Ever so slightly successful stereo embossing

[jjwharris]

I've been attempting to emboss a stereo signal into PC, I've read a few things saying it is possible to emboss stereophonic information, but the playback of that information isn't possible - possibly to do with the 'lean-back' of the cutting head when embossing.

I was curious as to what would happen if I reversed the rotation of the turntable, the embossing stylus and the lean-back angle of the head. My consideration was that this could create a geometry closer to that of a cut groove.

So to play back a record, you would need to reverse the source audio, and play the record inside-out (or run the carriage inside out)

It works to some extent, they're noisy as hell, but I do think there is separation there above the noise floor.

I apologise for the uploads, they're noisy and horrible. But I do believe there is some stereo., I was hoping to calibrate more, but the stereo head is so difficult to work with my mounting situation that I eventually gave up out of frustration. I'd love it if someone with the ability to move their cutting head more freely could give this an attempt - I'm wondering if one of piaptk embossing styli may work better as it sit's more parallel to the record surface than mine do.

I also think the surface noise may be from the playback stylus essentially now travelling 'upstream' from the original embossing direction.

I've attached a few samples;

diamondcutseparation.mp3 - the is L / R with a cutting stylus in the head - essentially a baseline of what a diamond in the stereo head can do.
diamondblank.mp3 - this is a diamond blank, turntable and stylus reversed. seems to have some separation.
embossing70degreecorrectway.mp3 - this is an eposlab style stylus that I make/use, it usually requires 14-20 degrees of 'leanback'. There wasn't enough space for my to physically lean back with my cutting head and setup, so there's a lot of surface noise. The turntable and stylus are not reversed. There doesn't seem to be stereo information.
70degree stylus.mp3 - This is the same stylus as above, but turntable and stylus reversed. Stereo information seems to be present underneath the surface noise.
30degreestylus.mp3 - this is a quick stylus I made up, I changed the back angle, so it should have cut a quieter groove, being more perpendicular to the blank. The noise wasn't diminished much, and I think theres less separation.


I want to work more on this in the future, but I thought I'd throw it out there in case anyone else wants to experiment.

Is panning white noise the correct way to test stereo separation? Should I have been using a tone?

It was a nightmare to get the diamond stylus set back up in the head, so I'll be leaving it until I build rev 2 of my stereo head and have this as a spare.

[juba bc]

hi, i can move my cutting head to any angle i want, i have a little more stereo aperture with an inverted cutting needle where i get a lot more sharpness. I'm doing other stylus geometry types with interesting results

[jjwharris]

Hi Juba, is that with the platter rotation reversed too? If not, I'd love to hear if there is a difference!

[juba bc]

I've been working at different angles, here I made a polished edge like in lacquer cutting styluses, and with a slight curvature that gives me a very good and clean audio





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[juba bc]

I never tried to do it the other way around (reverse rotation), I didn't think it could make any difference, I'll try to do it

[jjwharris]

Oh wow!

Can you share some audio samples of what you have so far?

[juba bc]

hi, i get a good separation of l r channels, tell me how to post audio here, could you send me a song that you know well and i can audition

[juba bc]

I recorded a song that has very open stereo, I didn't put the bass in mono and I had problems as you will notice in the audio, there were some jumps and landurfing. See in the video the angle of the shaving head and the stylus, if you can use a headphone you will be able to perceive the stereo with a good definition
https://drive.google.com/file/d/19wkvR9wp1w0W-tDmtGddE72smCJP1Q86/view?usp=sharing
https://drive.google.com/file/d/1OvEF2jKfSNRfJRbeBxxQVkSW_MwPcc1U/view?usp=sharing

[Dogtemple]

just wondering, what methods are you guys using to shape your stylus?

[jjwharris]

I'm using an aliexpress lapidary table, seems to work okay for embossing stylus, but I'm looking into modifying a D-Bit Grinder...

I've made a (very brief) video of the process for instagram, which I've uploaded on youtube.

https://youtu.be/2hDFtZRJ0O0

[Dogtemple]

I'm using an aliexpress lapidary table, seems to work okay for embossing stylus, but I'm looking into modifying a D-Bit Grinder...

I've made a (very brief) video of the process for instagram, which I've uploaded on youtube.

https://youtu.be/2hDFtZRJ0O0

cool thanks, a lapidary machine is something I have considered but then I thought it might be possible just to use a lapidary disc in my lathe... needs a little more thought I guess.