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Topic: Any advice on noise removal in Audacity (Read 13433 times) previous topic - next topic
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Any advice on noise removal in Audacity

Hi,
Interested to hear any views on using noise removal tools when recording vinyl to digital for archiving (and listening!).  Having finally decided that it makes sense to rip my vinyl to FLAC or some other lossless format - so I can transcode to whatever in the future, as required, I'm now considering my options for 'cleaning up' the signal, or if I should even do anything of that sort.

I've messed around a little with noise removal in Audacity (v 1.2.6) to get a feel for it.  On an admittedly quite well used copy of Pixies 'Doolittle' training the noise removal tool can leave things sounding 'hollow' or 'echo-y'.  You can back the noise removal off, and those undesirable side effects are reduced - although so is the noise removal.

Any advice on best practice in this area?  Do others generally avoid this sort of post-processing?  If not, do you use Audacity?  Other tools?

Any advice on noise removal in Audacity

Reply #1 –
I even do noise reduction of CD material. I have used the once popular Cool Edit 2000 with noise reduction plug-in with good results on analog recordings such as Tullio Serafin's La Bohème from 1959.
As one of the Amazon.com reviewers writes,
Quote
Decca's sound is phenomenal especially for a recording made in 1959 with a perfect balance between orchestra and vocals and believable stage sound effects all presented in crystal clear warm analogue stereo sound.

The dynamics of this recording can truly blow you away at loud listening volumes, but then a strong but regular hiss from the analog tape appears, which is easy to lower by taking a noise print on a silent part and use it to remove from all the recording.
I also made the experience that it's better to leave some of the hiss rather than have things sounding 'hollow' or 'echo-y', as you say.

Any advice on noise removal in Audacity

Reply #2 –
Noise reduction can be very good and completely free of artifacts if done properly. Unfortunately, not all programs are equal. I have written posts here with detailed instructions for CoolEdit/Audition and the SonicFoundry NR 2 pluggin. No doubt there are other good programs, but these are the only two I use. My limited experience with Audacity was that its NR wasn't worth using, but one might be able to get acceptable results if only a very small reduction is desired.

Any advice on noise removal in Audacity

Reply #3 –
Maybe you should ask advice directly from the Audacity support forum  - http://forum.audacityteam.org/

I know they ask you to upgrade to newer version ... to get better tools available.

Juha

Any advice on noise removal in Audacity

Reply #4 –
Quote from: davidos on
Any advice on best practice in this area?

If you're talking about broadband noise reduction, using a "noise fingerprint", then my advice is to use multiple light touch passes rather than a single pass with more aggressive settings.

Quote from: davidos on
Do others generally avoid this sort of post-processing?

In many cases there's no need for any noise reduction. But my LPs are typically rock albums in good condition, which are probably rather easier to deal with than, say, historical jazz or classical releases.

Where I do feel some noise reduction is worthwhile, I tend to only use it on the parts where the noise is actually audible (ie. quiet sections). This has the advantage that you don't lose any of the "sparkle" throughout the main part of the music. On the downside, it leads to the added complication of having to vary the amount of noise reduction according to the level of the music, otherwise you get an obvious transition point where the noise reduces. But I think it's worth the effort.

My own personal view is that careful removal of impulsive nose (pops, ticks and crackle) is more important when archiving vinyl. (Constant noise can be "dialed out" by the brain, but random glitches can't). It's more involved than dealing with constant noise, and unfortunately for you Audacity doesn't have the kind of features you need. Which tools should you use for this? I'd better not say, as I have a vested interest.

Any advice on noise removal in Audacity

Reply #5 –
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or if I should even do anything of that sort.
Yes, you should!  In cases where I've done lot's of processing (i.e. lots of EQ), or if there are some artifacts, I'll keep an unprocessed archive too.

Quote
I've messed around a little with noise removal in Audacity (v 1.2.6) to get a feel for it.
This kind of noise reduction works best on constant low-level backgound noise (like tape hiss).  But, even then, the cure is sometimes worse than the disease.  For, vinyl "snap", "crackle", and "pop", you need special-purpose software.

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My own personal view is that careful removal of impulsive nose (pops, ticks and crackle) is more important when archiving vinyl....  Which tools should you use for this? I'd better not say, as I have a vested interest.
  I'll say it!  I use Clive's  Wave Repair[/color] ($30 USD) for removing "ticks" and "pops".  Most of these kinds of defects can be perfectly repaired, and only the few-milliseconds of defect are altered, so 99.999%  of the recording is not touched.  The downside to Wave Repair is that it works best in the manual mode, and I typically spend a full day or a full weekend fixing-up a vinyl transfer.  The results can be amazing, but it's not always "CD quality"...    And I always recommend that you buy the CD if it's available. 

Clive has another web page[/color] where he offers lots of advice and lists/recomends some other software, including some automatic de-clickers.

Besides click removal, I'll usually try some "regular" noise reduction or (noise gate).  And since older recordings are often a little dull sounding, I'll sometimes boost the high-frequencies a bit.  As a final step, I'll normalize the album (set the volume so the peaks are at, or near, 0dBFS).
 

Any advice on noise removal in Audacity

Reply #6 –
Quote from: DVDdoug on
For, vinyl "snap", "crackle", and "pop", you need special-purpose software.

I do have a copy of something called WaveCorrector DeClick from Ganymede Test and Measurement.  It's a very cut-down version, which came with the Xitel Inport device USB ADC device I'm using for the recording, and is not very tuneable - just a detection threshold setting.  All it does is automatic 'declicking'.  It doesn't remove all the pops - you can still see 'em on the waveforms in Audacity.  There's still pronounced background noise, particularly in the quiet sections, which was how I came to be trying out the Audacity NR.

