Noise Removal settings and useage

[patcurci]

I am "digitizing" my collection of old (45-55year old) vinyl LPs, so I can burn CDs of these albums for easier listening on a high quality sound system.

Attached is a "Noise Sample" recorded by Audacity, and exported, with out any effects applied, which I would call "line noise". It is present whenever I'm recording to the computer. The noise level seems constant whether the turntable is running or not. I'm using Windows Vista SP2, 64 bit; Audacity 1.3.12.

The turntable RCA plugs are connected to the "input" of a Behringer USB preamp, and the turntable ground is also connected to the ground stud on the preamp. The "line out" of the preamp is connected to the "line in" of the integrated sound card on the computer and recording volume is controlled by the Realtek software for the computer sound card. The noise sample was recorded with Audacity recording levels set at the recommended level of about -.6 db, or a shade more, for the "Recent Peak Level" (when I normally record my LPs).

I have read the help files and browsed the Forum, but hope folks can answer several questions:

1. Is the amount of noise "a lot", relatively speaking, or pretty common in my kind of setup?

2. Do I have to record a bit of this noise each recording session of Audacity? In a separate track?

3. Do I have to "Get Noise Profile" each time I want to use the tool, or does Audacity remember the noise throughout the current recording session?

4. Audacity recommends reducing the volume of the noise sample using the "Amplify" effect before applying the Noise Removal Tool. Why? What are appropriate settings for the "Amplify" dialogue in this case? I assume I have to "Get Noise Profile" again after the "Amplify" effect has been applied to the noise sample, before applying the Noise Removal Tool to the music?

5. Are the default values in the Noise Removal Tool dialogue appropriate for this kind of noise? If not, where should I start?

6. Is the effect of using the Noise Removal Tool cumulative, when used more than once on the same piece of music? What happens if a change is made in 1 or more of the parameters in the Noise Removal dialogue? I assume "best practice" is to undo the previous Noise Removal and redo with changed settings?

7. Will I hear the difference after removing the noise? This is a silly question, since I'm already a little hard of hearing.

I think the Audacity software is just great, and I certainly appreciate this Forum and those experts helping us novices work through some difficult subjects. Thanks very much.

Regards, Pat

NoiseSampleTT.wav

(860.04 KiB) Downloaded 114 times

[steve]

The noise level seems a bit excessive which is probably because you are going through the Behringer pre-amp and the computer (RealTek) pre-amp.
As you have a Behringer USB pre-amp you do not need to go through the RealTek.

Connect the Behringer USB lead to a USB socket on the computer.
Allow windows enough time to recognise and connect to the pre-amp then start Audacity.
In Audacity go to "Edit menu > Preferences > Devices" and set the recording device to the USB option.
Set the playback device to either the USB or the RealTek according to where your headphones/speakers are connected.
If you are listen via the RealTek, enable "software playthrough" in the "Recording" tab of Audacity Preferences.
If you are listening via the Behringer outputs, do not enable "software playthrough".
Do not connect the Behringer outputs to the RealTek.

More information about recording vinyl is on the wiki: http://wiki.audacityteam.org/wiki/Trans ... uter_or_CD

Do I have to record a bit of this noise each recording session of Audacity? In a separate track?

Usually there will be a sufficient noise sample at the beginning of the recording provided that you start the recording from the edge of the record. You only need a second or two. For best results, grab a new noise profile for each record (the surface noise will be slightly different from one record to another).

Audacity recommends reducing the volume of the noise sample using the "Amplify" effect before applying the Noise Removal Tool. Why?

I'm not sure what that is referring to. Can you post a link to where you read that.

There's a tutorial about removing clicks: http://wiki.audacityteam.org/wiki/Click_Removal
and one about reducing noise: http://wiki.audacityteam.org/wiki/Noise_Removal

[patcurci]

stevethefiddle:

Thanks for your reply.

Regarding the Behringer preamp. I have a Hauppage WinTV tuner card hooked up via USB (no other option available to me) and the computer sound card is integrated. Audacity does not see the Behringer. It only sees the mono TV tuner card. I've spent a lot of time on this "hardware" issue and simply can't get the computer, Windows and Audacity to find the Behringer. Although I haven't tried this yet, it's not conveient to unplug the TV tuner card from the back of the machine. I'm attaching a file from the Audio Device Info from Audacity; there are 5 choices from Preferences/Device/Recording. I've tried all 5 and the only way I get Audacity to record anything is via the line-in on the sound card.

The following is from the Audacity Wiki page on Noise Removal. I don't know how to post the link to the exact place on the page. Sorry.

However if the problem is that too much of the signal (music, voice, etc.) has been removed along with the noise, you can also try going back to the selection chosen for the Noise Profile and reducing its amplification (Effect > Amplify). Then use this as a new Noise Profile.

Again, my thanks.

Regards, Pat

Audacity Device.txt

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[patcurci]

stevethefiddle:

Thanks for your suggestions. With a great deal of digging in the Windows and Realtac software, I finally got Audacity to see the Behringer preamp.

This is what Audacity sees:

AudAudioInfo.JPG (42.78 KiB) Viewed 3731 times

I've disconnected the Behringer preamp output to the "line-in" for the computer sound card and told Audacity to record from the Behringer preamp through the USB port, in stereo, which it does.

The bad news is Audacity still sees the same noise (as best as I can determine) as when using the "line-in' for the computer sound card. Again, this noise does not seem to be affected whether the turntable motor is running or not. So the noise, without any hardware fix, yet, still is present.

