I've been using using Audacity freeware for years to record vinyl and radio programmes onto my PC, and for me the results are good enough for burning the resultant files to CD to listen to in the car or in the house - except extended quiet passages when there is some sort of wowing effect created in the sound which is obviously some 'digital artefact'.

Only noticed the problem on a few occasions and most recently when I recorded and heard the first few bars of the Joyce Hatto Rachmaninov PC, which I had placed in the sendspace site for for folks to listen to.

Is this wowing effect due to the inadequacies of the Audacity software?

http://www.sendspace.com/file/bmp4uw


John W

Hi Bryn,

Listening to the vinyl on headphones suggests the vinyl is ok (it is mono) and the hardware amp, deck, stylus are all ok  - except there is low hum from the record deck which you probably heard

I have noticed the same problem with quiet music recorded off the DAB using Audacity, most recently Petrushka from Elder/Halle that was on Ao3 or Po3 last month.

The 'loudness' function on the amp is off.

I have a .wav file of the Rachmaninov vinyl which also has the wow. I can put an extract of that on sendspace.

http://www.sendspace.com/file/s19fk4

John W

Bryn,

What I refer to as 'wow' is that sort of whooshing oscillating noise on the early part of the soundclip, in fact I think it IS 'the noise' (deck, amp hiss etc), background noise, that seems to oscillate as the quiet music with silent bars is heard, once the music gets going the noise settles down to a level and isn't heard when the music gets louder.

I am using a jack from the amp stereo headphone socket, I know that might not be best but the volume is a lot better than from the amp line-out. The connections at the back of the PC are the usual mini jack sockets.

I don't know what sound card I have the PC was built for me, I only have the motherboard manual. I suppose somewhere in the Windows Control Panel will tell me?

John W

Thanks Bryn, I might look out for that. As I say I only have the problem with very quiet music.

I've used Audacity for years. For noise removal, the sound wave can be expanded to isolate and remove loud clicks (or replace them with bits of adjacent sound) and the background noise removal facility can remove a uniform hum, also a uniform cassette tape hiss, and works quite well also with good 78's but not very effective with worn 78's whose crackle is not uniform. There are more expensive products that do a better job there.


John W

Hi Bryn,

The draw tool sounds an easy tool, though dealing with the occasional loud click from vinyl or 78 is quite easy with the Audacity once you get the hang of it. A good condition disc may only feature one or two audible clicks. Bit more work required for less good discs, for example a near mint 78 with a hairline crack or a vinyl scratch will show a regular click, if the crack is about 1" long then you could have 50 clicks to deal with but there's one ever rev so you know where they are on the sound wave.

The noise reduction tool on Audacity, as I say, works well under some circumstances when the noise is uniform or fairly uniform. It's not much good when you have a variable noise like a swishing effect. And if you use the software too often, or try too high an application of it, then you introduce 'digital artefacts' which produces odd whistles and whines presumably due or partly due to some noise frequencies remaining. I'm sure you know more about all that than I do.

Even mint 1920s/1930's 78's have 'noise' because the shellac included an abrasive material that was meant to wear down steel needles (to wear out the needle rather than the disc). The abrasive material causes the crackly noise even with a diamond stylus.
 
If 78's have been played with a steel needle in their past then they tend to be a bit more worn in the early grooves as the sharp needles gouged into the early grooves, the mid-section of the 78 will likely have the best sound as the needle will become shaped by the abrasive, but towards the end of the 78 as the steel needle gets very worn and becomes chisel-shaped it will start gouging the last few grooves. The resultant damage and therfore additional noise added is different, from beginning to end, and that is also affected by the real 'speed' of the needle which is lower in the latter grooves because the 'circumference' of the grooves is much less there so the relative speed is slower.

John W

My problem with Audacity is that I use it to record, via microphone, my acoustic guitar and violin playing. The violin records fine but there is far too much bass on the guitar recording. Does anyone know how I might correct this?

http://en.wikipedia.org/wiki/Proximity_effect#In_audio

It's good to experiment with your mic placement, as Bryn suggested.  If you have a spare, consider setting up two mics - one close (<6") and one a few feet back.  You can then mix these to your taste and get just the balance you're after.

Yes. In Audacity you can use your mouse/cursor to select any part of the file, start from 0.000 or anywhere in the time of the track, click and hold, drag the mouse to the right until you reach the time you want (remember to scale the time  or zoom in for accuracy in your selection). The 'track you want is the dark area selected.

Then do File>Save selection and you can choose either WAV or mp3.


Check if your PC has a file named lame-enc.dll  which Audacity needs for mp3 format. I remember the first time Audacity showed a screen where you could search for lame-enc.dll on your PC.

You can search the web for lame and download free.


John W