OP
ray_parkhurst
Member
- Joined
- May 18, 2023
- Messages
- 95
- Likes
- 99
- Thread Starter
- #61
It is when the groove width at the top hits the minimum RIAA spec.
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Macro Photos of Record Grooves
- Thread starter ray_parkhurst
- Start date
OP
ray_parkhurst
Member
- Joined
- May 18, 2023
- Messages
- 95
- Likes
- 99
- Thread Starter
- #63
Even brand new record grooves have such lines, so I am not convinced they are due to stylus wear. More likely they are artifacts of the manufacturing process, though I could be wrong. I'm still working on a database of sorts to understand what grooves really look like.
Agree. What gets me is how a mechanical medium like that can sound as good as it does with decent playback equipment.
OP
ray_parkhurst
Member
- Joined
- May 18, 2023
- Messages
- 95
- Likes
- 99
- Thread Starter
- #65
Yes indeed, it is amazing.
Hm - strange that new record grooves would have it. Cutters should not make them. So what can it be?
OP
ray_parkhurst
Member
- Joined
- May 18, 2023
- Messages
- 95
- Likes
- 99
- Thread Starter
- #67
No, probably not the cutting stylus. Lots of other processes though.
restorer-john
Grand Contributor
I can now say for sure, having viewed maybe 50 or so random old styli from my scavenged cart/stylus boxes of various vintages and usage in the last week, that the wear does indeed present itself as very obvious flat areas with very sharp edges to the flat spots. It is trivial to see uneven wear caused by faulty/incorrect antiskate (more common than I would have expected).
I have been using my various optical scopes, with movable/fixed lateral slightly elevated diffuse lights. There is no need to go esoteric or lash out on a SEK-2, x150 to x200 on my trusty Olympus scope shows all the detail I will ever need.
I have some wonderfully worn, new and lightly used identical AT conical styli which demonstrate the textbook perfect Shure 'cat's eyes' in various stages right up to an almost flat screwdriver type heavily worn profile when viewed from directly above. Once seen, it cannot be unseen and it's much better to skip the cat's eye reflection and view directly with diffuse light, the flat wear surfaces themselves. What is also clear, is many of the salvaged styli and carts I pulled of stripped tables over the decades were in perfect condition. Others were heavily worn. Age had nothing to do with it. A V15 III original supertrack plus stylus from the mid 1970s appears unused with not even a tiny patch of wear.
As I don't really care for preserving my various test records, I think I'll try say 6 or 8 identical, but variably worn AT conicals ('cos I have a pile of them) for distortion, starting with the NOS styli and working back to the worst worn to see how bad THD becomes.
Last edited:
Phonograph Stylus Wear Experiment
From <https://www.audiosciencereview.com/forum/index.php?threads/phonograph-stylus-wear-experiment.44872/>
From <https://www.audiosciencereview.com/forum/index.php?threads/phonograph-stylus-wear-experiment.44872/>
It's why I can sometimes be seen listening with my lower jaw flapping somewhere in the region of my chest
The manufacturing pressing process has three likely sources, and all three could be possible. The reasons I suspect these sources are as follows. First, lack of leading and trailing edge consistency (it's not dynamic playback of any sort). Second, the rough patch is not consistently top to bottom. Third, the size and length of the patches varying. What pressing process would account for all these symptoms? First, the plastic flat record with no grooves, about to be pressed with the groove mold plate, the plastic is not evenly heated, therefore where the plastic is harder, not soft enough, the groove mold plate pushes down into the too hard, not hot enough, plastic flat surface, and scrapes unevenly the volume of plastic that was not at the right temperature. Thus, leading or trailing edges would be just about equally marred, as well as the depth of the volume of too hard plastic, if shallow, would leave a smooth portion at the bottom of the groove. And the size and length of the rough patches would vary. Second, the plastic might not be evenly mixed before the flat plastic record was molded. Thus, the places where additional mixing is needed creates a rough patch. Third, the pressing groove mold might have these rough spots. If so, then every new record would have the identical spot placement. While the first two causes would not have identical spot placement, but random placement on the same music record. I do not favor the groove mold pressing has the rough spots, as the milling process would be pretty flawed if so. Also, the groove mold would have near identical depth, not leaving the bottom part smooth, I would think, as well the overall "pattern" of the roughness would have a high degree of patterning, that likely could be recognized once an observing eyeball knows what to look for. Thus, the plastic mixing and heating and pouring process is my favorite suspect.
Sources of what? You're responding to a 1 year and more old, 4 page thread. It'd be useful if you let us know which post you are responding to.
Last edited:
It would be interesting to see pictures like this before and after cleaning a record with various methods/devices.
somebodyelse
Major Contributor
- Joined
- Dec 5, 2018
- Messages
- 4,673
- Likes
- 4,118
That's not how it works in any pressing plant I've seen video from. They all start with a blob or puck of hot vinyl about the diameter of the label which expands outwards when pressed.
It certainly wasn't unknown to find foreign matter pressed into the record, like paper from the old labels that made it into the recycled vinyl. It was a good reason to inspect the record for obvious problems before leaving the shop.
The entire post is based on a faulty premise of how records are made.
It is nice to see these images.
It immediately makes me think of the possibility of an optical, non-contact record player.
It could use a camera to image the groove and a servo controlled arm to track it.
All sorts of further possibilities then occur...
* Real time identification of dust particles and interpretive error correction.
* Simulation of different stylus tip radius.
* Simulation of differing stylus weight and momentum (including an ideal weightless response).
* Storage of groove data in video form (I know, not very efficient).
* Comparison of different records from the same pressing.
* Perhaps perform this optical non-contact scanning of the original masters rather than pressed records.
* Conversions from optical scanned data to standard digital audio formats.
* Archiving of rare and valuable or irreplacable masters, without causing any wear.
* Laser 3d surface scanning rather than 2d camera images.
I sort of suspect this has all been done before though.
It immediately makes me think of the possibility of an optical, non-contact record player.
It could use a camera to image the groove and a servo controlled arm to track it.
All sorts of further possibilities then occur...
* Real time identification of dust particles and interpretive error correction.
* Simulation of different stylus tip radius.
* Simulation of differing stylus weight and momentum (including an ideal weightless response).
* Storage of groove data in video form (I know, not very efficient).
* Comparison of different records from the same pressing.
* Perhaps perform this optical non-contact scanning of the original masters rather than pressed records.
* Conversions from optical scanned data to standard digital audio formats.
* Archiving of rare and valuable or irreplacable masters, without causing any wear.
* Laser 3d surface scanning rather than 2d camera images.
I sort of suspect this has all been done before though.
Already been done - at least something similar:
Laser turntable - Wikipedia
Didn't work very well. Decttion of dust is not actually that easy (and wasn't implemented in any case - as far as I know. And even if it were, there is no way to know what Is behind the dust.
Then you have the problem that the laser doesn't sweep the dust away like a stylus does.
Already been done - at least something similar:
Laser turntable - Wikipedia
en.wikipedia.org
Didn't work very well. Decttion of dust is not actually that easy (and wasn't implemented in any case - as far as I know. And even if it were, there is no way to know what Is behind the dust.
Then you have the problem that the laser doesn't sweep the dust away like a stylus does.
A better approach would be to use a video feed with AI image recognition to read the grooves, reject dust particles and other defects, and then output a nice clean digital signal.
Similar threads
