Legit or lunacy?

One of my mates has one, and it does bring out a smidgen more detail. As I find the quest for the ultimate detail is one of the main reasons why people are never satisfied with their so called "accurate", "revealing" expensive systems, and are always complaining that the things irritate them. I see no need to add fuel to the fire, of what is taking the true musical enjoyment out of this hobby for me at least; with overly cynical, bright, amplifiers, DAC's etc. and tinkle box speakers.

Like asking me; what is your favorite tweeter? The one that does not draw attention to it's self!

I like the way that they describe all the improvements it brings but offer no explanation as to how it actually achieves them.
That's because it does absolutely F#ck-all.

The thing is, if the laser was not tracking accurately then you'd get skips, drop outs or that nasty squeeling sort of sound. A CD either plays 100% perfectly or it will have audible issues. It won't just sound 'not as good'.

Lots of products seem to be aimed at the punter who thinks a cd is a lot like a vinyl record as in it spins around and the laser 'tracks' it like a stylus tracks a groove. But aside from them both being circular discs and both are spinning around they have nothing in common in how they work.

You also see people stocking up on 'spare laser mechs' as though the laser will wear out like a stylus does, but that doesn't happen either. It will gradually lose power over the years but it's so slow a process that it will never likely be an issue.

If the player won't read or is skipping it is 99.9& certain to be something other than the laser.

On one player I had it was a failed ribbon connector. On another it was a component that had gone way out of tolerance - can't recall if it was a cap or a resistor now.

A bloke who fixes my kit, a rather eccentric Serbian, told me to always keep a disc in the CDP, keeps the dust off the laser, makes sense and what harm can it do.

The CD lathe trims the outside edge to be perfectly concentric with the centre hole. Assuming the centre hole is concentric with the data spiral it can improve the balance and reduce vibrations in the transport. The optic still has to track the data spiral though, it has no effect on that. But it can reduce a single source of vibration that may modulate anything attached to the optics.

Essentially it can reduce vibrations that exist at the speed of the cd's varying rpm, which is 200-500 rpm. It places the motor under less load, reduces load on spindle bearings, reduces noise in the player and removes a potential source of non correlated frequency modulation.

Generally it does f-ck all to the sound with any decent disk and transport. An off centre data spiral and centre hole is much more problematic and it does absolutely sfa to help this.

lol, this has to be the craziest thing I have seen.

Don't buy one. I read after cutting it can loosen the top layer were the music is stored.
I have read good reports about that Nespa thingy, that flashes a light on the cd. Don't know how it works though.

By the power of suggestion.

If you trim to much it can expose the sputtered aluminium layer which can oxide. Remember those rusty 80s CDs?

If you have an old cd player with aging servo and poor isolation of the rails between optics and data servo board I can see a reason for it with poorly centred cd's. Maybe 1 in 100 discs.

I had one on demo, it definitely reduced servo shake on some CDs and make the mech physically quieter. Dunno if it sounded better out of the speakers, but it fixed an issue, perhaps a trivial one.

I would buy one if they were a 100 notes. Just to ease the neurosis

But yeh, all that sort of stuff is bollocks, cd and vinyl demag units, led spiny things, green pens, all bollocks.