I was thinking about the proportional relationship between energy level and a cutter moving through wax this morning. Problems especially noticeable in acoustic recs when no sustaining energy other than fleeting sound pressure is involved and problems are amplified by diaphragm mass etc.
Issues that come to mind:
Initial impulses are damped before inertia is built to move through the medium
Once inertia is created, amplitude increases relative to original signal and pre and post state signals of the recording
As energy falls during note sustain, resistance from the wax medium rises relative to available energy driving the cut, causing unnatural fall off in sound.
This is why acoustic recs sound pokey.
I use peak limiting on this aside from bass boost cutting some high freq hiss energy on this test. It is why the sustain seems a bit more natural vs naxos meh original. This only improve part of No. 2 tho
When I get more time I’ll experiment with stripping to stems of tonal and non tonal sound and try expanders on problem 1, and compressors on problem 3 to see if it creates a more natural piano sound.
Altering the characteristics of the attack phase of a note can have serious timbral implications in my experience, so that probably tallies with what you’re saying.
I’m curious if there is anything workable to amplify on the weaker signal bits. Also splitting into noise and tonal not a perfect art. Probably won’t work but keeps the brain busy while I wait for my toys.
I’m most interested in transimpedance phono stage in playback chain. That should keep playback from making all that stuff worse by being mechanically more transparent in how the load interacts with the movement of the stylus. On 78s the stylus moving like crazy which maybe screws with that whole approach more than vinyl.
Could be cool but only works with MC carts and most everything good for 78s is MM carts.
If the signal strength is divisible into clear frequency segments with different strengths then you could manipulate it (though overdoing it will just sound weird).
I remember trying to do reverse deconvolution to find out horn characteristics and energy drop offs way back. I bet there is a better way to do that than hacking things together using the video of someone singing into cam while cutting a cylinder and comparing the freq responses between that and playback on cylinder.
Might have worked better if mic wasn’t just a regular ambient placement for that vid. Or if those fools had any sense they’d run a freqency sweep so I could have a pure reference!
Horns are so fucked. Different based on how far you go from it and angle you put sound into it. Here the famous Melba test at various distances to horn.
Damn, electroplating not necessary. Epoxy resin better than shellac or vinyl even when it come to friction coefficients.
Still can’t think of how to smooth roughness due to fill and damage, during molding and casting tho…
For static friction (the force required to initiate movement between two surfaces in contact), the friction coefficient of epoxy resin typically ranges from 0.2 to 0.6.
For kinetic friction (the force required to maintain movement between two surfaces in contact), the friction coefficient of epoxy resin is usually lower and may range from 0.1 to 0.4.
The friction coefficient for vinyl records typically falls within a range of approximately 0.3 to 0.6 for static friction (the force required to initiate movement between two surfaces in contact) and around 0.2 to 0.4 for kinetic friction (the force required to maintain movement between two surfaces in contact).
Gonna teflon coat that epoxy cast. Should reduce fricion by at least 10x vs a vinyl pressing. More likely 50x
The friction coefficients of diamond with or without Teflon can vary depending on the specific conditions, surface roughness, and other factors. Here are approximate values for the friction coefficients:
1. Diamond without Teflon: The friction coefficient of diamond in contact with other materials can vary but is generally quite low. For dry sliding against most materials, the kinetic friction coefficient of diamond is typically in the range of 0.1 to 0.2. The static friction coefficient may be slightly higher, typically around 0.2 to 0.5. 2. Diamond with Teflon (PTFE) coating or in contact with Teflon: When diamond is in contact with Teflon, its friction coefficient can be further reduced due to Teflon’s non-stick and self-lubricating properties. The kinetic friction coefficient can be extremely low, often ranging from 0.02 to 0.05, or even lower. The static friction coefficient is also significantly reduced when diamond comes into contact with Teflon.
I had a thought that was pretty good but has ton of maybe impossible execution issues to work out.
Say you take a regular transfer going forward, but then take a transfer playing backward at an equal speed. I’d bet some of the mechanical errors from inertia issues would cancel out if you flipped and mixed them. Additionally curious if a backward travel path would exhibit less wear as that travel path would have opposing forces on stylus wiggling through the groove.
Motor speed variance probably impossible to align across a whole record though and tiniest time issue would just cause phase poop. Hmmm
Depends, could go either way depending on how similar the music and noise signals are, and how perfectly they double or not.
More curious on what it does to the sonic signature of playback, cuz the needle is flapping around in the groove from different directions. Maybe it comes out a little cleaner being averaged in the middle of extremes of overshoot and slip and skip in there? But no dice if even a little off cuz then phase hell starts.
I cancelled my microscope and am gonna pass on plan to do fine detail repair by hand. The grooves are apparently hundreds of feet long. Fuck that sheeyat.
Also, been chatting with Ron Sutherland the engineer who designed the Transimpedence amp I bought. He’s not sure standard 78 cartridges I can get will work with his exotic design, so I’m having a guy modify some carts to fit the spec.
Hopefully everything will be in hands by late August cuz I travel all Sept to early Oct.
