[lamode]

  During one of the rehearsals of the same orchestra in the same hall, I asked if I can seat in within the orchestra - of course I am curious how members of the orchestra hear it. I can assure you that it is LESS noisy than in the audience...

 
As someone who has played in an orchestra, I have to disagree, and the very notion of sound becoming louder with distance is absurd.

 

[Krutsch]

   
As someone who has played in an orchestra, I have to disagree, and the very notion of sound becoming louder with distance is absurd.

You don't need to be a musician to know that... we (well, many of us) learned that in freshman physics class.

 

[lamode]

  Remember, that 113 dB SPL peak reached lasted probably no more than 2 seconds - in a 2 hour 2 part concert.  With dynamic range > 80 dB (if we disregard buzzing from dimmed lights - lots and lots of them do add up to audible "Call From The Grave" by Nikola Tesla ). Average levels were well within safe limits regarding hearing damage.

 
For the love of all things holy... stop trolling!
 
113dB is FAR from being "well within safe limits regarding hearing damage"

 

[analogsurviver]

   
Yet again, you are changing the goal line to try and win an argument. You should really see someone about that.
 
I was talking about a snare drum rim shot, and suddenly you want to compare this with an orchestra, measured on an iPhone? LOL. Desperation has no shame, it seems.

Ok, I will get an calibrated SPL meter and will ask a friend drummer to record some rim shot readings at precisely measured distance(s). And will report the readings. 
 
I was not trying to win an argument - just saying music live can and does sound loud. Most of my audiphile friends are shocked how loud it can be for real - since they are acustomed to compressed recordings played back on equipment that can not support full dynamic range. Hence 

 expression on their faces - when 5X or so kg soprano pull out all the stops, for example... - for real, this  is NOT Norah Jones dreamy soothing lullalaby...

 

[lamode]

  If that shopping-mall-grade Pioneer happens to have turntable like platter, on which you put the CD with data/pits facing up, being read by the laser from above and being supported over entire CD surface, than go to the shopping mall you bought it from and thank them by purchasing more from them. In this case, not only you do not need CD mat, you can not even use it. You already own the best possible transport - at least from the disc vibration point of view.

 
Wrong again, you can't improve on 100% data retrieval.

 

[RRod]

   
For the love of all things holy... stop trolling!
 
113dB is FAR from being "well within safe limits regarding hearing damage"

 
I have to defend him here: he said the *average* levels were well within safe limits. A 113dB peak is believable for the type of pieces he mentioned but probably won't last for more than a second or two.

 

[analogsurviver]

   
As someone who has played in an orchestra, I have to disagree, and the very notion of sound becoming louder with distance is absurd.

It does depend on the venue. And which section of the orchestra you are in. 
 
I have a very interesting project in mind - wish me luck with it. It should answer such questions once and for all.

 

[analogsurviver]

   
For the love of all things holy... stop trolling!
 
113dB is FAR from being "well within safe limits regarding hearing damage"

It is exposure OVER TIME - average, not peak - that are dangerous for hearing damage. And peaks or exceeding the threshold of pain, that is around 120 dB. 7 dB or more than twice below that. For more level vs time, please see : http://www.head-fi.org/t/723464/hearing-safety-and-ear-health-thread-a-diary-of-a-ear-health-noob
 
Slamming/closing the door in a car produces such peaks on regular basis - but as it is a few times a day lasting together for perhaps a second, it will leave no permanent damage. 
 
I did write AVERAGE level were well within safe limits - why are you now  trying to win the argument by twisting the words or taking things out of context  ?
 
I guess I should now pre-load an app to smartphone with the composition to be played - and put mufflers the minute SPL prescribed by XY is exceeded by 1 dB ? LOL

 

[wakibaki]

  It is exposure OVER TIME - average, not peak - that are dangerous for hearing damage. And peaks or exceeding the threshold of pain, that is around 120 dB. 7 dB or more than twice below that. For more level vs time, please see : http://www.head-fi.org/t/723464/hearing-safety-and-ear-health-thread-a-diary-of-a-ear-health-noob
 
Slamming/closing the door in a car produces such peaks on regular basis - but as it is a few times a day lasting together for perhaps a second, it will leave no permanent damage. 
 
I did write AVERAGE level were well within safe limits - why are you now  trying to win the argument by twisting the words or taking things out of context  ?
 
I guess I should now pre-load an app to smartphone with the composition to be played - and put mufflers the minute SPL prescribed by XY is exceeded by 1 dB ? LOL

 
Rubbish.
 
It's well known that a sufficiently loud explosion can perforate your eardrums. Instantaneously.

 

[StanD]

   
Rubbish.
 
It's well known that a sufficiently loud explosion can perforate your eardrums. Instantaneously.

That's probably why he thinks he can hear above 20 kHz, it's really tinnitus.

 

[lamode]

  It is exposure OVER TIME - average, not peak - that are dangerous for hearing damage. And peaks or exceeding the threshold of pain, that is around 120 dB. 7 dB or more than twice below that. For more level vs time, please see : http://www.head-fi.org/t/723464/hearing-safety-and-ear-health-thread-a-diary-of-a-ear-health-noob

I'm well aware of the relationship between hearing loss and SPL over time.
 
If the orchestra was really producing 113dB for several seconds from 30m away, then I would expect hearing damage among the musicians, where the SPL levels would be 120dB+ (and who are rehearsing this over and over).
 
Frankly, no-one should be taking a smartphone's SPL reading seriously, but you seem to.
 

  Slamming/closing the door in a car produces such peaks on regular basis - but as it is a few times a day lasting together for perhaps a second, it will leave no permanent damage.

 
Wow, more nonsense. Have you ever bothered to measure a car door slam? These guys have, and it measured 92dB: http://www.thehills.nsw.gov.au/files/sharedassets/public/ecm-website-documents/page-documents/major-plans-on-exhibition/160-162-excelsior-ave-castle-hill-planning-proposal-32015plp/1-acoustic_report.pdf
 
 

 

[analogsurviver]

   
Wrong again, you can't improve on 100% data retrieval.

A disc player, playing in real time,  will never tell you it did not succeed to read all the data. What will be missed will be replaced by for such a case "preloaded" error correction system - different for CD, different for CD-R - and further variations from make to make and model to model. 
 
CD mat makes sure this error correction is triggered as few times as possible - so that what is "100% retrieved data" is actually approaching 100% and not ( 100 - X )%, that X which could not be read properly being an average , based on the last succession of the properly read 0s and 1s, supplied by one type or another of error correction system INSTEAD of the proper data. It is this where the improvement by using a CD mat is stemming from.
 
Take any CD and put it on any of your fingers that support it with one finger alone. Than flicker the edge of the CD with a fingernail of the other hand. LISTEN to the resonance this produces. You will need quiet environment for this.
 
The mechanical amplitude of this resonance is greater than is the pit size. If the laser optics has to constantly "hunt" for focus - the errors are so to speak prescribed.
By playing the disc in as resonance free mode as possible, optics has MUCH easier time, produces less data dropouts and thus injects less "guessed" replacement data supplied by error correction. 
 
Is that so hard to understand ?

 

[analogsurviver]

   
Rubbish.
 
It's well known that a sufficiently loud explosion can perforate your eardrums. Instantaneously.

Sure. 
 
But explosions that can do that are WAY over 120 dB.
 
http://listverse.com/2007/11/30/top-10-loudest-noises/
 
http://www.bksv.com/NewsEvents/measurement-moments

 

[lamode]

  A disc player, playing in real time,  will never tell you it did not succeed to read all the data. What will be missed will be replaced by for such a case "preloaded" error correction system - different for CD, different for CD-R - and further variations from make to make and model to model. 
 
CD mat makes sure this error correction is triggered as few times as possible - so that what is "100% retrieved data" is actually approaching 100% and not ( 100 - X )%, that X which could not be read properly being an average , based on the last succession of the properly read 0s and 1s, supplied by one type or another of error correction system INSTEAD of the proper data. It is this where the improvement by using a CD mat is stemming from.
 
Take any CD and put it on any of your fingers that support it with one finger alone. Than flicker the edge of the CD with a fingernail of the other hand. LISTEN to the resonance this produces. You will need quiet environment for this.
 
The mechanical amplitude of this resonance is greater than is the pit size. If the laser optics has to constantly "hunt" for focus - the errors are so to speak prescribed.
By playing the disc in as resonance free mode as possible, optics has MUCH easier time, produces less data dropouts and thus injects less "guessed" replacement data supplied by error correction. 
 
Is that so hard to understand ?

 
No, it's easy to understand - it's uninformed conjecture.

 

[analogsurviver]

   
No, it's easy to understand - it's uninformed conjecture.

If it did not work, I would not be using it.
 
And I do not  paint CDs with green marker, do not demagnetize them, etc. I use what proved itself, time and time again, with my equipment and everybody else's where we tried this CD mat. Or DVD mat, if you are more of a video guy.
 
YMMV - but only after you try it, not a priori rejecting it as an audio myth.