Home |
Search |
Today's Posts |
#1
Posted to rec.audio.tech
|
|||
|
|||
CD-RWs in the car
1) Why don't they work
2) How much more would the unit cost to make if it did And How much more would my KIA CD player cost to make if it advanced and reversed within a track. BTW I thought this unit was broken so I called the dealer for the replacement cost--$867. He said he was not kidding. I fixed it myself. Abbedd |
#2
Posted to rec.audio.tech
|
|||
|
|||
CD-RWs in the car
"ansermetniac" wrote...
1) Why don't they work Because they have lower contrast than CD-R or moulded CD discs. But CDRs cost only a few cents each, so why bother with CDRW? 2) How much more would the unit cost to make if it did Probably a few dollars (at design time). Hundreds of dollars by the time it gets to the end-user (you). How much more would my KIA CD player cost to make if it advanced and reversed within a track. Much more than just replacing it with a unit that has the features you want. |
#3
Posted to rec.audio.tech
|
|||
|
|||
CD-RWs in the car
1) Why don't they work
CD-RW discs use a "phase change alloy" as a way of storing information (the ones and zeros). The alloy is changed between a crystalline, and an amorphous phase by the laser which writes the data onto the disc. This is a different method than is used in CD-R discs (which use a dye layer that is actually "burned" by the laser) and manufactured CDs (which uses molded pits). Although the two alloy phases do differ in the amount of laser light that they reflect, the difference is quite a bit less (and the resulting RF data signal is weaker) than is the case for manufactured/stamped CDs (strongest signal) and CD-R discs (intermediate). In order to play CD-RW discs, the "front end" circuitry in the laser/photodiode system needs an automatic gain control system, so that it can boost the amplitude of the (weak) RF data signal from a CD-RW, without being overwhelmed by the stronger signal from a CD-R. This sort of AGC circuitry is commonplace these days... almost all CD-ROM drives built within the past five (or more) years have it, as do a good majority of home audio CD players and car-audio CD players. Even the little $40 Discman-style player I bought for my wife last fall has it. Older CD players often don't have AGC. They'll work with manufactured CDs, and will often work with high-quality CD-Rs, but will usually not work with CD-RW discs. There's another possibility, though. It's possible that your car system *will* play CD-RW discs, but only if they've been properly "finalized" or "closed" (the final step in writing a discs, which writes the Red Book table-of-contents in the leadin area). Some CD-burning packages won't close the disc until you tell them to do so. An un-finalized CD-RW may play just fine in the computer's CD-RW drive, but would not play in most CD-audio players (including car players). 2) How much more would the unit cost to make if it did These days, not much at all. I'd guess that the additional bill-of- materials difference is under a dollar, and may be as small as zero due to the fact that CD-RW compatibility is widely available and is built into many of the chipsets. And How much more would my KIA CD player cost to make if it advanced and reversed within a track. Again, very-little-to-nothing... it's probably just a matter of programming, rather than the need for any difference in the actual electronics. You might want to double-check - your KIA player *may* already have this capability. My car CD player uses the same pair of buttons for "track skip" and "track advance". A quick press-and-release jumps to the beginning of the previous / next track, while a press-and-hold will advance or replay through the current track. BTW I thought this unit was broken so I called the dealer for the replacement cost--$867. He said he was not kidding. That probably includes a "book standard" of 2 hours of labor for a 15-minute job to de-install the old radio and install a completely new one (the old one is probably junked rather than repaired), plus retail markup, plus the Dealer's Wife Needs A New Lexus fee, plus the Car Owner Insists On Having Exactly The Same Model And Faceplate On Which We Have An Exclusive Monopoly tax, plus the Owner Is Too Busy To Shop Around surcharge, etc. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |