Syntrillium Backup Forums :: View topic - Eliminating Low Freq Clicks & Pops (Neg Spikes)

KenGAce · Posted - Mon Apr 02, 2001 12:40 pm

This may have been discussed already somewhere in the depths of the forum. I've been trying to get rid of low frequency clicks and pops that sound more like dull thuds due to small bumps in the vinyl. On the frequency spectrum, they appear as negative (direction) spikes. For some reason CE Pro doesn't detect/correct these as readily/easily as the more common high frequency (positive) spikes. Has anyone discovered a way to get rid of these neg spikes? I thought about inverting the signal (and possibly provide some amplification) so that the neg become positive spikes and then do a de-click on the signal. Thanks.

seanbaker · Posted - Mon Apr 02, 2001 1:21 pm

I don't knwo if these thuds are the same as what I've encountered before, but I simply went in and removed the bass in those areas.

beetle · Location: USA

I use the scientific filter. Just keep adjusting the high pass filtering until the thud is removed without harming the music.

urumuqi74 · Posted - Tue Apr 03, 2001 6:25 am

Well Ken, you brought up a nice thread here. In art of restoring vinyl, there's 2 gray areas for which I need more "practice".

The first was the bump (vertical) until I read Beetle's comments. That should do it after I register the add-in!!!

The other one is the "horizontal sway" sound which is more likely an off centered vinyl. The stylus will at one point hit the groove wall producing this high freq. noisy hiss. Almost like the end of the record loop sound without the pop. Can't be removed with the hiss or noise reduction features without harming the real audio. I am cooking something with noise reduction and dynamic processing but it's rather primitive at this point.

Anyone with a miracle cure for this?

beetle · Location: USA

To correct off center 45's I just don't use the 45 adapter and align the record by hand until it the grooves are even.

LP's present a much tougher problem. In some cases I elevate the LP high enough on the turntable to where it won't sit down on the spindle and adjust it to eliminate the wow. It get's tricky because if the album is warped the tone arm won't track it very well. I have resoored several LP's this way.

urumuqi74 · Posted - Tue Apr 03, 2001 11:13 am

Ok Beetle, if i understand it well, in the case of horizontal sway:

-you elevate the lp to a certain point so you create a kind of opposition to the sway.
The needle won't go it the groove wall as much as if it's play full flat on the plater.

I wil try that, quite tricky though!!!

beetle · Location: USA

The reason for elevating the record is so that you can move the LP around in order to correct the off-center pressing.

Yes, the stylus (needle) may noe track the record as well but doing this may be the only way to get a good pass out of an off center record.

If you're like me, hearing even a small amount of wow or flutter can drive you up the wall! It's like being cursed with perfect pitch, which I am!

urumuqi74 · Posted - Wed Apr 04, 2001 9:06 am

Frank Burnett · Posted - Wed Apr 04, 2001 9:53 am

Beetle or Urumqui
I'm still learning so please pardon my dumb question. I have heard the terms "flutter and wow" before but what is it exactly? Thanks for your patience....

Syntrillium M.D. · Location: USA

Hello Frank. This really relates mostly to analog tape, but can be heard on turntables with [unwanted] varispeed. By definition, 'Wow' is a product of slow-speed variations in a tape-transport system causing a taffy-like sound quality, ie, slurred, varying pitch (sometimes), dragging and a generally 'muddied' lower mid-range.

'Flutter' is the result of rapid-speed variations in a tape-transport system causing a fluttery sound, typically experienced in the high-mids and high freq. bands.

--Syntrillium Support

Edited by - syntrillium support on 04/04/2001 10:05:20 AM

invader9000 · Posted - Wed Apr 04, 2001 10:03 am

Wow and Flutter is a term for LPs and cassetes and describes the pitch changes of audio, related to instant speed changes to the record rotation or casette tape pass in front of the heads. This is a problem to LPs and cassetes, but not an issue to CD's.

Frank Burnett · Posted - Fri Apr 06, 2001 4:09 am