Golden Earring wrote: > Hi Arny! > > I1. Is it your position that all reasonably well-implemented DAC's will > be *-audibly-* indistinguishable from one another (& themselves from > 16bit/44.1kHz PCM upwards), unless the unit has been specifically > designed to modify the sound in some way (which to my mind would be > contrary to the objectives of high fidelity sound reproduction)? >
It is not my position, it is a reasonably easy to observe scientific fact. Just abandon relying exclusively on sighted and otherwise defective listening tests. > > > 2. Why do CD's, DVD's & Blu-Ray discs play from the inner available > radius outwards, when LP's (& 78's) work from the outside available > radius inwards? I presume that there is some engineering/practical > benefit from this inversion? > It depend, partially because there is another variable with optical discs, that is whether they are CAV (constant angular velocity or constant rotational speed) or CLV (constant linear velocity which implies that the rotational speed is higher near the center of the disc). They can be cut either way. I've seen vinyl discs cut from the center, but it only really makes sense in context if the disc is full. Of course cutting lathes can have variable pitch, and so the disc can appear to be full, regardless. If a disc is played with constant linear speed (IOW spins faster near the middle than the edge and follows the rule that the groove's linear speed remains the same) then some of the justifications for starting at the middle go away. But at least one remains, and that is that the grooves are less susceptible to scratching due to handling near the middle of the disc. Look at some scratched discs, the scratches often are worse around the edige. If you start at the middle then you optimized the use of that space that is less likely to be damaged. If you load the disc and track it with an automated mechanism, then the grooves or tracks are always at the same place when you start near the middle, regardless of the length of the program material on the disc. If a disc is played with constant rotational speed, then the amount of information per lineal inch of groove is maximized, and more susceptible to all sorts of problems, near the middle of the disc. The outer grooves become preferred (in the case of the LP) with less distortion and better frequency response at high frequencies. OTOH warp wow is usually maximized at the outside edge, and minimized towards the center. ------------------------------------------------------------------------ arnyk's Profile: http://forums.slimdevices.com/member.php?userid=64365 View this thread: http://forums.slimdevices.com/showthread.php?t=106914 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
