Talk:Improving and Remastering Audio

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"Whomper" wrote:

if not here then where if not now then when someplace in all the docs we really need info on how to connect all the software and settings that can affect using audacity including the sound cards, drivers, control panels, options, yada yada. and explain how they interact andor undo each others attempts at controlling audio on a pc. some places that may be involved include the two control panels under start settings control_panel (win xp). the windows ap for sound recording has two places for settings under properties and audio properties (system; sounds_etc; but maybe also the speech, video, modem [tbd]). audacity has settings. the audio card has its control panel with mucho settings. and windoze has at least two volume control panels that can affect recording/playback especially if something is checked "mute". these are much more important than knowing what connector to plug in where (although that info should be documented it is far from sufficient). also needed is a good block flow diagram that shows how things go in/out , loop around, get saved, retrieved, etc.

Gale: 24Feb10 There are a couple of tutorials in the Beta manual covering digitising LPs and tapes and recording from other sources, and another setup page that is mostly duplication of the Tutorials. These cover Audacity setup to some extent. The general feeling is that the Manual can't go beyond that into the quagmire of problems configuring playback and recording setup on several different Windows operating systems with a huge potential variety of sound devices. The nearest we have to that is Mixer Toolbar Issues. Our Wiki Tips page collects a lot of useful links together, especially for recording.

Notes from edgar:

The Reverb tutorial describes Audacity 1.2.2 and is obsolete since approx. two years. The current version is, which is contained in the german Audacity users manual.

Gale: I think the link from 1.3 help you gave must be wrong? That one seems to be about splitting into separate tracks then multiple export. Perhaps you mean:

Edgar: yes, of course my link was wrong. I just returned to fix it but you were faster than me.  :)

Another question: is there no english translation available? IMHO this is one of the most important Audacity tutorials.

Gale: Splitting into separate tracks, which does not have much to do with this article, is at Splitting recordings into separate tracks on this Wiki and will in some form be in the 1.4 Manual. There is quite a lot of help with GVerb and other reverb tools on the Wiki at GVerb. Again I'm not really sure if links to specific reverb effects are meaningful in the context of this article as he's written it. In the 1.4 Manual there will of course be a description of the Effect Menu and how the particular effects work and an explanation that 1.4 by default will select all audio if none is selected. At the moment all we have as regards an "effects" tutorial for the 1.4 Manual are some old, incomplete or podcasting-related pages which can't be fitted in to the Manual as they are. I think the point of the German tutorial is copying an original dry track then mixing with the wet track so you get as much of the effect as you want? Yes this is useful, but I think it's advanced usage - nice to have but to be done if we get time at the end rather than mission-critical.

I agree with your other comment that prevention is better than cure where audio noise is concerned, and this should have some mention (for example as regards dropouts being in the recording), though I think the article is primarily about cleaning up pre-existing recordings especially from tape and LP media.

The Effects tutorials is undoubtfully one of the most extensive effects tutorials I know but unfortunately describes most of all VST effects, which were known not to work with most Audacity versions. So I don't know how much this really helps.

Nontheless: thanks to master of pausbacken for this tutorial.

Notes from Gale Andrews:


Sorry I have not got round to looking at your big effort until now.

I make some comments on Sections 1 - 4 which I have read more or less thoroughly. I made some edits to reduce text and improve grammar plus the comments below. Otherwise I only correct a few spelling mistakes. I will try and do the remainder (probably in a few sessions in the next few days).

Editing - General

  • I am not convinced for this article you need to mention any of those Preference settings, except possibly Select-all-on-none (which is on by default anyway). Even so, if someone changed it, probably they know what they are doing...
  • Save the original file and intermediate versions - do you mean save an Audacity Project?
  • Do any effects other than Equalization have presets? Maybe mention that only when discussing EQ.

Editing - The Individual Steps

1 Two channel mono files

Why not say something like "If you have a stereo track with little or no difference between the channels where you won't be editing the channels separately, you could compare them and choose the best one". Is that your main point? But why make a new track? Why not split the stereo track and simply compare the two with mute/solo?

4 Noise Reduction

"If you are working on a mono file, of which you saved the original 2-channel file at the start, check for replacements from this file." is a little unclear/insufficiently explained. If you want to compare channels in your first step why not explicitly mention to listen for noise there? If you decide to keep both channels (because one channel lacks a crackle that is in the higher quality channel), how do you replace the affected section?

- Where to take the noise profile?

Sometimes taking noise profiles in a band between tracks is more representative. This is true with LPs where lead-in and lead-out are typically the noisiest parts of the surface, the noise sometimes running into the playing surface. I recommend a separate profile for lead- ins/outs and bands between tracks which latter may be better for the majority of the audio.

- Special conditions

"When your file contains gradually changing noise, try to apply the "envelope technique" described in the step about equalization, substituting the term "equalization" by "noise reduction"." needs a little more explanation here. The user wants a phrase or two to decide if he wants to go to #7.

"(on older tapes possibly changed due to tape stretching)" - I don't see the relevance in this context.

" Small band noise (mains hum, a single high frequency) is best removed using a notch filter - I think you are saying any noise confined to a small bandwidth including 50/60 Hz hum is best dealt with using a notch. In this case I suggest removing the separate bullet thus:

Narrow band noise While hiss is a mixture of many frequencies, noise can consist of only one essential frequency, such as mains hum at 50 or 60 Hz, or a constant high frequency whine. Such a high frequency might even be inaudible (supersonic) but nevertheless has to be removed, because it could optically mask small spikes. Any noise restricted to a narrow band of frequencies is best removed using a notch filter. "

Should you suggest looking at a spectrum plot to identify narrow band noise which you can't hear?



PS We made a fix for dragging envelope points off the waveform that works except that when dragging off right, you have to go absolutely to the far right of the screen, or the point won't be removed.

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