The Groove Probe, for optimizing and evaluating record cleaning systems

RexC

New Member
Feb 21, 2020
5
5
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#1
I am writing to inform you of some fairly simple and cost-free techniques that I have used to evaluate the effectiveness of record cleaning. I would like to be able to fine-tune my own system or to buy another system on the basis of something better than just listening and guessing how much dirt is left.

With any system there are almost always some clicks left, which could be either dirt, or scratches or other defects. It's difficult to tell the difference. A subjective listening test is helpful but somewhat limited. It would be much better if we could quantite the amount of dirt remaining, and distinguish between dirt and permanent defects.

Furthermore, every record cleaning system, whether expensive or inexpensive, has dedicated users who attest to wonderful results. But that's not very helpful for comparison, because you can find good or bad reviews for just about any system. I'm pretty sure that you can get pretty good results from any system. The problem with almost all of these reviews is that I doubt whether they can distinguish between remaining dirt and defects.

Fortunately, any turntable can be used as a scanning probe microscope that feels the groove and faithfully records every little defect. You just need to digitize the record as you play it. I call this the Groove Probe.

The Groove Probe can be used for visual examination of the sound file, which, depending how you use it, can be quite revealing and diagnostic. Also, there is software available that can be used to count pops and clicks. This allows quanitification.

As an example, the first figure shows an excerpt of sound files from a very noisy record that has been cleaned.* The top two channels show the first playing after cleaning (L and R channels). The bottom two channels show the third playing. To make it easy to see defects and dirt, I looked at the (supposedly) silent tracks between bands.
1stAnd3rdPlays.jpg
Pops and clicks can easily be seen in all the tracks, which are due to both dirt and permanent defects. Two features are immediately apparent. First, the record grooves were much cleaner after being played twice, and many of the defects are missing from the third playback. Evidently there was quite a bit of dirt and debris still in the grooves, but it was moved or removed by the needle. Second, there are some residual defects that are essentially unaffected after being played twice. Since the needle didn't move them or alter them substantially, I believe these are defects in the plastic, and not dirt. Notice that the dirt and defects look quite similar, and they can be distinguished only because the needle moved the dirt.

The second figure also shows another short excerpt after one and three plays. Here you can see one permanent defect, one piece of dirt that was removed, and one piece of dirt that was moved or redeposited.
1gone1same1new.png

Here is a count of the pops and clicks detected.

Results:
1st play:
12544 left
18288 right
4482940 total samples

3rd play
8758 left
13452 right
4482940 total samples

The needle has removed 26 to 30% of the dirt after two plays. This seems consistent with the visual evidence. I could also have presented data from before and after cleaning.



=====
* Methods
The LP was wet-cleaned, brushed on the platter with a carbon brush, and digitized with a clean needle and a CD recorder. An excerpt was played three times without moving the record. The first and third times were recorded. The sound file was examined by Audacity (free, open-source program). A second stereo track was added, so that two separate playbacks could be compared. Audacity allows you to move one stereo track by dragging so the tracks could aligned and compared visually.

Identical excerpts from the two sound files were examined by ClickRepair (a commercial program with a free trial period). Clicks were removed in default stereo mode, and the number of clicks removed was recorded.
 

RexC

New Member
Feb 21, 2020
5
5
3
#2
The Short Version

I examined the wave form of the silent part (between tracks) from a cleaned, digitized LP, before and after playing. The purpose was (1) to count the clicks remaining after cleaning; and (2) to distinguish dirt and debris from scratches and other defects.

The stylus removed about 28% of the dirt and debris after two plays. (Clearly my procedure needs improvement.) Visual comparison shows that any of the remaining clicks were not moved or changed by the stylus, and are therefore due to scratches or other defects. (This was a used record in only fair condition.)

ADDED NOTEI would feel very good if I could say, for example, that I looked at 50 clicks from a good record, and 90% of them were scratches? Wouldn't be nice if we could get that sort of claim in reviews? As it is, in terms of verified performance, I'm not sure whether to buy the $50 system, the $5000 system, or something in between.
 

tima

Industry Expert
Mar 4, 2014
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the Upper Midwest
#3
Comparing RCMs can be challenging. I heard of a chap who allows his cleaning solution to evaporate and he weighs the remaining solids.

RexC, this is actually rather interesting: Using software to count clicks on a LP signal and using that data to compare different states of a record, then using that as a basis for comparing record cleaning machines.

Suggest someone (I'm past my coding days) write sotware to do this realtime and show a result, with the option to set up an A/B and show relative difference. Keep it simple. Digitizing to a CD or visual output is probably not necessary - maybe those are options in the 'Pro' version. Ideally you'd want a way to define what counts as audible clicks and distinguish those from others.

I suspect you'd need a large number of samples from various RCMs to make any claim about one being more effective than another. You cannot clean the same record twice, so comparison of two machines would need to be done statistically. Or somehow offer standardized dirty records - records without scratches with a uniformity of dirt on each. Perhaps a standardized 'cleaning cartridge' if you want to include use of the stylus as a trowel. (I'd prefer to let the RCM do the cleaning and not count on a normal or go-to cartridge as an excavator.)

