CD stoplight - some analysis

Interesting but unfortunately relatively meaningless until we've got an idea of the experimental error. Another couple of runs with each disk and we'll be ready to rumble though :) As you've got all the data handy it might be an idea to show some frequency-domain difference plots rather than trying to compare them by eye (especially as I have to scroll up and down to see both graphs :D )
 
Isaac - it's great to see someone making the effort to investigate this green pen thing properly. Nice one :cool: .

I am defintitely a green pen skeptic, and actually this very morning tried comparing two versions of Massive Attack's "Blue Lines" CD, one with Stoplight treatment and the other without, and couldn't in all honesty confidently say I could hear a difference. At present my money would be on the differences between the data sets shown being statistically insignificant (i.e. repeat tests on a number of untreated discs generating this much difference), but I really hope Isaac has the chance to carry out these measurements so we can find out.

Martin
 
Isaac, as said by others, more experimentation and results will be required before we can refer to you as 'Newton' (rather than 'Sibson') :)

In the case that the results are verifiable and repeatable, it would be interesting to use a different colour pen and see what that would do.
 
I personally don't believe in the stoplight, but why don't those of us who have never tried it put in and buy one and circulate it and report our findings, as is being done with the DeMagic?
 
The Green pen works ....period.

Now does it make the sound better, I'm not certain .It makes the CD 's sound different. THe recent bakeoff at julians I think I can say that most people heard the change. I'd Like to think it was better as I use a green pen.........

For those that want the cheaper option try the Posca pen by uni go for the darker green. THis should cost you about £3-00 from a good art shop.

I have both pens and the only detectable difference is that the stoplight has a sculpted nib and is a shade lighter in colour ....and oh yes has a different label. The rest is the same, ink type, dry time and performance.
 
I will repeat the tests using the same discs. However, it might not be today, since I'm knackered (7 hours at an IAM course, then did the shopping, and since getting back I've done nothing but clean up after the cat, clean up after my brother, clean up after myself, laundry, etc.... :SLEEP: ). Unfortunately the presented graphs are the only analysis option in the "lite" version of the software I'm using.
 
Hey Tones
Does it have to be the £20 pen or can a £0.99 one from WH Smith do?

Secondly and much more importantly, if the answer comes out to be " no diffrence" will the snake oil zealots accept the answer? I doubt it. Which leads me onto the third point.

I am at a loss as to why anyone would want to try and test something that was started as a joke and goes against the basic design principle of the CD laser pickup assembly...:SLEEP:
 
Stebbo,

A question for you.

If Isaac can conduct some more testing, eliminating experimantal/random errors and demonstrate there are measurable differences between treated and untreated discs, would you be prepared to accept that these differences may well be audible?
 
Originally posted by stebbo
Hey Tones
Does it have to be the £20 pen or can a £0.99 one from WH Smith do?

Secondly and much more importantly, if the answer comes out to be " no diffrence" will the snake oil zealots accept the answer? I doubt it. Which leads me onto the third point.

I am at a loss as to why anyone would want to try and test something that was started as a joke and goes against the basic design principle of the CD laser pickup assembly...:SLEEP:
Click to expand...

Stebbo, I think we should try one of which the SOZs approve. I pesonally don't believe in it, but I'm always willing to be proved wrong. Will the SOZs believe a negative result? Of course not, But then, they heard what they heard; the fact that what they heard may have no existence in reality has nothing to do with the price of fish, or even green pens.
 
The first plot looks much spikier the higher up the range you go. To my eyes at least. But not even that high - from those plots there appears to be a huge spike at circa 450hz on the top one that is absent/much lower in the plot below it. I have no idea which is which. :)
 
Originally posted by stebbo

I am at a loss as to why anyone would want to try and test something that was started as a joke and goes against the basic design principle of the CD laser pickup assembly...
Click to expand...

The green pen business is as good a point as any at which to take a stand against the SOZs I suppose (nice acronym BTW :D )
 
Originally posted by stebbo
Hey Tones
Does it have to be the £20 pen or can a £0.99 one from WH Smith do?

Secondly and much more importantly, if the answer comes out to be " no diffrence" will the snake oil zealots accept the answer? I doubt it. Which leads me onto the third point.

I am at a loss as to why anyone would want to try and test something that was started as a joke and goes against the basic design principle of the CD laser pickup assembly...:SLEEP:
Click to expand...

I would accept it if it was written up and submitted for peer review.
that is the generally accepted standard for any scientific paper what ever the subject.

If those criteria were met and passed i would.

Now Robbo.
Please could you Tell us what criteria are required for you to accept that you percieved a difference rather than there actually being one.?


Oops sorry i "quoted" the wrong entry.
 
But Merlin
I was asked in what circumstances I would accept Issacs measurements.
That is a scientific argument.

I agree that music art. But we are talking about the hardware, which is engineering


I hear many pieces of music that I really like on the car radio. I enjoy them because they are the piece of music I like. It may be a lot more clear and have greater definition on my hifi but I still enjoy the piece. How many times have you seem people siging along to music in the car etc etc.
 
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Stebbo,

The thing is, I am a subjectivist when it comes to listening to hifi so I am really not too bothered one way or another what Isaac measures. I generally decide upon what works best in my system using the most appropriate measuring device - my ears. It works for me. Perhaps you should try it sometime.

I was only hoping that he could come up with some well conducted experiments that perhaps would satisfy the 'Measurements R Us' objectivists who seem to be more interested in arguing the toss on these forums than anything else. But I fear that whatever he measures, it is highly unlikely to satisfy the objectivists as they will just cry foul anyway.

I really cannot be bothered getting into arguments on this matter. Sorry, but I have more interesting things to do.
 
Usual double standards from one of the snake oil brigade.

An IBM research fellow I worked with on a development project once used a wonderful phrase which will always sticks in my mind.

If you measure a room with a rubber ruler it remains unmeasured

Not only is that a wonderful phrase, it certainly was in his Texan accent, but is Oh so relevant for the golden ear'd SOZ's.

(You are right PeteH, that is a good acronym)

I really think you people who think you can detect so much with your golden ears should spend a bit of time understanding how over the last 150 years the scientific world has proved beyond all doubt that the human mind is too willing to make up for a lack of ability of the human ear.

I wouldnt normally do the leg work for you SOZ's but a fairly decent place to start would be a gentleman called "Hermann Ludwig Ferdinand von Helmholtz".

Thank the lord for people like Newton, Faraday etc, if it was left up to the audio geeks we would still in the dark ages. Worshipping a bit of cable.
 
Stuart, you just like playing the stuffed shirt sir :) I admire your stance, however what ever anyone does nothing will ever convince you of any of it. so 3 cheers and keep up the good work sir :)
 
Stuart,

I hardly think I am one of the snake oil brigade, and certainly not a zealot. Yes I happen to think that the green pen makes a worthwhile improvement. I also think cables make a difference. But only in the context of a well balanced system and only to tweak the final sound once you have all of the ingredients in place. In fact the cables in my system are less than 10% of overall system retail cost.

As all you seem to like to do is to insult people who are not averse to trying a few leftfield things in the pursuit of better sound, and have never posted anything constructive on this forum, I have concluded you have nothing of relevence to say and are now on my ignore list.

Perhaps it would be better if you removed that chip from your shoulder.


Isaac,

Sorry for disrupting your thread. I did not intend for it to go OT like this.
 


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