Based on your initial reply, the quality of my recordings should improve if the noise is removed to some extent. Therefore, I still have some questions:

1. Do I have to record a bit of this noise each recording session of Audacity? In a separate track?

2. Do I have to "Get Noise Profile" each time I want to use the tool, or does Audacity remember the noise throughout the current recording session?

3. Are the default values in the Noise Removal Tool dialogue appropriate for this kind of noise? If not, where should I start? Noise Reduction? Frequency Smoothing? Attack/decay time?

4. Is the effect of using the Noise Removal Tool cumulative, when used more than once on the same piece of music? What happens if a change is made in 1 or more of the parameters in the Noise Removal dialogue? I assume "best practice" is to undo the previous Noise Removal and redo with changed settings?

I realize the importance of experimenting on my own, but any additional help would sure be appreciated.

Much thanks in advance.

Regards, Pat

[patcurci]

Sorry folks, I showed the wrong jpg on the previous reply.

Here is what Audacity sees for the Behringer preamp

Capture.JPG (41.82 KiB) Viewed 3733 times

Regards, Pat

[ignatz]

Therefore, I still have some questions:

1. Do I have to record a bit of this noise each recording session of Audacity? In a separate track?

2. Do I have to "Get Noise Profile" each time I want to use the tool, or does Audacity remember the noise throughout the current recording session?

3. Are the default values in the Noise Removal Tool dialogue appropriate for this kind of noise? If not, where should I start? Noise Reduction? Frequency Smoothing? Attack/decay time?

4. Is the effect of using the Noise Removal Tool cumulative, when used more than once on the same piece of music? What happens if a change is made in 1 or more of the parameters in the Noise Removal dialogue? I assume "best practice" is to undo the previous Noise Removal and redo with changed settings?

Pat:

I'm not the expert, but here is my offhand opinion based on experience.

Question 1 and 2, I don't know.

Question 3: I'd say trust your ears. After the smoke clears, that's who you have to satisfy. I have not yet been able to detect differences in slider positions for attack/decay or frequency smoothing, but I have not done a lot of experimentation. The top slider makes an obvious difference.

Question 4: Yes. each pass adds more to the effect. Obvious artifacts show up pretty quickly. I have occasionally experimented with 2 passes with the slider at say 6 or 8 rather than 1 pass at 12 to 18 and didn't necessarily notice obvious differences. It's a subtle tool that you just have to listen to and experiment with. I always undo one level before reapplying because there are actually 2 "undos" available after the application of NR to a file: one for the sample grab and one for the application to the whole file. If you sample and then apply, and then "undo" only once, you will still see another "undo noise removal" available. I think the first undo gets rid of the noise removal on the whole song and the second would get rid of the sample. If I want to get rid of the sample, I undo twice, but I assume you could just undo once and take a new sample, which would overwrite the first sample. If you want to keep the same sample, but adjust the sliders and reapply, undo just once so the noise sample is still available.

[waxcylinder]

2. Do I have to "Get Noise Profile" each time I want to use the tool, or does Audacity remember the noise throughout the current recording session?

AFAIK I think Audacity will "remember" the noise profile, until you change it by resampling later, within any current Audacity session. A few simple tests with some radical noise removal should confirm this for you - or otherwise ...

1. Do I have to record a bit of this noise each recording session of Audacity? In a separate track?

I seem to recall a posting from a while back on NR where somebody recommended recording a sample of the run-in on a separate temporary track to be used for noise removal later in the project. But provided you have noise samples available throughout the project this may not be necessary. And don't forget that noise can vary across a single side of an LP.

But the noise sample you posted is coming from your soundcard, right? In which case you can just record a sample of that in a small separate track for NR sampling. But don't forget to remove (or in 1.3 Mute) the "noise" track before you export the project.

WC

[patcurci]

Ignatz:

I think your absolutely right about "trusting your ears". In the last question of my original post, I joked some about the fact that I am a bit hard of hearing. So I may not hear incremental improvements from a technical level. I'm not a sound engineer, and the results of my work are for my own enjoyment. But I do want to do the best job I can.

The Audacity/Wiki page on Noise Removal, in the section on "Improved Noise Removal in 1.3 Beta", talks about the parameters in the Noise Removal dialogue but it's not clear to me what "values" might be entered since they don't use the same terms for the 3 sliders in the actual tool. They seem to recommend something other than the default values in the actual tool.

Your answer about the cumulative effect of the tool was extremely helpful. Many thanks.

Waxcylinder:

Your answers to my questions about getting noise samples certainly helped to clarified these issues for me. Grateful thanks.

In answer to your question about "where the noise comes from", I am now convinced the Computer Gremlin is at work. Since I was ultimately successful about bypassing the integrated sound card (I think) by having Audacity see the Behringer (Device ID: 1 Microphone) and record from this device, and still have this noise, it's not coming from the sound card. Ergo, the noise is coming from the Ether.

The important question for me is whether this noise is significant enough to deal with based on the final use of the recordings I'm making. That's a question only I can answer, but I want to do the best job I can with the limited tools and knowledge I have.

I really appreciate the time folks are taking with this topic. I think it can be a troublesome one, particularly for novices like me.

Regards, Pat

[steve]

When recording from vinyl, the majority of the noise is likely to be from the vinyl itself rather than from the sound card.
Therefore the noise sample that you use should be taken from a "silent" part of the record (such as the lead-in before/between/after tracks).

[ignatz]

Pat:

I just saw this quote by Stevethefiddle in a nearby thread on NR:

"The Attack/Decay setting in Audacity 1.3.12 does not work - it doesn't do anything."

Apparently this has been corrected in 1.3.13, which I have not yet tried. I guess NR has a "sensitivity" setting in 1.3.13---which can help slightly in certain circumstances.