Of course there are a variety of factors to consider in rating or choosing an RCM besides cleaning effectiveness, eg.build quality, reliability, throughput, cost of supplies, ease of operation, etc. And It's not just the machine that matters. Technique (handling, solution, temperature, drying, etc.) is relevant to any cleaning cycle.

Maybe some Edu's Engineering Department could obtain a grant to establish 'RCM Labs' to do research, develop standardized tests while offering appropriate certification.

In the meantime I'll continue to use my regular subjective Ellington Test: if it sounds clean, it is clean.
 

RexC

New Member
Feb 21, 2020
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#4
Thanks for your reply. I think it's pretty interesting too.

There's no need to get too elaborate just yet. My suggestion is, just use it. For example, if I could say that the number of pops was greatly reduced by cleaning, and that 90% of the remaining clicks on my best records were defects and not dirt, then I would be pretty happy with my method, and I would report that. As you pointed out, it's somewhat difficult to compare machines on that basis, but if I heard reports like that, then I would find that persuasive. The other use, of course, is to refine my technique with the equipment I have. That's where I am now.

Specific comments follow.

Suggest someone (I'm past my coding days) write sotware to do this realtime and show a result, with the option to set up an A/B and show relative difference. Keep it simple. Digitizing to a CD or visual output is probably not necessary - maybe those are options in the 'Pro' version. Ideally you'd want a way to define what counts as audible clicks and distinguish those from others.
Software evaluation inherently requires recording, and thus, digitization. This is something you might want to do anyway, if you're not shocked by the thought. Also, you want to compare exactly the same portion of the record, and this is something that's better done with a digitized version. Detailed comparison of tracks requires careful alignment of the tracks. Ideally you could just subtract the "before" recording from the "after" recording. In principle this should be easy to do, but one problem is that to do this automatically, the playback speed must be absolutely constant, but that's probably not going to be the case. Continuously adjusting the speed with software to align would be a special problem, and that may be more than someone is willing to do.

However, if you are willing to look around at the groove and use the tool like a microscope, this is not too difficult to do, and it can be very revealing. It's probably best to look mostly at lead-in grooves. Audacity allows you to put the "before" recording in one track and the "after" recording in a second track. Then you can drag the second track to line it up visually with the first. You can align on defects and recorded sound.

...if you want to include use of the stylus as a trowel. (I'd prefer to let the RCM do the cleaning and not count on a normal or go-to cartridge as an excavator.)
Unless someone can devise a perfect cleaning method, use of the stylus as a trowel is unfortunately inevitable. I would prefer to minimize it, but it can be useful as a diagnostic tool. :)

In the meantime I'll continue to use my regular subjective Ellington Test: if it sounds clean, it is clean.
I hope I can entice you to try it. If it's really that clean, then ClickRepair can tell you how clean it is. (It may be a little too sensitive, but I think the sensitivity is adjustable.)
 
Likes: tima

tima

Industry Expert
Mar 4, 2014
1,565
1,076
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the Upper Midwest
#5
Also, you want to compare exactly the same portion of the record, and this is something that's better done with a digitized version. Detailed comparison of tracks requires careful alignment of the tracks. Ideally you could just subtract the "before" recording from the "after" recording. In principle this should be easy to do, but one problem is that to do this automatically, the playback speed must be absolutely constant, but that's probably not going to be the case.
I appreciate a finer grained level of detail and being able to say "there, 2mm into band two is a big problem." Personally I don't know if that level of information will be helpful to me given I should be able to hear and visually locate at the time I hear the problem. The detailed information may be more valuable for gauging different solutions in the same machine although cleaning a record a second time likely results in a cleaner record even with the same solution. For assessing different machines, absent a standardzed dirty test record, I still think a large amount of data is needed, say 100-200 records or more per machine, leveling out the differences between dirty records through volume.

Fwiw, I remain pretty satisfied with my current diy setup and the belief system behind it. Having directly examined several of the single-slot desktop machines and many others on paper, I think I understand what's availalble and their strengths and weaknesses. But that doesn't mean I can't applaud anyone who comes up with a viable method for comparing records for cleanliness and being able to causally associate that to particular RCMs. I appreciate your interest in the topic and I look forward to your future experiments.
 

RexC

New Member
Feb 21, 2020
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#6
Tima, I looked around this forum, and I see that you have done a lot of work on this, and you've spent a lot of money on it. Can you say that your records are all perfects after cleaning? That would be fantastic.

If pops and clicks remain, are you certain that they are not due to dirt? And if the records are truly clean, the question I have is whether that could be done economically. Most of us are not going to spend thousands of dollars on this.
 

tima

Industry Expert
Mar 4, 2014
1,565
1,076
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the Upper Midwest
#7
Tima, I looked around this forum, and I see that you have done a lot of work on this, and you've spent a lot of money on it.
Hi Rex, nice to hear from your again.

