two digitallish questions.

[Steve Ridley]

> 2.) Digital to digital copying is clipping.
> The following is weird: In our school one of my tasks is to splice up
> music students dance too. Sometimes they come up with Aphex Twin :-)
> other times, they bring in Britney Spears :-(
> The odd thing is, the top40 cd's sound OK in my cd player,
> but when copied into my Mac, digitally, they CLIP!!!
> Not only do they hit 0dB, the waves actually look clipped when I zoom in.
> Also, it sounds clippeder then from the cdplayes analogue out*!
> Other cd's come in at expected volumes, toasting my ow cd and reloading
> them into the Mac shows hardly** any difference.
> As a test: The lexicon's dig-in is pushed into the redled district as
well,
> but again only by those top40 cd's. What can be going on here?

Clipping is very common on CDs.  I think it is intentional, to make chart
music sound loudest for radio play.  It shouldn't happen by accident, as
standards for professional digital audio specify around 10dB of headroom
between peak audio and digital clipping.

Elektor did a project to detect clipping on SPDIF digital signals a couple
of years ago - fairly simple - just a CS8412 and a bit of logic to detect
0000 or FFFF.


Steve Ridley