Removing Rumble before DeClicking

WaveLab
1

I am restoring a collection of 1200 LPs and am trying to understand how to configure WL to complete the task. Before I allow the needle to touch the surface of the record, I noticed that the VU meters are jumping around in the ‘Recording’ window in the sub- (-30db) range. There appears to be two other bars steady at about -39db. My desire is to reduced this rumble/hum (probably from both the turntable and pre-amp) to the -39db level.

I recorded/rendered a few minutes worth of this to play with. I’m assuming I should do this before I focus on the click/pop/crackle clean up of the LP.

When I do a 3D spectrum analysis I see a huge peak at 60Hz, so I assume I have AC hum issues. Sadly, the 3D analysis does not have a graticule for the Z plane, so it is rather difficult to determine quantitatively the amount of attenuation required.

Should I be using EQ to kill this, and how can I tell if it is ‘enough’ and not too much without the actual sound material/music rendered?

I toyed with DeBuzzer, but matching the pitch is somewhat subjective and it is unclear to me what the sequence for adjusting the various dials should be on the tool (how high before freezing, when is it ‘enough’).

Any help would be appreciated.

This message is related to the following thread/topics:
LP Restoration questions
Setting levels with DeBuzzer
How to determine the max settings with DeClicker

2

Hi there …

From time to time I do some restoration work from vinyl (where the original masters have been lost). Not my favorite work.

If you are unhappy with the level of noise from your reproduction system it is that to which you should possibly be directing your efforts … rather than ‘fixing’ noise post transfer.

Do you have the usual turntable earth lead (single wire typically with a spade connector) connected to your pre amp?

If you gently move the headshell does the hum alter? If it does you need to explore that further.

Also, you should probably ensure that your pre amp deals satisfactorily with the RIAA curve.

Do you have a transformer between the pre amp and your transfer console (the path to your A/D converters)? Depending on your pre amp and transfer console this may or may not be ‘desirable’.

A good quality turntable and high end pre amp combo that’s properly connected shouldn’t normally be presenting you with difficulties in themselves.

Constructively: Perhaps experiment with stuff you wouldn’t normally turn to … eg the Sonnox Suppressor which allows for boom reduction and other subtle low end tricks.

Hope this helps in some small way.

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On that narrow point I suggest you look at one of the many excellent free vst frequency analysers, for example Voxengo SPAN.

Otherwise generally reading through the above and your other post I had to smile since I recognised so many of your sentiments; if anything I was more scathing in my early criticism, but from my experience it is certainly worth persevering as I am now obtaining excellent results. However, this has not been the result of sudden epiphanies received from repeatedly re-reading the manual :smiley:

Good luck!

4

Thank you both for your replies.

For reference the Turntable is a Technics SL-BD22 and the preamp is an RCA SA-155 (Radio Shack). I did connect the ground wire (duh) and the VU meter signal chatter ended (the dual green bars). What is odd though is I still get pulsing Orange/Yellow bars in the Pan section. The orange goes from +3.55 to +5.3 to the left and the yellow +3.5 to +3.75 to the left. I have both the tone and balance knobs on the pre-amp set to the center and rotating either one with no record playing has no effect.

If I move the arm to start the turntable, I see the L/R VU levels jump then zero, so I know that is working and ‘silent’ now, but the meaning and cause of the bouncing Pan indicator is a mystery to me.

Previously I had ‘recorded’ the line noise, so now that it was corrected I recorded another 50s worth of the ‘silent’ input for comparison. In the Audio File view the resulting wave is now dead flat lined (previously it was a thick blue line based on the small amplitude).

Now another mystery … the 3D Spectrum Analysis. As I stated above I was seeing a peak at what looked like 60 HZ. On the new sample, I also ran the analyzer and saw the rest of the spectrum flatten out, but the peak on the low end still exists. I noticed under settings that I can change the frequency range reported (so it appears) so I changed it from 20-20000HZ to 50-70Hz. To my surprise (and I actually used a magnifying glass to the display to read the incredibly tiny display) the report still went out to 100Hz and the legend from left to right is 50Hz, 54 Hz, 59Hz, 54Hz 70Hz, etc. Yes, not 64 Hz but 54 Hz. I still get the highest peak at 60 Hz.

The amplitude of the ‘peak’ of the spectrum analysis appears to be % of maximum gain. Is that correct? Now that the recorded signal is much lower, I still see the peak jumping very high at 60 hz but the rest (now fewer) of the frequencies seem to be higher peaks than before in comparison. It appears to me to be a relative strength rather than an absolute measurement in the Z axis. Is that correct?

Having paid close to $500 for the software I am disappointed that the included EQ plug-ins do not allow you to select just one frequency as a low pass. The GEQ-30 has an adjustment at 63 Hz, but double clicking on the number does not allow me to change it. The very nice tutorial on YouTube used plug-ins from Waves which cost more than Wavelab, so I will check out the freeware plug-in you cited above.

All I’m trying to do is get everything to 0 before I send the recorded audio through. Making progress, but still looking for guidance.

5

Hi Rolan de Fleur …

I am happy that you have contained your line noise earthing issue.

With the L/R VU pan fluctuations you are seeing, I’m thinking that this is merely a representation of the ‘at rest’ signals that your pre amp is sending to your converters.

If you can’t hear it I wonder if this is worth too much consideration in the ‘big picture’ of the exercise: restoring vinyl.

Indeed, I wonder if it will be possible to achieve the ‘zero’ that you are after … see the Radio Shack specs here: http://support.radioshack.com/support_audio/doc64/64802.pdf

Or, even if that matters from a practical standpoint now that you’ve got the overall signal to basically ‘flat-line’.

To be honest I can’t recall ever using the 3D spectrum analysis. I’ll try and check it out.

FWIW, my expectation would be that when you start work, the frequencies and compromises that that you need to think about when restoring less than pristine vinyl are likely to overshadow your concerns with stuff that you are only ‘seeing’ on an meter at present.

In the meantime, maybe also review your leads … which I’m sure will be good quality … making sure the lines from the RCA connections don’t cross power leads or digital leads on their way from the pre amp to their destination.

Failed solder joints (inside the unit) on the RCA connectors on the rear can also be an enemy.

Good luck!

6

Thanks again Rat for you input.

TBH, as I am listening with headphones (Sony MDR-XD200) I’m more bothered by the minor ‘squeals’ I’m hearing from the computer proper. Most likely a capacitor or some other component not seated properly … another adventure awaits trying to eliminate that as well.

I’d be interested in hearing some experiences folks have had trying to get things truly silent from the Audio Engineering perspective. The computer I have is only about a year old (MicroCenter PowerSpec B211), has many fans but their noise is more of a white noise effect in the room. I assume most of you place your CPUs outside of your Engineering area so you can listen without putting up with ambient ‘wind’, plus your studios have been acoustically dampened which should minimize such sounds.

From what I can see searching the problem on the internet, the low-level squealing of components is quite common.

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Hi Rolan …

BTW, you’d be surprised how much difference it can make … in terms of recording signal/noise quality … to have the turntable properly ‘isolated’ from the floor etc as well.

Soundproofing: well, the place I work at has spent a lot of money on the room.

To be serious, the first point of call are experienced acoustics consultants. Expensive.

But there are easy and practical alternatives.

Here is a useful document when soundproofing a room:
http://prorecordingworkshop.lefora.com/composition/attachment/b6d0aa389a3bf42d06b5066c3ae70ade/1052752/brn217.pdf

The most obvious is simply placing the computer in the adjoining room and employ a couple of extension leads for the necessary controls.

Good luck!