"Tuning" CD's

I used Allstop (?)… the yellow edge marker on all CDs. It seemed to improve the sound a bit on my earlier CD players. I experimented a fair amount 25 years ago to verify. There was a little lathe to cut the sides. All, intending, I believe to stop internal light reflections from the exterior edges. 
 

I had treated all my CDs. But I don’t listen to CDs any more.

I still have CDs where I painted the edge with a special, audiophile-marketed green marker. Did it help? Maybe when I played them on my first CD player, a player that went belly-up maybe three days out of warranty.  I can't recall the player's brand name. In any event, I haven't painted a CD edge since.

Then this has been a thing for quite some time! I had no idea there were markers made for the task.

The point of first sanding the edge is to ensure that the edge is matte black - not gloss black which would just create a black mirror. What I noticed immediately is that treble glare was reduced most noticeably on piano and higher pitched wind instruments. There was also a widening of sound stage and better separation with longer decay. I have a fairly resolving system.

Were the pens you used actually matte? Looking on Amazon I found one marker advertised as "matte," but the reviews said it was actually gloss.

I don't see anything odd about this idea. It is not a violation of the sacrosanct rebuttal that "it's always and only ones and zeroes." The theory in play here is that the transmission of data is being smeared.

Thanks for your replies.

Ok, I should have researched this topic first:

https://positive-feedback.com/Issue43/green_pen.htm

@armandoday,​​​​​ that is exactly what @edcyn wrote.

Some of my cd’s still have the Audioprism’s Stop Light green paint, gave up, never tried it again (funny but it seems that i did only REM at the time).

Yes it was mate finish.

Sony in 2009 introduced the green labeled SACD’s but i am not sure if they continued that project.

Tuning CD's is a thing.   

Many, many hours of experimentation with a variety of solutions gave us very positive results ranging from "notable improvement" to "jaw-dropping".  We provided a complementary service to customers and allowed them to bring in a couple of CD's to "tune".  This package included CD cleaning, treatments (we used the Ultrabit system) as well as trimming the CD's with a CD cutter.

We always performed "before" and "after" comparisons.  An unsolicited nearly universal comment/question was:  "Did you turn up the volume?"  The answer". "No I didn't".  Other accolades followed as well.  What we didn't hear was: "I don't hear any difference".  They may have been trying to be polite and didn't want to hurt our feelings, but we sit there with them, and heard what they heard.

We can agonize over the science related to making changes to physical media, but here are some observations after, literally, hundreds of cases:

- good CDs sound better

- unlistenable, poorly recorded, want to hit the eject button in 3 seconds CDs have some added siblance of detail, reduced harshness, and improved dynamic range

- BluRay soundtracks are improved.  I kept "untreated"  and "untreated" copies around for demo.  Always better sound quality -- similar to CD improvements

- burned CD ROMS are improved

- "audiophile" versions of CDs sound better

- Improvements in virtually every CD transport/player we tried including car stereos, entry-level to "very good" players, and BluRay players.

bolong

... my system plays CD's only which are burned from downloaded flac files ...

What's the point of burning FLAC files to CD?

I have tried many treatments  over the decades. They all eventually oxidize, Easy to hear as the music sounds dull. 2 things that work well

*SystemDesk edge trimmer, though it's a PITA in use

* Machina New Dark Matter. Perhaps the very best (and passive) way to improve the sound. It's a one time insert into your CD tray or well. ccut to shape, comes with gouble sided tape. It absorbs the laser light scattering inside the mechanism. IMHO, it's the best $39 you will ever spend to improve CD sound quality

I’ve many green edged CDs, but I must admit that I view CD players and transports as unnecessary when you can do bit perfect rips that are played by a high quality server/streamer.

@tweak1 I have an Esoteric SACD player.  Esoteric states in the user manual do not use any type of tray matt or insert.  There must be a good reason for them to state this? 

@bigtwin 

There's always an exception, but I would first check NDM out then ask Esoteric. Hard to imagine not being able to use NDM unless you have a slot load player

Yep, they were a thing.

Audio Prisim StopLight pens. I still have a couple.

https://store.acousticsounds.com/includes/image_browser.cfm?title_id=12484

@bolong "blackening the edge of the CD with a magic marker - all in the service of nullifying incident laser reflections bouncing off the glossy edges of CD's."

New Dark Matter "The color black is ineffective for absorbing infrared light; for CDs black is effective only (rpt only) for the inner edge. When black is used for the CD outer edge or the CD label it hurts the sound"

Guess one of you is wrong.

It occurred to me last night that simply sanding (i.e. frosting) the CD edge should be plenty sufficient to stop reflections. No paint or marker necessary. Since I am a furniture maker and have the requisite tools in my shop it shouldn't be difficult to make a CD edge sanding setup on my lathe thus speeding up the process and allowing for batch processing.

100 grit "coated" paper (to reduce grit contamination) is what I have been using. It is available from all the box stores or Amazon.

https://www.amazon.com/s?k=100+grit+disc+sandpaper&crid=3TEK5GWZUCQPW&sprefix=100+grit+disc+sandpaper%2Caps%2C103&ref=nb_sb_noss_2

The plot thickens.

Lesson Explainer - Infrared Radiation

"In the other direction, rough surfaces such as fabric or cloth will not reflect IR well, instead absorbing it nicely."

"An object with strong reflectivity will reflect more IR, meaning it must be weakly reflecting to absorb more IR."

"Besides color, the second factor affecting how much IR is absorbed or emitted is the reflectivity of a surface. A highly reflective or glossy material, such as cut obsidian, will poorly absorb and emit IR, even though it may be a deep black color."

I have used 3 different CD mats in the past 20 years.  I have found that on lesser CD players, they do make a difference.  On the more high end players, not so much.  Once I moved on to Esoteric, there was no reason to use them. 

I am running a Jay's Audio CDT2 mk3 - not exactly a slouch. Would love to have an upper end Esoteric one day, but $15,000 and up is beyond me for the time being.

Not using "mats" - just abrading the edges to stop IR reflections. Finding it "worth it," The only added cost is a little time spent abrading

I still have CDs where I painted the edge with a special, audiophile-marketed green marker. Did it help? Maybe when I played them on my first CD player, a player that went belly-up maybe three days out of warranty.  I can't recall the player's brand name. In any event, I haven't painted a CD edge since.  upsers portal
 

Well looky here - a guy who thought of sanding CD edges 13 years ago.

Oddiophile CD Tweak

I have also just started using "Auric Illuminator" which does indeed clarify CD output though I am not sure it works the way the manufacturer claims. It may simply be cleaning off age related chemical plastic degradation.

Not to belabor the obvious here but these CD tweaks should also be performed on blank CD's prior to burning music data on them - not after. We want to start with superior data collection on our discs.