signal is slightly above the noise, you'll get distortion and artifacts.

A noisegate is similar, but it is more like a mute-button. When the sound-level is above the threshold, it has no effect. When the level is below the threshold, it shuts-off all sound. When the noise is bad, I usually prefer a noisegate.... fewer artifacts & side-effects.

You will NOT be able to completely eliminate your "telephone static" noise. Noise reduction can make a good recording into an excellent recording, but with a bad recording, the cure can be worse than the disease. :( There is a good reason recording studios are soundproof!
GoldWave Inc.
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Post by GoldWave Inc. »

The "u-Law, mono, 8000Hz, 64kbps" attributes are the ones you'll need to use. Those create a "u-Law, mono" file with a sampling rate of 8000Hz. In the rare cases when you need to use a custom sampling rate, you can use the Resample effect and save with just "u-Law, mono" attributes.

Chris
donrandall
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Joined: Wed Dec 01, 2004 11:06 pm
Location: Denver, Colorado

Post by donrandall »

Togglehead -

Here are some things you may want to try.

1) Find a section where the noise exists with no other noise. No conversation, no background noise. Just the noise to be filtered.

2) Mark the beginning and end points of that noise sample and click "Save".

3) Open the Noise Filter. Select "Clipboard". The default setting is 100%. Click "OK" and see what you get. If you don't like the result, click "Undo". Try changing the setting to something higher or lower than the 100% default setting - you will find it labeled as "Scale (%)". A little experimenting can help you find what works best.

4) You may benefit from a little downward expansion. To try this, open the Compressor/Expander. Select "Expander". Select "Anticipate". Select "Smoother". Set the "Multiplier" at -6.0. Set the "Threshold" at -45.0. Set the "Attack" at .020. Set the "Release" at .020.

These are suggested settings, and you may find that you are filtering too aggressively, and you can always back off. If that is necessary, I would suggest leaving the threshold as is for the moment and try reducing the multiplier setting to -4 and see if that is appropriate. Again, a little experimenting will probably be necessary.

I hope these suggestions help!
Togglehead
Posts: 98
Joined: Mon Apr 10, 2006 1:37 pm
Location: Jersey

Post by Togglehead »

hey guys thanks so much for your replies....!!!

I get the noise reduction, i get the sound sampling and expender stuff.....ive tried some of this, and since the issues vary so much, many suggestions here have helped....=]

the question that still remains is about the u-law files.

just to clarify....we use u-law mono files. Youre right, they do default to 8,000/64kbps. However when we recived a file from a client, sampled this way, it was all digital static and a big color on the bottom half of the center line.....looks like it was sampled with a different codec.....
the response looked similar to opening a wav file in the GSM 7.11 codec....just get unusable data....

Was wondering how to correct that....or if it can be
GoldWave Inc.
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Post by GoldWave Inc. »

If you select u-Law attributes and you get static, then the files are not u-Law encoded. Have you tried other attributes, such as A-Law or ADPCM 4-bit? Contact your client to make sure the audio is in the correct format.

Chris
Togglehead
Posts: 98
Joined: Mon Apr 10, 2006 1:37 pm
Location: Jersey

Post by Togglehead »

yeah they confirmed it was correct....

strange....this may be a P.E.B.K.A.C issue on their end....in this case, i can say im doing nothing wrong...lol

thanks again for your help chris
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