Over NN years being an audiophile I've had several record cleaning machines:

1. 'Record Doctor' - a poor man's Nitty Gritty; its a box with a velvet-lipped slot in it and a spindle to hold a record over the slot. You manually rotate the record while vacuum pulls moisture off a record into the box where there is a sponge that captures the water that dries by evaporation. Like any horizontal machine it is a vacuum. Actual cleaning happens separately. Years ago that meant manually cleaning with the record sitting on a piece of newspaper while you rubbed cleaning fluid on it. Messy and time consuming, relatively effective.

2. Loricraft PRC3 - Another horizontal machine. This turns the record with a motor while a tonearm style point nozzle courses across the record and vacuums moisture off the record into a jar. Again, cleaning and rinsing are separate manual tasks. The Loricraft's fancier big brother, the Keith Monks, lets you squirt cleaning fluid on the record and swing a brush onto it. You still need to rinse. Messy and time consuming, but can be very effective. You can read more about my Loricraft with a focus on cleaning products here.

3. Audio-Desk Systeme - The first successful automated desktop RCM. Fit a record into a tank of cleaning solution via a vertical slot. A motor rotates the record while brushes rotate across it surface and a cavitator emits ultrasonic energy into the tank. The brushes are the primary cleaners. The tank drains, a fan turns on while the record rotates and that dries it. It is largely a one-step fully automated method and is the precursor to other desktop machines such as the (now defunct) KLAudio, the Degritter, Kirmuss and various others. These use only ultrasonic cavitation with no brushes. Mostly mess free, convenient, relatively effective. Overtime all have tradeoffs and limitations but gauge for yourself.

4. tima's DIY USC/RCM - My own vertical unit, dscussed in this WBF thread and described in articles published on The Vinyl Press. It cleans 5-6 records at a time using two ultrasonic frequencies and allows control over various cleaning parameters. I encourage you to read my articles.

So, yes, I've spent money on record cleaning during my life as an audiophile. As a dedicated vinylist I consider clean records a necessary condition to enjoying their play. I believe dissatisfaction with noise from dirty records was a significant contributor to the rise of the CD. Advances in cleaning technique and technology over the past 5-10 years considerably bolster the continued viability of playing records.

I've also done, and continue to do research on this topic. It's kind of a sub-hobby.

Can you say that your records are all perfects after cleaning? That would be fantastic. ...
Are all my cleaned records "perfects" ? If you're asking are they perfectly clean, the answer is no. I doubt there are many (any?) perfectly clean records in anyone's collection. I agree it would be fantastic. But I don't require perfection. As I said upthread, if a record sounds clean, it is clean.

If pops and clicks remain, are you certain that they are not due to dirt? And if the records are truly clean, the question I have is whether that could be done economically. Most of us are not going to spend thousands of dollars on this.
I hate record noise caused by clicks and pops. I have not developed a ranking system but I know when a record's noise is unacceptable and admit to being pretty darn finicky about this. At present, I'm quite satisfied with my approach. I also tolerate a few, just a few, clicks on a record - for two sides that may be around four total. But I don't count while I listen; the noise is gone; as long as it's minor, my ears move on. I have no problem cleaning a record a second time and it is very difficult to keep records free of all particules if you play them.

And if the records are truly clean, the question I have is whether that could be done economically. Most of us are not going to spend thousands of dollars on this.
How much do you have invested in your record collection?
How much do you have invested in your vinyl front end?

Are you willing to spend the cost of a mid-level cartridge to take care of your records?

Wrt cleaning, you get what you pay for. Choose your method of payment: money, time, effort.

Loricraft - basic ~$2k +
Degritter ~$3k +
AudioDesk ~$4k +
DIY ~$1.5k - $4.5k +
+ means fluids, distilled water, accessories, etc.

How much time do you want to spend cleaning records? If you're willing to spend, say 35-50 minutes to clean one record, then something like the Loricraft can work well. I can clean 20 records in two hours with results as good as (I believe better than) any other system. Of course I'm biased. You can DIY a system similar to what I did for one-third to one-half the cost, but without the same throughput and with lower quality components that will not last as long. Depends on what you want.

The important thing is that you clean your records.
 

RexC

New Member
Feb 21, 2020
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#8
But I don't require perfection. As I said upthread, if a record sounds clean, it is clean.

...I also tolerate a few, just a few, clicks on a record - for two sides that may be around four total. But I don't count while I listen; the noise is gone; as long as it's minor, my ears move on.
There we go. A specific claim of results. I think those results are about as good as one could hope for, and you've evidently had spectacular success.

Yes, I've read many of your posts. Thanks for your reply.


Just to reiterate, here are my suggested criteria that I suggest for ideal cleaning:
1. The record should be audibly perfect, with no pops or clicks.
2. If it's not perfect, then most of the remaining pops and clicks should be demonstrably due to scratches and defects, not to dirt.
3. The record should also be free of surface noise.
4. Surface noise can be measured, and any claim of noise improvement can be verified by measurement.

Here's a challenge. It would be wonderful if people can claim wonderful results without spending thousands of dollars. And it's a big plus if claims can be measured objectively.
 
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