Ringing Noise

[richardeichholtz]

I seem to be adding a ringing noise to my recording when I follow the sample work flow for processing LPs. I saw a refence to this while reading some Audacity literature but I can't seem to find it now. I believe the ringing was added either with the Normalize or High or Low pass filters. Can you help me?

[steve]

Perhaps you applied too much "Noise Removal".
Perhaps you read something in one of the Tutorials?

[DVDdoug]

Normalizing is just a volume change, it doesn't change the "character" of the sound.

You shouldn't get ringing with high & low-pass filters either. But with filters, EQ, noise reduction, or anything that does affect the character of the sound, it's very important to experiment... An audio editor is just like any other tool... It's a lot easier to break something with a hammer than to fix something.

Noise reduction can be tricky, and you can sometimes get artifacts (side effects). Sometimes these artifacts are described as "metalic" or "tinkling" sounds, or sometimes it sounds like a bad cell phone connection. Sometimes, "The cure is worse than the disease". Vinyl clicks & pops are especially tricky. If you want the best sound quality, buy the CD! (...if it's avaliable.)

[richardeichholtz]

I'll redo with less noise removal and see what happens. What I read was in one piece of literature it referenced something about a 0.7 setting being either too high or too low not sure which. If I remember correctly there were two other settings in the same dialog box.

[waxcylinder]

As Doug says, but ...

Vinyl clicks & pops are especially tricky.

Yes, especially tricky - but handled excellently (magically almost) by ClickRepair , a piece of software written by Australian mathematician Brian Davies. It costs a little at $40 but is well worth it if you have more than a few LPs to convert. See this sticky thread: http://forum.audacityteam.org/viewtopic.php?f=28&t=1994

If you want the best sound quality, buy the CD! (...if it's avaliable.)

Curiously this is not always the best approach - the reason being is the the engineers and record companys cannot resist "remastering" which mostly involves making the re-released CD sound "louder" (see this article in Wikipedia on loudness wars: http://en.wikipedia.org/wiki/Loudness_wars ). So this often means that the repaired vinyl can actually sound better than a newly "remastered" CD.

But in general Doug is right it's often better to buy the CD when available - it saves an awful lot of time, and the prices have generally fallen a lot ...
I rebought about half of my collection (those I hadn't already rebought) and converted t'other half.

WC

[steve]

What I read was in one piece of literature it referenced something about a 0.7 setting being either too high or too low not sure which.

That's either the high-pass filter or the low-pass filter. Both of these effects have an option called "Filter quality [q] for 12 dB rolloff:"

Both of these filters have an option to select the "steepness" of the filter slope. For the 12dB per octave option (and only for the 12dB per octave option) there is an additional parameter that can be used which is called "Q" (quality). The optimum value for Q is about 0.7 (the default), so that value should not normally be changed.
Personally I wish that option was removed from these two effects as I expect that most users misunderstand what that control does.

[richardeichholtz]

Everyone has been very helpful. The one recording I really need to copy is a 1957 print of a 1936 recording. While most of my questions have been addressed, no one has told me how to keep the "ringing" out of the digital copy. Maybe I just don't use the filters and take what I get?

[waxcylinder]

Richard,

now that I know you are only working on one particular recording, you can get to use Brian Davies' tools effectively for free, as he offers a 21-day free trial of his software.

In addition to ClickRepair he has an other packge DeNoise and DeNoise LF (all three can be downloaded for the free trial).

The DeNoise is a little trickier to use than CR but not too hard. In some some people's opinion these focussed tools are superior to those provided in Audacity.

Outline workflow would be:
1) Record in Audacity at 32-bit float (and probably 44.1kHz)
2) Export a 32-bit WAV of the capture
3) Process the exported WAV though ClickRepair (I soften the default settings using Declick=30, pitch protection-on, reverse=on - I don't use the de-crackle though you may need to.
4) If you do need de-crackle some folk recommend two passes - one for the clicks and the second for the crackle
5) Process the repaired WAV file through DeNoise (you will need to experiment with settings)
6) Import the fully repaired file back into Audacity for any further processing
7) Export the production audio files (probably at 44.1kHz 16-bit PCM Stereo WAV)
8) backups

One of the great things about Brian's tools is that you can set them to listen to:
1) raw input signal
2) processed cleaned up signal
3) the "noise" that is being removed
Mode 3 is particularly helpful as it helps you ensure that you are not removing too much of the signal you wish to retain.

WC