25 Dec
2010
25 Dec
'10
1:01 p.m.
On Sat, 25 Dec 2010 12:40:33 +0100
fons(a)kokkinizita.net wrote:
On Fri, Dec 24, 2010 at 06:51:18PM +0100, Jörn
Nettingsmeier wrote:
In theory it could be any value. In practice it's limited by the lenght
of the antialiasing filter. You get the maximum output for a series of
samples at max amplitude (+ or - 1) and matching the sign of the IR of
the filter at half a sample delay.
For example, if '+' means a sample of +1, and '-' a -1, then the
sequence of 20 samples:
-+-+-+-+-++-+-+-+-+-
will produce of peak of more than 8 dB above FS.
It's very unlikely to get such a sequence with natural sounds,
but quite possible with synthetic signals or when using agressive
mastering techniques.
Ciao,
Interesting.
When I first started to use a digital recorder I used -6dBFS as my target
value simply on a 'gut feeling' basis. Seems I wasn't so far out then.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
On 12/24/2010 06:07 PM, Q wrote:
Out of
interest, how high can intersample peaks get above the highest
peaks in a file?
imagine the positive half of a sine wave, so that two consecutive
samples representing the very top of the wave are at 0dBFS. it is clear
that between those samples, the real peak value of the sound must be
higher than 0dBFS, and the reconstruction filter will see this higher
value. that means unless your analog stage has headroom for this, it
will clip. the higher the frequency, the higher above full scale those
inter-sample peaks can be.