Quote from: DVDdoug on
The downside to Wave Repair is that it works best in the manual mode, and I typically spend a full day or a full weekend fixing-up a vinyl transfer.

I'll take a look at the evaluation copy, but that sort of time commitment is just not an option - kudos to you if you have the time and the patience!  I'm really after something a lot more automatic.  Of course, I do understand that you get what you pay for (in time or money), so maybe I just have to live with that 'authentic' vinyl ambience on my recordings!

Also, I've a feeling that a well-played Pixies 'Doolittle' album may be a particularly tough test case - the whole loud-soft-loud dynamic, beefy bass guitar, and the bright edges on the loud jangly guitar segments aren't going to make it easy for any one-size-fits-all approach.  Certainly, R.E.M.'s 'Green' is nothing like as obviously noisy as 'Doolittle'.  Maybe the approach should be selective re-purchasing of a few particularly valued items - have to admit I was blown away by the J&MC's 'Psychocandy' remaster on CD, which set me back about $5 new!

Any advice on noise removal in Audacity

Reply #7 –
Quote from: davidos on
I do have a copy of something called WaveCorrector DeClick from Ganymede Test and Measurement.  It's a very cut-down version, which came with the Xitel Inport device USB ADC device I'm using for the recording, and is not very tuneable - just a detection threshold setting.  All it does is automatic 'declicking'.  It doesn't remove all the pops - you can still see 'em on the waveforms in Audacity.  There's still pronounced background noise, particularly in the quiet sections, which was how I came to be trying out the Audacity NR.

Since we're talking about automatic declickers here, I feel able to offer some impartial advice. My own program (Wave Repair) is not really usable purely as an automatic declicker - there are better options around. Wave Corrector (no relation) is one of the better ones. I don't know about the cut-down version you've got, but the full version has some unique features among auto-declickers - it does a detection pass then allows you to review the clicks it has found, during which you can reject phantom positives and/or alter the repair strategy on a click-by-click basis. I also feel that it has a somewhat better approach to big defects: whereas most other auto declickers replace big clicks with dull thuds and plops, Wave Corrector tends to partially mute. The end result sounds a bit like a  brief mild tape dropout instead of a low frequency "pop".

Other auto declickers I've tried and would say are worth taking a look at are: Sony's Noise Reduction 2.0 plug-in for Sound Forge (possibly the best of the bunch), Adobe Audition, Click Repair, and perhaps Groove Mechanic.

Quote from: davidos on
Quote from: DVDdoug on
The downside to Wave Repair is that it works best in the manual mode, and I typically spend a full day or a full weekend fixing-up a vinyl transfer.

I'll take a look at the evaluation copy, but that sort of time commitment is just not an option - kudos to you if you have the time and the patience!

Restoring vinyl manually is a labour of love. If you don't have the time or the motivation, then it will be a very frustrating exercise. I happen to enjoy the process itself, but I'm probably strange in that respect. (Mind you, I find it strange that lots of people enjoy sitting in front of games consoles pretending to shoot bad guys, so each to his own).

To reiterate what DVDdoug said, it's far simpler to just buy the CD, provided that (i) it's actually available, (ii) hasn't been remixed or edited in some unacceptable way, and (iii) hasn't been "remastered" to the point of destroying the dynamics.

Any advice on noise removal in Audacity

Reply #8 –
With v1.33 Audacity got a completely rewritten Noise Removal algorithm with both less distortion and artefacts, also two sliders were added ("Frequency smoothing", "Attack/decay time") for a better control over the effect. Versions > 1.3x are able of batch processing (File: Edit Chains, File: Apply Chain), so you could try to clean up your LP records with an updated Audacity as already mentioned by Juha.

Audacity's Noise Removal (all versions) is suitable for static noise only, to reduce noise which is changing in frequency or loudness you need an adaptive noise reduction.

If you are dissatisfied with Audacity's own noise removal effect you also have the option to use VSTs. Whether you need therefore Audacity's VST Enabler depends on Audacity's version as far as I remember.
This is HA. Not the Jerry Springer Show.

Any advice on noise removal in Audacity

Reply #9 –
Re: cut-down WaveCorrector program:
It doesn't provide the auditioning and tuning of each correction - I need the Pro edition for that - although it does look like I can get an upgrade to that version cheaply with my bundled Xitel Inport copy.  I'll look into that.  I like the look of WaveRepair too - still exploring it!

On noise-reduction more generally:
Having spent some time with my 'problem' tracks in the last couple of days, and playing around some more with the tools available to me (trial or free), I can see that as DVDdoug and cliveb have said, doing a good job on vinyl clean up is a difficult and time-consuming job.  I can see how it could get to be fun - and certainly how it would bring a sense of accomplishment, when done well.  It's probably something I'd enjoy too, but unfortunately, it's just not something I have the spare time to commit to on any scale.

Saying all that, with the exception of a few ill-used records here and there in the collection (including a few purchased second hand) most of my records are in fairly good shape, and most of the noticeable background noise is between tracks, not during them.  The clicks and pops... well... I'll spend a bit more time with all these great tools people have pointed me to, and see if I can get better with them.  But for the bad cases, I think it may have to be a case of CD replacement if I'm strongly enough attached!

Curses... this is one situtation where being a late adopter (of CDs) has come back to bite me in the end (usu early adoption is the riskier option - like all those low bitrate MP3's I now need to re-rip...).